Zoology 651 Exam 2

Threats to Biodiversity Climate Change

Extremely Tight correlation of emissions with human population growth -As population grows, CO2 emissions grow Current Climate Change -Emissions decline during Covid 19 pandemic -CO2 concentrations Hit Highest levels in 3 million years (415.39ppm) -Annual atmospheric CO2 and global average temperature compared to the average over the same period -Human activity has already warmed the planet 1 degree C pre-industrial levels. -Global temperatures increase as CO2 increases -Observed US precipitation change (it has increased about 10%) -Greater overall precipitation will occur globally due to solid--> liquid phase change of water Projected Emissions and Temperatures - Average global temperature increase will depend on policy pathways to reduce GHG emissions --Highest emissiond 8.5 (4 degree increase in temp) ---Higher 6 (2 degree increase) ---lower 4.5 ( Lower the 2 degree increase) ---Lowest 2.6 ( 1 degree increase) Projected temperature change - -180 years temp could rise 11 degrees - not all places are equally affected -Polar and high latitudes will experience the greatest warming and increase precipitation - Mid latitude regions and parts of the tropics will experience the increased drought What does History tell us? -HTM= Holocene Thermal Maximum (9000-5000 years ago) -LIG= Last Interglacial (130,000-116,000 Years ago) -MPWP= Mid pliocene Warm Period (5.3 to 2.6 million years ago) - Similar changes occurred during past warming events --Reduction in ice cover --Poleward shifts of biomes --Species range shift -Species have shift ranges in the past ---Historical range shifts between glacial and interglacial periods -Rainforest tree diversity increased during historical warming event (Wisconsin jack pine and red pine) Is Current climate change Different from past? -Compared to historical periods og elevation CO2, todays climate change is.. --MUCH faster: on the order of 100's rather than 10,000 of years --occuring in a world already dramatically altered by humans --Higher CO2 than perious 3 million years (peaks are interglacial warming periods, Valleys are glacial cold periods) Human induced climate change -over the past decade 90% of CO2 emissions come from burning fossil fuels - CO2 Sink: Ocean 25%, Atmosphere 44%, Land Sink 31% -CO2 Sources: Land use change 9%, Fossil fuels and industry 91% Human induced climate change -Emissions from fossil fuels and industry: Gas, renewable, oil, coal, nuclear -China largest contributor -USA (largest per capita emissions) -EU -India -Coal has the least used but greatest CO2 emissions Emissions by activities Where do greenhouse gas emissions come from? -25% electric and heat -20.4% agriculture and land -17.9% Industry Understanding land use and Climate -Forest are the largest storehouse of terrestrial carbon -boreal forests have lower NPP but a larger area than temprate or tropical forest so it stores more carbon Understanding land use and climate -Forest hold a carbon stock because they sequester carbon -cellular respiration is the opposite process -Photosythesis CO2-->O2 Glucose + O2 - Decomposition and burning = rapid release of CO2 -Photosynthetic sequestration of CO2 can help offset climate change - Human-induced climate change -Deforestation and Land use change release CO2 -Converting forest to non forest releases the balence of the carbon stock in the system to the atmosphere and reduces the lands ability to sequester C -Primary forest -managed forest/ logged -Shifting cultivatior -Extensive agroforest -Intesnsive tree crop system -Crop,pasture, grassland How can species respond to shift in climate? -Toleration -Habitat shift -Range shift -Migration -Extinction Tolerance of climate change -Phenological change --earlier onset of spring events (flowering) --Longer growing season (Length of green cover period days: north America with 1-2 days earlier every decade) Toleration and Biotic interaction mismatch -Baby great tits starve because their caterpillar pray have already peaked in abundance Ecological Impact of Climate Change -Range shift: --6-16km per decade poleward --1km up in elevation on average for species studies --winners: expansion>loss (incressed range) --losers: Expansion< loss (decreased range) --Whales could expand their range with ice melting -- Adelir panguins rely on sea ice to reach krill and could lose range Ecological impacts of climate change -Range shift: of arctic species --Declining sea ice extent -Range shifts: on mountain --Climate change causes upslope shifts and mountaintop extirpations in a tropical bird community --106 bird species on peruvian mountain --high elevation species have shrunk in range size and declined in abundance --Climate change on mountains as "escalator to extinction" -Range shift: the ocean --Sea surface temperatures has risen at 0.13 degrees per decade since 1950 -ocean warming -Possible scenarios for range shifts --Climate envelope= minimum and maximum value of climate conditions within a species occurs --Ecological interactions with other species make responses complex -Climatically sutiable -Shift to newly sutiable - Declining habitat size -Migration barrier (mountain or unsuitable habitat) -Limited dispersal ability -Critical unknowns -Altered disturbance regimes-FIRE --Western wildfires and climate change - -Altered disturbance regimes and degradation of amazon forest -positive feedback loop -Forest degradation can convert tropical forests from a net sink to a net source CO2 -Human degradation of forest causes climate change which causes further degradation of forest---> Positive feedback loop -861.7 tg/y total loss - 539.7 tg/y loss due to degradation (burning, selective logging, edge effects)= 268 tg/y natually respired If we could stop degradation, forest could absorb 168.5 tg/ y! -68.9% of losses are from degradation/ disturbance Where are emissions coming from -76.4% from Americas 17% africa 6.6% Asia Pest outbreak- Synergism with disturbance -Example: Pests of conifers --tree already weakened by drought, fire, damage --warmer temps favor survival and spread of pest species --tree killed by pest= increased fire risk --conifers globally are suffering unprecedented mortality (spruce beetle, spruce budworm, pountain pine beetle) Positive feedback loop Biological impacts of climate change - Boreal forest (norther hemisphere) vs. tundra --As artic region warms, boreal forest replace tundra northward... --and is being replaced by broadleaf forest at its southern limit -Risks and or impact for specific natural, managed and human systems --Coral reefs are already at very high risk of sever impact --Can't shift range very fast, sensitive to disturbance, narrow climate envelope (Warm-water coarl reefs) Then artic and coastal region Ocean Carbon Cycle -Ocean are CO2 sink --absorb 1/3 of CO2 emissions --CO2 readily dissolves in water Where does the CO2 go? -Photosythesis foxes CO2 -Calcification by chelled organisms fixed HCO3- to make calcium carbonate -Long term storage in bottom sediments (deep ocean C storage) Can oceans buffer against climate change? Ocean Acidification - Adding CO2 increases H+ ion concentration in seawater Low pH: reduces the availability of carbonate for calcifying organisms like corals. molluscs. crustataceans, and plancton May not be able to build shells or shells may even dissolve THe shells of wild sea butterflies are already dissolving -16-45% decrease calcification rate in pteopods, an important plankton food source 70% have corroded shells Ocean Acidification -Flordia coral reef is disintegrating The risk of positive feed back -Inceased temp = reduced CO2 fixation through photosythesis -Decreased pH= reduced CO2 fixation through calcification Further reduces ability of oceans to absorb CO2 = increased warming Deoxygenation -Higher temps= decreased dissolved O2 -Less mixing due to 'lid' of less dense warm and fresh water -Nutrient pollution= bacterial bloom die-offs use up available O2 Current coastal dead zones and open ocean anoxic zones Oxygen concentrations in oceans has already declines 2 % globally THe Ocean is running out od breath - predicted future deoxygenation --Even small declines in O2 (1%) have impacts on zooplanktion behavior and survival Bottom up trophic cascades -higher sea surface temperatures -acidification -deoxygenation -over fishing Summary: 1. Altered Phenology -Earlier onset of spring events -Longer growing Seasons 2. Range shifts of species -poleward and upward 3. Altered disturbance regimes -increased frequency and intensive (fire, drought, flood) -pest outbreaks, spread of invasive, biological homogenization 4. Ocean Acidification -loss of calcifying organisms, including reef corals and pteropods -pH dependent physiological and behavioral change in fish 5. Deoxygenation of aquatic systems 6. Biome Shift (expansion and contraction) -tundra -coastal ecosystems -rainforests -mountain ecosystems -coral reefs

