Yellowstone National Park rev
How the presence and absence of a top predator can u
YELLOWSTONE NATIONAL PARK Shikha Mehta UI3815 | Shail Sheth UI3515
Category: National Resources Typology: Revival
REVIVAL THROUGH WOLVES
TIMELINE 1800s
How the presence and absence of a top predator can utterly reshape an ecosystem.
1872
Yellow Stone National Park establishment
Gray wolves were reintroduced into Yellowstone National park in 1995, resulting in a trophic cascade through the entire eco-system. After the wolves were driven extinct in the region nearly 100 years ago, scientists began to fully understand their role in the foodchain as a keystone species. The presence of wolves triggered a still-unfolding cascade effect among animals and plants-one that will take decades of research to understand.
Killing of wolves
1907
Animal Damage controk targeted killing of wolves
TIM EC IM TH
1920
Complete extirpation of wolves from Yellowstone National park
INTR 1920 - 1955
Increase in Elk population which resulted into decrease of vegetation which impacted the Ecosystem of the park
Gray w cascad 100 ye species plants-
ABO
Yellows Mostly lakes, r lush for animal
1975
US Government declared wolves as endangered species banning killing
1995
23 Wolves were re-introduced in the Yellow stone National Park (Phase 1)
Location of National Park In the United States of America
1996
16 wolves were re-introduced in the Yellow stone National park (Phase 2)
ABOUT THE PARK : Yellowstone features 9100 sq km of dramatic canyons, alpine rivers, lush forests, hot springs and gushing geysers and a rich ecosystem. It is home to hundreds of animal species, including bears, wolves, bison, elk and antelope.
• Elk population was brought in control • Migration path of the Elk’s were changed keeping them far from the tree area increasing the number of trees • Migratory birds return to the park • Increase of trees provided lumber for beavers making an healthy impact on 9 beaver colonies • Beavers colonies giving way to small ponds and impact on river • Permanence of river bed and forest
KILLING OF THE WOLVES : From the middle of the 1800’s until 1926 the wolves of Yellowstone National Park were hunted and killed as a nuisance for preying on elk and deer, the parks most beloved animals. In 1907, under political pressure from the western cattle and livestock industries, this agency began a concerted program which eventually was called: Animal Damage Control - killing many wolves in the park. In 1926 wolves were completely exterminated from the park.
Effects of the reintroduction of wolves in the park
2009
Removal of wolves from the endangered species list
1
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From t Nationa elk and nationa and go 1900s 1907, industr was ca alone k Forests the par
ECO (192
Once t Yellows woody method
Elk con congre Yellows rise. As was th Yellows
With w began beaver
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ECOLOGICAL IMPACTS IN ABSENCE OF WOLVES :
The elk began multiplying inside e of the 1800’s until 1926 the wolves of Yellowstone theandpark woodfor species were hunted killed asand a nuisance preying on he parks most beloved animals. creation of the suffered from The overgrazing. d not provide protection for wolves or other predators, wolvesin the missing from t predatorWith control programs first decades of the ly helped eliminate the gray wolf from Yellowstone. this complex ecosystem theIn litical pressure from the western cattle and livestock coyotes became the alpha agency began a concerted program which eventually predator, began off mal Damage Control. This predator killing control program 00 wolves and 23,000 coyotes in 39 U.S. National smaller species and ultimately . In 1926 wolves were completely exterminated from shrinking the population of smaller mammals like beavers, foxes, and other small predators.
Year
No. killed
1915
7
1916
14
1917
4
1918
36
1919
6
1920
28
1921
12
1922
24
1923
8
1924-35
0
This decline in elk has resulted in changes in flora, most specifically willows, co aspens along the fringes of heavily timbered areas. Although wolf kills are directl declines in elk numbers, some research has shown that elk behavior has been sign by wolf predation. The constant presence of wolves have pushed elk into less fav raised their stress level, lowered their nutrition and their overall birth rate. 180 160 Number of wolves
CLINEElk OFpopulations WOLVESbegan to rise.
Yellowstone delta
Bechler
140 120 100 80 60 40
GICAL IMPACTS IN ABSENCE ON WOLVES )
20 0
s were gone, elk populations began to rise. Over the next few years conditions of ional Park declined drastically. The elk were multiplying inside the park and deciduous, such as aspen and cottonwood suffered from overgrazing. Elk population control ued for more than 30 years.
Year
’97 ’98 ’99 ’00 ’01 ’02 ’03 ’04 ’05 ’06 ’07 ’08 ’09 ’10 ’11
Yellow stone national park wolf density after revival
Yellow stone national park
16000
120 Number of wolves
inued into the 1960s. In the late 1960s, local hunters began to complain to their hat there were too few elk and the congressmen threatened to stop funding ling elk was given up as control method which allowed elk populations to again pulations rose, the quality of the range decreased affecting many other animals. It arge elk populations that caused the most profound changes to the ecosystem of h the absence of wolves. Elk herds
14000
100
12000
80
10000
60
8000
Thereby 6000 The decrease degrading 4000 When wolves were ballooned, Beavers lost 20 The lack of dams in trees ssing from thisexterminated complex ecosystem, the vast alpha predator andled to conditions 2000 from thethe coyotes became overgazing their food 1995-2015 caused streams smaller species andstone ultimately shrinking the population of land smaller mammals less like the willow Yellow National tracts of source and and other smallpark predators inside the Yellowstone National park. erode, making bio-diversity Northern and 1995-2015 aspen range: Bison winter counts ,the interwoven and trees such lumber to Wolves, Elkstoand them deeper and and habitat for trees need to ecosystem was altered as willow and build their not as wide. birds. grow. leading to imbalance aspen. dams. 40
RE-INTRODUCTION OF WOLVES : 8 Mile
Wolves brought in from Canada were re-introduced in the park. The resultant decline in elk has resulted in changes in flora, most specifically willows, cottonwoods and aspens along the fringes of heavily timbered areas.
