Invasive Species Unit 6

permafrost

a perennially frozen portion of the Arctic tundra soil

algal bloom

a rapid increase of algae in an aquatic system

estuary

a region where fresh water and salt water mix where a river discharges into an ocean or sea

bush meat

a wild-caught animal used as food (typically mammals, birds, and reptiles); usually referring to hunting in the tropics of sub-Saharan Africa, Asia, and the Americas

planktivore

an animal that eats plankton

tragedy of the commons

an economic principle that resources held in common will inevitably be over-exploited

extinction

removes species from earth

Increasing numbers of zebra and quagga muscles in Lake Michigan allow for an increase in the amount of aquatic plant growth.

true

channel

the bed and banks of a river or stream

emergent vegetation

the plants living in bodies of water that are rooted in the soil but have portions of leaves, stems, and flowers extending above the water's surface

source water

the point of origin of a river or stream

Typically, where are oxygen levels the highest and nutrient levels the lowest in a stream?

not an estuary

What is the predominant type of vegetation in a tropical wet forest?

not broad leaved evergreen trees

aphotic zone

the part of the ocean where photosynthesis cannot occur

Asian Carp

Bighead and Silver carp Bighead and silver carp are invasive fish moving toward Wisconsin waters from the Illinois River and the Mississippi River at a rate of about 50 miles a year. The term "Asian Carp" is sometimes used to describe these two invasive species, along with the black and grass carp (neither of which are currently considered to pose an imminent threat to Wisconsin waters). Bighead and silver carp were brought to North America from China in the early 1970s to improve water quality by removing algae from aquaculture ponds, and possibly to be marketed as a food fish. Both species have low-set eyes and large upturned mouths without barbels. Their heads have no scales, and their body scales are very small. The bighead carp has dark blotches along the top of its body (in the dorsal region). Bighead and silver carp are spreading to lakes, rivers and streams in several areas of North America, particularly the Mississippi River and Great Lakes region. Their populations have been doubling annually, with the fastest expansions occurring in the Missouri and Illinois Rivers. They live in temperate freshwater in both their native and introduced habitats, requiring bodies of water with some current for eggs to float and develop properly. They are well-suited to the climate of the Great Lakes region, which is similar to that in their native Asian habitats, and particularly favor large rivers and connecting lakes. Asian carp migrate up streams or rivers to breed; eggs and larvae float downstream to floodplain zones. These fish are fast growing and become very large: They can weigh up to 100 pounds, and can grow to a length of more than four feet. Asian carp also reproduce prolifically. Bighead carp females produce between 200,000 to 1 million eggs in their lifetime, while silver carp females produce between 300 to 5,000 eggs. Bighead and silver carp are filter feeders, straining tiny animals and plants (plankton) out of the water. Some may eat their weight in plankton daily. In eating plankton, these fish directly compete with native filter feeders such as mussels and fish. This competition for food can potentially disrupt the entire food web in a water body. Some scientists fear that, if introduced, they could become a dominant species in the Great Lakes. The only thing that is keeping these fish from moving into Lake Michigan is an electrical barrier system on the Chicago Sanitary and Ship Canal, though this is not a fail-safe system. Although the barrier acts to repel the fish, it doesn't actually kill them. Also, flooding on the Des Plaines River could carry water (and carp) overland into the Canal upstream of the barrier. The construction of similar barriers at two points along the Mississippi has been recommended, though this system will need to be more technologically advanced and thus will be more expensive. This is because the design must allow the free flow of native fish up and downstream for spawning while simultaneously blocking movement of the Asian carp upstream. University of Minnesota researchers are evaluating the possible release of sterile or genetically modified fish, as well as the use of pheromones or other sensory cues, to reduce the numbers of Asian carp in the wild. Early detection of isolated populations may help slow or restrict the spread of these Asian carp. To report a sighting, note exact location. Freeze specimen in a sealed plastic bag and call your local DNR Service Center.

Giant toad (cane or marine toad)

Bufo Marinus origin: South America Introduction: to control sugar cane pests preys on native species highly toxic to predators introduction: accidental release of 100 toads in 1955 by pet dealer sometimes mistaken with the native souther toad (souther toad has two ridges on head that end in knobs and smaller kidney-shaped paranoid gland) southern toad ranges from 1.75-4.5 inches Giant toad has large paranoid gland that is angled downward over shoulder and size range from 4-6 inches Identification: Rhinella marina is an enormous, warty bufonid (true toad) with snout-vent length 4-over 9.25 in. Individuals found in the U.S. rarely exceed 178 mm (7 in). Females may weigh up to 1.5 kg (3.3 lbs). Large individuals sitting on roadways are easily mistaken for boulders. Adult males have more robust forelimbs than adult females. These massive brown or dark-mottled toads have a pair of enormous, deeply pitted parotoid glands, each extending from the temporal region of the head, far down the side of the body, well past the axillary region. The call is a low-pitched, staccato trill that is slow and often likened to the sound of a distant tractor. Recordings of the calls of R. marina are available on several CDs (Library of Natural Sounds, 1996; Bogert, 1998; Rivero, 1998). The tadpoles are black dorsally, with a venter (belly) that is silvery white with black spots. Native Range: Cane Toads are indigenous to northern South America (Argentina, Bolivia, Brazil, Ecuador, Colombia, Paraguay, Venezuela, the Guianas, mainland Honduras, Peru, Trinidad and Tobago), Central America, and Mexico northward to extreme southern Texas. non-indigenous occurrences: In Florida, 200 R. marina were intentionally introduced to Canal Point and Belle Glade, Palm Beach County, prior to 1936 (Lobdell, 1936, 1937), and another group of Cane Toads were introduced to Clewiston, Hendry County, prior to 1944 (Oliver, 1949; Riemer, 1958; Lever, 2001). Further introductions were made to Miami-Dade and Sarasota Counties prior to 1958 (Riemer, 1958; Crowder, 1974; Lever, 2001). Other introductions of R. marina occurred in Miami-Dade County (Kendall) in 1964 and prior to 1966 (Miami International Airport), and Pembroke Park, Broward County in 1963 (King and Krakauer, 1966; Crowder, 1974). Over the years Cane Toads have been recorded from the following Florida counties: Bay, Citrus, Clay, Glades, Highlands, Hillsborough, Lee, Marion, Martin, Monroe, Okeechobee, Orange, Pasco, Pinellas, and Polk (Duellman and Schwartz, 1958; Krakauer, 1968; Stevenson, 1976; Easteal, 1981; Wilson and Porras, 1983; Ashton and Ashton, 1988; Lazell, 1989; Stevenson and Crowe, 1992; McCann et al., 1996; Butterfield et al., 1997; Meshaka, 1997, 1999a, b; Conant and Collins, 1998; Meshaka et al., 2000, 2004; Lever, 2001; Krysko et al., 2005; Himes, 2007). Several introductions of R. marina to Louisiana have been made, many prior to 1935, one of which could have been on the Grand Terre Islands (Jefferson and Plaquemines Parishes) (Easteal, 1981; Lever, 2001). Rhinella marina were first introduced to Oahu, Hawaii in 1932 (Pemberton, 1933; Oliver, 1949; Oliver and Shaw, 1953; McKeown, 1978, 1996; Lever, 2001). Descendants of this original introduction were subsequently spread, intentionally, throughout the Hawaiian Islands (Oliver, 1949; Oliver and Shaw, 1953; Easteal, 1981; McKeown, 1996; Lever, 2001, 2003). For references and other worldwide introductions - see http://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=48 Means of Introduction: Both in the U.S. and worldwide, R. marina is normally introduced intentionally in a misguided attempt to control insect agricultural pests, primarily in cane fields. In Florida, intentional and accidental releases from animal importers also have occurred (King and Krakauer, 1966). Those R. marina collected from Bay County, in the Florida Panhandle, escaped from a local zoo (Himes, 2007). Some nonindigenous Cane Toads released in Papua New Guinea were from animals used in laboratories for human pregnancy testing. Impact of Introduction: In many nonindigenous localities, such as Florida and Hawaii, the exact impact of R. marina on indigenous ecosystems remains unclear. Pets that eat or bite Cane Toads become seriously ill from the milky venom contained within the massive parotoid glands and human poisonings are not unknown (Oliver, 1949; Ashton and Ashton, 1998; Lee, 1996; McCann et al., 1996; Lever, 2001, 2003; Beltz, 2005). The complex toxic secretion from these glands can be squirted into the eyes when toads are handled roughly, causing intense pain and a potential medical emergency (Blair, 1947; Lewis, 1989; Lever, 2001). The widely touted use of R. marina venom as a narcotic in the U. S. may be an urban myth, at least for this particular species of bufonid; it is difficult to determine what complex method would have to be devised to selectively neutralize some of the toxins so that it can be used as a hallucinogen (Lee, 1996; Lever, 2001; Beltz, 2005). However, some cultures utilize extracts from the venom to concoct traditional medicines (Crump, 2000; Beltz, 2005). Lee (1996) provides an extensive discussion on the toxicity and potential pharmacological properties of Cane Toad venom.

water hyacinth

Eichhornia crassipes DESCRIPTION Water hyacinth (Eichhornia crassipes) has been called the world's worst aquatic weed. It is a free floating water plant that is native to South America. It can vary in size from a few inches tall to over three feet. This plant has blue-green leaves, thick stalks and a showy purple or lavender flower. It thrives in tropical regions and in waters that are high in nutrients. Its beautiful, large purple and violet flowers have made it a popular ornamental, and the plant is now naturalized in most of the southern United States. It reproduces mostly by clonal propagation, but seeds also play a role in its survival and colonization. Massive weed colonies can grow when introduced into areas that are conducive for their proliferation. In addition, infestation can occur given a disruption in the natural ecological balance by human activities such as impounding of flowing waters by dams, channeling and allowing the buildup of eutrophication. identification: •free-floating, robust plant grows up to three feet off the water's surface •shiny green leaves are round to oval, four to eight inches in diameter, with gently incurved sides •leaf veins are dense and numerous so leaves stand erect •stalks are bulbous and spongy, and help keep the plant buoyant •flowers have six petals, purplish blue or lavender with yellow •several flowers grow at the top of a single stalk •a mass of fine purplish black and feathery roots hangs in the water underneath the plant IMPACTS The primary attribute of water hyacinth is its ability to grow under a wide range of nutrient and environmental conditions. The plant is able to develop at an astounding rate, effectively out-competing other native aquatics. Its growth rate is among the highest of any plant known: hyacinth populations can double in as little as 12 days. This rapid growth can cause an imposing amount of biomass. The level of biomass accumulation will determine its nuisance value and the impact on water quality. Excessive infestation by this weed can severely constrain human activities, affecting accesses to water, navigation, irrigation and fisheries. In other words, Incredibly dense mats of free-floating vegetation block boat traffic and prevent swimming and fishing, and keep sunlight from reaching the water column and submerged plants. ORIGIN Water hyacinth is native to South America, and was introduced to the United States in the 1880s. It probably originated in the swamps associated with the great river systems of northern and central South America. Water hyacinth has not yet (1998) been found in the wild in Washington State, but has been sold as an ornamental in plant nurseries. Its use as an ornamental means that it could be introduced to our lakes and rivers, and this is expected to be its primary method of spread. Control Water hyacinth Water hyacinth can be controlled by harvesting, aquatic herbicides, and biological control agents. Locally, the best way to manage water hyacinth is to prevent it from becoming established. Plants purchased at local nurseries should be disposed of away from waterbodies. Mechanical Control: Swamp Devil & Harvester The Swamp Devil is a heavy duty aquatic vegetation cutter that features tow blades at the front which measure 2.4 meters across. It had a 234 horsepower engine and can easily shred trees up to 15 cm in diameter. It will be collecting and removing a portion of the chopped debris. The harvester has the ability to carry four tons of vegetation on board in a single load. Depending on the weight and volume of the vegetation and the distance to the shore, the harvester can potentially remove 16 to 32 loads of chopped hyacinths in eight hours. Water Hyacinth Uses: As Fodder for Pigs Boiled water hyacinth is used in Southeast Asia as a feed for pigs. The plants are chopped and sometimes mixed with other vegetable wastes, such as banana stems, and boiled slowly for a few hours until the ingredients turn into a paste, to which oil cake, rice bran and sometimes maize and salt are added. The cooked mixture is good for only three days, after which it turns sour. A common formula is 40 kg of water hyacinth, 15 kg of rice bran, 2.5 kg of fish meal and 5 kg of coconut meal.

conservation in preserves

Establishment of wildlife and ecosystem preserves is one of the key tools in conservation efforts (Figure). A preserve is an area of land set aside with varying degrees of protection for the organisms that exist within the boundaries of the preserve. Preserves can be effective for protecting both species and ecosystems, but they have some serious drawbacks. A simple measure of success in setting aside preserves for biodiversity protection is to set a target percentage of land or marine habitat to protect. However, a more detailed preserve design and choice of location is usually necessary because of the way protected lands are allocated and how biodiversity is distributed: protected lands tend to contain less economically valuable resources rather than being set aside specifically for the species or ecosystems at risk. In 2003, the IUCN World Parks Congress estimated that 11.5 percent of Earth's land surface was covered by preserves of various kinds. This area is greater than previous goals; however, it only represents 9 out of 14 recognized major biomes and research has shown that 12 percent of all species live outside preserves; these percentages are much higher when threatened species are considered and when only high quality preserves are considered. For example, high quality preserves include only about 50 percent of threatened amphibian species. The conclusion must be that either the percentage of area protected must be increased, the percentage of high quality preserves must be increased, or preserves must be targeted with greater attention to biodiversity protection. Researchers argue that more attention to the latter solution is required. A biodiversity hotspot is a conservation concept developed by Norman Myers in 1988. Hotspots are geographical areas that contain high numbers of endemic species. The purpose of the concept was to identify important locations on the planet for conservation efforts, a kind of conservation triage. By protecting hotspots, governments are able to protect a larger number of species. The original criteria for a hotspot included the presence of 1500 or more species of endemic plants and 70 percent of the area disturbed by human activity. There are now 34 biodiversity hotspots (Figure) that contain large numbers of endemic species, which include half of Earth's endemic plants. There has been extensive research into optimal preserve designs for maintaining biodiversity. The fundamental principles behind much of the research have come from the seminal theoretical work of Robert H. MacArthur and Edward O. Wilson published in 1967 on island biogeography.1 This work sought to understand the factors affecting biodiversity on islands. Conservation preserves can be seen as "islands" of habitat within "an ocean" of non-habitat. In general, large preserves are better because they support more species, including species with large home ranges; they have more core area of optimal habitat for individual species; they have more niches to support more species; and they attract more species because they can be found and reached more easily. Preserves perform better when there are partially protected buffer zones around them of suboptimal habitat. The buffer allows organisms to exit the boundaries of the preserve without immediate negative consequences from hunting or lack of resources. One large preserve is better than the same area of several smaller preserves because there is more core habitat unaffected by less hospitable ecosystems outside the preserve boundary. For this same reason, preserves in the shape of a square or circle will be better than a preserve with many thin "arms." If preserves must be smaller, then providing wildlife corridors between them so that species and their genes can move between the preserves; for example, preserves along rivers and streams will make the smaller preserves behave more like a large one. All of these factors are taken into consideration when planning the nature of a preserve before the land is set aside. In addition to the physical specifications of a preserve, there are a variety of regulations related to the use of a preserve. These can include anything from timber extraction, mineral extraction, regulated hunting, human habitation, and nondestructive human recreation. Many of the decisions to include these other uses are made based on political pressures rather than conservation considerations. On the other hand, in some cases, wildlife protection policies have been so strict that subsistence-living indigenous populations have been forced from ancestral lands that fell within a preserve. In other cases, even if a preserve is designed to protect wildlife, if the protections are not or cannot be enforced, the preserve status will have little meaning in the face of illegal poaching and timber extraction. This is a widespread problem with preserves in the tropics. Some of the limitations on preserves as conservation tools are evident from the discussion of preserve design. Political and economic pressures typically make preserves smaller, never larger, so setting aside areas that are large enough is difficult. Enforcement of protections is also a significant issue in countries without the resources or political will to prevent poaching and illegal resource extraction. Climate change will create inevitable problems with the location of preserves as the species within them migrate to higher latitudes as the habitat of the preserve becomes less favorable. Planning for the effects of global warming on future preserves, or adding new preserves to accommodate the changes expected from global warming is in progress, but will only be as effective as the accuracy of the predictions of the effects of global warming on future habitats. Finally, an argument can be made that conservation preserves reinforce the cultural perception that humans are separate from nature, can exist outside of it, and can only operate in ways that do damage to biodiversity. Creating preserves reduces the pressure on human activities outside the preserves to be sustainable and non-damaging to biodiversity. Ultimately, the political, economic, and human demographic pressures will degrade and reduce the size of conservation preserves if the activities outside them are not altered to be less damaging to biodiversity.