Module 2: Threats to Biodiversity Part 1: Habitat Loss & Fragmentation #1 cause of biodiversity crisis

Interaction between threats create a complex problem Cause: Increasing human population and consumption 1.Agriculture 2. Logging 3. Fisheries 4. Industry and fossil fuel use 5. International trade Problem: -Habitat loss -Habitat fragmentation -Habitat degradation (and pollution) -Climate change -Overexploitation -Invasive species -Disease Effect: -Extinction of species and populations -Degradation of ecosystems -Erosion of genetic diversity and evolutionary potential - Loss of ecosystem services -Erosion of support systems for human societies -------------- -compare the magnitude of human‐induced habitat disturbance compared to natural disturbance • identify biomes and regions that have suffered the greatest loss of habitat • explain the principal drivers of habitat loss • define and describe physical and biological edge effects • predict which species are at greatest risk of extinction due to habitat loss • define and give examples of trophic cascades ------------------- Disturbance in Natural -Fire -Windthrow -Landslide -Hurricane Intermediate Disturbance Hypothesis - Disturbances varies in intensity -Pioneers, weedy species (lots of disturbance) vs late successional species (little disturbance) -Diversity is maximized at intermediate levels of disturbance Natural Landscapes are Shifting Mosaics Shifting mosaic: patches of habitat in different successional stages shift through time and space Communities are in "Dynamic equilibrium" (Gap, Building, Mature) The Scale of Human Disturbance -Humans have altered natural ecosystems at a scale and intensity never before seen -Suburbs and city The Principal Cause of the Biodiversity Crisis -Habitat loss and degradation explains ~45% of species identified as threatened --Habitat degrigation/change 31.4% --Exploration 37% --Habitat loss 13.4% --Climate Change 7.1% --Invasive species 5.1% --Pollution 4% --Disease 2% ...except in marine ecosystems -Habitat loss and degradation (habitat modification) is especially serious in terrestrial ecosystems -In freshwater it is habitat modification -In marine realms, overexploitation is a bigger threat Loss of Terrestrial Habitats -~70% of temperate forest cleared by 1950 ---98% of arable land is already in production Tropical forests are suffering rapid loss • tropical dry forest more threatened than rainforest Temperate forest projected to increase slightly by 2050 Tropical Forest Loss -Annual net change was stable/ positive in each climatic zone except the tropics ( Net change was a loss) -Tropical forests have not lost the greatest %, but have lost the greatest total extent. >70% of Amazon deforestation has happened in Brazil Amazon deforestation has accelerated in the past 5 years Drivers of Deforestation -Agricultural commodities drive tropical deforestation especially in Latin America (beef, soybeans, palm oil, sugar cane) Destiny of Deforested Land in the Amazon -Pastures 63% -Small-scale 12% -Selective logging 6% -Fire 9% -Crops 7% Drivers of Deforestation -Forest degradation often precedes deforestation in a predictable sequence: 1. ROADS 2. LOGGING 3. CROPLAND 4. PASTURE Why pasture? -Many tropical soils cannot support crops without major agrochemical inputs ...and beef demand continues to rise The Role of Roads -#1 Predictor of Habitat Loss! Drivers of Deforestation -Fuelwood collection: A major source of forest & scrub habitats degradation in Africa and the Middle East Drivers of Non-Forest Habitat Loss: -Overgrazing is major driver of grassland/steppe habitat loss -Wetlands --drainage for agriculture coastal development dumping diversion and damming • 87% loss globally • 42% loss in U.S. -Loss in fresh water species, living planet index, marine species, terrestrial Habitat loss is almost always accompanied by fragmentation -Island Biogeography Theory and Habitat Loss -Habitat loss--> Fragmentation--> Habitat size and isolation, altered extinction and immigration Fragmentation and edge effects -Edge effects = Changes in abiotic & biotic conditions of the habitat near boundary with non-habitat area (Core vs. Edge) -Edge effects reduce core habitat for sensitive species edge effect vs. edge penetration graph -INcreased wind (largest penitration) -elevated tree mortality -altered species composition - altered abundance -reduced canopy -reduced soil moisture -increased air temprature - Fragmentation and edge effects -Fragment Area ≠ Habitat Area - Smaller and more linear fragments have higher edge:area ratio Habitat loss statistics don't usually account for edge effects! Most habitat is small and close to an edge -There are few large wilderness areas -Most forest is <1 km from an edge (large wilderness is rare!) Effect of Fragment Size -As habitat size decreases, abundance and diversity decrease -Recall Island Biogeography Theory! -(Time to loss of 50% of bird species in Amazon forest fragments) -Most habitat fragments are small Fragmentation harms forest interior birds (WI) Fragment Isolation -Impacts on species that need to move depends on: 1• Distance between habitat patches 2• Risk of crossing 3• Matrix permeability or suitability (Are paths connected/ safe/ changes to route animal usually takes) (Tens of millions of animals die on roads annually) -Direct mortality on road claims hundreds of millions of animals' lives worldwide each year Distance between Habitat Patches -Percolation theory: As habitat cover declines, there is a threshold where no continuous path of habitat exists between opposite sides -(percolation threshold) -60% forest left usually only has one continuous path between habitats • As forest cover declines, connectivity of habitat is lost • Impact depends distance between patches & species' mobility Matrix Permeability -Cacao plantations were a better matrix environment than pastures for two‐toed sloths -...but not for three‐toed sloths -Human settlements are a death‐trap for birds (windows, domestic cats) Winners and Losers -Diet and territory requirements Spider Monkey (frugivore) -loser Capuchin Monkey (omnivore ) Howler Monkey (folivore) -winner Losers most often -LOSER: Predators 1 jaguar requires 10,000 ha to find sufficient prey -LOSERS: Large animals (both carnivores and herbivores) that require large ranges (--African Elephants --Hippopotamus --Black rhihno huge habitat loss in africa) Cascading Trophic Effects -Loss of predators has cascading effects Removal of "top down" control (Predictors down--> Small omnivore increase--> Frogs and tree seeds decrease) -Impacts on community are complex and unpredictable if ecology is unknown. -"Trophic downgrading" = the effects of removing predators from an ecosystem Cascading Trophic Effects -Reduced herbivory after wolf reintroduction in Yellowstone --No wolves: No seedlings survive (left) ---Wolves: seedlings survive (right) -Collapse of sea otters resulted in transition of kelp forests to "urchin barrens" (Aleutian islands) -Removal of bass results algae blooms due to increase in zooplanktivorous fishes, decrease in zooplankton, increase in phytoplankton Winners and Losers -LOSER: Mutualists and dependent species --Loss of pollinator -->Loss of seed disperser -->Recruitment failure -Loss of key interactions: Reproductive failure & "the living dead" Winners and Losers -LOSER: Habitat interior specialists -- Black-throated Huet-huet (Pteroptochos tarnii) or "Huet-huet" --Cavity nester (old hollow trees) Low nest site density < 1/ha Requires min. 10 ha patch Numerous traits make it vulnerable: - habitat specialist, prefers forest interior, rare, poor flyer Winners and Losers -LOSERS: Migratory species --Migration: Annual movement of species/populations from one habitat to another in response to resource availability or climate tolerance. LOSERS: Migratory species • ~ 100 miles a day, up to 3,000 miles • Multi generation migration from south to north • Last generation in summer migrates south to dwindling forest habitats in Mexico Winners and Losers -LOSERS: Species requiring dispersal ---Dispersal: The movement of young or propagules away from the parent to find resources & avoid competition or to enable genetic mixing Summary • Habitat loss affects millions of square km globally • Different biomes have suffered different rates of loss, depending on suitability for human use • Fragmentation of habitat exacerbates negative effects of loss of total area due edge effects, reduced patch size, and isolation • Certain traits predict extinction proneness with habitat loss • Loss of large home-range species (predators) leads to trophic cascades • Movement, which is key for species persistence on the landscape, is impeded by habitat loss and fragmentation