Blacktail Lamar canyon
Cougar
Canyon Mollies
Although wolf kills are directly attributable to declines in elk numbers, some research has shown that elk behavior has been significantly altered by wolf predation. The constant presence of wolves have pushed elk into less favorable habitats, raised their stress level, lowered their nutrition and their overall birth rate.
Mary mountain
Numerous ecological impacts in the park are being observed till a micro-level till date.
Bechler
Yellowstone delta Wolf packs formed in the park after re-introduction
2
Northern
EFFECTS ON OTHER ANIMALS: EFFECTS ON COYOTES:
EFFECTS ON BEARS :
Yellowstone coyotes have had to shift their territories as a result, moving from open meadows to steep terrain. As Coyotes naturally suppress foxes, the diminished coyote population has led to a rise in foxes, and shifts the odds of survival for coyote prey such as hares and young deer, as well as for the small rodents and ground-nesting birds the foxes stalk.
After the wolves reintroduction, their increased predation of elk benefited Yellowstone’s grizzly bear population, as it led to a significant increase in the growth of berries in the national park, an important food source for the grizzly bears.
Number of wolves
14000
100
12000
80
10000
60
8000
40 20 1995-2015
Number of Elk
16000
120
6000
Wolves
4000
Elk
2000
Bison
Northern range: Wolves, Elks and Bison winter counts 1995-2015
Increase in wolves bringing down the population of elks
EFFECTS ON BEAVERS : The presence of wolves seems to have encouraged elk to browse more widely, diminishing their pressure on stands of willow, a plant that beavers need to survive the winter. The renewed presence of beavers in the ecosystem revived the existence of beaver dams. Beaver dams also counter erosion and create “new pond and marsh habitats for moose, otters, mink, wading birds, waterfowl, fish, amphibians and more.” Beaver dams have multiple effects on stream hydrology. They even out the seasonal pulses of runoff; store water for recharging the water table; and provide cold, shaded water for fish, and revive birds.
AFTER - Increase in trees and permanency of river beds
Re-introduction of wolves leading to other animals eating plants
3
CHALLENGES :
BIBLIOGRAPHY :
• The re-introduction of wolves in the Park evoked opposition from the locals. The hunters complained that too many elk have become wolf food. In a region struggling with economic hardship such as lumber mill closures, wolves are direct competitors for meat to feed the family. The hunters had talk about shooting the wolves like their fore-fathers did.
• Law, Yao-Hua. “Earth - When Wolves Return to the Wild, Everything Changes.” BBC, BBC, 17 May 2017, www.bbc.com/earth/story/20170516-when-wolves-return-to-the-wildeverything-changes. • National Geographic Society. “Wolves of Yellowstone.” National Geographic Society, 26 Jan. 2015, www.nationalgeographic.org/media/ wolves-yellowstone/. • “Global Business.” Google Books, Google, books.google.co.in/books?id=3fgWAAAAQBAJ&pg=PA574&lpg=PA574&dq=national%2Bgeographic%2Byellowstone%2Brevival%2Bby%2Bwolves&source=bl&ots=TBsfGpxDFp&sig=ACfU3U2gyIjsEU84CiOngB-KiRGb6gEFGg&hl=en&sa=X&ved=2ahUKEwjD5Kv0ltrjAhVIOY8KHQ7qCt8Q6AEwInoECAYQAQ#v=onepage&q=national%20geographic%20 yellowstone%20revival%20by%20wolves&f=false. • Human, Sustainable. “How Wolves Change Rivers.” YouTube, YouTube, 13 Feb. 2014, www. youtube.com/watch?v=ysa5OBhXz-Q. • Mossotti, Travis. “Yellowstone Wolf Project.” Prairie Schooner, vol. 86, no. 3, 2012, pp. 115– 122., doi:10.1353/psg.2012.0101. • Sensitivity Analysis of wolf restoration in Yellowstone National park using Omnivory model • Peng, Mike W. Global Business. South-Western / Cengage Learning, 2014.
• A second group that opposes the re-appearance of grey wolves are ranchers who raise live-stock such as cattle and sheep for a living. Wolves literally eat into the thin profits of ranchers and jack up the price of beef, lamb, milk, cheese, yoghurt that the public has to pay. Livestock with injuries scratched by unsuccessful wolf chases or with infectionsfrom wounds are not marketable and ranchers have to eat such losses. Also, stress results in lot of livestock miscarriages. Frustated ranchers cannot defend their private property by shooting wolves. Instead they vote politicians on a pro-wolf platform out of office and fill state legislatures in Idaho, Montana and Wyoming with candidates who vow to make wolves go away. • Public outreach included giving 285 formal talks, participating in 94 interviews, helping 19,000 people view wolves,making 16,780 visitor contacts, and giving 573 informal talksin the field.
CONCLUSION: The project is an example of a trophic cascade - The top-down effect of the reintroduction of an apex predator like the wolf on other flora and fauna in an ecosystem.
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