estimates of present-day extinction rates

Estimates of extinction rates are hampered by the fact that most extinctions are probably happening without being observed. The extinction of a bird or mammal is often noticed by humans, especially if it has been hunted or used in some other way. But there are many organisms that are less noticeable to humans (not necessarily of less value) and many that are undescribed. The background extinction rate is estimated to be about 1 per million species years (E/MSY). One "species year" is one species in existence for one year. One million species years could be one species persisting for one million years, or a million species persisting for one year. If it is the latter, then one extinction per million species years would be one of those million species becoming extinct in that year. For example, if there are 10 million species in existence, then we would expect 10 of those species to become extinct in a year. This is the background rate. One contemporary extinction-rate estimate uses the extinctions in the written record since the year 1500. For birds alone, this method yields an estimate of 26 E/MSY, almost three times the background rate. However, this value may be underestimated for three reasons. First, many existing species would not have been described until much later in the time period and so their loss would have gone unnoticed. Second, we know the number is higher than the written record suggests because now extinct species are being described from skeletal remains that were never mentioned in written history. And third, some species are probably already extinct even though conservationists are reluctant to name them as such. Taking these factors into account raises the estimated extinction rate to nearer 100 E/MSY. The predicted rate by the end of the century is 1500 E/MSY. A second approach to estimating present-time extinction rates is to correlate species loss with habitat loss, and it is based on measuring forest-area loss and understanding species-area relationships. The species-area relationship is the rate at which new species are seen when the area surveyed is increased (Figure). Likewise, if the habitat area is reduced, the number of species seen will also decline. This kind of relationship is also seen in the relationship between an island's area and the number of species present on the island: as one increases, so does the other, though not in a straight line. Estimates of extinction rates based on habitat loss and species-area relationships have suggested that with about 90 percent of habitat loss an expected 50 percent of species would become extinct. Figure shows that reducing forest area from 100 km2 to 10 km2, a decline of 90 percent, reduces the number of species by about 50 percent. Species-area estimates have led to estimates of present-day species extinction rates of about 1000 E/MSY and higher. In general, actual observations do not show this amount of loss and one explanation put forward is that there is a delay in extinction. According to this explanation, it takes some time for species to fully suffer the effects of habitat loss and they linger on for some time after their habitat is destroyed, but eventually they will become extinct. Recent work has also called into question the applicability of the species-area relationship when estimating the loss of species. This work argues that the species- area relationship leads to an overestimate of extinction rates. Using an alternate method would bring estimates down to around 500 E/MSY in the coming century. Note that this value is still 500 times the background rate.

hydrilla verticillata

Frog-bit family (Hydrocharitaceae) Background: Hydrilla first appeared in the Crystal River system of Florida in 1960. Imported by the aquarium trade, its presence on the Delmarva Peninsula was confirmed in 1981. It attracted national attention when infestations were found in the Potomac River in Washington, D.C. in the early 1980s. It is a federal noxious weed. Distribution and Habitat: Hydrilla is documented throughout the southern United States from California to Delaware. In the mid-Atlantic, it occurs in much of the Potomac River, in Virginia and Maryland freshwater tributaries of the Chesapeake Bay, in the Delaware portion of the Nanticoke River, most southern Delaware ponds, and in sites in eastern Pennsylvania. It is not salt tolerant. Ecological Threat: Hydrilla outcompetes native submerged aquatic vegetation and can quickly fill a pond or lake, thus choking off the water body for boating, fishing, swimming and other recreational uses. Although non-native and invasive, it provides good quality habitat for fish and shellfish as well as water quality benefits. description and biology: •Plant: rooted aquatic plant. •Leaves: in whorls of 4-5; about ½ in. long; fine-toothed margins, spine at tip. •Flowers, fruits and seeds: tiny, translucent to white flowers produced on the upper branches in late summer and fall; tubers grow from the roots; winter buds (turions) are produced in the leaf axils. •Spreads: vegetatively through fragments of stems, stolons, or rhizomes, turions, or tubers which are carried on boat livewells, motors and trailers, bait pails and other items, and by ingestion of tubers and turions by waterfowl. •Look-alikes: native common waterweed (Elodea canadensis) with leaves in whorls of 3 and no teeth or spines. Prevention and Control: Physical, chemical and biological controls have been used for control of hydrilla, with varying levels of success. Water level drawdowns have generally been ineffective in our area. Mechanical aquatic weed harvesters provide temporary relief and open boating lanes, but resulting plant fragments can help spread the vegetation faster. Contact herbicides provide temporary control, but systemic herbicides provide more long-term control. Herbivorous fish such as sterile grass carp have been used for hydrilla control where allowed by law. Other biological controls are still being investigated. Each control method has its drawbacks and liabilities. On the Potomac River and other parts of the Chesapeake Bay watershed, resource managers struggle with hydrilla because submerged aquatic vegetation, including hydrilla, provides water quality benefits and habitat for fish and shellfish. Native alternatives: Aquatic plant species are difficult to tell apart to the untrained eye. Contact your state natural resource agency, native plant society or other resource (see References) for assistance.

Overharvesting

Overharvesting is a serious threat to many species, but particularly to aquatic species. There are many examples of regulated fisheries (including hunting of marine mammals and harvesting of crustaceans and other species) monitored by fisheries scientists that have nevertheless collapsed. The western Atlantic cod fishery is the most spectacular recent collapse. While it was a hugely productive fishery for 400 years, the introduction of modern factory trawlers in the 1980s and the pressure on the fishery led to it becoming unsustainable. The causes of fishery collapse are both economic and political in nature. Most fisheries are managed as a common resource, available to anyone willing to fish, even when the fishing territory lies within a country's territorial waters. Common resources are subject to an economic pressure known as the tragedy of the commons, in which fishers have little motivation to exercise restraint in harvesting a fishery when they do not own the fishery. The general outcome of harvests of resources held in common is their overexploitation. While large fisheries are regulated to attempt to avoid this pressure, it still exists in the background. This overexploitation is exacerbated when access to the fishery is open and unregulated and when technology gives fishers the ability to overfish. In a few fisheries, the biological growth of the resource is less than the potential growth of the profits made from fishing if that time and money were invested elsewhere. In these cases—whales are an example—economic forces will drive toward fishing the population to extinction. For the most part, fishery extinction is not equivalent to biological extinction—the last fish of a species is rarely fished out of the ocean. But there are some instances in which true extinction is a possibility. Whales have slow-growing populations and are at risk of complete extinction through hunting. Also, there are some species of sharks with restricted distributions that are at risk of extinction. The groupers are another population of generally slow-growing fishes that, in the Caribbean, includes a number of species that are at risk of extinction from overfishing. Coral reefs are extremely diverse marine ecosystems that face peril from several processes. Reefs are home to 1/3 of the world's marine fish species—about 4000 species—despite making up only one percent of marine habitat. Most home marine aquaria house coral reef species that are wild- caught organisms—not cultured organisms. Although no marine species is known to have been driven extinct by the pet trade, there are studies showing that populations of some species have declined in response to harvesting, indicating that the harvest is not sustainable at those levels. There are also concerns about the effect of the pet trade on some terrestrial species such as turtles, amphibians, birds, plants, and even the orangutans. Bush meat is the generic term used for wild animals killed for food. Hunting is practiced throughout the world, but hunting practices, particularly in equatorial Africa and parts of Asia, are believed to threaten several species with extinction. Traditionally, bush meat in Africa was hunted to feed families directly; however, recent commercialization of the practice now has bush meat available in grocery stores, which has increased harvest rates to the level of unsustainability. Additionally, human population growth has increased the need for protein foods that are not being met from agriculture. Species threatened by the bush meat trade are mostly mammals including many monkeys and the great apes living in the Congo basin.

deserts

Subtropical deserts exist between 15o and 30o north and south latitude and are centered on the Tropic of Cancer and the Tropic of Capricorn (Figure). Deserts are frequently located on the downwind or lee side of mountain ranges, which create a rain shadow after prevailing winds drop their water content on the mountains. This is typical of the North American deserts, such as the Mohave and Sonoran deserts. Deserts in other regions, such as the Sahara Desert in northern Africa or the Namib Desert in southwestern Africa are dry because of the high-pressure, dry air descending at those latitudes. Subtropical deserts are very dry; evaporation typically exceeds precipitation. Subtropical hot deserts can have daytime soil surface temperatures above 60oC (140oF) and nighttime temperatures approaching 0oC (32oF). The temperature drops so far because there is little water vapor in the air to prevent radiative cooling of the land surface. Subtropical deserts are characterized by low annual precipitation of fewer than 30 cm (12 in) with little monthly variation and lack of predictability in rainfall. Some years may receive tiny amounts of rainfall, while others receive more. In some cases, the annual rainfall can be as low as 2 cm (0.8 in) in subtropical deserts located in central Australia ("the Outback") and northern Africa. The low species diversity of this biome is closely related to its low and unpredictable precipitation. Despite the relatively low diversity, desert species exhibit fascinating adaptations to the harshness of their environment. Very dry deserts lack perennial vegetation that lives from one year to the next; instead, many plants are annuals that grow quickly and reproduce when rainfall does occur, then they die. Perennial plants in deserts are characterized by adaptations that conserve water: deep roots, reduced foliage, and water-storing stems (Figure). Seed plants in the desert produce seeds that can lie dormant for extended periods between rains. Most animal life in subtropical deserts has adapted to a nocturnal life, spending the hot daytime hours beneath the ground. The Namib Desert is the oldest on the planet, and has probably been dry for more than 55 million years. It supports a number of endemic species (species found only there) because of this great age. For example, the unusual gymnosperm Welwitschia mirabilis is the only extant species of an entire order of plants. There are also five species of reptiles considered endemic to the Namib. In addition to subtropical deserts there are cold deserts that experience freezing temperatures during the winter and any precipitation is in the form of snowfall. The largest of these deserts are the Gobi Desert in northern China and southern Mongolia, the Taklimakan Desert in western China, the Turkestan Desert, and the Great Basin Desert of the United States. Many desert plants have tiny leaves or no leaves at all to reduce water loss. The leaves of ocotillo, shown here in the Chihuahuan Desert in Big Bend National Park, Texas, appear only after rainfall and then are shed. (credit "bare ocotillo": "Leaflet"/Wikimedia Commons)

2012 Asian Carp control strategy framework

The Great Lakes food web has been significantly degraded in recent decades by aquatic invasive species (AIS). The most acute AIS threat facing the Great Lakes today is movement of carp not native to the United Sates (bighead and silver)—collectively known as Asian carp—through the Chicago Area Waterway System (CAWS), Wabash River, Grand Calumet River, and possibly other pathways that can connect the Great Lakes to the outside Mississippi River Basin. The Asian Carp Regional Coordinating Committee (ACRCC), with support from federal, state, and local agencies, and other private stakeholder entities, is working to create a sustainable Asian carp control program and to implement actions for protecting and maintaining the integrity and safety of the Great Lakes ecosystem from an Asian carp invasion via all viable pathways. This Framework lays out the strategy and presents the proposed action items to achieve this goal. The Obama Administration is implementing an unprecedented and comprehensive set of actions to prevent Asian carp introduction into the Great Lakes, and to ensure sustainable Asian carp populations do not exist within the Great Lakes. The Administration's actions include studying options or controls that could be utilized to implement ecological separation, which could include hydrological separation, of the Mississippi River and Great Lakes Basins to permanently solve the potential Asian carp problem at the connection points, as well as to address other AIS. Engineering controls, biological controls, and rapid responses to achieve eradication throughout the two basins are also under development in order to deal with possible Asian carp introductions to the Great Lakes via other vectors such as human transport or error. The ACRCC has specified the following goals/actions within the 2012 Framework: • Provide a sound strategy for addressing the threat of an Asian carp invasion in the Great Lakes such that the Framework continues to provide direction to participating agencies and actions, and identify areas for future action. • Identify efforts that supplement direct management action, such as education and outreach, or increased regulatory structure. • Increase program sustainability through Framework action items. Action items such as rotenone stockpiling, net development, and the use of DIDSON technology will build the program base and can implemented if an emergency arises. Further development of biological control agents will assist with the eradication of populations below the electric barrier system. • Identify ongoing or potential collaboration between ACRCC entities, and specify partner roles. • Document, track, and communicate the monumental actions of ACRCC partners in applying full authorities, capabilities, and resources to prevent introduction and establishment of Asian carp in the Great Lakes. • Further engage with governmental, industry, environmental, and other stakeholders. ES-1 FY2012 Asian Carp Control Strategy Framework February 2012 • Apply technologies and lessons learned to below the electric dispersal barriers and concurrent national Asian carp efforts where applicable. The best science available underscores this Framework. Widespread agreement exists among scientists and stakeholders that preventing movement of Asian carp into Lake Michigan is critical to reducing the probability of Asian carp establishment in the Great Lakes. This document describes ACRCC management strategy and its current and future actions. This Framework is designed to be inclusive, allowing government agencies and outside stakeholders to engage in developing and implementing all plausible control actions. Management actions that comprise the Framework's strategy are based upon the three typical stages of invasive species invasion. Each Framework action item is categorized within one of the following stages of invasion and management action it would impact the most: • Prevention and Development of Prevention Technologies • Monitoring and Development of Monitoring Technologies • Development of Control Technology and Impact Mitigation • Other Supporting Actions (Education, Outreach, Regulatory Support). In addition to the many efforts described in this document as part of the ACRCC strategy, the Great Lakes' States continue to undertake efforts against Asian carp and other invasive species. Through a cost-share grant program, the U.S. Fish and Wildlife Service have been able to provide assistance to states for creating and implementing AIS management plans and activities. In 2009 and 2010, the Great Lakes States invested over $26.7 million in prevention and control of aquatic invasive species—of which almost $900,000 was committed to Asian carp control efforts. The following are previous or current efforts by the Great Lakes states as part of their AIS prevention, management, and control programs: • New rapid response plans developed by Great Lakes states and approved by the AIS Task Force • State-led rapid response actions and other control efforts • AIS education and outreach, including increased signage to inform the public about various AIS • Inspections and enforcement of laws regarding AIS • AIS barrier studies and design • AIS monitoring and surveillance. The ACRCC seeks development of an effective and fiscally sustainable Asian carp biological control program throughout the Great Lakes Basin, as well as throughout the Mississippi River Basin. The near term goal is to prevent entry of Asian carp to the Great Lakes, which will give the ACRCC time to do the research and development necessary to meet the long term goal of eradication/management through biological controls or other ecological separation measures. Because Asian carp are already well established throughout the Mississippi River Basin, this ES-2 FY2012 Asian Carp Control Strategy Framework February 2012 program will be essential to decrease spread of Asian carp and prevent establishment of Asian carp in new waterway systems. This Framework is a living document and is a continuation of the efforts of previous Asian Carp Framework iterations. It recognizes potential hurdles while providing a baseline reference for collaboration among agencies and the interested communities through which a compelling plan of action can be initiated. Preventing establishment of a self-sustaining Asian carp population requires an understanding of ecological, economic, and hydrological complexities—leading to the conclusion that a comprehensive approach, which cannot rely on only a single strategy, is necessary to reduce the risk of Asian carp invasion.

