Assessing the influence of prey-predator ratio, prey age structure and packs size on wolf kill rates
Assessing the influence of prey-predator ratio, prey age structure and packs size on wolf kill rates
复制标题
评估猎物-捕食者比例、猎物年龄结构和狼群规模对狼杀率的影响
DOI：
10.1111/j.1600-0706.2012.20082.x
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发表时间：
2012
期刊：
影响因子：
3.4
通讯作者：
O. Liberg
中科院分区：
文献类型：
--
作者：
H. Sand;J. Vucetich;B. Zimmermann;Petter Wabakken;C. Wikenros;H. C. Pedersen;R. Peterson;O. Liberg
传统的捕食理论认为猎物密度是决定捕食率的主要因素。最近，被捕食者与捕食者的比例被证明是一个更好的预测杀死率。然而，许多捕食者的选择性行为也表明，猎物种群的年龄结构应该是一个重要的预测杀死率。我们比较了狼驼鹿捕食动态在两个网站，中南部斯堪的纳维亚半岛（SCA）和皇家岛，上级湖，北美（IR），猎物密度是相似的，但猎物的年龄结构和猎物捕食者的比例不同。在SCA中捕食驼鹿的狼的人均杀死率是IR中的三倍。因为SCA和IR具有相似的猎物密度，所以杀死率的差异不能用猎物密度来解释。相反，杀死率的差异解释的猎物捕食者的比例，包大小和年龄结构的猎物种群的差异。虽然比率依赖性功能反应是解释SCA和IR之间杀死率差异的重要变量，但当小牛在狼的饮食中占更大比例时，杀死率往往更高（p <0.05）。我们的研究是第一次提出猎物种群的年龄结构如何影响哺乳动物捕食者的杀死率。SCA和IR猎物种群的年龄结构的差异，在很大程度上，驼鹿和森林被利用在SCA的结果，但不是在IR。虽然捕食者保护在很大程度上是出于恢复营养级联和其他自上而下的影响，我们的研究结果表明，人类企业也可以通过自下而上的过程改变捕食。
Traditional predation theory assumes that prey density is the primary determinant of kill rate. More recently, the ratio of prey-to-predator has been shown to be a better predictor of kill rate. However, the selective behavior of many predators also suggests that age structure of the prey population should be an important predictor of kill rate. We compared wolf– moose predation dynamics in two sites, south-central Scandinavia (SCA) and Isle Royale, Lake Superior, North America (IR), where prey density was similar, but where prey age structure and prey-to-predator ratio differed. Per capita kill rates of wolves preying on moose in SCA are three times greater than on IR. Because SCA and IR have similar prey densities differences in kill rate cannot be explained by prey density. Instead, differences in kill rate are explained by differences in the ratio of prey-to-predator, pack size and age structure of the prey populations. Although ratio-dependent functional responses was an important variable for explaining differences in kill rates between SCA and IR, kill rates tended to be higher when calves comprised a greater portion of wolves’ diet (p 0.05). Our study is the first to suggest how age structure of the prey population can affect kill rate for a mammalian predator. Differences in age structure of the SCA and IR prey populations are, in large part, the result of moose and forests being exploited in SCA, but not in IR. While predator conservation is largely motivated by restoring trophic cascades and other top–down influences, our results show how human enterprises can also alter predation through bottom–up processes.