Linking wolves to willows via risk-sensitive foraging by ungulates in the northern Yellowstone ecosystem
Linking wolves to willows via risk-sensitive foraging by ungulates in the northern Yellowstone ecosystem
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DOI：
10.1016/j.foreco.2006.04.023
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发表时间：
2006-07-15
影响因子：
3.7
通讯作者：
Beschta, Robert L.
中科院分区：
文献类型：
--
作者：
Ripple, William J.;Beschta, Robert L.
在消失了大约70年后，灰狼（Canis lupus）在20世纪90年代中期重新引入黄石国家公园。我们研究了狼/有蹄类动物相互作用对杨柳（Salix spp.）在北方黄石生态系统的加勒廷河和拉马尔河以及斯劳河和苏打山小溪的山谷中生长。当我们比较杨柳高度从1998年之前拍摄的照片（柳树< 2米高）与2004年拍摄的照片时，我们发现研究区域内42个地点中有22个的杨柳高度增加。基于时序照片的比较，自狼引进没有16个高地河岸网站表现出增加杨柳高度，而22的26个谷底河岸网站有杨柳高度增加。在2004年，杨柳高度与被蛀干率呈显著负相关（r =-0.81，p < 0.01，n = 42）。谷底位置的回归结果表明，视距，障碍距离，和野牛（野牛野牛）的数量与杨柳高度呈负相关（p < 0.02）。增加杨柳高度没有显着（p = 0.18）相关的模式的水分供应。本研究中记录的杨柳高度增加似乎至少部分是由于行为介导的营养级联涉及狼和有蹄类动物，通过捕食风险的机制。当杨柳释放（即，虽然研究区域内的高生长（高生长增加）处于非常早期的阶段，但结果表明，陆地食物链中的顶级食肉动物可能产生重要的间接影响，这可能有助于恢复河岸物种和保护生物多样性。(c)2006 Elsevier B. V.保留所有权利。
After an absence of approximately 70 years, gray wolves (Canis lupus) were re-introduced into Yellowstone National Park in the mid-1990s. We studied the potential influence of wolf/ungulate interactions upon willow (Salix spp.) growth in the valleys of the Gallatin and Lamar Rivers, as well as Slough and Soda Butte Creeks, in the northern Yellowstone ecosystem. When we compared willow heights from photographs taken prior to 1998 (willows < 2 m tall) with those taken in 2004, we found an increase in willow height for 22 of 42 sites within the study area. Based on comparisons of the chronosequence photos, since wolf introduction none of the 16 upland riparian sites showed an increase in willow height, while 22 of 26 of the valley-bottom riparian sites had willow height increases. In 2004, willow height exhibited a strong inverse relationship with the percentage of browsed stems (r = -0.81, p < 0.01, n = 42). Results of regressions for valley-bottom sites indicated that view distance, impediment distance, and the number of bison (Bison bison) flops were inversely related to willow height (p < 0.02). Increased willow heights were not significantly (p = 0.18) related to patterns of moisture availability. Willow height increases documented in this study appear to have been at least partially due to behaviorally mediated trophic cascades involving wolves and ungulates, via a mechanism of predation risk. While willow release (i.e., increased height growth) within the study area is in a very early stage, results suggest potentially important indirect effects of a top carnivore in a terrestrial food chain that may aid in the restoration of riparian species and the preservation of biodiversity. (c) 2006 Elsevier B.V. All rights reserved.