ocean

The physical diversity of the ocean has a significant influence on the diversity of organisms that live within it. The ocean is categorized into different zones based on how far light reaches into the water. Each zone has a distinct group of species adapted to the biotic and abiotic conditions particular to that zone. The intertidal zone (Figure) is the oceanic region that is closest to land. With each tidal cycle, the intertidal zone alternates between being inundated with water and left high and dry. Generally, most people think of this portion of the ocean as a sandy beach. In some cases, the intertidal zone is indeed a sandy beach, but it can also be rocky, muddy, or dense with tangled roots in mangrove forests. The intertidal zone is an extremely variable environment because of tides. Organisms may be exposed to air at low tide and are underwater during high tide. Therefore, living things that thrive in the intertidal zone are often adapted to being dry for long periods of time. The shore of the intertidal zone is also repeatedly struck by waves and the organisms found there are adapted to withstand damage from the pounding action of the waves (Figure). The exoskeletons of shoreline crustaceans (such as the shore crab, Carcinus maenas) are tough and protect them from desiccation (drying out) and wave damage. Another consequence of the pounding waves is that few algae and plants establish themselves in constantly moving sand or mud. The neritic zone (Figure) extends from the margin of the intertidal zone to depths of about 200 m (or 650 ft) at the edge of the continental shelf. When the water is relatively clear, photosynthesis can occur in the neritic zone. The water contains silt and is well-oxygenated, low in pressure, and stable in temperature. These factors all contribute to the neritic zone having the highest productivity and biodiversity of the ocean. Phytoplankton, including photosynthetic bacteria and larger species of algae, are responsible for the bulk of this primary productivity. Zooplankton, protists, small fishes, and shrimp feed on the producers and are the primary food source for most of the world's fisheries. The majority of these fisheries exist within the neritic zone. Beyond the neritic zone is the open ocean area known as the oceanic zone (Figure). Within the oceanic zone there is thermal stratification. Abundant phytoplankton and zooplankton support populations of fish and whales. Nutrients are scarce and this is a relatively less productive part of the marine biome. When photosynthetic organisms and the organisms that feed on them die, their bodies fall to the bottom of the ocean where they remain; the open ocean lacks a process for bringing the organic nutrients back up to the surface. Beneath the pelagic zone is the benthic realm, the deepwater region beyond the continental shelf (Figure). The bottom of the benthic realm is comprised of sand, silt, and dead organisms. Temperature decreases as water depth increases. This is a nutrient-rich portion of the ocean because of the dead organisms that fall from the upper layers of the ocean. Because of this high level of nutrients, a diversity of fungi, sponges, sea anemones, marine worms, sea stars, fishes, and bacteria exists. The deepest part of the ocean is the abyssal zone, which is at depths of 4000 m or greater. The abyssal zone (Figure) is very cold and has very high pressure, high oxygen content, and low nutrient content. There are a variety of invertebrates and fishes found in this zone, but the abyssal zone does not have photosynthetic organisms. Chemosynthetic bacteria use the hydrogen sulfide and other minerals emitted from deep hydrothermal vents. These chemosynthetic bacteria use the hydrogen sulfide as an energy source and serve as the base of the food chain found around the vents.

Why is the tundra treeless?

lack of sufficient water

abyssal zone

the deepest part of the ocean at depths of 4000 m or greater

oceanic zone

the part of the ocean that begins offshore where the water measures 200 m deep or deeper

neritic zone

the part of the ocean that extends from low tide to the edge of the continental shelf

importance of biodiversity

Loss of biodiversity eventually threatens other species we do not impact directly because of their interconnectedness; as species disappear from an ecosystem other species are threatened by the changes in available resources. Biodiversity is important to the survival and welfare of human populations because it has impacts on our health and our ability to feed ourselves through agriculture and harvesting populations of wild animals.

temperate grassland

a biome dominated by grasses and herbaceous plants due to low precipitation, periodic fires, and grazing

Pollination is an example of

ecosystem service

Bighead Carp

hypophthalmichthys nobilis

intertidal zone

the part of the ocean that is closest to land; parts extend above the water at low tide

pelagic realm

(also, pelagic zone) the open ocean waters that are not close to the bottom or near the shore

Round Goby

Neogobius Melanostomus The round goby, Neogobius melanstomus, is a small, bottom - dwelling fish that was first found in the Great Lakes region in 1990. Originally from the Black and Caspian Sea areas of Eastern Europe, it is believed that this exotic species arrived in the ballast water of vessels coming into the Great Lakes. Since the first sighting in the St. Clair River, round gobies have spread to all of the Great Lakes and are working their way inland through the rivers and canal systems. Round gobies can reach up to 10 inches in length as adults, but usually they are less than 7 inches long in the Great Lakes. Females and immature male round gobies are a mottled gray and brown color. Spawning males turn almost solid black. Round gobies have a soft body and a large, rounded head with eyes that protrude near the top. Round gobies look similar to our native sculpins, but the two species can be easily separated by the fused pelvic fins on the underside of round gobies. Sculpins have two distinct pelvic fins, not one large fin. This fin can be used by gobies as a suction cup to anchor to rocks and other hard substrates during times of high water flow. Scientists at the Great Lakes Science Center, in cooperation with the University of Michigan, Smith-Root, Inc. and the U.S. Army Corps of Engineers, recently finished a project evaluating the potential for using an electric barrier to slow the spread of round gobies from Lake Michigan through the Illinois Waterway System and into the Mississippi River drainage. Our scientists first worked with round gobies in the laboratory to determine the most effective electrical parameters and then participated in a small-scale field study to test the barrier in a more realistic setting. We were able to establish electrical parameters that successfully deterred passage of the majority of round gobies present. These tests provided guidance for the operation of the electrical barrier scheduled to be built soon in the Illinois Waterway System. Current research at the Great Lakes Science Center involves comparing the interactions of round goby and Eurasian ruffe, another exotic species. Ruffe were introduced via ballast water to the Duluth Harbor of Lake Superior in 1986. Both species use similar bottom habitats and share the traits of voracious appetites, prolific spawning, and aggressive behavior. The two species are know to occur together in the Duluth Harbor area of Lake Superior and in the Thunder Bay River, a tributary to Lake Huron. Given the impacts both species are already having on native species individually, there is concern over what will happen when these two species occupy the same space. Current studies are focusing on competition for limited food, shelter and space with special interest in aggressive interactions. New work will be starting soon to see if these interactions change in low light conditions, as both species are generally more active at night. Round gobies are found in all of the Great Lakes with the greatest numbers in Lake Erie, Lake St. Claire and southern Lake Michigan. Many of the areas with round goby populations are best described as infested. Once round gobies arrive they can become the dominant fish species. Round gobies prefer rocky, shallow areas, but have flourished in a variety of habitat types. Regardless of the habitat, round gobies are very aggressive fish that compete with native fishes for food and space. Anglers who fish in areas with round gobies often find that the gobies steal their bait and appear to be the only type of fish in the area. Round gobies spawn from April-September with females visiting multiple nests to spawn with several different males. Round gobies attach their eggs to the underside of rocks, in pieces of pipe, or in other types of shelter. Male round gobies stay in the nest to provide care for the developing young and will ferociously defend their nests from any intruders. As a result, round gobies can produce a large number of healthy offspring in a very short time. Round gobies can eat zebra mussels in addition to fish eggs, plankton, fish, and benthic invertebrates. Because zebra mussels are filter feeders that accumulate contaminants in their body tissues, round gobies that eat zebra mussels may be consuming a high level of contaminants. When a predatory fish such as a walleye eats a round go by that has fed primarily on zebra mussels, they may be getting a much larger load of contaminants than they would from eating other types of prey fish. This could putdangerous concentrations of contaminants into sport-fish at a much faster rate. HOW YOU CAN HELP Do not use round gobies as bait. Dump bait buckets on land. Help stop the spread of all aquatic exotics by cleaning your boat and trailer before going to a new water body. Drain the water from your boat motor and wells on land. Remove plants and debris from your trailer before leaving the launch ramp.

canopy

the branches and foliage of trees that form a layer of overhead coverage in a forest

ecosystem services

the human benefits provided by natural ecosystems

cryptofauna

the invertebrates found within the calcium carbonate substrate of coral reefs

habitat heterogeneity

the number of ecological niches

extinction rate

the number of species becoming extinct over time, sometimes defined as extinctions per million species-years to make numbers manageable (E/MSY)

benthic realm

(also, benthic zone) the part of the ocean that extends along the ocean bottom from the shoreline to the deepest parts of the ocean floor

Exotic Species

Exotic species are species that have been intentionally or unintentionally introduced by humans into an ecosystem in which they did not evolve. Human transportation of people and goods, including the intentional transport of organisms for trade, has dramatically increased the introduction of species into new ecosystems. These new introductions are sometimes at distances that are well beyond the capacity of the species to ever travel itself and outside the range of the species' natural predators. Most exotic species introductions probably fail because of the low number of individuals introduced or poor adaptation to the ecosystem they enter. Some species, however, have characteristics that can make them especially successful in a new ecosystem. These exotic species often undergo dramatic population increases in their new habitat and reset the ecological conditions in the new environment, threatening the species that exist there. When this happens, the exotic species also becomes an invasive species. Invasive species can threaten other species through competition for resources, predation, or disease. Lakes and islands are particularly vulnerable to extinction threats from introduced species. In Lake Victoria, the intentional introduction of the Nile perch was largely responsible for the extinction of over 400 species of cichlids. Watch this National Geographic video clip to learn more about why the Lake perch were introduced and the unexpected disruption of fish biodiversity. https://www.nationalgeographic.org/media/impact-invasive-species/ The accidental introduction of the brown tree snake via aircraft (Figure) from the Solomon Islands to Guam in 1950 has led to the extinction of ten of the twelve species of island birds and most of the native forest vertebrate species on the island. Several other species are still threatened. The brown tree snake is adept at exploiting human transportation as a means to migrate; one was even found on an aircraft arriving in Corpus Christi, Texas. Constant vigilance on the part of airport, military, and commercial aircraft personnel is required to prevent the snake from moving from Guam to other islands in the Pacific, especially Hawaii. Islands do not make up a large area of land on the globe, but they do contain a disproportionate number of endemic species because of their isolation from mainland ancestors. Many introductions of aquatic species, both marine and freshwater, have occurred when ships have dumped ballast water taken on at a port of origin into waters at a destination port. Water from the port of origin is pumped into tanks on a ship empty of cargo to increase stability. The water is drawn from the ocean or estuary of the port and typically contains living organisms such as plant parts, microorganisms, eggs, larvae, or aquatic animals. The water is then pumped out before the ship takes on cargo at the destination port, which may be on a different continent. The zebra mussel was introduced to the Great Lakes from Europe prior to 1988 in ship ballast. The zebra mussels in the Great Lakes have cost the industry millions of dollars in clean up costs to maintain water intakes and other facilities. The mussels have also altered the ecology of the lakes dramatically. They threaten native mollusk populations, but have also benefited some species, such as smallmouth bass. The mussels are filter feeders and have dramatically improved water clarity, which in turn has allowed aquatic plants to grow along shorelines, providing shelter for young fish where it did not exist before. The European green crab, Carcinus maenas, was introduced to San Francisco Bay in the late 1990s, likely in ship ballast water, and has spread north along the coast to Washington. The crabs have been found to dramatically reduce the abundance of native clams and crabs with resulting increases in the prey of native crabs. Invading exotic species can also be disease organisms. It now appears that the global decline in amphibian species recognized in the 1990s is, in some part, caused by the fungus Batrachochytrium dendrobatidis, which causes the disease chytridiomycosis (Figure). There is evidence that the fungus is native to Africa and may have been spread throughout the world by transport of a commonly used laboratory and pet species: the African clawed frog, Xenopus laevis. It may well be that biologists themselves are responsible for spreading this disease worldwide. The North American bullfrog, Rana catesbeiana, which has also been widely introduced as a food animal but which easily escapes captivity, survives most infections of B. dendrobatidis and can act as a reservoir for the disease. Early evidence suggests that another fungal pathogen, Geomyces destructans, introduced from Europe is responsible for white-nose syndrome, which infects cave-hibernating bats in eastern North America and has spread from a point of origin in western New York State (Figure). The disease has decimated bat populations and threatens extinction of species already listed as endangered: the Indiana bat, Myotis sodalis, and potentially the Virginia big-eared bat, Corynorhinus townsendii virginianus. How the fungus was introduced is unknown, but one logical presumption would be that recreational cavers unintentionally brought the fungus on clothes or equipment from Europe.

