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Environmental Biology 105 Lecture Notes Lisa Snyder Biodiversity Exotic Invasive Species Kudzu: Introduced to USA –1876 Planted in SE USA (1950) for Feed & erosion control Grows up to 1 ft. per day (60-100 ft per season) Smothers all in its path (block sunlight, snap stems & trunks under its weight) Controlled by freezing winter temps in native habitat Fire Ant (Brazil & Argentina) Introduced to USA (Mobile, AL) in 1920’s 4 species now in USA Introduced to Orange County (1998) in Trabuco Canyon Nursery plants (Now at 523 + sites) Painful bites (toxic venom) = rash Lethal to pets, wildlife, allergic humans Require H2O to survive (unlike native ants) Benefit from home & garden irrigation Controlled by micro-organisms, fungus, & parasites in S. America Arundo Donaz (Giant Reed) Native to China, India Introduced for Riverbank stabilization Spreads by vegetative growth Any broken piece can root Out-competes & completely suppresses native vegetation Chokes H2O ways, fire hazard Others: Black Mustard, Artichoke Thistle, Red Fox, Northern Pike, Cowbird Over-hunting & Extinctions Extinct Species: Steller's Sea Cow Relative to manatee & dugong Size: to 8 m long, weighed > 6000 kg. In Pacific (Bering Sea - Mexico & Japan) Fed on kelp in shallow water Estimated population of 2000 Extinct by 1768 - intensive hunting by seal hunters (for meat) 1st recent extinction of a marine mammal Passenger Pigeon World’s most numerous bird >5 billion in U.S. alone Eaten to extinction in 1914 Dodo Bird Only on Mauritius isle- Largest animal (no native people) Flightless, fearless -no predator Humans (1505) brought dogs, pigs, rats (destroyed Dodo nests) Humans destroyed forests Extinct by 1693 (100 yrs. after discovery) Nearly Extinct Species: North American Bison Original Bison pop.: ~60–100 million 1890: ~750 – 400 Losses primarily due to U.S. Government/Military strategy to starve-out native Americans Current pop: ~350,000 Sea Otters, Beavers – hunted for pelts (fur) Gray Wolf – primarily hunted by Government for livestock protection Blue Whale – hunted for oil (for lamps & industrial uses), meat, bone, etc. Hunting in the Ocean 18% Total Animal Protein from Ocean Fishing fleets 75% of harvest by huge commercial fleets that Work year-round Scouting vessels locate fish Factory ships follow fleet: Process, can, freeze at sea Commercial Fishing Technology 1950-1997: Marine catch has increased more than (five-fold) 5X Due to improvements to & increased use of fishing gear technology HUGE Nets: Can hold up to 12 747 airplanes o Gigantic trawl nets (as big as statue of liberty) that drag on seafloor & also catch mid-water fish & invertebrates Shrimp trawls are especially damaging to seafloor Purse Seines – slowly enclose around surface & mid-water species Satellite Technology: o Tracks plankton blooms (help locate fish) & fish schools Maximum sustainable yield (MST): Maximum amount of a population that can be harvested without impairing future populations. World MST Estimate: 110-135 million metric tons 2001 world harvest = 130.2 MMT We’re at limit or have exceeded it Exceeding Maximum Sustainable Yield Properly managed fisheries can be renewable resources, however Despite a major increase in fishing effort, yield has decreased since 1980’s ~70% of marine fisheries are out-fished or over-fished o Not enough breeders left to replenish the population Money (not science) drives the fishing industry o Greatly impacted by consumer demand Georges Bank Cod Fishery North Atlantic (Maine) Landings decreased ~91% from 1990-1999 Industry response: increase use of technology & increase the number of fishing boats Over-fishing became so severe that the Cod population crashed (nearly no fish left) Regulations had to be implemented to save the Cod from extinction: Daily catch limits o Increased Minimum size requirements (so more young could survive to adulthood for breeding) Increased Trawl mesh size (so small, young fish could escape) Permit restrictions (fewer permits) Rolling area closures Other Mismanaged Fisheries Orange Roughy (New Zealand) o 1980’s “favorite fish” o Take 25-30 yrs. to sexually mature o Commercially extinct in 13 years (so few left = not profitable to catch) Chilean Seabass (Tootfish) o High Demand causing severe overfishing o Unless demand decreases, it may be commercially extinct in 5 yrs. o A large percentage are caught illegally Consumer Choices You, the consumer, have an impact on the health & survival of marine species o Choose well-managed, harvested & farmed species o Monterey Bay Aquarium’s Seafood Watch www.mbayaq.org/cr/seafoodwatch.asp UNDERSTANDING THE ENDANGERED SPECIES ACT What is the ESA? Federal Law : 1973 (USA), 1976 (Canada) protecting wildlife & plants Conserve & recover species in danger of extinction Preserve ecosystems that sensitive species depend upon Each State also has their own laws protecting species FEDERAL AGENCIES IN CHARGE U.S. Fish and Wildlife Service in the Dept. of Interior Terrestrial & freshwater species plus migratory birds National Marine Fisheries Service in the Dept. of Commerce Marine, estuarine, & anadromous species Examples of Federally Listed Species Bull trout ,Mexican spotted owl, San Joaquin kit fox, Oregon silverspot, Giant kangaroo rat California jewelflower, Indiana bat, Canada lynx, Piping plover, Desert tortoise Number of U.S. Listed Species per Calendar Year: 2002 (cumulative = 1260) Species Recovery Plans Restore populations to sustainable levels Stop & reverse decline, remove threats Habitat protection or restoration, removal of exotic species, clean up pollution, captive breeding USFWS, State & Federal Agencies, Universities, private institutions, local stakeholders May take years Habitat Conservation Plans Agreements with private landowners: allow resource harvest or development on part of their land if endangered species on their property benefit overall Restore habitat, fund conservation research, remove exotic species 250 HCP’s (200 in progress) 18.5 million acres ESA Successes Bald Eagle – Listed 1973 >100,000 pairs in lower 48 states 417 pairs - 1963 Hunting, DDT Downlisted (Threatened) 1995 Still Endangered in California American Peregrine Falcon Listed 1970 (324 pairs) DDT 6,000 breed in captivity & released De-listed 1999 1,300 breeding pairs (41 states) More Recovered Species: Gray Whale, Canada Goose, Red Kangaroo, Colombian White-tailed Deer International Wildlife Treaties U.S./Canada/Mexico Trilateral Committee for Wildlife & Ecosystem Conservation & Management (1996) CITES - Convention on International Trade in Endangered Species (1975) 164 member countries Protects & regulates trade in endangered species (live specimens & products) > 700 species listed