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In NA, exotic species are?
Non-native species to North America
Why are exotic species an issue?
- hybridization with native species
- competition for food and habitat with native species
- can sometimes severly outcompete native species for food and habitat
Name some examples of exotic species:
- Canada Geese in the UK
- Mute Swan in NA
- Ruddy Ducks in Europe
- Feral cats in Europe, NA, and SA
What was the recorded annual growth rate of Mute Swan in the US portion of the Atlantic Flyway during the Mid-summer Mute Swan Survey?
Name all the problems with Mute swans.
- displace native waterbirds
- kill native species
- hybridize with trumpeter swans
- consume and uproot large quantities of aquatic vegetation
- they're non-migratory and don't field feed
What is the estimated growth rate range of Mute Swans according to the four data sets talked about in lecture?
10% to 21%
The rapid growth of mute swans in NA is probably the consequence of:
- habitat is climatically similar to native range
- NA has few natural predators of mute swans
- little inhibition from native waterfowl
- minimal disturbance, as they're protected under the Migratory Birds Act
- reduced availability of lead artifacts
- high reproductive output
- recent warming trend = increased reproductive output and overwinter survival
How large is the Mute Swan population around the Great Lakes expected to be at maximum capacity? How long will it take to get there?
30,000 birds within 30 years or less
It will probably be necessary to remove at least ____ to _____ of the lower Great Lakes population every year to lead to a reduction.
30% to 40%
What are two of Scott's suggestions in regards to Mute Swans?
- Mute Swans should be removed from the list of species protected in Canada and the United States
- An appropriate international management plan should be devised to deal with this problem right away
What is an example of a species that sucessfully integrated into NA both ecologically and socially?
Ring-necked Pheasant from China in 1881
Why has the Ring-necked Pheasant integrated into NA so successfully?
- They filled an unoccupied niche
- They found virtually identical habitat to their native range (thanks to humans pushing out prairie grouse due to agricultural expansion)
What is the most widely established exotic game bird?
What are some reasons for the failure of some re-introductions?
- failure to properly evaluate the life history strategy and habitat requirement of the species
- failure to release sufficient healthy numbers
- failure to "condition" hand-reared individuals prior to release
- failure to manage population once established
- failure to release wild-strain individuals
Was the re-introduction of wild turkeys successful?
It was too successful, as wild turkeys were originally only found in 36 US states and 1 Canadian province, they can now be found in 49 US states and 4 Canadian provinces.
What are two major criteria for deciding whether or not to re-introduce?
- What is/are the factor(s) responsible for extirpation and are these factors still operating?
- Is the introduction socially/politcally acceptable?
Name some re-introduction success stories?
- Bighorn Sheep in many areas of western NA
- Fisher in northern Michigan
- Woodland caribou in Manitoba
- Moose in northern Michigan
- River Otter in MO, NE, IA, KY
- Trumpeter Swans in several states and provinces
- Whooping Cranes
- Bald Eagles
- Black-footed Ferrets
- Swift Fox
- Peregrine Falcons