Invasive species

Negative Effects of Non natives on Native Species Direct Competition -Predation and disease -Contests over recourses (Food, Shelter, etc) Scramble competition for resources Habitat modification and transmission of pathogens Climate change is facilitating European red fox migration into endangered Artic fox habitats in Scandinavia Many chilean digs roam free, some with homes to return to, others without. SOme dogs have gone Feral= reproducing in the wild. Some non-native dogs harm native wildlife, spread disease and pollute, pray on other dogs, or threaten people Moral values and other value judgment: Is the life of such a dog high quality? Should one kill dogs to save Puda?(northern PUda is IUCN Red listed as vulnerable) So far, the Chilean government had been unwilling to enforce laws against free- running dogs or capture them. The pro-dog movement in Chile is strong Accidental introductions can become invasions that imperil native species and ecosystem services (Zebra mussel vs. Native Mussel) -Geo graphic spread in the US. Huge spread all around Wisconsin and surrounding states -Zebra mussels threaten 140 native species with extinction. Total cost to USA estimated at $3.1 billion per decade. Which effect is higher to you? Abiotic and Biotic Filters determine if introduction leads to invasion -bio geo graphic filters -Physiological filter -Biotic filter -Local assemblage -Human introduction -Human alter enviromental chemistry -Human deplete native competitors -Globalization -introduction and spread The south American cane toad introduced to Australia intentionally to control cane beetles -Among the world's 100 worst invaders (IUCN 2008) -Eats virtually anything (dead or alive): animals. dog food, garbage -Habitat generalist that can disperse far by road. Non-Native -Negative effects far outweigh rare, positive effects -Filters determine invasions but globalization and human value judgments can weaken or strengthen the filters -Appropriate interventions reflect a balance of human value judgments (economic, ecological moral, etc)