Sea Lamprey

Petromyzon Marinus Introduction: From Atlantic Ocean in the 1830s The sea lamprey (Petromyzon marinus) is a marine invader from the Atlantic Ocean that entered the Great Lakes through the ship canals and locks built to bypass obstacles like Niagara Falls. An unintended consequence of these canals has been the introduction of invasive species. primitive, jawless fish anadromous The sea lamprey was one of the first to invade the Great Lakes. It has been very damaging because part of its life cycle is spent feeding parasitically on the blood of host fish like the native lake trout. Sea lampreys are a very primitive, jawless fish. In the Great Lakes, people mistakenly referred to them as "eels or lamprey-eels." But, sea lampreys are only very distantly related to eels and are correctly referred to only as "lampreys". Although they are classified as a vertebrate, they lack bones and have only a cartilaginous rod or "notochord" for a spine. The paired fins found on most fish are also absent. The most remarkable feature of the sea lamprey is the toothstudded oral disk. During the parasitic period of their life cycle, they use the oral disc like a suction cup to attach to the side of a host fish. The many teeth on the rim of the disc provide traction and make it very difficult for a fish to dislodge a sea lamprey. Once attached, they use the teeth on the tongue in the center of the disk to rasp through the skin. An anticoagulant in their saliva maintains blood flow as they feed. Often the host dies from the blood loss. Estimates of the number of pounds of fish killed by each sea lamprey vary from about 15 to 40 pounds. Several characteristics of the sea lamprey made it an effective marine invader of the Great Lakes. First, the sea lamprey is an "anadromous" fish. This means that it spawns in fresh water streams, the juvenile phase is spent in salt water in the ocean (or one of the Great Lakes as a substitute), and the adult returns to freshwater streams to spawn. Other anadromous, non-native fish in the Great Lakes include coho salmon, chinook salmon, pink salmon, Atlantic salmon, brown trout, rainbow trout, rainbow smelt, and alewives. Special modifications of their kidneys allows these species to live in either fresh or salt water. If you haven't thought of these species as non-native, they are. Second, sea lampreys produce large numbers of eggs. The Great Lakes contained several smaller, native lampreys, but the sea lamprey rapidly out competed them wherever their range overlapped. Third, we believe that lampreys locate streams for spawning using a pheromone excreted by larvae. This pheromone identifies streams successfully producing young. Because the native lampreys also produced this pheromone, the larger, invading sea lampreys had an effective "road map" for expansion. Sea lampreys quickly devastated the fish communities of the Great Lakes. Sea lampreys probably entered Lake Ontario in the 1830s via manmade locks and ship canals. Improvements to the Welland Canal in 1919 allowed sea lampreys to bypass Niagara Falls and enter Lake Erie. After sea lampreys were discovered above Niagara Falls (in Lake Erie in 1921 and Lake Huron in the early 1930s), they spread throughout the upper Great Lakes by 1939. The lake trout was the main predatory species at that time and the sea lamprey's preferred host. Although early declines in lake trout abundance in the 1940s are suspected to have been caused by overfishing, sea lampreys are believed to be responsible for the very rapid decline in the later 1940s and 1950s. Lake trout actually became extinct in Lakes Ontario, Erie, Huron (except a few inlets of Georgian Bay), and Michigan. Only remnant native stocks remained in Lake Superior. Two factors contributed to the devastating effect of sea lampreys. First, sea lampreys lacked effective predators. Second, the Great Lakes probably have as many miles of tributaries and as many acres of larval habitat as the native range of the sea lamprey along the Atlantic Coast. Host fishes in the Great Lakes are much smaller than those attacked in the Atlantic Ocean and are more likely to be killed by a sea lamprey attack. Between 40% and 60% of lake trout attacked by a sea lamprey will die from loss of blood. These attacks were a major cause of the collapse of lake trout, whitefish, and chub populations in the Great Lakes in the 1940s and 1950s. Lake trout harvests in the U. S. and Canada averaged 15 million pounds per year before the sea lamprey, but declined to record lows within 20 years of the sea lamprey's appearance. Other equally important secondary effects were caused by cascading changes in the fish communities. After the elimination of predators like lake trout, the populations of invasive prey species like the rainbow smelt and alewife increased rapidly in the absence of predation. Those invasive species then out competed native species or preyed on their young. Extinctions of sculpin and deepwater cisco species have been suspected of being linked to extended periods of high abundance of smelt and alewives. The massive annual die offs of alewives that fouled the beaches in Michigan during the 1950s and 1960s were due to overcrowding and poor condition and were a secondary effect of the invasion of the sea lamprey. Alewives also prey heavily on zooplankton. Because zooplankton graze on phytoplankton, the density of phytoplankton increased and the color and clarity of water were affected, particularly in the lower Great Lakes. Human activities were affected first through the loss of sport and commercial fisheries across the Great Lakes. Following those losses, came other, equally important economic effects caused by the disappearance of fishery-related jobs and the loss of fishing tourism. With the beaches fouled with dead alewives, there were also losses of tourism associated with beach use. LIFE CYCLE: Fortunately, only one year in the life of a sea lamprey is spent in parasitic feeding. They are unusual in having a complex life cycle, whereas most fish have a simple life cycle. A. Sea lampreys go through an extended larval phase before metamorphosing into the bloodsucking parasitic phase. Each summer and fall there is one group of parasitic sea lampreys actively feeding in the Great Lakes. B. The next spring, that group leaves the lake and migrates into tributary streams where they must build nests in clean gravel with flowing water. C. Each female spawns an average of 60 to 70 thousand eggs. D. After hatch, the larvae drift downstream to areas with slower currents and sand/silt bottoms. There, they establish permanent burrows and enter a larval stage varying in duration from 3 to 10-ormore years. E. Larvae lack eyes and the oral disc. Living concealed in their burrows, they are harmless and filter microscopic material from the water for food. When they reach lengths of 120 mm or more, some individuals begin metamorphosis in mid summer. F. During metamorphosis they develop eyes, the oral disc, and changes in their kidneys that (in their native range) would allow them to enter the salt water of the Atlantic Ocean. That fall or the following spring, they instead enter the Great Lakes to feed parasitically on fish that summer and fall, and mature and spawn the next spring—completing their life cycle. Sea lampreys only spawn once and then die after spawning. CONTROL: The sea lamprey is one of the few aquatic invasive species that is being successfully controlled. In the late 1940s the State of Michigan began investigations into the biology of sea lampreys. In 1950, this became a federal program. In 1955, the Great Lakes Fishery Commission (GLFC) was created under a convention between the United States and Canada for the purpose of restoring fisheries. One of the GLFC's primary duties was the control or eradication of sea lampreys. It currently manages sea lamprey populations across the Great Lakes to about 10% of their former levels. Control is delivered through its control agents, the U.S. Fish and Wildlife Service and the Department of Fisheries and Oceans, Canada. The commission also funds research on sea lampreys at the U.S. Geological Survey's Hammond Bay Biological Station, at Michigan State University, and at the University of Guelph, Ontario Control depends on breaking the life cycle. The first control efforts attempted to do that by blocking access to the spawning areas in streams. This was only partially successful because the weirs used to do this were impossible to maintain 100% of the time. There were attempts to use electric fields alone or in conjunction with the weirs, but that was eventually abandoned as too dangerous. A second vulnerable point in the life cycle is during the larval stage, when sea lampreys spend at least three years burrowed in the stream sediment. During the 1950s, over 6,000 chemicals were screened before finding one that was selectively toxic to sea lampreys. That chemical, TFM, has been carefully applied to infested streams, beginning in Lake Superior in 1958. Treatments quickly decreased sea lamprey numbers to 10% or less of their former numbers. Reduced lamprey numbers allowed native and stocked lake trout to survive and the lake trout populations to rebound. Recently, the restoration of lake trout in Lake Superior was declared a success and federal stocking of lake trout was stopped. Lake trout stocks in Lake Superior are once again self-sustaining. Treatments with TFM start with electrofishing surveys of the Great Lakes tributaries known to potentially produce sea lampreys. Based on estimates of the number of metamorphosed sea lampreys to be produced and on treatment costs, a list of streams to be treated is made each year. Because of the duration of the larval stage, streams are treated at intervals of 3 to 5 years or longer. We now have extensive knowledge of the effect of water chemistry on safe levels of TFM and treatments rarely kill fish. TFM also degrades and does not bioaccumulate. In over 40 years of use there has been no documentation of accumulation or of long-term effects on streams despite repeated studies with that objective. The return on treatments is the reestablishment of predators and predator/prey balance in the Great Lakes and protection of native species from extinction. Treatment with TFM is currently still the primary tool for control, but the GLFC, partnered with the Great Lakes Science Center, is committed to providing an integrated program of sea lamprey management in the future that will rely on an increasing number of new control methods. We are now revisiting some of the older concepts such as blocking spawning migration, but using new technologies. Ineffective and labor-intensive screen weirs have been replaced with low-head barriers that block sea lampreys but allow jumping fish to pass. We are also investigating adjustable height barriers that can be lowered after the spawning run, new electrical barriers that use safe levels of pulsed-DC current, and velocity barriers that use the relatively poor swimming ability of sea lampreys to block them but pass other fish. Lampricide Together with the UMESC in LaCrosse, the Hammond Bay Biological Station has played a major role in the discovery of lampricides and the refinement of techniques for their use. We continue to provide technical assistance to that program by supporting purchases of lampricide through a QA program, providing FWS personnel in the field with analytical support and standards, and through continuing research to refine our capability to predict safe and effect concentrations of lampricides in stream treatments. Ecology and Assessment Research done at Hammond Bay accounts for a significant part of our knowledge of the life cycle and ecology of sea lampreys in the Great Lakes, including effects on host species. Recent accomplishments include the first comprehensive analysis of parasitic growth, proof that there is no fidelity of sea lampreys to a natal stream, introduction of coded wire tags and mark recapture to estimate lake wide populations of parasites, estimates of attack lethality, and proof of the relationship between sea lamprey marks observed on fish and losses of lake trout. We contributed substantially to development of a spatial approach to assessment and treatment of sea lamprey larvae in the St. Marys River, resulting (in combination with sterile male releases, below) in lamprey populations in Lake Huron approaching fish community goals. Alternative Control Methods The station has played a key role in the development of several alternatives to lampricides. Initial development of barriers to block sea lampreys from spawning areas in stream was done at Hammond Bay. The most recent evolution of that technology, a combination of a low head barrier that blocks lampreys under normal spring flows and a pulsed-DC barrier that blocks them under flood conditions, was developed at the station. Nearly 30 years of research into the sterile male release technique resulted in successful implementation by the FWS on the St. Marys River and publication of proof of the effect on recruitment. NEW DIRECTION: Sea Lamprey Pheromones Exciting new discoveries in pheromone communication by sea lampreys promise new tools. In part due to fieldwork conducted at the HBBS over the last decade, Michigan State University and University of Minnesota researchers identified two pheromones. Larvae burrowed in streams excrete a "migratory" pheromone. HBBS scientists had previously shown that sea lampreys do not home to natal streams, yet spawners are consistently found in the same streams. Evidence from tests by Peter Sorensen in two-choice mazes in raceways at the HBBS suggests the migratory pheromone is the method of stream selection. Field tests in the Hammond Bay area will attempt to direct movements of migrating adult sea lampreys. A second "sex" pheromone is released only by spermiated (ripe) adult male sea lampreys. It appears to trigger ovulation in females, and later (but only after the females are ovulated), attracts ripe females to the ripe males. Recent tests by Weiming Li in the Ocqueoc River showed that every ovulated female that made a choice between traps containing a ripe or non-ripe male chose the ripe male. Both pheromones may disrupt sea lamprey migrations or reproduction, or enhance trapping. Emerging Technologies in Telemetry to Address Knowledge Gaps in Fish Community Ecology Most of what we know of species interaction on temporal, depth, or thermal scales are derived from point observations with fishing gear or hydroacoustics. Progress in telemetry will soon allow us to reveal these interactions on a scale not imagined a decade ago. We are currently using new data storage tags to gain new insights into the depths and temperatures occupied by different strains of lake trout and by lake whitefish, chinook salmon, lake sturgeon and sea lampreys. Currently, we are limited to studying species where commercial or sport exploitation produces tag recoveries. Depths and distance in the Great Lakes preclude conventional radio or ultrasonic telemetry. We are presently working with the GLFC and LOTEK to develop a new type of tag for use with unexploited species or populations. Barriers Reemerge A combined low-head and electrical barrier was constructed on the Ocqueoc River, which functions effectively as a low-head barrier but also blocks sea lampreys during high water on this flood-prone stream. This combination of proven technologies allows effective blockage of migrating sea lampreys and passage of jumping fishes under a much broader range of stream flows. Under normal flows, the low-head barrier is functional, no current flows to the electrical barrier, and jumping fish can pass. During flood conditions, when the low-head barrier is inundated, the electric barrier automatically turns on and blocks sea lampreys. Scientists at HBBS will be working in the future with Robert McLaughlin and Gordon McDonald of the University of Guelph to better block sea lamprey migration and improve passage of other fishes at electrical, low-head, and inflatable barriers, and further reduce any negative effects of barriers on stream communities.

types of biodiversity

A common meaning of biodiversity is simply the number of species in a location or on Earth; for example, the American Ornithologists' Union lists 2078 species of birds in North and Central America. This is one measure of the bird biodiversity on the continent. More sophisticated measures of diversity take into account the relative abundances of species. For example, a forest with 10 equally common species of trees is more diverse than a forest that has 10 species of trees wherein just one of those species makes up 95 percent of the trees rather than them being equally distributed. Biologists have also identified alternate measures of biodiversity, some of which are important in planning how to preserve biodiversity.

unit 4 summary

Earth's biomes can be either terrestrial or aquatic. Terrestrial biomes are based on land, while aquatic biomes include both ocean and freshwater biomes. The eight major terrestrial biomes on Earth are each distinguished by characteristic temperatures and amount of precipitation. Annual totals and fluctuations of precipitation affect the kinds of vegetation and animal life that can exist in broad geographical regions. Temperature variation on a daily and seasonal basis is also important for predicting the geographic distribution of a biome. Since a biome is defined by climate, the same biome can occur in geographically distinct areas with similar climates (Figure). There are also large areas on Antarctica, Greenland, and in mountain ranges that are covered by permanent glaciers and support very little life. Strictly speaking, these are not considered biomes and in addition to extremes of cold, they are also often deserts with very low precipitation

Silver carp

Hypophthalmichthys molitrix Silver carp (and bighead carp to a lesser extent) are renowned for leaping high out of the water when disturbed by watercraft. Boaters traveling at high speeds can actually be injured by these leaping fish. (Imagine hitting a 100-pound, four-foot-long fish at 30 miles per hour!). They also diminish the opportunities of fisherman as native fishes decline from carp competition.

changing human behavior

Legislation has been enacted to protect species throughout the world. The legislation includes international treaties as well as national and state laws. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) treaty came into force in 1975. The treaty, and the national legislation that supports it, provides a legal framework for preventing "listed" species from being transported across nations' borders, thus protecting them from being caught or killed in the first place when the purpose involves international trade. The listed species that are protected to one degree or another by the treaty number some 33,000. The treaty is limited in its reach because it only deals with international movement of organisms or their parts. It is also limited by various countries' ability or willingness to enforce the treaty and supporting legislation. The illegal trade in organisms and their parts is probably a market in the hundreds of millions of dollars. Within many countries there are laws that protect endangered species and that regulate hunting and fishing. In the United States, the Endangered Species Act was enacted in 1973. When an at-risk species is listed by the Act, the U.S. Fish & Wildlife Service is required by law to develop a management plan to protect the species and bring it back to sustainable numbers. The Act, and others like it in other countries, is a useful tool, but it suffers because it is often difficult to get a species listed, or to get an effective management plan in place once a species is listed. Additionally, species may be controversially taken off the list without necessarily having had a change in their situation. More fundamentally, the approach to protecting individual species rather than entire ecosystems (although the management plans commonly involve protection of the individual species' habitat) is both inefficient and focuses efforts on a few highly visible and often charismatic species, perhaps at the expense of other species that go unprotected. The Migratory Bird Treaty Act (MBTA) is an agreement between the United States and Canada that was signed into law in 1918 in response to declines in North American bird species caused by hunting. The Act now lists over 800 protected species. It makes it illegal to disturb or kill the protected species or distribute their parts (much of the hunting of birds in the past was for their feathers). Examples of protected species include northern cardinals, the red-tailed hawk, and the American black vulture. Global warming is expected to be a major driver of biodiversity loss. Many governments are concerned about the effects of anthropogenic global warming, primarily on their economies and food resources. Since greenhouse gas emissions do not respect national boundaries, the effort to curb them is an international one. The international response to global warming has been mixed. The Kyoto Protocol, an international agreement that came out of the United Nations Framework Convention on Climate Change that committed countries to reducing greenhouse gas emissions by 2012, was ratified by some countries, but spurned by others. Two countries that were especially important in terms of their potential impact that did not ratify the Kyoto protocol were the United States and China. Some goals for reduction in greenhouse gasses were met and exceeded by individual countries, but, worldwide, the effort to limit greenhouse gas production is not succeeding. The intended replacement for the Kyoto Protocol has not materialized because governments cannot agree on timelines and benchmarks. Meanwhile, the resulting costs to human societies and biodiversity predicted by a majority of climate scientists will be high. As already mentioned, the non-profit, non-governmental sector plays a large role in conservation effort both in North America and around the world. The approaches range from species-specific organizations to the broadly focused IUCN and Trade Records Analysis of Flora and Fauna in Commerce (TRAFFIC). The Nature Conservancy takes a novel approach. It purchases land and protects it in an attempt to set up preserves for ecosystems. Ultimately, human behavior will change when human values change. At present, the growing urbanization of the human population is a force that mitigates against valuing biodiversity, because many people no longer come in contact with natural environments and the species that inhabit them.

