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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
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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