Chapter 8
Define species, population, and community and give an example of each.
-A species is a group of organisms that have similar genetic and other characteristics that distinguish them from other groups of organisms. ex: Organisms of sexually reproducing species have the ability to mate and produce offspring that are, in turn, capable of mating and reproducing -population- a group of individuals of the same species that live in the same space. ex: People, Insects - community- two or more populations of different species living and interacting in a certain space. ex: a forest of trees and undergrowth plants, inhabited by animals and rooted in soil containing bacteria and fungi, constitutes a biological community
What are two ways in which climate change is likely to affect the rate of species extinction?
By the end of this century, climate change could cause the extinction of one-fourth to one-half of all species of land animals and plants. Scientific studies indicate that polar bears and 10 of the world's 17 penguin species are already threatened because temperatures in the polar regions where they live are rising much faster than in other parts of the world. ----------------- Projected climate change will likely cause more flooding in some areas and prolonged droughts in others. It will make some habitats unlivable for certain species faster than those species can move to other areas or adapt to the warmer, wetter, or drier conditions. It is already melting ice at the earth's poles and on many mountaintops. These changes are altering some land-based habitats and will likely raise sea levels and destroy areas of biologically diverse coral reefs and coastal wetlands during this century.
How are population growth, pollution, and climate change interrelated as contributors to the rising rate of extinction?
So far, most pollution laws have focused on trying to clean up air and water pollution instead of trying to prevent it. Most air pollution and gases such as carbon dioxide that contribute to projected climate change are caused by the burning of fossil fuels. (((( the outdoor air pollution that kills at least half a million people a year and damages forests and crops; climate change that is projected to disrupt ecosystems, food supplies, and the habitats of humans and other species; and the rapidly rising rate of extinction and loss of biodiversity discussed in this module. ))))
Distinguish among habitat destruction, degradation, and fragmentation, and give an example of each.
The biggest cause of species endangerment is habitat loss. Ex: by clear-cutting a single forest, we eliminate the habitats for hundreds to thousands of species. In this category, we also include habitat degradation- which occurs when natural habitat is damaged such that wildlife can no longer use it. Ex:, when the pollution in a stream reaches a certain level, the stream can no longer support fish populations. -------------------- This category also includes habitat fragmentation- which occurs when a large, intact area of habitat is partially destroyed and divided into smaller, isolated patches, typically by roads, crop fields, logging, and urban development. Ex: Species such as wolves, which need large areas of forest for mating, rearing young, and feeding, cannot survive in fragmented forests. --------------------- Many species, including the Indian tiger, the black rhino, and the African and Asian elephants, have been threatened by a combination of habitat loss, degradation, and fragmentation. Adding to this threat is the illegal hunting (poaching) of these species for their valuable skins and body parts.
Define extinction and describe two methods that scientists use to study historical evidence of extinction.
extinction- the process by which a species ceases to exist on the earth. ----------------------- Scientists study extinction by looking for information about early life on the planet as they analyze fossils—mineralized replicas of ancient bones, shells, leaves, and other items and the impressions of these things found in some rocks—along with the contents of ice cores drilled out of glaciers. They also study records of mammals and birds that have become extinct since humans evolved and compare this with fossil records of extinctions that happened before humans were here.
What is the precautionary principle?
precautionary principle: When evidence indicates that an activity can harm human health or the environment, we should take precautionary measures to prevent or reduce such harm even if scientific research has not established some of its cause-and-effect relationships. Applying this principle to species extinction means taking precautions to protect the habitat of any species that could likely become threatened, even if we don't have conclusive evidence that this will happen.
What are two factors that can increase a species' chances of becoming extinct? List the six major causes of the endangerment of wild species.
Some species have characteristics that raise their chances of becoming extinct. Ex: the giant panda bear eats mostly bamboo, which severely limits its habitat area. The endangered blue whale and endangered sea turtles travel the oceans within fixed corridors, or migration routes, making them vulnerable to potentially harmful human activities such as industrialized fishing. Species such as the Florida panther and the grizzly bear are vulnerable because they need large territories to find enough food. Other species, including popular ocean fish such as the orange roughy, are prone to extinction because of their low reproductive rates, which makes it difficult for the species to recover once their populations decline. The Siberian tiger, as well as other tiger species, are endangered because of shrinking habitat areas and the high market prices for their skins and bones. There are only about 3,200 tigers left in the wild, and extinction experts project that before the end of this century, they will probably be extinct. ----------------------- HIPPCO which stands for 1. Habitat destruction, degradation, and fragmentation 2. Invasive species 3. Population growth and rising rates of resource use per person 4. Pollution 5. Climate change 6. Over-exploitation
Define interspecific competition and give an example of it. What is resource partitioning?
