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Wildlife Ecology
Updated 26 August 2009
Bolen and Robinson (2003) - Ch. 3 - Some Successes in Managing Wildlife
Read biography of Gifford Pinchot – page 21
1.
Bison - plains bison interbred with other subspecies of bison, in particular, wood bison (the
hybrids were very susceptible to tuberculosis); then in "Wood Buffalo National Park" in
1960, they found about 200 pure-bred wood bison
- they bred European bison from those captives left after WWI
2.
Lead Poisoning: Almost Gone
- lead shot has accumulated in areas where hunting is heavy and takes place at the same
location year after year -- especially a problem in wetland areas; waterfowl ingest the shot
and died of lead poisoning
- there was opposition to using steel shot at first, but now it is calming down
- opposition included:
1.
crippling (steel shot is less dense)
2.
gun damage (steel shot is harder on inside of barrel)
3.
cost (steel is more expensive)
- lead sinkers have also killed common loons in states where they were threatened or
endangered (Michigan, New Hampshire, Vermont)
- trumpeter swans in western US have suffered
- mute swans in England - died from lead sinkers
3.
Wood Ducks - protected by the Migratory Bird Treaty Act of 1918 - no hunting
- nesting boxes and closing the hunting season helped bring up numbers
- numbers were up by the 1930's (but nesting habitat seemed to be limiting factor; hunting
season restored by 1941
4.
Wild Turkeys - they finally reintroduced the proper subspecies for the area (i.e., they were
adapted to local conditions) - before this, introductions didn't "take" very well
5.
Restoration of Mammals in North America - read
- deer
- pronghorn
- elk - Yellowstone and Jackson Hole, WY - beaver
-snowshoe hare
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6.
Marine Mammals
Marine Mammal Protection Act of 1972 bolstered the Endangered Species Act of 1973 – it
provided federal protection for marine mammals within the territorial waters of the US – covers
mainly pinnipeds (seals), sirenians (manatees), and cetatceans (dolphins, whales), and depending
of the group, falls under the jurisdiction of either the National Marine Fisheries Service of the
USFWS
Sea otters – formerly hunted for their fur – very dense; decreased due to oil spills (oil gets in fur
and the can’t keep warm
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they have relatively high metabolisms to keep their body temperature up – they
often eat shellfish and other foods of commercial value to humans
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some natural recovery now that they are protected, but killer whales, which normally
feed on blubber-rich seals and sea lions started to eat sea otters in parts of the
Aleutian Archipelago – population declined 25% each year of the 1990’s (they think
seals and sea lions have declined due to lost food resources after years of heavy
trawling in the Bering Sea and increasing ocean temperatures
gray whales – they were exploited for years because they migrated fairly close to the North
American Pacific shore and they had a predictable migration route
The International Whaling Commission banned further harvests of gray whales in 1946; Mexico
established the first protected area for the species in 1971
Numbers increasing – in 1994, gray whales were removed from the list of endangered species
remained protected by the Marine mammal Protection Act
By 1999, population reached 26,600 – almost double the estimate for 1980
In 1997, proposal was put forth to build a big salt factory at a major calving area – caused lots of
controversy – would damage whale population – idea was dropped
Lots of dead whales washed ashore starting in 1999- they seem emaciated – might be out-stripped
their carrying capacity – but they don’t know for sure; read about whales – interesting reading
7.
Some Successes with Birds - sage grouse
- whooping cranes (to a point)
Still having problems with- California condor
- trumpeter swan
- roseate spoonbill
- black-footed ferret
Elusive Measures of Successful Management - read