savana

a biome located in the tropics with an extended dry season and characterized by a grassland with sparsely distributed trees

coral reefs

an ocean ridge formed by marine invertebrates living in warm shallow waters within the photic zone Coral reefs are ocean ridges formed by marine invertebrates living in warm shallow waters within the photic zone of the ocean. They are found within 30 ̊ north and south of the equator. The Great Barrier Reef is a well-known reef system located several miles off the northeastern coast of Australia. Other coral reefs are fringing islands, which are directly adjacent to land, or atolls, which are circular reefs surrounding a former island that is now underwater. The coral-forming colonies of organisms (members of phylum Cnidaria) secrete a calcium carbonate skeleton. These calcium-rich skeletons slowly accumulate, thus forming the underwater reef Corals found in shallower waters (at a depth of approximately 60 m or about 200 ft) have a mutualistic relationship with photosynthetic unicellular protists. The relationship provides corals with the majority of the nutrition and the energy they require. The waters in which these corals live are nutritionally poor and, without this mutualism, it would not be possible for large corals to grow because there are few planktonic organisms for them to feed on. Some corals living in deeper and colder water do not have a mutualistic relationship with protists; these corals must obtain their energy exclusively by feeding on plankton using stinging cells on their tentacles. Coral reefs are one of the most diverse biomes. It is estimated that more than 4000 fish species inhabit coral reefs. These fishes can feed on coral, the cryptofauna (invertebrates found within the calcium carbonate structures of the coral reefs), or the seaweed and algae that are associated with the coral. These species include predators, herbivores, or planktivores. Predators are animal species that hunt and are carnivores or "flesh eaters." Herbivores eat plant material, and planktivores eat plankton. Coral reefs are formed by the calcium carbonate skeletons of coral organisms, which are marine invertebrates in the phylum Cnidaria.

ecosystem diversity

the variety of ecosystems It is also useful to define ecosystem diversity: the number of different ecosystems on Earth or in a geographical area. Whole ecosystems can disappear even if some of the species might survive by adapting to other ecosystems. The loss of an ecosystem means the loss of the interactions between species, the loss of unique features of coadaptation, and the loss of biological productivity that an ecosystem is able to create. An example of a largely extinct ecosystem in North America is the prairie ecosystem (Figure). Prairies once spanned central North America from the boreal forest in northern Canada down into Mexico. They are now all but gone, replaced by crop fields, pasture lands, and suburban sprawl. Many of the species survive, but the hugely productive ecosystem that was responsible for creating our most productive agricultural soils is now gone. As a consequence, their soils are now being depleted unless they are maintained artificially at greater expense. The decline in soil productivity occurs because the interactions in the original ecosystem have been lost; this was a far more important loss than the relatively few species that were driven extinct when the prairie ecosystem was destroyed.

genetic diversity

the variety of genes and alleles in a species or other taxonomic group or ecosystem; the term can refer to allelic diversity or genome-wide diversity

chemical diversity

the variety of metabolic compounds in an ecosystem

patterns of biodiversity

Biodiversity is not evenly distributed on the planet. Lake Victoria contained almost 500 species of cichlids (only one family of fishes present in the lake) before the introduction of an exotic species in the 1980s and 1990s caused a mass extinction. All of these species were found only in Lake Victoria, which is to say they were endemic. Endemic species are found in only one location. For example, the blue jay is endemic to North America, while the Barton Springs salamander is endemic to the mouth of one spring in Austin, Texas. Endemics with highly restricted distributions, like the Barton Springs salamander, are particularly vulnerable to extinction. Higher taxonomic levels, such as genera and families, can also be endemic.

rivers and streams

Rivers and the narrower streams that feed into the rivers are continuously moving bodies of water that carry water from the source or headwater to the mouth at a lake or ocean. The largest rivers include the Nile River in Africa, the Amazon River in South America, and the Mississippi River in North America Abiotic features of rivers and streams vary along the length of the river or stream. Streams begin at a point of origin referred to as source water. The source water is usually cold, low in nutrients, and clear. The channel (the width of the river or stream) is narrower here than at any other place along the length of the river or stream. Headwater streams are of necessity at a higher elevation than the mouth of the river and often originate in regions with steep grades leading to higher flow rates than lower elevation stretches of the river. Faster-moving water and the short distance from its origin results in minimal silt levels in headwater streams; therefore, the water is clear. Photosynthesis here is mostly attributed to algae that are growing on rocks; the swift current inhibits the growth of phytoplankton. Photosynthesis may be further reduced by tree cover reaching over the narrow stream. This shading also keeps temperatures lower. An additional input of energy can come from leaves or other organic material that falls into a river or stream from the trees and other plants that border the water. When the leaves decompose, the organic material and nutrients in the leaves are returned to the water. The leaves also support a food chain of invertebrates that eat them and are in turn eaten by predatory invertebrates and fish. Plants and animals have adapted to this fast-moving water. For instance, leeches (phylum Annelida) have elongated bodies and suckers on both ends. These suckers attach to the substrate, keeping the leech anchored in place. In temperate regions, freshwater trout species (phylum Chordata) may be an important predator in these fast-moving and colder river and streams. As the river or stream flows away from the source, the width of the channel gradually widens, the current slows, and the temperature characteristically increases. The increasing width results from the increased volume of water from more and more tributaries. Gradients are typically lower farther along the river, which accounts for the slowing flow. With increasing volume can come increased silt, and as the flow rate slows, the silt may settle, thus increasing the deposition of sediment. Phytoplankton can also be suspended in slow-moving water. Therefore, the water will not be as clear as it is near the source. The water is also warmer as a result of longer exposure to sunlight and the absence of tree cover over wider expanses between banks. Worms (phylum Annelida) and insects (phylum Arthropoda) can be found burrowing into the mud. Predatory vertebrates (phylum Chordata) include waterfowl, frogs, and fishes. In heavily silt-laden rivers, these predators must find food in the murky waters, and, unlike the trout in the clear waters at the source, these vertebrates cannot use vision as their primary sense to find food. Instead, they are more likely to use taste or chemical cues to find prey. When a river reaches the ocean or a large lake, the water typically slows dramatically and any silt in the river water will settle. Rivers with high silt content discharging into oceans with minimal currents and wave action will build deltas, low-elevation areas of sand and mud, as the silt settles onto the ocean bottom. Rivers with low silt content or in areas where ocean currents or wave action are high create estuarine areas where the fresh water and salt water mix.

agricultural

Since the beginning of human agriculture more than 10,000 years ago, human groups have been breeding and selecting crop varieties. This crop diversity matched the cultural diversity of highly subdivided populations of humans. For example, potatoes were domesticated beginning around 7,000 years ago in the central Andes of Peru and Bolivia. The people in this region traditionally lived in relatively isolated settlements separated by mountains. The potatoes grown in that region belong to seven species and the number of varieties likely is in the thousands. Each variety has been bred to thrive at particular elevations and soil and climate conditions. The diversity is driven by the diverse demands of the dramatic elevation changes, the limited movement of people, and the demands created by crop rotation for different varieties that will do well in different fields. Potatoes are only one example of agricultural diversity. Every plant, animal, and fungus that has been cultivated by humans has been bred from original wild ancestor species into diverse varieties arising from the demands for food value, adaptation to growing conditions, and resistance to pests. The potato demonstrates a well-known example of the risks of low crop diversity: during the tragic Irish potato famine (1845-1852 AD), the single potato variety grown in Ireland became susceptible to a potato blight—wiping out the crop. The loss of the crop led to famine, death, and mass emigration. Resistance to disease is a chief benefit to maintaining crop biodiversity and lack of diversity in contemporary crop species carries similar risks. Seed companies, which are the source of most crop varieties in developed countries, must continually breed new varieties to keep up with evolving pest organisms. These same seed companies, however, have participated in the decline of the number of varieties available as they focus on selling fewer varieties in more areas of the world replacing traditional local varieties. The ability to create new crop varieties relies on the diversity of varieties available and the availability of wild forms related to the crop plant. These wild forms are often the source of new gene variants that can be bred with existing varieties to create varieties with new attributes. Loss of wild species related to a crop will mean the loss of potential in crop improvement. Maintaining the genetic diversity of wild species related to domesticated species ensures our continued supply of food. Since the 1920s, government agriculture departments have maintained seed banks of crop varieties as a way to maintain crop diversity. This system has flaws because over time seed varieties are lost through accidents and there is no way to replace them. In 2008, the Svalbard Global seed Vault, located on Spitsbergen island, Norway, (Figure) began storing seeds from around the world as a backup system to the regional seed banks. If a regional seed bank stores varieties in Svalbard, losses can be replaced from Svalbard should something happen to the regional seeds. The Svalbard seed vault is deep into the rock of the arctic island. Conditions within the vault are maintained at ideal temperature and humidity for seed survival, but the deep underground location of the vault in the arctic means that failure of the vault's systems will not compromise the climatic conditions inside the vault.

temperate grasslands

Temperate grasslands are found throughout central North America, where they are also known as prairies, and in Eurasia, where they are known as steppes (Figure). Temperate grasslands have pronounced annual fluctuations in temperature with hot summers and cold winters. The annual temperature variation produces specific growing seasons for plants. Plant growth is possible when temperatures are warm enough to sustain plant growth, which occurs in the spring, summer, and fall. Annual precipitation ranges from 25.4 cm to 88.9 cm (10-35 in). Temperate grasslands have few trees except for those found growing along rivers or streams. The dominant vegetation tends to consist of grasses. The treeless condition is maintained by low precipitation, frequent fires, and grazing (Figure). The vegetation is very dense and the soils are fertile because the subsurface of the soil is packed with the roots and rhizomes (underground stems) of these grasses. The roots and rhizomes act to anchor plants into the ground and replenish the organic material (humus) in the soil when they die and decay. The American bison (Bison bison), more commonly called the buffalo, is a grazing mammal that once populated American prairies in huge numbers. (credit: Jack Dykinga, USDA ARS) Fires, which are a natural disturbance in temperate grasslands, can be ignited by lightning strikes. It also appears that the lightning-caused fire regime in North American grasslands was enhanced by intentional burning by humans. When fire is suppressed in temperate grasslands, the vegetation eventually converts to scrub and dense forests. Often, the restoration or management of temperate grasslands requires the use of controlled burns to suppress the growth of trees and maintain the grasses.

freshwater biomes

Freshwater biomes include lakes, ponds, and wetlands (standing water) as well as rivers and streams (flowing water). Humans rely on freshwater biomes to provide aquatic resources for drinking water, crop irrigation, sanitation, recreation, and industry. These various roles and human benefits are referred to as ecosystem services. Lakes and ponds are found in terrestrial landscapes and are therefore connected with abiotic and biotic factors influencing these terrestrial biomes.

tropical forest

Tropical rainforests are also referred to as tropical wet forests. This biome is found in equatorial regions (Figure). Tropical rainforests are the most diverse terrestrial biome. This biodiversity is still largely unknown to science and is under extraordinary threat primarily through logging and deforestation for agriculture. Tropical rainforests have also been described as nature's pharmacy because of the potential for new drugs that is largely hidden in the chemicals produced by the huge diversity of plants, animals, and other organisms. The vegetation is characterized by plants with spreading roots and broad leaves that fall off throughout the year, unlike the trees of deciduous forests that lose their leaves in one season. These forests are "evergreen," year-round. The temperature and sunlight profiles of tropical rainforests are stable in comparison to that of other terrestrial biomes, with average temperatures ranging from 20oC to 34oC (68oF to 93oF). Month-to- month temperatures are relatively constant in tropical rainforests, in contrast to forests further from the equator. This lack of temperature seasonality leads to year-round plant growth, rather than the seasonal growth seen in other biomes. In contrast to other ecosystems, a more constant daily amount of sunlight (11-12 hours per day) provides more solar radiation, thereby a longer period of time for plant growth. The annual rainfall in tropical rainforests ranges from 250 cm to more than 450 cm (8.2-14.8 ft) with considerable seasonal variation. Tropical rainforests have wet months in which there can be more than 30 cm (11-12 in) of precipitation, as well as dry months in which there are fewer than 10 cm (3.5 in) of rainfall. However, the driest month of a tropical rainforest can still exceed the annual rainfall of some other biomes, such as deserts. Tropical rainforests have high net primary productivity because the annual temperatures and precipitation values support rapid plant growth (Figure). However, the high rainfall quickly leaches nutrients from the soils of these forests, which are typically low in nutrients. Tropical rainforests are characterized by vertical layering of vegetation and the formation of distinct habitats for animals within each layer. On the forest floor is a sparse layer of plants and decaying plant matter. Above that is an understory of short, shrubby foliage. A layer of trees rises above this understory and is topped by a closed upper canopy—the uppermost overhead layer of branches and leaves. Some additional trees emerge through this closed upper canopy. These layers provide diverse and complex habitats for the variety of plants, animals, and other organisms within the tropical wet forests. Many species of animals use the variety of plants and the complex structure of the tropical wet forests for food and shelter. Some organisms live several meters above ground rarely ever descending to the forest floor. Rainforests are not the only forest biome in the tropics; there are also tropical dry forests, which are characterized by a dry season of varying lengths. These forests commonly experience leaf loss during the dry season to one degree or another. The loss of leaves from taller trees during the dry season opens up the canopy and allows sunlight to the forest floor that allows the growth of thick ground-level brush, which is absent in tropical rainforests. Extensive tropical dry forests occur in Africa (including Madagascar), India, southern Mexico, and South America.

endemic species

a species native to one place

Benthification

is a change from water column dominated communities (plankton) to bottom-dwelling organisms (benthon) and has completely changed the Lake Michigan "benthiscape." Great Lakes Water Institute has been researching mussels in Lake Michigan for several years. Following is research information from the labs of Dr. Carmen Aguilar and Dr. Russell Cuhel.