The first of five basic types of species interactions. Interspecific competition- in which members of two or more species try to make use of the same limited resources such as food, water, light, and space. Some interspecific competition results in a species becoming more efficient in making use of a resource, which can give that species an advantage over competing species. Ex: the compass flower is a plant that has evolved to turn its leaves during the day to maximize the amount of sunlight that hits them. This helps the compass flower to keep from being shaded out by other plants.
How can invasive species threaten native species and the ecosystems in which they live?
The second biggest factor in the rising rate of species extinction is the deliberate or accidental introduction of harmful invasive species into ecosystems by humans. Many introductions of nonnative species have caused serious ecological harm. Deliberately or accidentally introduced species have taken over ecosystems where there are few or no natural predators, competitors, or parasites that can help to control their population growth. These invaders can crowd out or decrease populations of some native species and disrupt the ecosystem services they provide.
Define speciation and explain how it can occur.
a long-term process in which one species splits into two or more new species. When two or more different populations of a sexually reproducing species remain separated for a very long time and evolve independently under different environmental conditions. Eventually, the genetic makeup of individuals from the separated populations may become so different that they will not be able to produce live, fertile offspring if they happen to come into contact with one another again. In such a case, one species has become two, and speciation has occurred
Define predation and give an example. How can predation benefit a prey species?
predation, in which, a member of one species (the predator) feeds directly on all or part of a living organism of another species (the prey) an alaskan brown bear (the predator) has captured and will eat this salmon (the prey) Benefit Helps to promote evolution by natural selection. Predators tend to kill the sick, weak, and aged members of a population because they are the easiest to catch. This leaves behind more offspring with traits that might help them avoid predation. Predation also helps to control the population sizes of prey species.
How do current and projected rates of extinction compare with the background rate?
the annual rate of extinction is now about 1,000 times the background rate that existed before modern humans appeared on earth about 200,000 years ago. These scientists projected that during this century, the extinction rate is likely to rise to at least 10,000 times the background rate—largely because of the projected growth of the human population and the projected increase in rates of resource use per person during this century. This could lead to the extinction of 25-50% of all land-based species by 2100. In addition, they noted that areas that contain most of the world's biodiversity, such as tropical forests and coral reefs, are among the planet's most threatened habitats.
Why do experts think the rate of extinction has risen steadily and will rise even more sharply during this century?
the human population has grown and spread over the earth and used more and more of the planet's resources, an increasing number of species have lost their habitats and access to the resources they need. As a result, the estimated rate of extinction has risen steadily
State the scientific theory of evolution by natural selection.
A population of any species can change when some individuals in the population have traits, or characteristics, that give them a better chance of surviving and reproducing under a particular set of environmental conditions than other individuals that do not have those traits. The theory also says that the trait in question must be a genetic trait, or one that can be passed on to an organism's offspring.
Give three examples of overexploitation of plant and animal species. For each example, give a reason why it happens.
A sixth major cause for rising extinction rates is over-exploitation—the O in HIPPCO. With the rapid growth of the human population, hunters and fishers trying to help feed growing populations have depleted populations of many wild species. 1.Poaching However, some protected species are still illegally killed or captured for sale—a practice called poaching. Poachers sell the live animals and the hides, horns, and other body parts that are highly prized, to collectors in the largely illegal wildlife trade. Few of the poachers are caught or punished, and many of the live wild animals transported between countries die in transit. This threatened white rhinoceros in South Africa was killed by a poacher for its horn. The horn can be worth many thousands of dollars because it is used to make dagger handles and is ground into powders that are used to make medicines. Tigers, for example, are highly valued for their furs, and for body parts that are used for medicinal purposes in China and other parts of Asia. A coat made from the fur of the highly endangered Bengal or Indian tiger can sell for $100,000. 2. Wildlife biologists estimate that for every wild animal captured and sold in the pet trade, an estimated 50 others are killed or die in transit. Tropical birds are popular in this market, and at least 80% of these birds are imported legally or illegally from tropical forests, according to the IUCN. As a result of the pet trade, more than 60 bird species—most of them parrots—are classified as endangered or threatened The pet trade also affects coral reef ecosystems, especially in Indonesia and the Philippines. Divers go to the reefs and catch tropical fish by squirting poisonous cyanide into the water to stun the fish. This means that many fish die for each fish that is caught and sold. The cyanide solution also kills the coral animals that build and maintain the reefs. Other wild species that are being exploited and depleted because of the pet trade include amphibians and reptiles. 3. Several plant species, too, are in danger of being depleted, largely because of the buying and selling of these plants for use in decorating houses, offices, and lawns. Several species of orchids and cacti are endangered for this reason.