Overfishing

Overfishing is catching more fish than can be replaced by natural reproduction Collapsed = A fish population at 10% or less of unfished abundance A fishery is an entity engaged in raising or harvesting fish. Includes a combination of fish and fishers in a region, as determined by some authority. For example: • the Alaskan pollock fishery • the North Atlantic cod fishery A fish stock is a semi-discrete subpopulation of a given fish species of interest to fishery managers. It is the unit of population assessment for fisheries management. The Nature of the Problem -OVERFISHING is the #1 THREAT TO MARINE ECOSYSTEMS -90% of fish stocks are being fished at or over capacity -61% of stocks are fully exploited The Nature of the Problem -90% OF STOCKS ARE BEING FISHED AT OR OVER CAPACITY ->10% OF THE WORLDʼS POPULATION RELIES ON FISHING OR AQUACULTURE FOR THEIR LIVELIHOOD -NEARLY 3 BILLION PEOPLE RELY ON FISH AS THEIR MAJOR PROTEIN SOURCE. -DEMAND FOR FISH IS EXPECTED TO DOUBLE IN 25 YEARS Who's Fishing? -Top 10 Fishing Nations -1.China -2. Indonesia -3. USA -4. Russain federation -5.Japan -6. Peru -7. India -8.Viet Nam -9.Myannar -10. Norway Size distribution of motorized vessels, 2016 -~75% of catch is by industrial fishers -85% of fishermen are in Asia -86% of fishing boats are <12 m long How are fish caught? INDUSTRIAL FISHING METHODS 1. Purse-seine = circular net, 600m wide to surround schooling fish 2. Longlines = 40-60 km lines with thousands of baited hooks for large dispersed pelagics (mahi mahi, swordfish, sharks, halibut) 3. Gill nets = wall of net floating at specified depth; may be 10s of km long; indiscriminate 4.Trawlers = huge scoop-shaped net dragged through water or on bottom; for shrimp and "groundfish" Industrial purse-seine catch brought aboard with "fish pump" How many fish are caught? -Global capture fisheries production -Global demand for fish is increasingly being met by aquaculture -Catch of ~ 91 million metric tons reported catch in 2016 (~81 mmt marine) Peak catch at 93.8 mmt in 1996, declining since -Wild fish catch has leveled of, but fishing efforts have not decreased -Aquaculture fisheries on the rise How many fish are caught? -World fish utilization and consumption -Catch of ~ 91 million metric tons reported catch in 2016 (~81 mmt marine) Peak catch at 93.8 mmt in 1996, declining since About 25% is for fish meal, fish oil, and other non-food uses -Fishes used for food and non food purposes How many fish are caught? -Estimated Global Fish Catch including Bycatch and IUU -IUU = illegal, unreported or unregulated catches -True catch closer to 130 mmt (million tons per year) -~20% "Bycatch" /discard (accidently caught) IUU and Bycatch -sea shepherd ANPA/ Marine Nationale How many fish are caught? -Shrimp trawling has highest bycatch Up to 8:1 bycatch (by weight) (62% discard) -Tuna 28% discard -Dredge 28% Where are fish caught? -Greatest fishery productivity is over continental shelves -8% of ocean area; 90% of effort -Why? Greater NPP, benthic habitat, and easier access -Less than 15% is caught in oceanic zones (the "high seas") - Oceanic species (tuna & billfish) - Skipjack Tuna (Canned tuna spp.) -Albacore Tuna (Canned tuna spp.) -Yellowfin Tuna ( ahi, steaks) -Biggeye (ahi,sushi) -Northern Bluefin Tuna (Atlantic bluefin tuna ENDANGERED) -Southern Bluefin ( Toro, $$$, sushi) -increase in tuna fishing Bycatch and the tuna-porpoise problem Tuna purse seines "set on dolphins" - 1959-1972: 5 million dolphins killed in tuna fishery -1990: 52,000 killed in U.S. -1992: Method banned; dolphin-safe labelling -Setting on dolphin replaced by "fish aggregating devices" (FADS) -decrease killing of dolphins but huge increase in bycatch and killing other species (they arent carred about in society ) How do we know overfishing is occurring? -EVIDENCE OF OVERFISHING -Reduced catch per unit effort -Efforts are increasing but catch is not changing/ leveling off • Reduced catch per unit effort = population (stock) declines -Stock collapse • Reduced average size of fish ---• evolutionary pressure for earlier reproduction ---• Smaller fish have fewer less viable offspring ---the "shifting baseline" Reduced average size of fish -Impact of Size‐selectivity of Harvest on Growth and Size of Fish --Harvest only large fish >>> mean weight of harvested fish goes down --Fishing as a selective force for evolutionary change Smaller fish have fewer offspring -Selectively removing large fish reduces ability of population to grow • a 60 cm snapper lays 3.5 million eggs • a 30 cm snapper lays only 360,000! • Thus one 60 cm snapper = Ten 30 cm snappers! How do we know overfishing is occurring? -Tuna and relatives (Scombridae) down ~75% -Sharks down 90% (Over 100 million sharks are killed every year) Shark finning - How do we know overfishing is occurring? EVIDENCE OF OVERFISHING -Decline of predators • Direct predation by fisherman • AND loss of prey -Value of forage fish as direct cath 5.6 billion -Value of forage fish as prey for other commercially valuable fish 11.3 billion - How do we know overfishing is occurring? TROPHIC CASCADES • Altered ecosystem composition • Reduction in mean trophic level of fish caught Habitat loss from trawling & dredging Habitat loss from trawling & dredging -Bottom trawling Why is overfishing occurring? Industrialization of fleet • larger, faster ships • stronger nets & powered gear • go farther, deeper • on‐board freezing & processing • sophisticated fish‐finding & bottom mapping -"Factory ships" Menhaden purse seine - 2nd largest U.S. fishery Why is overfishing occurring? Government Subsidies -~$20 billion spent globally on fisheries subsidies, many of which are harmful -Subsidies enhance revenues by reducing costs (fuel, managment, parts, moderdization, research) • increases profit margin • more participation • greater effort • "perverse incentives" • 85% go to large fleets Why is overfishing occurring? Overcapacity -Currently we have 2.5X the capacity to catch fish than there are fish in the sea! -"Too many fishermen with too much sophisticated equipment chasing too few fish" Why is overfishing occurring? Fisheries governance & management history -Prior to 17th century: No laws governed fishing - Freedom of the Seas - During 17th century: 3-mile territorial waters ("cannon-shot rule") • beyond that "Freedom of the High seas" "No part of the sea may be regarded as pertaining to the domain of any nation" 'Mare Liberum' Grotius 1609 Fisheries governance -1973-1982 U.N. Convention on the Law of the Sea (UNCLOS) • established maritime zones around all countries • 200 mile EEZ (economic exclusive zone) • ratified by 168 nations, took effect 1994 • still the most important international agreement governing use of the sea High Seas Fisheries -= International waters ("high seas") -"There isn't even an agreed upon definition of what sustainable use of the high seas means." - MacDonald 2018 Why is overfishing occurring? -U.S. Fisheries Management Policy -stocks managed by fishers declining yields led to demand for better management US Magnuson-Stevens Fishery Conservation and Management Act (FCMA) - 1976 • National Marine Fisheries Service (NMFS - Dept. Commerce) • 8 Regional Fisheries Management Councils (RFMCs) • Responsible for setting quotas, licensing fleet, monitor catch, etc. 1996 Amendment: Sustainable Fisheries Act • prevent overfishing, ensure sustainable harvests • "minimize" bycatch • conserve "Essential Fish Habitat" Why is overfishing occurring? Shaky science -Population size before season, total allowed catch, desired population size at end of season -MSY = Maximum Sustained Yield -Max. # of fish that can be caught without depleting the stock • used to set Total Allowable Catch (TAC) Shaky Science PROBLEMSWITH CONVENTIONAL CATCH LIMITS -• Population size historically estimated from catch ---• <1% of species have scientific assessments ---• inherently biased • inherently oversimplified ----• e.g. fishing prey may change K ----• e.g. fish change sex with age (skewed sex ratio of catch) • bycatch not accounted for • no incentive for precautionary approach Shaky Science • Over-estimation of stock based on catch alone • No precautionary approach -(Fishing in non random) Why is overfishing occurring? TAC and the "Race to Fish" • TAC up for grabs! = intense competition • RACE TO FISH - season opens; if you don't get it someone else will • dangerous, risky behavior • overcapitalization (more & faster boats, more gear, etc) • chronic overfishing by everyone What are the impacts of overfishing? -Overfishing hurts both fish and economies - Yield overfishing = Harvesting more fish than would produce the best long‐term yield • more fish could be harvested each year if we left more fish in the sea Economic overfishing = Putting in more fishing effort than would make the most profit • reducing capacity would result in higher profitability of fishing -If fish were managed sustainably, 16.5 million tons more fish could be harvested, and $32 billion in additional revenue could be gained What are the solutions? -Solutions are many, but #1 is we must kill fewer fish 1. Better Science 2. Precautionary Quotas 3. Better management • eliminate bad subsidies • Individual Fishing Quotas ("Catch Shares") • enforcement • ecosystem‐based management 4. No‐take Zones + Habitat Protection 5. Education / Individual Action

