analysis of a predator-prey relationship ecological study at isle royale, michigan, u.s

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Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S.

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Page 1: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Analysis of a Predator-Prey Relationship

Ecological Study atIsle Royale, Michigan,

U.S.

Page 2: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Michigan

Can you name the Great Lakes?

Page 3: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Largest island in Lake Superior

45+ miles in length

Isle Royale

Page 4: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Isle Royale National Park

• Established April 3, 1940

• Designated as Wilderness Area 1976

• International Biosphere Reserve 1980

• 894 square miles 209 square miles above water

• 17 smaller islands part of park

Page 5: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Ecology of Isle Royale

• Known for its wolf and moose populations

• Celebrating 50 years of study of closed system predator-prey relationship

• On average:– Wolf population: 25 wolves– Moose population: 1000 moose

• Population fluctuations (1980 wolf – 50; 1995 moose – 2422)

Page 6: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Wolf - Moose

Moose first arrived ~ 1900 via swimming(?)

from Canada

Wolf first arrived in 1950 via ice bridge from Canada

Page 7: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Moose

• During summer, moose eat ~30-40 pounds of vegetation each day, increase body weight by 25%

• Winter feeding is difficult, eat twigs and balsam fir / cedar needles; snow depth makes foraging difficult

Page 8: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Wolf

• Complex pack behavior with alpha male and alpha female

• http://isleroyalewolf.org/overview/overview/wolves.html

Page 9: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Other Wildlife on Isle Royale

There are not many species living on the Isle

• Loons, osprey, beaver, red fox, squirrels

• Will not find porcupine, coyote, white-tailed deer, black bear, chipmunk, skunk

Page 10: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Causes of Fluctuations

• Moose population tends to increase in mild winters, early spring green-up, abundant winter forage, low wolf numbers, low tick infestation – wolf is the only predator

• Wolf population tends to decrease due to disease, starvation, injury - ~90% of wolf diet is moose (few other species available)

Page 11: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Simplicity of the Chain

Isle Royale’s simplified wolf food chain compared to Yellowstone’s more complex

wolf food web.

Isolation of these species from others makes it ideal to study the direct

predator-prey relationship

Page 12: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Impact of Global Warming(?)

• Five of last six summers hottest in past 50 years

• Both moose and wolf populations declining• Increased temp. → moose rest more, eat less

(heavy foraging in summer helps moose survive winters)

• Increasingly warm summers cause increase in tick populations; weaken moose → easy prey

• As moose populations decrease, what happens to the wolf population?

Page 13: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Changing Fortunes of Wolf And Moose Moose and wolf population fluctuations on Isle Royale depend on factors like weather, disease and possibly genetic problems. Scientists are trying to sort out reasons for the current wolf resurgence. j

                                                                                

Page 14: Analysis of a Predator-Prey Relationship Ecological Study at Isle Royale, Michigan, U.S

Recent Data

Year Wolf Moose1998 14 699

1999 25 750

2000 29 850

2001 19 900

2002 17 1100

2003 19 900

2004 29 750

2005 30 540

2006 30 450

2007 21 385