Define parasitism and give an example. Define and give examples of mutualism and commensalism.
A third type of species interaction is parasitism, which occurs when one organism (the parasite) feeds on the body of, or otherwise makes use of the energy of, another organism (the host). The parasite is typically much smaller than its host and rarely kills its host. Ex: Tapeworms- live inside their hosts. Blood-sucking sea lampreys- attach themselves to the outsides of their hosts. Some parasites move from one host to another, as fleas and ticks do. Parasitism can benefit ecosystems by helping to control the populations of host species. Mutualism In a fourth type of species interaction, called mutualism, both species benefit by providing one another with food, shelter, or some other resource. Ex: Clownfish- usually live with sea anemones, whose tentacles sting and paralyze most fish that touch them except for the clownfish. The clownfish also feed on the leftovers of the anemones' meals. In turn, the clownfish fight off or eat some of the predators and parasites that threaten the anemones. armies of bacteria that live in our digestive tracts and help us digest our food. They in turn get a safe habitat and a food supply from us, their hosts. Commensalism A fifth type of species interaction, called commensalism, benefits one species but has little or no effect on the other. Ex: Plants called epiphytes attach themselves to the trunks or branches of large trees in tropical and subtropical forests. They benefit by having a solid base from which to receive sunlight, rainwater, moisture from the humid air, and nutrients falling from the tree's upper leaves and limbs. Their growth apparently does not harm the tree.
Describe the decline of many bird species and explain how the extinction of bird species can affect ecosystems.
About 70% of the earth's known bird species are declining in numbers, and roughly 12% are threatened with extinction, mostly because of the loss, degradation, and fragmentation of their habitats. About 75% of the word's threatened bird species live in forests. Many of these forests, especially in the tropical areas in Asia and Latin America, are rapidly being cleared or fragmented by roads and development. In North America, populations of many forest songbirds, including tanagers, orioles, and thrushes, which spend their winters in these tropical areas, have also declined sharply. Among the world's aquatic, or water-based bird species, about 40% are in danger, many because of the draining and degradation of their wetland habitats. Other threats to these birds' habitats are oil spills, runoff of pesticides and fertilizers from farm fields, and other pollutants such as sediments and factory emissions. Another threat to a number of migrating bird species are electrical power lines, cell phone and radio towers, wind turbines, and tall buildings. Every year, hundreds of millions of migrating birds are killed when they collide with such structures wherever they have been erected within bird migration routes. -------------------- The extinction of bird species can have a devastating ripple effect on the ecosystems of which they are a part. Birds help to control populations of rodents and insects that would otherwise devour many plants. They also help to sustain plant populations through pollination and dispersal of seeds. Without these free ecosystem services, many plants would become extinct, especially in tropical areas, and this would be followed by the loss of the specialized animal species that feed on those plants.
Give two examples of how pollution can threaten wild species.
Affects aquatic species living in lakes, rivers, and oceans. About 45% of the world's people live on or close to the oceans' coasts, and this percentage is increasing. With this growing coastal population come more boats, road and housing construction, oil leaks and spills, garbage dumping, and other activities that add wastes and harmful chemicals to coastal waters. These activities threaten populations of some fish and other aquatic species, and can upset aquatic food webs. Every year, pesticides kill more than 67 million birds and millions of fish. The U.S. Fish and Wildlife Service estimates that about one-fifth of the endangered and threatened species in the United States are at risk from pesticide poisoning. Also, oil pollution in the Gulf of Mexico adds to the threats that have endangered all species of sea turtles living in the gulf. Since 2006, certain pesticides have been shown to play a role in the widespread loss of many honeybee colonies in the United States and in parts of Europe because of a mysterious problem called colony collapse disorder. Other factors, such as an invasive parasitic mite from Asia, are possibly involved in this disorder. Researchers are trying to learn why this is happening and what can be done to reduce this loss of honeybees, which pollinate almost a third of all U.S. food crops.
Define and distinguish between endangered and threatened species and give two examples of each.