Pollution

Pollution -Roughly 84,000 Chemicals have been manufactured or processed in the United states - 8,707 were used in commerce in 2016 -Only small proportion have been rigorously screened for biological and human health effects The major threat to 4% of RedList assessed threatened species -Pollutants --Mercury and other heavy metals --Pessticides --Nutrients --Industrial waste and oil spills --Pharmaceuticals --Plastic -Processes/Effects --Biomagnification --Endocrine Disruption --Eutrophication --Disease Persistent Organic Pollutants -DDT, polychlorinated biphenyls (PCBs), dioxin -Persistent=dont break down easily in the environment -Fat soluble= stored in fatty tissue and accumulates (not excreted, except in milk) -Toxic= physiological effects and lethality even at low doses --Birth defects --Altered behavior and reduced IQ --Reduced immunity --Endocrine disruption DDT (pestiside) -Rachel Caeson publishes Silent spring -US banned DDT in 1972 -Stockholm Convention- Global treaty to band POPs -DDT caused eggshell thinning -Recovery of bald eagles, peregrine falcon, ospreys and other birds of prey "The breakdown products of DDT- a toxic pesticide banned in 1972- has been found in 99% of Americans tested in 2016" Bioaccumulation and Biomagnification -How brain- damage mercury puts artic kids at risk --inunit children, exposed in the womb, have lower IQ's because their mothers eat whale meant and other foods tainted with contaminants that drift north. -Bioaccumulation =increased in concentration of pollutants in an organisim -Biomagnification= increase in concentration of pollutant up a food chain Endocrine Disruptors -Chemicals that mimic hormones, especially estrogen mimics(e.g. Bisphenol-A, Phthalates, Pesticides, many plastics) -Produce biological effect at extremely low doses (ppb) -feminization of alligators, birth defects, low sperm count, obesity (frog reproduction impair) Endocrine Disruptors - Per- and polyfluoroalkyl substances added to the TEDX list of potential endocrine disruptors -Chemicals designed to repel oil and water, Per- and polyfluoroalkyl substances (PFAS), have been used in everything from food wrappers, cosmetics, and textiles. they have been detected in our food, water, and our bodies -Maternal exposure to some PFAS linked to altered thyroid hormone levels in mothers and umbilical cord Neonicotinoid Pesticides - related to nicotine -Colony collapse disorder of bees Herbicides -Roundup, cancer and furfure of food -Glyphosate is the worlds most commonly used herbicide- and it is carcinogenic -Also found to harm insects and other species Nutrient Pollution -Industrial Fertilizers --"Green Revolution" of the 1960's - food production to feed the world --Nitrogen: 1 ton of fertilizer takes energy of 2 tons of gasoline (Nitrogen global total is higher than Phosphorous and potassium) (All on the rise though, huge increase in the 1970) Sewage Pollution -80% of Earth's sewage is discharged untreated -Sewage brings not only nutrients, but parasites and pharmaceuticals (Caribbean, west and Central Africa , East/ Southern Asia discharges a lot untreated) (USA treats a lot of their sewage) Pollution From livestock Operations -Concentrated Animal Feeding Operation (CAFOs) --Release millions of tons of manure containing nutrients, pathogenic organisms, and veterinary drugs into US waters every year Nutrient Pollution -Atmospheric deposition and run-off of nutrients leads to eutrophication of freshwater and marine ecosystems -Run off: non-point source pollution -Dead Zones: >400 persists globally -Hypoxia--> Anoxia ---Bacterial decomposition of algae uses up O2 ---Leads to fish kills ---Made worse by warming water temps ---6,765 square mile dead zone in golf of Mexico Pharmaceutical Pollution -CAFOS give rise to antibiotic resistant superbugs -81% of antibiotics sold in in US to livestock -19% sold to Humans -Antibiotic resistance spreading to wild life genes Garbage and Plastic build up in the ocean Plastic Pollution - Microplastics killing fish -Great Pacific Garbage Patch and Seabird Mortality Summery -All species and ecosytems are exposed to thousands of chemical pollutions, most of which have not been studied for their adverse effect -Persistet organic pollutions biomagnify in food chains and often act as endocrine disruptors that alter development, reproduction, and survival of many species including humans -Nutrient pollution from industrial fertilizers, CAFOs and sewage cause eutrophication of aquatic systems, that can lead to anoxia and higher incidence of disease -Plastics waste is increasing in the environment and is threatening many species, particularly in marine ecosystems where plastic accumulates

Population Biology

Population Biology and Demography Population= "a potentially interbreeding group of individuals of the same species" Demography= "the study of populations" Demographic Variables -Abundance (or #/ area) -Growth rate (Change population) -Biomass -Sex ration -Age Structure -Size class structure -Range (distribution) Factors Affecting Population Growth -Natality (b) -Mortality (d) -Immigration (i) -Emigration (e) Simple Growth- Geometrical -Growth is punctuated, and births and deaths hard to measure ... then count Females define Lambda= F(t+1)/F(t) Lambda= Net reproductive rate N(t+1)=Lambda*N(t) -Growth rate N(t)=N(0)* Lambda^t -Future population size Simple Growth- Exponential N(t+1)= N(t) + b-d (+i-e) Define r= (b-d)/ pop. size r=Intrinsic population growth rate N(t+1) = r* N(t) +N(t) -Simple growth rate dN/dT= rN -Instantenous growthrate N(t)=N(0)*e^(rt) -Future population size doubling time= In(2)/ r Why cant growth proceed forever? Density-independent factors • kill constant proportion, regardless of pop. size • mostly abiotic, e.g., climate Density-dependent factors • ▲population --> ▼growth rate • mostly biotic, limited resources, competition: ----interspecific vs. intraspecific • Allee effect: difficulty at very low density (ex: finding mates) Human Population 1750 - 2050 -Developing countries size increase drastically - Industrialized countries rises a lot slower Covid-19 in USA -exponential growth Exponential & Logistic Growth Logistic Growth - 1 Species --growth is limited by density dependent factors ... setting a carrying capacity (K) dN/dT = rN -Growth rate dN/dT = rN * (1 - N/K) -Growth rate *note: as N --> K, growth declines; when N=K, growth = 0 Nt = K/ (1 + [ ( K - N0 ) / N0 ] * e-rt) -Future population size K-selected vs. r-selected Species Competition -intra-specific -inter-specific Competitive Exclusion & Release Exclusion: one species forces another to shift niche Release: evidence of exclusion • BCI Ocelots - larger prey w/out Jaguars • Squirrel Monkeys - larger fruit w/out Spider Monkeys Types of Competition: • interference: direct • exploitation: indirect --- Agoutis & Pacas eat same seeds, each reduces other's K Lotka-Volterra Competition Models SPECIES 1: Paca dN1/dT = r1N1 * (K1 - αN2 - N1)/K1 α: reduction of K1 by species 2 SPECIES 2: Agouti dN2/dT = r2N2 * (K2 - βN1 - N2)/K2 β: reduction of K2 by species 1 Resource Utilization & Competition -Niche Terminology Demography - Age Ratios "cohort" and "recruitment" Sustainable Harvest Constant Harvest • take fixed # individuals every season • inflexible - will crash population when recruitment is low Proportional Harvest • take proportion of current population, N(t) • flexible - harvest less when N(t) is small Maximum Sustained Yield (MSY) • repeated harvests • maintain population at most productive size Fisheries Management Maximum Sustained Yield -growth rate vs population size • growth rate is slope of the line -• harvest at max dN/dt ... when N = K/2 Population Viability Analysis - PVA 1) Model population over time (100 years) --Included factors: habitat area, hunting, nest predators, etc. 2) Repeat model 1000 times: % of runs that survive? 3) Adjust factors to improve survivability 4) can Calculate "Minimum Viable Population Size" (MVP) --Rule of thumb: 50 - 500 (*5000) PVA: Hawaiian Stilt (Ae'o) -1940: Population = 200 -2010: Recovery = 1400 (N ≈ K) ---Goal = 2000 PVA Extinction if: 1st-year mortality > 70% adult mortality > 30% ▼ Mortality: predator control ▲Population: expand protected areas Metapopulation Modeling Metapopulation = "population of sub-populations" Common when: -ephemeral habitats -fragmented habitats Source - Sink Dynamics -source ("core") patches -sink ("satellite") patches -core "rescues" satellites Metapopulation Modeling -PVA for each sub-pop; linked by migration -critical factors: patch quality & size, connectivity Howler Monkeys Model Components: -group size, density, reproductive rate -models: Isolated vs. Metapopulation Results: extinction ▲ exponentially w/ ▼Area 60% likelihood in fragments < 25 acres migration ▲▲ survival Output suggests management targets: • sustain fragment size • reforest corridors for connectivity Estimating Populations in the Field Mark - Recapture: -mark, release, recapture ... repeat -estimate Abundance -also: Survival, Capturability Types of Marks: -leg bands -bead collars -toe clipping -numbered buttons, stickers -subcutaneous chips Mark-Recapture: The Basics First Encounter: -capture animals, and mark them all: M -release back into population -wait for mixing Second Encounter: -capture animals: C -count recaptures: R Estimate Population Size: N = C x M R

