ECOL 1000 1nd Edition Lecture 22 Outline of Last Lecture I. MacArthur-Wilson Equilibrium Model II. Passenger pigeonIII. Carolina parakeetIV. Extinction EventOutline of Current Lecture II. Risk of ExtinctionIII. Threats to biodiversityIV. How to classify extinction?V. Endangered Species ActCurrent Lecture- What increases a species’ risk of extinctiono Endemic populations or a few local populationso Species that migrate seasonally (if one habitat disappears, species will not persist)o Specialized habitat requirementso Large home ranges (fragmentation restricts the availability of habitat) Large home ranges and isolation of individuals increases risk of extinction Natural habitat corridors neededo Conflicts with humans or used by humans- Threats to biodiversityo Habitat loss and alteration Atlantic coast forest of Brazil Loss of many endemic species and other threatened (golden lion tamarin) Decline of forests in Madagascar Deforestation projectsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Habitat fragmentations: localized clearing; reduction of large habitat into smaller, isolated patcheso Invasive species Dozens of tree snails live in Hawaii are now endangered species, although were once abundant- Shells were used in lei and other ornaments- Brought in predatory rosy wolf snails which would eat the giant African snails then the predatory snails started eating the tree snailso Coextinctions Flightless bird Moa driven to extinction on New Zealand by settlers followed by Haasts Eagle which relied on the Moa for foodo Commercial Exploitation The Great Auk-an overhunted penguino Diseaseo How to classify risk of extinction? IUCN “Red List” Critically endangered (50% likelihood of extinction in 10 years) Endangered (20% likelihood/ 20 years) Vulnerable (10% likelihood/ 100 years) To characterize each species, scientists need info:- Is there an observable decline- What geographic area is occupied- What is the total # alive and total # breeding- What is the expected decline if trends continue- What is the probability of going extinct in a finite time periodo Endangered Species Act (ESA 1973) Protect critically imperiled species from extinction as a consequence of economic growth The U.S. Supreme Court found that the plain intent of congress was to halt and reverse the trend toward species extinction whatever the cost Environmental law created in 1973 administered by two federal agencies (US Fish and Wildlife Service and the National Oceanic and Atmospheric Administration) Recognizes that critical habitat is a necessary link between habitat protection and recovery goals, requiring the identification and protection of all lands, waterand air necessary to recover endangered species- Space for individual and population growth- Food- Water- Breeding sites- Seed germination- Lack of disturbances Considers all areas essential to the conservation of the imperiled species and may fall on public or private land As of 2012 56 species have been delisted from the ESA
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