A coniferous forest is characterized by _____.

not all of the above

Climate Change

Climate change, and specifically the anthropogenic warming trend presently underway, is recognized as a major extinction threat, particularly when combined with other threats such as habitat loss. Anthropogenic warming of the planet has been observed and is hypothesized to continue due to past and continuing emission of greenhouse gases, primarily carbon dioxide and methane, into the atmosphere caused by the burning of fossil fuels and deforestation. These gases decrease the degree to which Earth is able to radiate heat energy created by the sunlight that enters the atmosphere. The changes in climate and energy balance caused by increasing greenhouse gases are complex and our understanding of them depends on predictions generated from detailed computer models. Scientists generally agree the present warming trend is caused by humans and some of the likely effects include dramatic and dangerous climate changes in the coming decades. However, there is still debate and a lack of understanding about specific outcomes. Scientists disagree about the likely magnitude of the effects on extinction rates, with estimates ranging from 15 to 40 percent of species committed to extinction by 2050. Scientists do agree that climate change will alter regional climates, including rainfall and snowfall patterns, making habitats less hospitable to the species living in them. The warming trend will shift colder climates toward the north and south poles, forcing species to move with their adapted climate norms, but also to face habitat gaps along the way. The shifting ranges will impose new competitive regimes on species as they find themselves in contact with other species not present in their historic range. One such unexpected species contact is between polar bears and grizzly bears. Previously, these two species had separate ranges. Now, their ranges are overlapping and there are documented cases of these two species mating and producing viable offspring. Changing climates also throw off the delicate timing adaptations that species have to seasonal food resources and breeding times. Scientists have already documented many contemporary mismatches to shifts in resource availability and timing. Range shifts are already being observed: for example, on average, European bird species ranges have moved 91 km (56.5 mi) northward. The same study suggested that the optimal shift based on warming trends was double that distance, suggesting that the populations are not moving quickly enough. Range shifts have also been observed in plants, butterflies, other insects, freshwater fishes, reptiles, amphibians, and mammals. Climate gradients will also move up mountains, eventually crowding species higher in altitude and eliminating the habitat for those species adapted to the highest elevations. Some climates will completely disappear. The rate of warming appears to be accelerated in the arctic, which is recognized as a serious threat to polar bear populations that require sea ice to hunt seals during the winter months: seals are the only source of protein available to polar bears. A trend to decreasing sea ice coverage has occurred since observations began in the mid-twentieth century. The rate of decline observed in recent years is far greater than previously predicted by climate models (Figure). Finally, global warming will raise ocean levels due to meltwater from glaciers and the greater volume occupied by warmer water. Shorelines will be inundated, reducing island size, which will have an effect on some species, and a number of islands will disappear entirely. Additionally, the gradual melting and subsequent refreezing of the poles, glaciers, and higher elevation mountains—a cycle that has provided freshwater to environments for centuries—will be altered. This could result in an overabundance of salt water and a shortage of fresh water.

savannas

Savannas are grasslands with scattered trees, and they are found in Africa, South America, and northern Australia (Figure). Savannas are hot, tropical areas with temperatures averaging from 24oC -29oC (75oF -84oF) and an annual rainfall of 51-127 cm (20-50 in). Savannas have an extensive dry season and consequent fires. As a result, scattered in the grasses and forbs (herbaceous flowering plants) that dominate the savanna, there are relatively few trees (Figure). Since fire is an important source of disturbance in this biome, plants have evolved well-developed root systems that allow them to quickly re-sprout after a fire. Although savannas are dominated by grasses, small woodlands, such as this one in Mount Archer National Park in Queensland, Australia, may dot the landscape. (credit: "Ethel Aardvark"/Wikimedia Commons)

quagga mussel

dreissena bugensis Native to: Dneiper River drainage of Ukraine (Eastern Europe) Date of U.S introduction: 1989 means of introduction: Ballast water Impact: extreme food/water filters removing large amounts of plankton; take in lots of pollutants which harm wildlife that eat them; clogs water-intake pipes -OUTCOMPETES the zebra mussels physical characteristics: -size: 20mm -topples over, will not sit flat on ventral side -rounder in shape -usually have dark concentric rings -paler in color near the hinge invasion: -Russell Cuhel and Carmen Aguilar, Principal Instigators UWM Center for Great Lakes Studies, Great Lakes WATER Institute -Western Lake Michigan has become colonized by yet another exotic species, the Quagga Mussel (QM; Dreissena bugensis). -QM were first seen on the MidLake Reefs during fall of 2002, and in inshore waters off Milwaukee in March 2003. By 2004 QM were the numerically dominant benthic (bottom-dwelling) bivalves, through displacement of zebra mussels and colonization of new territory. -Our exploratory study occurred through student and volunteer contributions to a NOAA Ocean Exploration project and 2 NSF Education programs. -The opportunity to study the very initial stages of a competitive displacement was too good to pass up. Although the lead Scientists are both plankton people, mussels "eat our guys", and no animal ecologists stepped forward. -The Investigators' long-term monitoring program provides a great background of data for assessing effects of the new community. invasion study team: 2003 Team Marisa Pankowski LTE and MPM Mark and Tim Gu Greendale HS Adam Meaux UWM student 12 Teacher Aquanauts 2004 Team Sarah Hinkfuss Rufus King HS & NOSB Emily Freer Brookfield E HS grad U South Carolina now Kelsey Poulson UWM Biology student 11 Teacher Aquanauts Alyson Olesen REU; distribution Stephen Levas REU; physiology Rebecca Rowland REU; selective feeding invasion support: -National Oceanic and Atmospheric Administration Ocean Exploration Program: Freshwater Seamounts and Reefs: Habitat Diversity and Invasion Foci (2004) Cuhel, PI/PD; Janssen, Aguilar Co-Pis -National Science Foundation GeoED: Education Aquanauts: Exploration-Based Interdisciplinary Science Skills Enhancement (2003-04) Aguilar, PI/PD; Cuhel, Ryder Co-PIs -NSF Ocean Sciences Division: Research Experience for Undergraduates at the Center for Great Lakes Studies (1990-present) Cuhel, PI/PD; Aguilar Co-PI -UWM WATER Institute Vessel and PI salary matching THE OUTCOME IS INEVITABLE. AFTER ONLY ONE YEAR, QUAGGAS OUTNUMBER ZEBRAS IN MOST SAMPLES But we don't just count 'em! Let's make some measurements and then test some more reasonable hypotheses of our own.....

Recent and Current Extinction Rates

A sixth, or Holocene, mass extinction has mostly to do with the activities of Homo sapiens. There are numerous recent extinctions of individual species that are recorded in human writings. Most of these are coincident with the expansion of the European colonies since the 1500s. One of the earlier and popularly known examples is the dodo bird. The dodo bird lived in the forests of Mauritius, an island in the Indian Ocean. The dodo bird became extinct around 1662. It was hunted for its meat by sailors and was easy prey because the dodo, which did not evolve with humans, would approach people without fear. Introduced pigs, rats, and dogs brought to the island by European ships also killed dodo young and eggs (Figure). The dodo bird was hunted to extinction around 1662. (credit: Ed Uthman, taken in Natural History Museum, London, England) Steller's sea cow became extinct in 1768; it was related to the manatee and probably once lived along the northwest coast of North America. Steller's sea cow was discovered by Europeans in 1741, and it was hunted for meat and oil. A total of 27 years elapsed between the sea cow's first contact with Europeans and extinction of the species. The last Steller's sea cow was killed in 1768. In another example, the last living passenger pigeon died in a zoo in Cincinnati, Ohio, in 1914. This species had once migrated in the millions but declined in numbers because of overhunting and loss of habitat through the clearing of forests for farmland. These are only a few of the recorded extinctions in the past 500 years. The International Union for Conservation of Nature (IUCN) keeps a list of extinct and endangered species called the Red List. The list is not complete, but it describes 380 vertebrates that became extinct after 1500 AD, 86 of which were driven extinct by overhunting or overfishing.

unit 5 section summary

Biodiversity exists at multiple levels of organization, and is measured in different ways depending on the goals of those taking the measurements. These include numbers of species, genetic diversity, chemical diversity, and ecosystem diversity. The number of described species is estimated to be 1.5 million with about 17,000 new species being described each year. Estimates for the total number of eukaryotic species on Earth vary but are on the order of 10 million. Biodiversity is negatively correlated with latitude for most taxa, meaning that biodiversity is higher in the tropics. The mechanism for this pattern is not known with certainty, but several plausible hypotheses have been advanced. Humans use many compounds that were first discovered or derived from living organisms as medicines: secondary plant compounds, animal toxins, and antibiotics produced by bacteria and fungi. More medicines are expected to be discovered in nature. Loss of biodiversity will impact the number of pharmaceuticals available to humans. Biodiversity may provide important psychological benefits to humans. Crop diversity is a requirement for food security, and it is being lost. The loss of wild relatives to crops also threatens breeders' abilities to create new varieties. Ecosystems provide ecosystem services that support human agriculture: pollination, nutrient cycling, pest control, and soil development and maintenance. Loss of biodiversity threatens these ecosystem services and risks making food production more expensive or impossible. Wild food sources are mainly aquatic, but few are being managed for sustainability. Fisheries' ability to provide protein to human populations is threatened when extinction occurs.

Brown tree snake

Boiga irregularis native to papua new guinea, Solomon islands and northern Australia Invasive species on the island of Guam-late 1940s Military Cargo Nocturnal Poisonous and constrictor Envenomated infants 3 feet at 1 year old 10 feet fully grown live in trees feed on birds, eggs, lizards, rats, mice, and other small mammals Native forest birds-9 out of 12 species extinct from island Hawaii has similar climate and fauna as Guam U.S dept. of Ag in Guam Trapping and night searchers, snake detecting dogs Hawaii dept. of Ag DLNR- trained staff for field searchers population difficult to control power outage caused every 3 days, the islands previously thriving poultry industry has been devastated because the snake crawls into coops and eats the eggs and chicks "You can help protect Hawai`i from brown tree snakes too. No snake species are native to Hawai`i (although the small, harmless blind snake has become established here this century), and all have the potential to become problems should they establish here. So if you see a snake anywhere in Hawai`i, immediately report it to the proper authorities, such as the Department of Agriculture (586-PEST) or the police. If it is safe to do so, it is best to kill the snake (e.g., drive over it, beat it with any blunt object, cut it in half with a machete) before calling. If not, keep the snake in visual contact until authorities arrive. A prompt response is essential to ensuring that the snake does not escape and can be captured by the proper authorities."

current species diversity

Despite considerable effort, knowledge of the species that inhabit the planet is limited. A recent estimate suggests that the eukaryote species for which science has names, about 1.5 million species, account for less than 20 percent of the total number of eukaryote species present on the planet (8.7 million species, by one estimate). Estimates of numbers of prokaryotic species are largely guesses, but biologists agree that science has only just begun to catalog their diversity. Even with what is known, there is no centralized repository of names or samples of the described species; therefore, there is no way to be sure that the 1.5 million descriptions is an accurate number. It is a best guess based on the opinions of experts on different taxonomic groups. Given that Earth is losing species at an accelerating pace, science knows little about what is being lost. Table presents recent estimates of biodiversity in different groups.

zebra mussel

Dreissena Polymorpha Native to: Eurasia Date of U.S introduction: 1988 Means of introduction: Ballast water Impact: competes with native species; clogs pipes, allows for increased algal growth Only one wisconsin lake infested in 1992; toady>100 successful invaders: -various aquatic habitats -breed prolifically -female can lay > 1 million eggs per year -Planktonic larval stage -Attached adult stage Economic impact: -Colonize living and nonliving surfaces Boats, water-intake pipes, docks, piers, buoys Slow moving animals, i.e. native clams, turtles, crayfish Attach to other zebra mussels. -Densities up to 1 million per square meter -Monroe, MI lost its water supply for three days due to massive numbers of zebra mussels clogging the city's water-intake pipeline -Power Co., golf courses, Municipal water: apply chemical treatment to prevent zebra mussel related problems. -Potentially billions of dollars over next 10 years to U.S. and Canadian Great Lakes region. Ecological impacts: -zebra mussels are filter feeders -One gallon per day per mussel is filtered -Every particle in water is removed -Therefore, plankton food supply diminished -Water clarity increases -Lake Erie - clarity from 6" in 1998, today >30 feet -Lakes' euphotic zone increases causing aquatic plants to increase in number and size control: -next to impossible to eradicate -chemicals can kill but species is tolerant -to date, no biological control methodology is available Physical characteristics: -adult size: 15mm -sits flat on ventral side -triangular in shape -color patterns vary

section summary 2

Five mass extinctions with losses of more than 50 percent of extant species are observable in the fossil record. Recent extinctions are recorded in written history and are the basis for one method of estimating contemporary extinction rates. The other method uses measures of habitat loss and species-area relationships. Estimates of contemporary extinction rates vary but are as high as 500 times the background rate, as determined from the fossil record, and are predicted to rise. There is a legislative framework for biodiversity protection. International treaties such as CITES regulate the transportation of endangered species across international borders. Legislation within individual countries protecting species and agreements on global warming have had limited success; there is at present no international agreement on targets for greenhouse gas emissions. In the United States, the Endangered Species Act protects listed species but is hampered by procedural difficulties and a focus on individual species. The Migratory Bird Act is an agreement between Canada and the United States to protect migratory birds. The non-profit sector is also very active in conservation efforts in a variety of ways. Conservation preserves are a major tool in biodiversity protection. Presently, 11 percent of Earth's land surface is protected in some way. The science of island biogeography has informed the optimal design of preserves; however, preserves have limitations imposed by political and economic forces. In addition, climate change will limit the effectiveness of present preserves in the future. A downside of preserves is that they may lessen the pressure on human societies to function more sustainably outside the preserves. Habitat restoration has the potential to restore ecosystems to previous biodiversity levels before species become extinct. Examples of restoration include reintroduction of keystone species and removal of dams on rivers. Zoos have attempted to take a more active role in conservation and can have a limited role in captive breeding programs. Zoos also have a useful role in education.

genetic and chemical biodiversity

Genetic diversity is one alternate concept of biodiversity. Genetic diversity (or variation) is the raw material for adaptation in a species. A species' future potential for adaptation depends on the genetic diversity held in the genomes of the individuals in populations that make up the species. The same is true for higher taxonomic categories. A genus with very different types of species will have more genetic diversity than a genus with species that look alike and have similar ecologies. The genus with the greatest potential for subsequent evolution is the most genetically diverse one. Most genes code for proteins, which in turn carry out the metabolic processes that keep organisms alive and reproducing. Genetic diversity can also be conceived of as chemical diversity in that species with different genetic makeups produce different assortments of chemicals in their cells (proteins as well as the products and byproducts of metabolism). This chemical diversity is important for humans because of the potential uses for these chemicals, such as medications. For example, the drug eptifibatide is derived from rattlesnake venom and is used to prevent heart attacks in individuals with certain heart conditions. At present, it is far cheaper to discover compounds made by an organism than to imagine them and then synthesize them in a laboratory. Chemical diversity is one way to measure diversity that is important to human health and welfare. Through selective breeding, humans have domesticated animals, plants, and fungi, but even this diversity is suffering losses because of market forces and increasing globalism in human agriculture and migration. For example, international seed companies produce only a very few varieties of a given crop and provide incentives around the world for farmers to buy these few varieties while abandoning their traditional varieties, which are far more diverse. The human population depends on crop diversity directly as a stable food source and its decline is troubling to biologists and agricultural scientists.