Conservation Genetics 2: Applications

Small Populations and the Extinction Vortex Small Populations--> Interbreeding/ Random genetic drift--> Loss of genetic variability --> Reduction in individual fitness and population adaptability--> Higher mortality/ Lower reproduction--> Smaller Population Conservation Genetics to Restore Diversity -Considerations for management of small, isolated populations and captive breeding programs Gene flow = movement of genes on the landscape • can offset loss of genetic diversity due to inbreeding and drift Interventions to prevent loss of genetic diversity • enable natural dispersal • corridors • reintroduction • translocation Genetic rescue....but avoid outbreeding depression Outbreeding Depression = reduced fitness from mating of individuals that are too distinct Outbreeding Depression Case Study -Reintroduction of Alpine Ibex (Capra ibex) to Czechoslovakia • Overhunting extirpated ibex in Tatra mountains, Czech • Successful reintroduction of a few individuals from Austria • To increase population size and genetic diversity, individuals from Turkish subpopulation further south were introduced... What happened? • Hybrids rutted in the fall, not winter • Kids were born in February (coldest month), not April • All offspring died • Population went extinct Outbreeding Depression = reduced fitness from mating of individuals that are too distinct (Mating between individuals from different species or windy different populations) Identifying Species: Phylogenetics -Phylogenetics: The study of the evolutionary relationships among taxa. -The basis of modern taxonomy; classification of organisms into nested groups with decreasing levels of relatedness Conservation applications: • phylogenetic diversity is positively correlated with: --• productivity --• functional diversity --• evolutionary potential • setting conservation priorities • prioritizing species protection • ecological restoration • genetic rescue of endangered species Identifying Species: DNA Barcoding -Identifying species using DNA sample from tissues, feces, hair, scales, mucus, environment • reliable identifier without taxonomic expertise • requires reference collection SO MANY conservation applications: • specimen identification • detecting invasives • identifying cryptic species or life stages (e.g., larva and adults) • combating fraud and illegal harvest (wildlife, timber, fish) DNA Barcoding and Fraud detection -mislabeled food Identifying Species: Environmental DNA (eDNA) -Extracting DNA from the environment (soil, water, air) • sources of eDNA: feces, skin, hair, scales, gametes, etc... • identify species present or detect target species • less time consuming and destructive than field surveys • can detect rare / difficult to find species • particularly useful in aquatic environments Species detection rates from eDNA in aquatic and terrestrial systems eDNA Applications eDNA lasts just hours or days; can see change through time • movements / migrations • impacts of disturbance • change through time New applications for estimating relative abundance

Conservation Genetics 1 Special Problems of Small Populations and an Introduction to Conservation Genetics