An endangered species is a species whose total population is so small that it could soon become extinct. Ex: Siberian Tiger, a florida panther, a Venus flytrap, a hawksbill sea turtle, and a whooping crane. Threatened Species still exists in numbers high enough to survive in the short term, but because its populations are declining, it is likely to become endangered in the near future Ex: the polar bear,
State the purpose of the U.S. Endangered Species Act and summarize its pros and cons.
Another related approach to protecting habitat is to find out where endangered and threatened species live, and to pass laws designed to protect such areas from certain human activities. This is an important part of the U.S. Endangered Species Act (ESA). Other countries, including Canada, have passed similar laws. Pros identify and list endangered and threatened species and to designate and protect habitat to help those species in recovering their population numbers. The ESA also makes it illegal for Americans to sell or buy any product made from an endangered or threatened species or to hunt, kill, collect, or injure such species in the United States. Cons it protects land that some people would like to use for various purposes that could harm protected species. They argue that the law puts the rights and welfare of endangered plants and animals above those of people. Some resent the fact that the law applies to private as well as public lands.
Why is human population growth a factor in the rising rate of extinction?
Because humans use a large and growing portion of the earth's land and other resources to meet their needs and wants. This leaves other species with fewer resources—especially food, water, and space for habitat.
Summarize the story of how polar bears survive and how they are threatened by climate change.
During winter, when floating sea ice in the Arctic expands, polar bears swim from one ice patch to another, hunting for seals (Figure 8.20). As the temperature rises during the brief summer, this ice melts at the outer edges and the whole mass of ice shrinks. In these warmer months, the bears fast and live off the body fat that they have accumulated during winter. Now, atmospheric warming is causing the floating sea ice on which the bears hunt to melt at increasing rates, which gives them less time for hunting. As a result, polar bears in the Arctic could suffer a sharp drop in their populations.
Explain how reducing our energy waste and use of fossil fuels, can help to slow the rate of biodiversity loss.
Equally important are efforts to cut energy waste, which contributes to pollution and projected climate change. However, a growing number of citizens and business leaders are calling for moving from dependence on nonrenewable fossil fuels to using a mixture of renewable energy sources such as the sun, wind, flowing water, and the geothermal heat stored naturally in the earth's crust.
Why should we care about species extinction hastened by human activities?
First, the earth's biodiversity provides us with essential resources, including food and oxygen, ecological services such as natural pest control, and pleasure, because nature is beautiful and interesting. Second, through various activities, we are eliminating and degrading many biologically diverse ecosystems, such as tropical forests, that are potential sites for the emergence of new species. These new species will be needed to replace species that will be going extinct and to maintain the planet's vital biodiversity. Third, many people share the ethical view that wild species have a right to exist as long as they can, regardless of their usefulness to us. ---------------- The current rapid loss of the species and ecosystems that make up the earth's biodiversity, hastened by human activities, as the most serious and long-lasting environmental and ethical issue that humanity faces.
Describe the harmful impacts of one deliberately introduced nonnative species and the impacts of one accidentally introduced nonnative species.
In the 1930s, the kudzu ("CUD-zoo") vine was imported from Japan and planted in the southeastern United States to help control soil erosion. That goal was achieved, but the vine grew so rapidly and was so hard to kill that it took over almost everything in its path, including gardens, trees, and abandoned cars and houses. It has overwhelmed many areas of the southeastern United States and is expected to spread northward as the climate gets warmer. So far, no one has found a good way to control the spread of kudzu. --------------- In recent years African and Burmese pythons and several boa constrictor species, acquired by people as pets, have ended up in Everglades National Park in Florida. Some of these snakes' owners found it hard to feed and manage them, and dumped them into the park's wetlands where the snakes have reproduced rapidly. These snakes can be as big around as a telephone pole, grow to 20 feet in length, and weigh more than 200 pounds. Because of their huge appetites, they eat whatever they can catch, including raccoons, birds, pet dogs and cats, full-grown deer, and occasionally an American alligator—the only species besides humans that are capable of killing these predators. These snake populations are slowly spreading to other areas and, by 2100, could be found in many wetlands in the southern half of the United States.
Distinguish between native and nonnative species, and give an example of each.
Native species- those that have evolved to live within a particular ecosystem and often to be an important part of that ecosystem. For example, certain fishes such as lake trout have lived in the Great Lakes of North America since the 1800s. They eat certain other species, helping to control those species' populations, and perform other functions that help to keep the lake ecosystem functioning. Nonnative Species (invasive species) Species that migrate into an ecosystem or are deliberately or accidentally introduced into an ecosystem by humans. They can upset an ecosystem by interfering with, harming, or crowding out native species that help to keep the ecosystem functioning. Ex: The sea lamprey is a parasitic species that preys on a variety of fish species. Since it invaded the Great Lakes in the early 1800s, it has multiplied and sharply reduced the numbers of lake trout and other native species of the Great Lakes.