Eurasian Ruffe

Gymnocephalus Cernuus Native to: Eurasia Introduced into lake superior in the mid 1980s in the ballast water of ocean-going vessel Ruffe (Gymnocephalus cernuus) are a small but aggressive exotic percid species native to Eurasia. It was introduced into Lake Superior in the mid-1980s in the ballast water of an ocean-going vessel. Explosive growth of the ruffe population means less food and space in the ecosystem for other fish with similar diets and feeding habits. Because of this, walleye, perch, and a number of small forage fish species are seriously threatened by continued expansion of the ruffe's range. Different chemicals and control methods are being looked at to control ruffe, but nothing has been successful yet. Ruffe were accidentally introduced to the Great Lakes at the St. Louis River near Duluth, Minnesota in the early to mid-1980s. Ruffe were first collected in the St. Louis River during 1986 and were identified in 1987. The Great Lakes Science Center has been studying the St. Louis River fish community since 1988 to evaluate any impacts the establishment of this exotic species may have on the native fish community. •Ruffe have steadily increased from about 10% of the catch in 1989 to nearly 90% of the catch in 1996. •Unlike ruffe, emerald shiners have declined from nearly 80% of the catch in 1989 to about 5% of the catch in 1996. •Little change has been observed for yellow perch, which have consistently made up about 10% of the catch for these three species. Bioenergetics modeling of prey consumption was used to determine the efficacy of a top-down predator control strategy implemented in 1989, and used to limit the dispersal and control the increasing abundance of ruffe in the St. Louis River, Western Lake Superior. Northern pike, walleye, smallmouth bass, bullheads, and yellow perch were modeled to determine their consumption of ruffe, along with that of four native prey fish species. Northern pike, brown bullhead, and walleye were the major predators of ruffe, with northern pike being the primary predator each year. All predators selected the native prey over ruffe. Top-down control is unlikely to occur in this system, by these specific predators, due to the many complex predator-prey interactions in the turbid St. Louis River environment, and the open nature of the system, which allows stocked predators to freely leave.

habitat restoration

Habitat restoration holds considerable promise as a mechanism for maintaining or restoring biodiversity. Of course once a species has become extinct, its restoration is impossible. However, restoration can improve the biodiversity of degraded ecosystems. Reintroducing wolves, a top predator, to Yellowstone National Park in 1995 led to dramatic changes in the ecosystem that increased biodiversity. The wolves (Figure) function to suppress elk and coyote populations and provide more abundant resources to the guild of carrion eaters. Reducing elk populations has allowed revegetation of riparian (the areas along the banks of a stream or river) areas, which has increased the diversity of species in that habitat. Suppression of coyotes has increased the species previously suppressed by this predator. The number of species of carrion eaters has increased because of the predatory activities of the wolves. In this habitat, the wolf is a keystone species, meaning a species that is instrumental in maintaining diversity within an ecosystem. Removing a keystone species from an ecological community causes a collapse in diversity. The results from the Yellowstone experiment suggest that restoring a keystone species effectively can have the effect of restoring biodiversity in the community. Ecologists have argued for the identification of keystone species where possible and for focusing protection efforts on these species. It makes sense to return the keystone species to the ecosystems where they have been removed. Other large-scale restoration experiments underway involve dam removal. In the United States, since the mid-1980s, many aging dams are being considered for removal rather than replacement because of shifting beliefs about the ecological value of free-flowing rivers. The measured benefits of dam removal include restoration of naturally fluctuating water levels (often the purpose of dams is to reduce variation in river flows), which leads to increased fish diversity and improved water quality. In the Pacific Northwest, dam removal projects are expected to increase populations of salmon, which is considered a keystone species because it transports nutrients to inland ecosystems during its annual spawning migrations. In other regions, such as the Atlantic coast, dam removal has allowed the return of other spawning anadromous fish species (species that are born in fresh water, live most of their lives in salt water, and return to fresh water to spawn). Some of the largest dam removal projects have yet to occur or have happened too recently for the consequences to be measured. The large-scale ecological experiments that these removal projects constitute will provide valuable data for other dam projects slated either for removal or construction.

Habitat Loss

Humans rely on technology to modify their environment and replace certain functions that were once performed by the natural ecosystem. Other species cannot do this. Elimination of their habitat— whether it is a forest, coral reef, grassland, or flowing river—will kill the individuals in the species. Remove the entire habitat within the range of a species and, unless they are one of the few species that do well in human-built environments, the species will become extinct. Human destruction of habitats (habitats generally refer to the part of the ecosystem required by a particular species) accelerated in the latter half of the twentieth century. Consider the exceptional biodiversity of Sumatra: it is home to one species of orangutan, a species of critically endangered elephant, and the Sumatran tiger, but half of Sumatra's forest is now gone. The neighboring island of Borneo, home to the other species of orangutan, has lost a similar area of forest. Forest loss continues in protected areas of Borneo. The orangutan in Borneo is listed as endangered by the International Union for Conservation of Nature (IUCN), but it is simply the most visible of thousands of species that will not survive the disappearance of the forests of Borneo. The forests are removed for timber and to plant palm oil plantations (Figure). Palm oil is used in many products including food products, cosmetics, and biodiesel in Europe. A 5-year estimate of global forest cover loss for the years from 2000 to 2005 was 3.1 percent. Much loss (2.4 percent) occurred in the humid tropics where forest loss is primarily from timber extraction. These losses certainly also represent the extinction of species unique to those areas. Habitat destruction can affect ecosystems other than forests. Rivers and streams are important ecosystems and are frequently the target of habitat modification through building and from damming or water removal. Damming of rivers affects flows and access to all parts of a river. Altering a flow regime can reduce or eliminate populations that are adapted to seasonal changes in flow. For example, an estimated 91 percent of river lengths in the United States have been modified with damming or bank modifications. Many fish species in the United States, especially rare species or species with restricted distributions, have seen declines caused by river damming and habitat loss. Research has confirmed that species of amphibians that must carry out parts of their life cycles in both aquatic and terrestrial habitats are at greater risk of population declines and extinction because of the increased likelihood that one of their habitats or access between them will be lost. This is of particular concern because amphibians have been declining in numbers and going extinct more rapidly than many other groups for a variety of possible reasons.

wild food sources

In addition to growing crops and raising food animals, humans obtain food resources from wild populations, primarily wild fish populations. For about one billion people, aquatic resources provide the main source of animal protein. But since 1990, production from global fisheries has declined. Despite considerable effort, few fisheries on Earth are managed sustainability. Fishery extinctions rarely lead to complete extinction of the harvested species, but rather to a radical restructuring of the marine ecosystem in which a dominant species is so over-harvested that it becomes a minor player, ecologically. In addition to humans losing the food source, these alterations affect many other species in ways that are difficult or impossible to predict. The collapse of fisheries has dramatic and long-lasting effects on local human populations that work in the fishery. In addition, the loss of an inexpensive protein source to populations that cannot afford to replace it will increase the cost of living and limit societies in other ways. In general, the fish taken from fisheries have shifted to smaller species and the larger species are overfished. The ultimate outcome could clearly be the loss of aquatic systems as food sources.

lakes and ponds

Lakes and ponds can range in area from a few square meters to thousands of square kilometers. Temperature is an important abiotic factor affecting living things found in lakes and ponds. During the summer in temperate regions, thermal stratification of deep lakes occurs when the upper layer of water is warmed by the Sun and does not mix with deeper, cooler water. The process produces a sharp transition between the warm water above and cold water beneath. The two layers do not mix until cooling temperatures and winds break down the stratification and the water in the lake mixes from top to bottom. During the period of stratification, most of the productivity occurs in the warm, well-illuminated, upper layer, while dead organisms slowly rain down into the cold, dark layer below where decomposing bacteria and cold-adapted species such as lake trout exist. Like the ocean, lakes and ponds have a photic layer in which photosynthesis can occur. Phytoplankton (algae and cyanobacteria) are found here and provide the base of the food web of lakes and ponds. Zooplankton, such as rotifers and small crustaceans, consume these phytoplankton. At the bottom of lakes and ponds, bacteria in the aphotic zone break down dead organisms that sink to the bottom. Nitrogen and particularly phosphorus are important limiting nutrients in lakes and ponds. Therefore, they are determining factors in the amount of phytoplankton growth in lakes and ponds. When there is a large input of nitrogen and phosphorus (e.g., from sewage and runoff from fertilized lawns and farms), the growth of algae skyrockets, resulting in a large accumulation of algae called an algal bloom. Algal blooms (Figure) can become so extensive that they reduce light penetration in water. As a result, the lake or pond becomes aphotic and photosynthetic plants cannot survive. When the algae die and decompose, severe oxygen depletion of the water occurs. Fishes and other organisms that require oxygen are then more likely to die The uncontrolled growth of algae in this waterway has resulted in an algal bloom.

secondary plant compound

a compound produced as a byproduct of plant metabolic processes that is typically toxic, but is sequestered by the plant to defend against herbivores

human health

Many medications are derived from natural chemicals made by a diverse group of organisms. For example, many plants produce secondary plant compounds, which are toxins used to protect the plant from insects and other animals that eat them. Some of these secondary plant compounds also work as human medicines. Contemporary societies that live close to the land often have a broad knowledge of the medicinal uses of plants growing in their area. For centuries in Europe, older knowledge about the medical uses of plants was compiled in herbals—books that identified the plants and their uses. Humans are not the only animals to use plants for medicinal reasons. The other great apes, orangutans, chimpanzees, bonobos, and gorillas have all been observed self- medicating with plants. Modern pharmaceutical science also recognizes the importance of these plant compounds. Examples of significant medicines derived from plant compounds include aspirin, codeine, digoxin, atropine, and vincristine (Figure). Many medications were once derived from plant extracts but are now synthesized. It is estimated that, at one time, 25 percent of modern drugs contained at least one plant extract. That number has probably decreased to about 10 percent as natural plant ingredients are replaced by synthetic versions of the plant compounds. Antibiotics, which are responsible for extraordinary improvements in health and lifespans in developed countries, are compounds largely derived from fungi and bacteria. In recent years, animal venoms and poisons have excited intense research for their medicinal potential. By 2007, the FDA had approved five drugs based on animal toxins to treat diseases such as hypertension, chronic pain, and diabetes. Another five drugs are undergoing clinical trials and at least six drugs are being used in other countries. Other toxins under investigation come from mammals, snakes, lizards, various amphibians, fish, snails, octopuses, and scorpions. Aside from representing billions of dollars in profits, these medications improve people's lives. Pharmaceutical companies are actively looking for new natural compounds that can function as medicines. It is estimated that one third of pharmaceutical research and development is spent on natural compounds and that about 35 percent of new drugs brought to market between 1981 and 2002 were from natural compounds. Finally, it has been argued that humans benefit psychologically from living in a biodiverse world. The chief proponent of this idea is entomologist E. O. Wilson. He argues that human evolutionary history has adapted us to living in a natural environment and that built environments generate stresses that affect human health and well-being. There is considerable research into the psychologically regenerative benefits of natural landscapes that suggest the hypothesis may hold some truth.

Preventing Habitat Destruction with Wise Wood Choices

Most consumers do not imagine that the home improvement products they buy might be contributing to habitat loss and species extinctions. Yet the market for illegally harvested tropical timber is huge, and the wood products often find themselves in building supply stores in the United States. One estimate is that 10 percent of the imported timber stream in the United States, which is the world's largest consumer of wood products, is potentially illegally logged. In 2006, this amounted to $3.6 billion in wood products. Most of the illegal products are imported from countries that act as intermediaries and are not the originators of the wood. How is it possible to determine if a wood product, such as flooring, was harvested sustainably or even legally? The Forest Stewardship Council (FSC) certifies sustainably harvested forest products; therefore, looking for their certification on flooring and other hardwood products is one way to ensure that the wood has not been taken illegally from a tropical forest. Certification applies to specific products, not to a producer; some producers' products may not have certification while other products are certified. There are certifications other than the FSC, but these are run by timber companies creating a conflict of interest. Another approach is to buy domestic wood species. While it would be great if there was a list of legal versus illegal woods, it is not that simple. Logging and forest management laws vary from country to country; what is illegal in one country may be legal in another. Where and how a product is harvested and whether the forest from which it comes is being sustainably maintained all factor into whether a wood product will be certified by the FSC. It is always a good idea to ask questions about where a wood product came from and how the supplier knows that it was harvested legally.

Burmese python

Python molurus bivittatus kohl origin: NE india and southern China introduction: imported for exotic pet trade. Releaseed into the everglades by pet owners ecology: grasslands, swamps, marshes and woodlands-require permanent waters source reproduction: clutch of 29-50 eggs size: 18-20 feet Non-venomous Description: Average size in Florida is 96 inches (8 feet, 244 cm). Males from Florida reach a maximum of 144 inches (12 feet, 365 cm), whereas the record female from Florida is 199 inches (16.6 feet, 506 cm). In its native range, females can reach more than 240 inches (20 feet, 609 cm). A stout-bodied snake with dark dorsal blotches and lateral markings, both usually edged in dark brown or black. Dorsal blotches are variable in size and shape and separated by thin light-colored bars that always extend laterally to the belly. The belly is dark spotted along the sides MIAMI --A python's eyes were apparently bigger than its stomach. Scientists in Florida are puzzling over a Burmese python that scarfed down a six-foot alligator before its stomach ruptured. They found the carcasses in an isolated part of Florida's Everglades National Park. Photos show the gator's hind legs and tail sticking out of the 13-foot snake's ruptured gut. The Miami Herald reported that scientists can't figure out how the snake got the critter down. The snake's head is also missing. Experts say the clash is interesting, but it also shows the exotic snakes are competing with gators to top the food chain in the Everglades. Park biologist Skip Snow said he's documented 156 python captures in the last two years. Range: In Florida, this snake has been introduced in numerous areas. However, it is currently known to be established in the Everglades region (Collier, Miami-Dade, and Monroe counties) and northern Key Largo (Monroe County). Outside Florida, this species occurs in northeastern India, Burma, southern China, Vietnam, and Thailand north of the Kra Isthmus. Its disjunct distribution on the Indonesian islands of Kalimantan, Java, Sumbawa, and Sulawesi may be due to human introductions like that in Florida. Habitat: In Florida, this species has been found in and around undeveloped seasonally flooded wetlands (i.e., The Everglades), hardwood hammocks, mangrove salt marshes, high density Melaleuca trees, agricultural areas, man-made canals and lakes, and housing developments. Since 1995, >1,200 Burmese Pythons have been removed from Florida. Record clutch size is 85 eggs from a single female in Florida. They are dietary generalists, eating primarily birds, mammals, and occasionally alligators. Burmese Pythons are powerful constrictors, and their bites and sharp teeth can cause severe lacerations. Comparison with other species: The Northern African Python (Python sebae) has bold dark dorsal blotches separated by thin light-colored bars that rarely extend laterally as they mostly terminate when contacting the dark lateral stripe, and a belly that is entirely speckled.