Vulnerability to Extinction • Small geographic range • Migrants (monarch butterflies, migratory birds, whales) • Specialists • Large territory requirements (jaguar) • Low reproductive rates (K-selected) • Palatable or in conflict with humans (hunting, development) • Recent rapid decline • Small population size (WHY?) Special Problems of Small Populations 1. INCREASED STOCHASTIC EXTINCTION RISK --Fluctuations in population size due to random environmental and demographic variation can lead to extinction in small populations --Environmental stochasticity due to random fluctuations in habitat conditions. Demographic stochasticity: random fluctuation in birth and death rates. Special Problems of Small Populations -Demographic Stochasticity Example: Bias sex-ratios in Tuatara lizards --"Extinction vortex" --Male based off spring --Male based survival rate Ne ≠ N effective population size Special Problems of Small Populations 2. LOSS OF GENETIC DIVERSITY Mechanisms: 1. bottleneck effect • founder effect 2. genetic drift 3. inbreeding -Small populations lose genetic diversity and thus adaptive ability -What is Ne? Ne = effective population size The # of breeding individuals Ne is nearly always <<< N Special Problems of Small Populations -HOW DO SMALL POPULATIONS LOSE GENETIC DIVERSITY? 1. Bottleneck & Founder Effects Reduced genetic diversity in a subset of a population that survived a large mortality event (bottleneck) or colonized a new site (founders). HOW DO SMALL POPULATIONS LOSE GENETIC DIVERSITY? 2. Genetic Drift • Random fluctuation in allele frequencies from one generation to the next • Little effect in large populations (wobbles around a mean) --• M&M analogy • Can result in loss or fixation of alleles in small populations Which alleles are most likely to get lost by drift in a small population? • Fixation of alleles = only 1 allele remains of a gene --• Heterozygosity declines -The rarer the allele, the more easily it is lost due to drift HOW DO SMALL POPULATIONS LOSE GENETIC DIVERSITY? 3. Inbreeding = Mating between organisms related by ancestry; leads to lower genetic diversity than would be expected, due to non-random mating How does this happen? • mating between close relatives • small isolated populations • self‐pollinating plants Consequences: • decrease in % of heterozygous genes • expression of recessive traits • loss of adaptive ability • inbreeding depression = loss of fitness due to strong inbreeding Examples of Inbreeding Depression -Failure of egg hatching increased with inbreeding of Parus major in habitat fragments -Reduced survival with inbreeding in Speke's gazelle following bottleneck -Reduced growth rate in inbred silver birch used in forestry in Finland What is Conservation Genetics? Conservation genetics is the application of genetic methods to conserving, restoring, and preventing extinction of biodiversity • Assess diversity of species and populations using specific genetic markers (genes or loci) or entire genomes. Review Genetic Definitions: Gene Allele Diploid Homozygote Heterozygote Gene pool Genetic definitions -Gene: a region of the DNA that codes for a particular trait (also called a locus) -Allele: variants of the DNA sequence that code for the same gene -Diploid: an individual having 2 alleles per gene (# of alleles in population = 2N) -Homozygote: An individual with 2 identical alleles for a gene -Heterozygote: An individual with 2 different alleles for a gene -Gene pool: the sum total of all alleles of every gene in a population Even though diploid individuals only carry 2 alleles for each locus, the total number of alleles for that locus in a population or species can be much higher! Definition of Genetic Diversity -Genetic diversity = the number of different genotypes, within and among individuals, populations, species, or a group of species. Also called genetic variation or polymorphism Genetic diversity is positively correlated with: • population size • habitat area / island size • range size • gene flow (dispersal ability) • species persistence Genetic diversity is the basis for natural selection and evolution How is Genetic Diversity Quantified? Within a population • % polymorphism: % of loci that have more than one allele • allelic diversity: average # of alleles at a locus or across a number of loci • observed heterozygosity (H): proportion of heterozygous individuals We can compare these measures within a population through time, between two or more populations, or between species 10 loci in yellow coneflower -Remnant Pop: 7 out of 10 had >1 allele -Restored Pop: 4 out of 10 had >1 allele (% polymorphic genes is 70% vs 40%) 14 loci in White‐tailed Deer -Population descended from a few reintroduced to Finland in 1934 --• Mean allelic diversity = 5.36 -White‐tailed deer in Oklahoma, USA --• Mean allelic diversity = 9.07 Example: Bottlenecks & Loss of Allelic Diversity Example: Loss of Genetic Diversity -Elephant populations Estimating Heterozygosity • If there are 2 alleles (A1 and A2) of a given gene, what are the 3 possible diploid genotypes? A1A1 A1A2 (Heterozygote) A2A2 Remember! N = # of individuals 2N = # of alleles What is the expected frequency of heterozygotes (HE) in the population? -Did you say 1:2:1? -Don't confuse frequency in a population with frequency from a test cross of two individuals with known genotype! -The frequency of the 3 diploid genotypes depends on the frequency (%) of the alleles in the population! What is the expected frequency of each genotype in a population? -If the frequency (%) of the A1 allele is p and the frequency of the A2 allele is q, then: (Sigma of)pi = 1 Genotype:Expected Frequency A1A1 (p x p = p^2) A1A2 or A2A1 (pq + pq (or 2pq)) ---Expected frequency of heterozygotes (HE) A2A2 (q x q = q^2) Note: if there are only 2 alleles, then p + q = 1. If there are n alleles, then p + q + r....n = 1 and the math gets more complicated! Estimating Heterozygosity -Hardy‐Weinberg Equilibrium: In a large, randomly mating population, the genotype frequencies in a diploid population will remain stable at... p^2 + 2pq + q^2 = 1 ...if the following assumptions are met • Mating occurs at random (every gamete has equal probability of being sampled) • Natural selection is not occurring • Migration (gene flow) is not occurring • Mutation is not occurring • Genetic drift is not occurring • drift is minimal when populations are large Deviations from expected frequencies indicate "something" is going on Practice Question A locus has 2 alleles. Population is 10 diploid individuals. How many total alleles in population? What is the frequency of the recessive allele? What is the frequency of the dominant allele? A1A2 A1A1 A1A2 A2A2 A1A2 A1A2 A1A1 A2A2 A1A1 A1A1 2N = 20 total alleles p = 1 - q = 0.60 q = 8/20 = 0.40 Alternate equation: A1 = p = (2*A1A1 + A1A2)/2N Recall: Diploids have 2 alleles at each locus, so number of alleles is 2N Under HWE what is the expected frequency of each genotype? p^2 + 2pq + q^2 = 1 p^2 = 0.6 * 0.6 = 0.360 (homozygous dominant) 2pq = 2 * 0.6 * 0.4 = 0.480 (heterozygous) q^2 = 0.4 * 0.4 = 0.160 (homozygous recessive) Non‐Random Mating Non‐random mating is the norm -Mating more likely between individuals within a certain distance Thus, proximate individuals are more closely related than more distant ones -Virtually all populations have some level of inbreeding Genetic Structure = patterns of genetic variation in time and space Quantifying Inbreeding -When there is inbreeding, the fraction of heterozygotes in a population is less than would be expected under random mating. Why? Consider the most extreme case of inbreeding: selfing The frequency of heterozygotes declines by half with every generation ofselfing! A1A1 x A1A1 (D+ 1/4 H) A1A2 x A1A2 (1/2 H) A2A2 x A2A2 (R+ 1/4 H) D and R= Initial Genotype Frequency Note: Inbreeding has no effect on allele frequencies, only on genotype frequencies Quantifying Inbreeding - Inbreeding Coefficient (F) is the deficiency of heterozygotes relative to what is expected under random mating F = (Hexp ‐ Hobs) /Hexp = 1 - HO/He With inbreeding, F ranges from 0 (no inbreeding; random mating) to 1 (all genes homozygous) Table: Self fertilisation 1/2 Full sibs, Parent-child, Double first cousins (first degree) 1/4 Half sibs, Grandparent-grandchild, Uncle-niece, Double first cousins 1/8 First cousins 1/16 Note: F can be <0 if there is an excess of heterozygotes due to hybrid vigor, excess outbreeding, etc. Quantifying Inbreeding F = (Hexp ‐ Hobs) /Hexp = 1 - HO/HE Is our population inbred? What is the observed frequency of heterozygotes? Recall, HE = 2pq = 0.480 HO = 4/10 = 0.40 F = 1 - 0.40/.480 = 0.167 Measuring Loss of Genetic Diversity Due to Genetic Drift -% Heterozygosity How much heterozygosity is lost over time? H = % heterozygosity t = # of generations The proportion of the original heterozygosity remaining after 1 generation at population size Ne: H1 = 1 - 1/2Ne Example: A population of 50 breeding individuals would retain 99% of their original heterozygosity after 1 generation. H = 1 - 1 / (2 x 50) = 1 - 1/100 = 1 - 0.01 = 0.99 After t generations, % of original heterozygosity is: Ht = H1 t So same 50 individuals after 3 generations = H3 = (.99)3 = 0.99 x 0.99 x 0.99 = 97% Assumes no mutation, no selection, no gene flow, no inbreeding Summary • There can be many alleles (n1, n2, n3...ni ) for a given gene with frequencies of (p, q, r....pi ). Loci with more than one allele are polymorphic. • The sum of all n allele frequencies for a gene is = 1 pi = 1 pi = 1 : In the case of only 2 alleles, 1 = p + q • The expected frequency of diploid genotypes is given by Hardy‐Weinberg Equilibrium: p^2 + 2pq + q^2 = 1 • The % of heterozygosity remaining after one generation of drift is: H1 = 1 - 1 / (2 Ne) or Ht = H1 t after t generations • The inbreeding coefficient (F) is the reduction in heterozygotes compared to expected under random mating: F = 1 - HO/HE

