Conservation of BIODIVERSITY. Biodiversity can be assessed and conserved at several levels: Molecular/Genetic (rare genes and alleles) Population Species Assemblage Ecosystem Global. BIODIVERSITY. Molecular/genetic is the level at which natural selection and evolution occurs
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Conservation of BIODIVERSITY • Biodiversity can be assessed and conserved at several levels: • Molecular/Genetic (rare genes and alleles) • Population • Species • Assemblage • Ecosystem • Global
BIODIVERSITY • Molecular/genetic is the level at which natural selection and evolution occurs • Loss of genetic diversity impedes “adaptability” • Loss of populations similarly handicaps a species’ chance of surviving uncertain circumstances in the future.
Loss of Biodiversity • Many reasons, often confounded • Historic extinctions • p/t extinction (250 mya) • k/t extinction (65 mya) • Holocene extinctions: 10,000 years ago to present
EXTINCTION • “Given evolutionary turnover, extinction is inevitable. Like death for the individual, nothing is more certain in the future of a species than its ultimate removal.” • P. Martin and R. G.Klein IN • Quarternary Extinctions: • A Prehistoric Revolution 1984
Current Extinctions • Current biodiversity crisis • Human mediated • Correlated with Homo sapiens expanding range and density • Ever-quickening rate of extinctions • Has led to increase of 1000 – 10,000% above the rate of background extinctions
Current Extinctions • Current biodiversity crisis • Before 1800 • Islands: many unique island assemblages decimated • Gigantic flightless birds • Gigantic tortoises • Dwarf elephants/hippos • Continents: severe extinctions among megafauna • North american mammals • South american marsupials
Current Extinctions • After 1800: • Extinctions on islands continue • Birds, endemic mammals, reptiles • Extinctions among smaller continental fauna increase in pace • Habitat destruction/conversion • Unregulated trade • Bounties on “undesirable” species
Conservation of Herpetofauna • Amphibians and reptiles face many of the same threats that face other non-human organisms: • Habitat modification and destruction • Introduction of exotic species • Pollution • Commercial exploitation • Traditional and modern medicine • Pets • Research and teaching • Traffic mortality • Persecution
Habitat modification and destruction • The most significant problem • Absolutely correlated with increasing human population size • Extensive and worldwide; all biomes, but tropical rainforests hit hardest • “At the current rate of deforestation, within 30 years there will remain neither extensive tropical forests, nor their endemic amphibian and reptile fauna” • from Pough et al. 2001
1) Habitat destruction • Deforestation of tropical forests • Destruction of coral reef ecosystems • Wetland alteration for development • Temperate regions altered for agriculture • Habitat fragmentation
Habitat modification and destruction • >95% of central California’s marshes were drained and converted before 1900. • Rana aurora draytonii (California red-legged frog), once California’s most common frog, all but disappeared • Thamnophis gigas (giant garter snake), slowly declined, now almost extinct
Habitat modification and destruction • In Florida, habitat conversion may have been responsible for a decline in Ambystoma cingulatum • 200-300 per night between 1970-1972 • <1 per night after habitat conversion in 1990-1992 • Anniella pulchra declines correlated with introduced plant spp.
Habitat modification and destruction • Often works in tandem with weedy or introduced species • In Arizona, alteration of hydrologic regime enables crayfish, game fish and bullfrogs to persist where they otherwise couldn’t • Argentine ants expanding range into U.S. deserts by utilizing lawns and other landscaping features. Decline in Phrynosoma coronatum and P. cornutum correlated with spread of fire ants
Introduced species • Declines (and extinctions) in many island species attributable to introduced exotics • Dogs and cats: Cyclura carinata in Caicos Islands • Cats: Brachylophus iguanas in the South Pacific • Goats: Crotalus unicolor on Aruba Island • Sheep, goats, rats: Sphenodon in New Zealand • Introduced fish in California’s high elevation lakes: Rana muscosa and Thamnophis spp. • Fire ants impacting Texas horned lizard (P. cornutum) and Coast horned lizard (P. coronutum) • Small Indian Mongoose: 7 species of reptile and amphibian from Puerto Rico
Introduced Species: Herps • Bullfrog: western U.S, C. and S. America, England, France, Asia, many other places • Boiga irregularis: Guam • Wiping out geckos and skinks (all birds, bats, many small mammals already gone) • Introduced herp assemblages at ports-of-call
Pollution • Acid rain: • Ambystoma tigrinum in the Rocky Mountains • Bufo calamita in Britain • Selenium/agriculture runoff: • Thamnophis gigas in California’s Central Valley • Pesticide wafting: Rana and Bufo spp. in the Sierra Nevada
Pollution • Solid Waste: marine turtles • PCB’s: effect endocrine systems of aquatic frogs and turtles • Acidic runoff from mines: Rana tarahumarae in Arizona
