Yellowstone National Park-changes in ecosystems

Question 1

location of yellowstone

Answer 1

Rocky mountains in USA

Question 2

why were wolves eradicated in 1944?

Answer 2

policy of predator eradication led to persecution by farmers and hunters for economic gain. it was a dominant large carnivore affecting elk levels

Question 3

impacts of wolf eradication

Answer 3

• numbers of herbivores increased

- impacted on plant growth and population of insects, birds and small mammals

Question 4

return of grey wolves in 1995

Answer 4

• 31 wolves released into national park and 35 into central Idaho
• part of programme to re-establish the species
• 10 years late wolf population had increased to 300, half of them in Yellowstone

Question 5

wolves returning affected elk population by

Answer 5

triggered a trophic cascade=affects entire ecosystem

90% of wolf kills large herbivores had been elk= elk numbers halved in 10 years

Question 6

indirect effect wolves had on plant species

Answer 6

-changes in elk species relieved grazing and browsing pressure on willow and aspen along streams and rivers

Question 7

indirect effect wolves had on other animal species

Answer 7

increased growth in plants, benefited songbirds. streams dammed by beavers have attracted more waterfowl, frogs, trout, vols etc
-decline in coyote numbers has increased in small, mammals which has boosted population of red foxes and birds of prey

Question 8

conclusion for an essay

Answer 8

had large impacts due to the interconnectedness of the food webs involved and interdependent nature. The ecosystem has been completely restructured and rebalanced