What percentage of the earth's land should be strictly protected, according to conservation biologists? What percentage is strictly protected?
Only 13% of the earth's land area (not including the polar areas) has been set aside as protected, and just 5% is strictly protected from human activities, even though (((((((((((((((( conservation biologists call for strictly protecting at least 20% of the land. )))))))))))))))))))) ---------------------- In other words, 95% of the earth's land is set aside for human use, which explains why so many of the planet's land species are increasingly threatened with extinction. Most politically and economically powerful mining and timber companies and land developers oppose even partially protecting 13% of the earth's land because of the valuable resources that might be on or under that land.
Define rate of extinction and background extinction rate, and give the best scientific estimate for the latter. What is a mass extinction?
Rate of extinction: the estimated number of species, or the percentage of known species, that go extinct during a certain time period, typically a year. Background Extinction Rate- Historic extinction rate that existed before humans dominated the planet Throughout most years before humans evolved, species disappeared at a very low background extinction rate, which biologists estimate was about 0.0001% a year, or 1 species for every 1 million species on the planet, on average. mass extinction Catastrophic, widespread, often global event in which major groups of species go extinct over a short period of time. There is growing evidence and concern that we might be entering into a new mass extinction caused by human activities—a threat that we will now explore in greater detail.
What are the limitations of seed banks, botanical gardens, zoos, and aquariums as places to preserve species? What roles can they play in preventing species extinction?
Scientists are using about 100 seed banks (one underground in the frozen Arctic) to preserve genetic information from endangered plant species by storing their seeds in refrigerated, low-humidity environments. About one-third of the world's known plant species are being preserved in 1,600 botanical gardens and arboreta throughout the world. However, these seed banks contain only about 3% of the world's rare and threatened plant species. -------------- We can use zoos, aquariums, game parks, and animal research centers as shelters to help build up populations of endangered species for possibly returning them to their natural habitats in the future. While these facilities can help to educate the public about the importance of preventing human activities that hasten species extinctions, we cannot rely on them to preserve species from extinction, mostly because of *************limited funds and space.
How does the U.S. government protect habitat? Define biodiversity hotspot and explain the hotspots approach to protecting biodiversity.
The U.S. government has established 548 partially protected National Wildlife Refuges. People can use these areas for limited purposes such as hiking and camping, and in some cases, hunting and fishing. Some of these refuges have been set aside specifically to protect certain endangered species. The trumpeter swan, Florida's key deer, and the brown pelican have been protected in this way, and it has helped their populations to recover from near extinction. ----- Biodiversity hotspot areas of land that are especially rich in highly endangered plant and animal species found nowhere else on the earth. An area especially rich in plant species that are found nowhere else and that are in great danger of extinction. All such areas have seen serious ecological disruption, primarily because of rapid human population growth and the resulting pressure on natural resources. they are home to most of the world's endangered or critically endangered species.
Why is prevention the best approach to dealing with invasive species? What are three ways to help prevent the spread of potentially harmful invasive species?
When a nonnative species is released into an ecosystem where conditions are favorable for its survival, it becomes next to impossible to reverse the impacts. So the best way to reduce this second-biggest cause of the rising rate of species extinction is to prevent the introduction of potentially harmful nonnative species into ecosystems in the first place. 1. step up research efforts to learn more about how certain species become successful invaders and about what makes an ecosystem vulnerable to invaders. 2. conduct new and regular ground surveys and satellite observations to detect and monitor species invasions while using computer modeling to predict how invasive species are likely to spread and what harmful effects they might have. 3. strengthen legal strategies for dealing with this problem by increasing the frequency of inspections of imported goods that might contain invasive species.
Summarize the story of the American alligator, explaining its importance to its ecosystem.
When the American alligator nearly disappeared from its natural habitat in the southeastern United States, the ecosystem it had occupied for thousands of years began to unravel Most of the people killing these alligators probably did not know about the important ecological roles that this keystone species plays in its wetland habitat. Alligators literally help to create their ecosystems by digging deep pits in the swamps, called "gator holes," which store freshwater during dry spells and serve as habitat for some species of fish, insects, snakes, and birds. They build large nesting mounds for themselves, but these mounds also become nesting and feeding sites for herons and egrets. Alligators also eat a lot of gar, a predatory fish that feeds on game fish such as bass and bream. In this way, they help maintain populations of these game fish. As alligators move from their gator holes to nesting mounds, they help to keep freshwater ponds and coastal wetlands free of invasive shrubs and trees that would otherwise crowd out native species of plants and animals.