Module 2: Threats to Biodiversity Part 2: Overexploitation The #2 Cause of the Biodiversity Crisis

• What types of overexploitation exist? • What taxa are most vulnerable? • How many are killed, and for what purpose? • What are the broader impacts of overexploitation? The #2 Cause of the Biodiversity Crisis -#1 for marine species -Overexploitation explains ~37% of species identified as threatened Overexploitation: Definition and Scope -Overexploitation = the taking of biological resources, or organisms, in larger numbers than their populations can withstand • Leads to population decline and, if no intervention, extinction Recall: Overkill hypothesis of Quaternary megafaunal extinctions... and many more since then Overexploitation: Definition and Scope: 1.overhunting -Large mammals -African mammals 2.unsustainable logging -Tropical trees -Temperate conifers 3.pet trade -Tropical fish -Birds -Reptiles -Orchid 4.overfishing -Sharks Marine fish • Numbers killed difficult to estimate, much is illicit • 200 million animals killed in U.S. alone. -"Currently, broad-scale data on the exploitation of terrestrial wildlife, needed to inform conservation policy and action, are lacking" Joppa et al. 2016 Overhunting for Food • bushmeat trade is the greatest threat to African wildlife • transition to commercial harvest, now outweighs subsistence • Brazil: 23.5 million animals/yr consumed • Central Africa: 1.1 million metric tons/yr consumed Overhunting for Food In Congo, 40-80% of animals sold are duikers Illegal Wildlife Trade -Poaching = illegal hunting or harvest --Elephants are the most seizure taxa (61.9% of all, 31.1 of mamals) Illegal Wildlife Trade (Poaching) -7 of the 350 remaining mountain gorillas in Virunga park killed in 2 months in 2009 -7,700% Rhino poaching in South Africa increased from 13 to 1,004 between 2007 and 2013. -2500 elephants poached in 2011 for their ivory -Traffickers in Peru earn $1,700 for every illegal mahogany tree sold on the black market Overhunting for Animal Parts -Wildlife trafficking is carried out by organized crime syndicates that also engage in illegal timber, arms, and human trafficking -rhino horn elephant tusks tiger bones pangolin scales furs and pelts shark fins Case study: the Pangolin -"the most heavily trafficked wild mammal in the world" TRAFFIC -nocturnal forest insectivore -4 species in Africa and Asia, all threatened -0.4 - 2.71 million killed every year in Central Africa - >145% increase since before 2000 -skyrocketing demand for meat and scales Overhunting for Pets -legally own exotic animals -Wisconsin you cab own tiger, bear, primates bans? declines in the wild? clandestine online sales? sold as "captive bred"? Overhunting for Pets: Birds -Birds are the most common live animal contraband (2-5 million birds per year) -60% of wild-caught birds die during capture or transport (too young, injured, mishandled) Overhunting for Pets: Fish -11 million tropical fish imported to U.S. per year -up to 90% of tropical fish that enter the US each year are caught illegally with cyanide -Captured on reefs, often with cyanide to stun fish. Up to 90% mortality. Human-Wildlife Conflict -Ruining crops - invading homes - crossing roads -eating live stock Hunting for Sport...Conservation? -"Well-managed trophy hunting can provide both revenue and incentives for people to conserve and restore wild populations, maintain areas of land for conservation, and protect wildlife from poaching" - IUCN website -African elephant numbers have declined from over 1 million a hundred years ago to ~400,000 today...can hunting them help save them? -A closer look at trophy hunting in africa shows that the industry employs few people and that the money from hunting fees that trickles down to needy villagers in minimal Is Hunting Really a Conservation Tool? -gray wolf debate in wisconsin Ecological Effects of Overexploitation: 1. Reduced body size: elimination of larger animals + trophic cascade 2. Ecosystem effects: seed-dispersal, trampling, bioturbation, nutrient cycle 3. Homogenization: reduced beta, and functional diversity 4. Behavioral changes: prey behavior, diet shifts, diel shifts Think about evolutionary consequences! 5. Coextinctions (e.g., sea otters and Stellar's sea cow) 6. Human disease: loss of pest control, proliferation of rodents 7. Extinction Ecological Effects of Overexploitation -Coextinction = the extinction of one species precipitates the extinction of another (often mutualistic or dependent species) Unsustainable and Illegal Logging • Rosewood (Dahlbergia spp.) • Mahogany and relatives • Many more species.... • Many late-successional tropical trees are K-selected --• rare, slow growing --• produce few large seeds --• prone to unsustainable harvest levels • Illegal logging is rife due to --• few laws and/or lax enforcement --• lack of expertise in wood ID --• high profit (no permits, taxes, fees) Where does illegal timber come from? -Brazil (largest legal wood form plantations, then second illegal in tropics) -indonisha (largest illegal) Consequences: • Depresses timber prices 7-16% --• undermines profitability of legal logging • Causes forest degradation --• maximizes short-term profit not longterm production --• no incentive to minimize damage --• no replanting Where does illegal timber come go? -china -japan -US Summary • Overexploitation involves overhunting, overfishing, unsustainable logging, and the pet trade • Many taxa are impacted, but large mammals represent >60% of the illegal wildlife trade, while birds and tropical fish are heavily targeted by the pet trade • The illicit trade in wildlife is carried out by organized crime • Millions of wild animals are killed each year for meat, sport, and marketable parts. Millions more are captured live and sold as pets. • Hunting is debated as a conservation tool for large mammals; it has been shown to increase poaching • Ecological impacts include trophic downgrading, behavioral changes, ecosystem-level effects, and coextinctions