Pollution • Biomagnification • The increase in the concentration of bioaccumulated toxic chemicals in organisms higher on the food chain due to preferential storage of the toxic chemical in edible body parts • There is abundant evidence that some carnivores at the ends of longer food chains (crocodiles, alligators, snakes) suffered serious declines in fecundity and hence in population size because of this phenomenon
Anthropogenic eutrophication Directly Impacts aquatic turtle, alligator, snake populations • Nutrients released, triggering chain of events
Commercial collecting: Food • Frogs: U.S., Europe, SE Aisa, Africa • Late 1800’s: extreme decline in availability of California red-legged frogs partially attributable to collecting pressure • 1976- 2.5 million KG frog legs imported into U.S. • Annual consumption in France: 2.7-3.6 million KG frog legs
Commercial collecting: Food • Declines in Iguana iguana and Ctenosaura similis • Monitors, pythons, tortoises, sea turtles
Commercial collecting: SE Asian Turtle Crisis • 12 million turtles sold per year in China’s food markets • China’s and Vietnam’s turtle populations depleted: now imported from all around the world, including the U.S. • Many of China’s turtles were only known from the food markets: no natural history or distribution information available • Many of those turtles have not been seen in markets for years
Commercial collecting: SE Asian Turtle Crisis • Low reproductive rate combined with great importance placed on age of turtle has dire consequences for natural populations
Commercial exploitation for skins • Civil war: Thousands of American alligators killed for skins • Legal importation of 304,189 pairs of Boa constrictor boots and 176,204 pairs of Python reticulatus into U.S in 1981 (all harvested from the wild) • >1 million crocodile skins per year from 1980 to 1985 • >12 million tegu skins during same period
Commercial exploitation for skins • Most species harvested for skins are long-lived • Until recently all have been harvested from the wild • Some progress being made to establish farms for commercially important species • The vast majority of skins are still collected from wild animals
Traditional and Modern Medicine • Bufo alvarius and Phyllomedusa bicolor used in shamanistic rituals • Snake venom used in antivenin and anticoagulant drugs • Batrachotoxin used in research to probe for voltage-sensitive sodium channels • Rattlesnake “shaker muscle” used in physiology studies
Pets • In Florida, 119,831 herps removed from the wild between 1990-1992 • 74,000 box turtles exported as pets between 1992-1994 • Habitat destruction often accompanies collecting for pets • Very little record kept regarding #’s of animals collected as pets from the wild
Pet trade • “In the United States, the retail trade in live reptiles, amphibians, and related products is worth a minimum of two billion dollars annually” -Joseph Franke MS and Teresa Telecky • If you wish a reptile as pet make sure you are dealing with dealer that can be trusted. Find out where the animals come from
Research • For scientific collections: usually very small impact • For bio and medical training • In early 1970’s 15 million leopard frogs collected from the wild • 1970-1971: 10 tons of leopard frogs collected from one western state • 250 lbs collected 4 years later
Traffic Mortality – Roadkill! Increases mortality of individuals and also decreases gene flow
Matthew Aresco, a 4th year PhD student in the Department of Biological Science at Florida State University built a temporary fence to divert turtles (and other wildlife, > 41 species) away from the road and into a culvert that joined the two lakes. Over the past 2.5 years he has monitored the temporary fence at least twice per day and maintained it at his personal expense (at least $2000 out-of-pocket). Species such as frogs, snapping turtles, large softshell turtles, alligators, and most mammals can climb over this low fence. The fence only covers 2000' - 3000' of the "killing zone".
Permanent guidewall and culvert system recently constructed at Paynes Prairie on US Highway 441 south of Gainesville, Florida.
Rattlesnake Roundups • Occur in several southeastern states • Run by either non-profit Jaycee’s clubs or for-profit companies • 5 Crotalus spp. are targets; other harmless snakes taken incidentally • Collecting methods often unethical
Rattlesnake Roundups • Snakes often stockpiled by collectors for long periods of time • At roundup, measured, weighed, poked fun at, submitted to stresses and injuries • Often skinned alive, in public
Rattlesnake Roundups • Justified as a way to “educate the public” • Also, to collect venom for research/antivenin industry • Claims that there’s no effect, or a beneficial effect, on native populations • However, effects of roundups on wild populations largely undocumented
Rattlesnake roundups • The only organized events in the U.S. in which profits are made off the unregulated harvest of a vertebrate group • WHY?
Declining Amphibians-History • In 1989, at an international herp conference, workers expressed concern that their study organisms weren’t as common as they once were
Declining Amphibians- • Species extinctions and population declines around the world prior to 1990 • Subsequent studies have documented declines as they happen • Few patterns emerged, other than that the most precipitous declines were among Anurans
Declining Amphibians- • Many of the same causes found for other biodiversity losses: • Habitat loss • Pollution, acid rain • Exotic species • Collecting