Give an example of how we can use education to help reduce the overexploitation of species. Give an example of how technology can help in this regard.
With the growth of ecotourism, people living near the habitats of endangered species such as sea turtles, tigers, and tropical birds are learning that these animals are worth more alive than dead For example, conservation biologist Michael Soulé estimated that one male lion living to age 7 can bring in about $515,000 in tourist dollars to Kenya, while the money that a hunter can get for a lion's hide is about $1,000. ------------------ Technology can provide solutions to some overexploitation problems. For example, one type of overexploitation is the overfishing of the oceans by industrialized fishing fleets. It not only threatens many fish species, but also results in the accidental capture of endangered sea turtles. Some turtles get trapped in the large nets towed by fishing boats or caught on one of the thousands of hooks that are dragged along behind some boats. However, several countries now require fishers to use turtle excluder devices, which allow turtles caught by the nets to escape before they drown. There are also special hooks that can catch fish, but are less likely to hook turtles. Use of these devices has reduced the number of sea turtle drownings.
What is biodiversity and why is it important to life on the earth?
biodiversity—the earth's great variety of species and ecosystems The variety of different species, the genetic variability among individuals within each species, and the variety of ecosystems, as well as the functions such as energy flow and matter cycling needed for the survival of species and biological communities.
Define and distinguish between ecological niche and habitat. Distinguish between generalist and specialist species, and give an example of each.
ecological niche A species' role, or total way of life, in an ecosystem. It includes all physical, chemical, and biological conditions that a species needs in order to live and reproduce in an ecosystem. A species' niche includes its habitat, which is the physical place where a species lives. ---------------- Generalist species Species with a broad ecological niche. They can live in many different places, eat a variety of foods, and tolerate a wide range of environmental conditions. Examples: flies, cockroaches, mice, rats, and humans, raccoon specialist species Species with a narrow ecological niche. They may be able to live in only one type of habitat, tolerate only a narrow range of climatic and other environmental conditions, or use only one type or a few types of food. Examples: the giant panda feeds almost exclusively on bamboo, which limits the areas where it can live. The corals that create spectacular coral reefs in tropical waters can thrive only within a narrow range of water temperatures.
What are indicator species and why are they important? Define and give an example of a keystone species, and explain why these species are important to their ecosystems.
indicator species—a species that is especially sensitive to, and very responsive to, changes in long-term environmental conditions. Such a species can provide early warnings of damage to an ecosystem. Ex: Most trout species found in lakes and streams cannot survive if the water they live in falls above or below a certain temperature range. They also need clear, clean water with high levels of dissolved oxygen. When their populations decline, it is a strong sign of changes in temperatures, clarity, or pollution levels in their waters. ------------------- Keystone Species any species that, by filling its niche, has a large effect on the types and abundances of other species found in its ecosystem. In short, it plays a key role in the functioning of its ecosystem. The loss of a keystone species can lead to population crashes and extinctions of other species that have evolved to depend on it for food or shelter or other benefits. For example, when the American alligator nearly disappeared from its natural habitat in the southeastern United States, the ecosystem it had occupied for thousands of years began to unravel certain species of bees, butterflies, hummingbirds and bats that play a critical role in pollinating flowering plant species.
What is integrated pest management, and how does using it reduce threats to biodiversity?
integrated pest management (IPM) in which each food crop and its pests are viewed as parts of an ecological system. With IPM, when pest populations reach an economically harmful level, farmers use various methods to control the pests. One is cultivation controls, such as altering planting times and changing the crops planted in a particular area in order to avoid the pests. Another is biological controls, including the use of natural predator insects, parasites, and disease organisms to kill the pests. Beyond those measures, farmers use conventional pesticides only as a last resort, and then very carefully and in small amounts. ***** These and other programs show that by using IPM, farmers can cut pesticide use dramatically, without reducing crop yields. Thus, IPM is an important pollution prevention approach that helps farmers to keep producing while reducing their harmful effects on biodiversity. Scientists call for using it more widely, especially in areas where the habitats of threatened and endangered species can be degraded by the use of pesticides on nearby farms.