What is Conservation Biology? •An overview “Crisis Discipline” Response to: •Biodiversity loss
Declining Biodiversity Examples •Steller’s Sea Cow •Lived in Bering Strait (Alaska) •Grew to 35 feet long, 3.5 tons •Slow-moving, docile •Hunted to extinction by 1768, less than 30 years after it was discovered.
Declining Biodiversity Examples •Bachman’s Warbler •Neotropical migrant • Bred in southeastern US •Wintered in Cuban tropical forests •Deforestation in Cuba for cane fields caused major decline in numbers •Last seen 1989.
Declining Biodiversity Examples •Franklin tree •Altamaha River, Georgia •Last seen in wild: 1803 •Maintained in gardens/arboreta.
Declining Biodiversity Examples •Only parrot native to Eastern US •Lived in large flocks in the SE US •Foraged on grains/fruits •Declared a pest: killed in the thousands by hunters and farmers •Affected by deforestation as well •Extinct by 1920.
Declining Biodiversity Examples •Abundant bird in eastern US (Canada to Gulf) •(estimates in billions of birds) •Flocks of billions of birds described (darkened sky) •Hunted heavily in 1800s •Forests destroyed •Extinct by 1914.
Declining Biodiversity Examples •Xerces Blue Butterfly •Inhabited sand dunes near San Francisco, CA •First North American butterfly to become extinct due to human disturbance •Habitat destruction as city developed was main probable cause.
“Crisis Discipline” Response to: •Disruption of ecosystem functions
Ecosystem Disruption: The Gulf of Mexico “Dead Zone” •Runoff from agricultural fields fertilizers (and other sources) in Mississippi drainage contains nutrients •Excessive nutrients delivered by Mississippi River to Gulf cause algal bloom •Dead algae die, sink, decompose. The Gulf of Mexico “Dead Zone” •Oxygen levels drop (hypoxia: low oxygen) •Aerobic sea life (fish, shrimp, crabs, etc.) dies •Bottom area affected is size of New Jersey (7,700 sq miles).
“Crisis Discipline” Response to: •Climate change Example: Bobolink •Breeds in summer in Northern US and Canada •Migrates to Argentina in winter. •Climate envelope
Climate Change and Species Distributions Special Risk: “Island” species •Ex, Alpine “Islands” Special Risk: “Island” species
Response to: •Invasive species
Example: Brown Tree Snake •Accidentally introduced to Guam (between 1945 and 1952) Example: Brown Tree Snake •Accidentally introduced to Guam (between 1945 and 1952) •Snake population exploded •Extirpated by predation most native forest vertebrates •Shorted power grids •Human hazard of snake bite (mildly venomous: danger to small children). Example: Purple Loosestrife •Change from 1968 to 1978. Loosestrife crowds out other wetland plants (central NY). “Crisis Discipline”
Overharvest of commercial species
Overharvest of Atlantic Cod •Grand Banks Fishery off Newfoundland in North Atlantic •Overfishing and environmental fluctuation caused major population crash •Harvest declined from 800,000 tons in 1968 to 140,000 tons in 1978 •Area closed to fishing in 1992 •May never re-open.
Pollution •May not be visible •Biomagnification may occur: concentration of pollutant increases up food chain •Ex, DDT. •Ex, DDT biomagnification •Caused eggshells to break, nest success dropped •Exs, bald eagle, peregrine falcon. •Bald eagle became federally threatened, peregrine falcon endangered •DDT use banned in U.S. •Recovery efforts have resulted in de-listing of peregrine falcon, proposed de-listing of eagle.
“Crisis Discipline” Response to: •Biodiversity loss •Disruption of ecosystem functions •Climate change •Invasive species •Overharvest of commercial species •Pollution impacts on species/ecosystems •And, #1………..Human population growth!
3 Goals of Conservation Biology •Document biological diversity on Earth •Investigate human impacts on species, communities, and ecosystems •Develop ways to prevent extinction, maintain genetic diversity, and protect or restore communities and ecosystems.
The New Field of Conservation Biology
ConBio’s 5 Ethical Principles •Preserve diversity of species/communities •Prevent extinction of populations/species •Maintain ecological complexity •Allow evolution to continue •Recognize the intrinsic value of biological diversity. •Recognize the intrinsic value of biological diversity…... Biophilia (E.O. Wilson): genetic predisposition of humans to prefer and promote biological diversity.
Some ConBio History •European view was anthropocentric •Nature created by God for humans to use •Resulted in massive exploitation for immediate profit/use •However, there were some surprisingly early conservation efforts!. •Poland 1564 •Reserve established to protect the last population of the aurochs •Ancestor of domestic cattle. •Went extinct anyway! •Breed re-created by German scientist from European domestic cattle. •But reserve did save wisent (European bison) from extinction!.
American ConBio History •John Muir •Founder of Sierra Club •(US conservation organization) •Preservationist ethic: set aside areas from human impact and development •Emphasized value of wilderness for spiritual and artistic uses. • •Gifford Pinchot •First head of US Forest Service in early 1900s •Resource conservation ethic: use resources wisely for all society •Quote: “greatest good of the greatest number in the long run” •Legacy is “multiple use” philosophy for government lands. • •Aldo Leopold •Evolutionary-ecological land ethic: •Management should maintain ecological processes and ecosystem health •Humans part of ecosystems rather than apart from them •Proper management can enhance diversity even beyond that of natural communities. •Recent “spin” on this is “reconciliation ecology” (Rosenzweig 2001) •Seeks how to modify human-dominated habitats to allow humans to share our range with other species.
ConBio Today •Well-established in science and government •Needs more attention by public •2001-2002 was International Biodiversity Observation Year •Needs more young and enthusiastic minds…yours??