european starling

Sternus Vulgaris Native to: Europe (Rome) and Central Asia introduced: 1890, released 80-100 birds in New York City present day: East to west coast, Arctic in Alaska to tropics in Mexico totals: 1/3 of world starling population identification: -pointed wings, short, square tail -glossy black iridescence -Male/Female ID: eye and bill difference -Molt in fall -Noisy birds Mainly in cities, suburban areas and agricultural areas forage in open grasslands eat soil insects; fruit, seeds, grain use nesting cavities well adapted to human disturbance such as crop land pest; cause severe crop damage responsible for more damage costs than any other bird in US

feral pigs

Sus Scrofa Origin: Europe and Asia known as: wild pigs, wild hogs, wild boars, European wild boars, Russian wild boars. razorbacks members of swine family don't confuse with peccary or javelina (only native pig-like animal in North America) estimates of 4 million in US aggressive animals long pointed head, stocky build with moderately long tail cloven feet similar in appearance to deer four continually growing tusks can be sharp Habitat: 10 square miles live: 15-25 years can reproduce year round rooting is a common sign wallows in wet soils rub on trees, fence posts, power poles Hair and mud cling 3ft high good hearing but poor eyesight eat anything from acorns to tubers to rats to berries to snakes to eggs hunting information: "The Wisconsin Department of Natural Resources has adopted the position that feral pigs are exotic, non-native wild animals that pose significant threats to both the environment and to agricultural operations. The Department promotes aggressive removal anywhere feral pigs are reported. Feral pigs are considered unprotected wild animals with no closed season or harvest limit. Feral pigs may be removed any time throughout the year as long as those choosing to pursue them possess a valid small game license and the permission of the landowner where they intend to hunt. Also, landowners may shoot feral pigs on their own property without a hunting license, under DNR's animal nuisance control authority."

biodiversity hotspot

a concept originated by Norman Myers to describe a geographical region with a large number of endemic species and a large percentage of degraded habitat

temperate forests

Temperate forests are the most common biome in eastern North America, Western Europe, Eastern Asia, Chile, and New Zealand (Figure). This biome is found throughout mid-latitude regions. Temperatures range between -30oC and 30oC (-22oF to 86oF) and drop to below freezing on an annual basis. These temperatures mean that temperate forests have defined growing seasons during the spring, summer, and early fall. Precipitation is relatively constant throughout the year and ranges between 75 cm and 150 cm (29.5-59 in). Deciduous trees are the dominant plant in this biome with fewer evergreen conifers. Deciduous trees lose their leaves each fall and remain leafless in the winter. Thus, little photosynthesis occurs during the dormant winter period. Each spring, new leaves appear as temperature increases. Because of the dormant period, the net primary productivity of temperate forests is less than that of tropical rainforests. In addition, temperate forests show far less diversity of tree species than tropical rainforest biomes. The trees of the temperate forests leaf out and shade much of the ground; however, more sunlight reaches the ground in this biome than in tropical rainforests because trees in temperate forests do not grow as tall as the trees in tropical rainforests. The soils of the temperate forests are rich in inorganic and organic nutrients compared to tropical rainforests. This is because of the thick layer of leaf litter on forest floors and reduced leaching of nutrients by rainfall. As this leaf litter decays, nutrients are returned to the soil. The leaf litter also protects soil from erosion, insulates the ground, and provides habitats for invertebrates and their predators Deciduous trees are the dominant plant in the temperate forest.

Which of the following statements about Lake Victoria are true?

The Lake perch have reached carrying capacity and have declined in size and quantity.

Ecology part VI Summary

The core threat to biodiversity on the planet, and therefore a threat to human welfare, is the combination of human population growth and the resources used by that population. The human population requires resources to survive and grow, and those resources are being removed unsustainably from the environment. The three greatest proximate threats to biodiversity are habitat loss, overharvesting, and introduction of exotic species. The first two of these are a direct result of human population growth and resource use. The third results from increased mobility and trade. A fourth major cause of extinction, anthropogenic (human-caused) climate change, has not yet had a large impact, but it is predicted to become significant during this century. Global climate change is also a consequence of human population needs for energy and the use of fossil fuels to meet those needs (Figure). Environmental issues, such as toxic pollution, have specific targeted effects on species, but are not generally seen as threats at the magnitude of the others. Atmospheric carbon dioxide levels fluctuate in a cyclical manner. However, the burning of fossil fuels in recent history has caused a dramatic increase in the levels of carbon dioxide in the Earth's atmosphere, which have now reached levels never before seen on Earth. Scientists predict that the addition of this "greenhouse gas" to the atmosphere is resulting in climate change that will significantly impact biodiversity in the coming century.

section summary

The core threats to biodiversity are human population growth and unsustainable resource use. To date, the most significant causes of extinction are habitat loss, introduction of exotic species, and overharvesting. Climate change is predicted to be a significant cause of extinction in the coming century. Habitat loss occurs through deforestation, damming of rivers, and other activities. Overharvesting is a threat particularly to aquatic species, but the taking of bush meat in the humid tropics threatens many species in Asia, Africa, and the Americas. Exotic species have been the cause of a number of extinctions and are especially damaging to islands and lakes. Exotic species' introductions are increasing because of the increased mobility of human populations and growing global trade and transportation. Climate change is forcing range changes that may lead to extinction. It is also affecting adaptations to the timing of resource availability that negatively affects species in seasonal environments. The impacts of climate change are currently greatest in the arctic. Global warming will also raise sea levels, eliminating some islands and reducing the area of all others.

marine biomes

The ocean is a continuous body of salt water that is relatively uniform in chemical composition. It is a weak solution of mineral salts and decayed biological matter. Within the ocean, coral reefs are a second type of marine biome. Estuaries, coastal areas where salt water and fresh water mix, form a third unique marine biome. The ocean is categorized by several zones (Figure). All of the ocean's open water is referred to as the pelagic realm (or zone). The benthic realm (or zone) extends along the ocean bottom from the shoreline to the deepest parts of the ocean floor. From the surface to the bottom or the limit to which photosynthesis occurs is the photic zone (approximately 200 m or 650 ft). At depths greater than 200 m, light cannot penetrate; thus, this is referred to as the aphotic zone. The majority of the ocean is aphotic and lacks sufficient light for photosynthesis. The deepest part of the ocean, the Challenger Deep (in the Mariana Trench, located in the western Pacific Ocean), is about 11,000 m (about 6.8 mi) deep. To give some perspective on the depth of this trench, the ocean is, on average, 4267 m or 14,000 ft deep.

Chytridiomycosis

a disease of amphibians caused by the fungus Batrachochytrium dendrobatidis; thought to be a major cause of the global amphibian decline

conservation of biodiversity

The threats to biodiversity at the genetic, species, and ecosystem levels have been recognized for some time. In the United States, the first national park with land set aside to remain in a wilderness state was Yellowstone Park in 1890. However, attempts to preserve nature for various reasons have occurred for centuries. Today, the main efforts to preserve biodiversity involve legislative approaches to regulate human and corporate behavior, setting aside protected areas, and habitat restoration.

white-nose syndrome

a disease of cave-hibernating bats in the eastern United States and Canada associated with the fungus Geomyces destructans

chaparral

a biome found in temperate coastal regions characterized by low trees and dry-adapted shrubs and forbs The chaparral is also called scrub forest and is found in California, along the Mediterranean Sea, and along the southern coast of Australia (Figure). The annual rainfall in this biome ranges from 65 cm to 75 cm (25.6-29.5 in) and the majority of the rain falls in the winter. Summers are very dry and many chaparral plants are dormant during the summertime. The chaparral vegetation is dominated by shrubs and is adapted to periodic fires, with some plants producing seeds that germinate only after a hot fire. The ashes left behind after a fire are rich in nutrients like nitrogen that fertilize the soil and promote plant regrowth. Fire is a natural part of the maintenance of this biome and frequently threatens human habitation in this biome in the U.S The chaparral is dominated by shrubs.

the role of zoos and captive breeding

Zoos have sought to play a role in conservation efforts both through captive breeding programs and education (Figure). The transformation of the missions of zoos from collection and exhibition facilities to organizations that are dedicated to conservation is ongoing. In general, it has been recognized that, except in some specific targeted cases, captive breeding programs for endangered species are inefficient and often prone to failure when the species are reintroduced to the wild. Zoo facilities are far too limited to contemplate captive breeding programs for the numbers of species that are now at risk. Education, on the other hand, is a potential positive impact of zoos on conservation efforts, particularly given the global trend to urbanization and the consequent reduction in contacts between people and wildlife. A number of studies have been performed to look at the effectiveness of zoos on people's attitudes and actions regarding conservation; at present, the results tend to be mixed.

arctic tundra

a biome characterized by low average temperatures, brief growing seasons, the presence of permafrost, and limited precipitation largely in the form of snow in which the dominant vegetation are low shrubs, lichens, mosses, and small herbaceous plants The Arctic tundra lies north of the subarctic boreal forests and is located throughout the Arctic regions of the Northern Hemisphere (Figure). Tundra also exists at elevations above the tree line on mountains. The average winter temperature is -34°C (-29.2°F) and the average summer temperature is 3°C-12°C (37°F -52°F). Plants in the Arctic tundra have a short growing season of approximately 50-60 days. However, during this time, there are almost 24 hours of daylight and plant growth is rapid. The annual precipitation of the Arctic tundra is low (15-25 cm or 6-10 in) with little annual variation in precipitation. And, as in the boreal forests, there is little evaporation because of the cold temperatures. Plants in the Arctic tundra are generally low to the ground and include low shrubs, grasses, lichens, and small flowering plants (Figure). There is little species diversity, low net primary productivity, and low aboveground biomass. The soils of the Arctic tundra may remain in a perennially frozen state referred to as permafrost. The permafrost makes it impossible for roots to penetrate far into the soil and slows the decay of organic matter, which inhibits the release of nutrients from organic matter. The melting of the permafrost in the brief summer provides water for a burst of productivity while temperatures and long days permit it. During the growing season, the ground of the Arctic tundra can be completely covered with plants or lichens. Low-growing plants such as shrub willow dominate the tundra landscape during the summer, shown here in the Arctic National Wildlife Refuge

boreal forests

a biome found in temperate and subarctic regions characterized by short growing seasons and dominated structurally by coniferous trees The boreal forest, also known as taiga or coniferous forest, is found roughly between 50o and 60onorth latitude across most of Canada, Alaska, Russia, and northern Europe (Figure). Boreal forests are also found above a certain elevation (and below high elevations where trees cannot grow) in mountain ranges throughout the Northern Hemisphere. This biome has cold, dry winters and short, cool, wet summers. The annual precipitation is from 40 cm to 100 cm (15.7-39 in) and usually takes the form of snow; little evaporation occurs because of the cold temperatures. The long and cold winters in the boreal forest have led to the predominance of cold-tolerant cone- bearing plants. These are evergreen coniferous trees like pines, spruce, and fir, which retain their needle-shaped leaves year-round. Evergreen trees can photosynthesize earlier in the spring than deciduous trees because less energy from the Sun is required to warm a needle-like leaf than a broad leaf. Evergreen trees grow faster than deciduous trees in the boreal forest. In addition, soils in boreal forest regions tend to be acidic with little available nitrogen. Leaves are a nitrogen-rich structure and deciduous trees must produce a new set of these nitrogen-rich structures each year. Therefore, coniferous trees that retain nitrogen-rich needles in a nitrogen limiting environment may have had a competitive advantage over the broad-leafed deciduous trees. The net primary productivity of boreal forests is lower than that of temperate forests and tropical wet forests. The aboveground biomass of boreal forests is high because these slow-growing tree species are long-lived and accumulate standing biomass over time. Species diversity is less than that seen in temperate forests and tropical rainforests. Boreal forests lack the layered forest structure seen in tropical rainforests or, to a lesser degree, temperate forests. The structure of a boreal forest is often only a tree layer and a ground layer. When conifer needles are dropped, they decompose more slowly than broad leaves; therefore, fewer nutrients are returned to the soil to fuel plant growth The boreal forest (taiga) has low lying plants and conifer trees.

temperate forest

a biome found in temperate regions with moderate rainfall and dominated structurally by deciduous trees

subtropical desert

a biome found in the subtropics with hot daily temperatures, very low and unpredictable precipitation, and characterized by a limited dry-adapted vegetation

tropical rainforest

a biome found near the equator characterized by stable temperatures with abundant and seasonal rainfall in which trees form the structurally important vegetation

There are many ecological services provided by rivers. Which of the following is not a service?

effectively drain wetlands

wetlands

environment in which the soil is either permanently or periodically saturated with water Wetlands are environments in which the soil is either permanently or periodically saturated with water. Wetlands are different from lakes and ponds because wetlands exhibit a near continuous cover of emergent vegetation. Emergent vegetation consists of wetland plants that are rooted in the soil but have portions of leaves, stems, and flowers extending above the water's surface. There are several types of wetlands including marshes, swamps, bogs, mudflats, and salt marshes Located in southern Florida, Everglades National Park is vast array of wetland environments, including sawgrass marshes, cypress swamps, and estuarine mangrove forests. Here, a great egret walks among cypress trees. (credit: NPS) Freshwater marshes and swamps are characterized by slow and steady water flow. Bogs develop in depressions where water flow is low or nonexistent. Bogs usually occur in areas where there is a clay bottom with poor percolation. Percolation is the movement of water through the pores in the soil or rocks. The water found in a bog is stagnant and oxygen depleted because the oxygen that is used during the decomposition of organic matter is not replaced. As the oxygen in the water is depleted, decomposition slows. This leads to organic acids and other acids building up and lowering the pH of the water. At a lower pH, nitrogen becomes unavailable to plants. This creates a challenge for plants because nitrogen is an important limiting resource. Some types of bog plants (such as sundews, pitcher plants, and Venus flytraps) capture insects and extract the nitrogen from their bodies. Bogs have low net primary productivity because the water found in bogs has low levels of nitrogen and oxygen.

Quagga mussels are a

not keystone species

If the temperature remains constant but precipitation decreases, a deciduous temperate forest biome will eventually evolve to a

not tropical desert

species-area relationship

the relationship between area surveyed and number of species encountered; typically measured by incrementally increasing the area of a survey and determining the cumulative numbers of species

photic zone

the upper layer of ocean water in which photosynthesis is able to take place

biodiversity

the variety of a biological system, typically conceived as the number of species, but also applying to genes, biochemistry, and ecosystems

estuaries

where the ocean meets fresh water Estuaries are biomes that occur where a river, a source of fresh water, meets the ocean. Therefore, both fresh water and salt water are found in the same vicinity; mixing results in a diluted (brackish) salt water. Estuaries form protected areas where many of the offspring of crustaceans, mollusks, and fish begin their lives. Salinity is an important factor that influences the organisms and the adaptations of the organisms found in estuaries. The salinity of estuaries varies and is based on the rate of flow of its freshwater sources. Once or twice a day, high tides bring salt water into the estuary. Low tides occurring at the same frequency reverse the current of salt water As estuary is where fresh water and salt water meet, such as the mouth of the Klamath River in California, shown here. (credit: U.S. Army Corps of Engineers) The daily mixing of fresh water and salt water is a physiological challenge for the plants and animals that inhabit estuaries. Many estuarine plant species are halophytes, plants that can tolerate salty conditions. Halophytic plants are adapted to deal with salt water spray and salt water on their roots. In some halophytes, filters in the roots remove the salt from the water that the plant absorbs. Animals, such as mussels and clams (phylum Mollusca), have developed behavioral adaptations that expend a lot of energy to function in this rapidly changing environment. When these animals are exposed to low salinity, they stop feeding, close their shells, and switch from aerobic respiration (in which they use gills) to anaerobic respiration (a process that does not require oxygen). When high tide returns to the estuary, the salinity and oxygen content of the water increases, and these animals open their shells, begin feeding, and return to aerobic respiration.