Yellowstone's Destabilized Ecosystem: Elk Effects, Science, and Policy ConflictOxford University Press, 25 мая 2006 г. - Всего страниц: 392 Wagner, one of our most distinguished wildlife biologists, is a strong critic of ecological practices in the national parks. This book provides an assessment of the ecological history of Yellowstone's northern range, since before the park existed, showing the impact of US Park Service policies on the health of the areas they oversee. He demonstrates that elk had been historically rare throughout the region and that overgrazing by elk has seriously degraded the landscape and altered the structure of the area. This is a major contribution to reconstructing the ecology of this region over the course of the past 500 years. It is also a critique of US Park Service management policies and their stewardship of the nation's most cherished natural areas. Wagner's book will generate substantial attention and debate both in the scientific and policy/management communities. |
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Стр. 11
... increase sufficiently to affect the herd size. By the winters of 2000–2001 and 2001–2002, elk calves/100 cow ratios had fallen from ~30–40/100 in prior years to 26–28/100 in 2001 and 14/100 in 2002 (T. O. Lemke, personal communication ...
... increase sufficiently to affect the herd size. By the winters of 2000–2001 and 2001–2002, elk calves/100 cow ratios had fallen from ~30–40/100 in prior years to 26–28/100 in 2001 and 14/100 in 2002 (T. O. Lemke, personal communication ...
Стр. 18
... increase continued through the uncensused years of 1979–80 and 1980–81 because the 48% increase between 1978–79 and 1981–82 would be unlikely, biologically, in 3 years. Mack and Singer (1992) pointed out that the low censuses in the ...
... increase continued through the uncensused years of 1979–80 and 1980–81 because the 48% increase between 1978–79 and 1981–82 would be unlikely, biologically, in 3 years. Mack and Singer (1992) pointed out that the low censuses in the ...
Стр. 22
... increase (r will be positive) in a year when the densityindependent factors ease their effects. This can occur in ... increases, it incurs rising density-dependent pressures (figure 2.1), which eventually force r to the negative despite ...
... increase (r will be positive) in a year when the densityindependent factors ease their effects. This can occur in ... increases, it incurs rising density-dependent pressures (figure 2.1), which eventually force r to the negative despite ...
Стр. 23
... increased winter migration outside the park since the 1970s with the total area now occupied having increased by as much as 41% (Lemke et al. 1998). These authors have speculated on whether this enlarged winter range area has increased ...
... increased winter migration outside the park since the 1970s with the total area now occupied having increased by as much as 41% (Lemke et al. 1998). These authors have speculated on whether this enlarged winter range area has increased ...
Стр. 24
... increased in series of years when removals fell below 11–15%, then held its numbers or declined following one or a ... increase through the early 1930s until 3 out of 4 years with removals ranging from 14.3% to 20.0% from 1935–38. With ...
... increased in series of years when removals fell below 11–15%, then held its numbers or declined following one or a ... increase through the early 1930s until 3 out of 4 years with removals ranging from 14.3% to 20.0% from 1935–38. With ...
Содержание
1 | |
13 | |
Part III Elk Effects on Ecosystem Structure and Function | 57 |
Part IV The Role of Science in Policy Process | 305 |
References | 335 |
Index | 359 |
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Yellowstone's Destabilized Ecosystem: Elk Effects, Science, and Policy Conflict Frederic H. Wagner Ограниченный просмотр - 2006 |
Yellowstone's Destabilized Ecosystem: Elk Effects, Science, and Policy Conflict Frederic H. Wagner Ограниченный просмотр - 2006 |
Yellowstone's Destabilized Ecosystem: Elk Effects, Science, and Policy Conflict Frederic H. Wagner Ограниченный просмотр - 2006 |
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abundance animals aspen authors Barmore beaver bighorn bighorn sheep biomass Bishop bison Butte Creek censuses century clones commented competition components conifers Coughenour Coughenour and Singer decades density Despain early ecological effects elk herd elk numbers elk population Engstrom ern range erosion estimates evidence exclosures factors figure forage grasses grazing habitat herbaceous herbaceous vegetation herbivory higher elevations highlining Houston hunting impacts increase indicates inferences inside the exclosures interspecific competition Kay’s Keigley Kittams lakes Lamar River levels lower measurements ment mule deer National Park northern herd northern range ecosystem observed occurred park establishment park history park’s period photographs plants processes production pronghorn r-values reduced reported result riparian riparian zones sagebrush Schullery sediment shrub significant soil species studies suggest tannin tion trees trends ungrazed ungulate Wagner Wambolt willow decline winter range Yellowstone Yellowstone National Park