DISSERTATION RESEARCH: Indirect Effects of Predators on Prey: Consequences of Wolf Predation for Elk behavio, Nutrition, and Reproduction

捕食者对猎物种群的总体影响包括杀死猎物和与反捕食者行为相关的不太明显的成本。 这些代价通常会影响猎物的生存或繁殖，并可能成为实验中种群动态的重要组成部分。 然而，在野外发现这些行为的成本是困难的，因为捕食风险往往会随着时间和空间的变化而不可预测。 联邦狼的重新引入和保护计划导致了北美几个地区狼的数量迅速增长和广泛扩大。 这些新的狼种群产生了一些高度公开的争议，特别是在被狼捕食的动物为当地社区提供了重要的娱乐和收入来源的景观中。 在蒙大拿州的加勒廷峡谷，麋鹿的人口规模和招聘表现出显着的抑郁水平，立即被狼的捕食，直接捕食似乎只有部分责任。 虽然冬季生存可能涉及，怀孕率和小牛生存表明麋鹿繁殖也可能受到最近到达的狼的影响。 这项研究表明，麋鹿会分成更小的群体，在针叶林中呆更长的时间，搬到更高的海拔地区，提高警惕性，当狼群靠近时，减少在开阔地区的放牧。 因此，与避免狼相关的成本可能存在，可能是麋鹿种群的一个重要因素。 这项研究将记录觅食行为，饮食组成，并在三个独立的鹿群的麋鹿作为狼移动整个冬季横跨加勒廷峡谷的饮食营养。 每天狼的位置和杀戮频率将被监测，以便每个麋鹿群的行为和营养数据可以与不同程度的捕食风险联系起来。 最后，麋鹿群之间的状况、生存和繁殖成功的差异将与对狼的行为反应有关。 除了为研究生完成这项工作提供经济支持和为本科生提供教育经验外，这些数据还将大大有助于我们理解在自然变化风险下反捕食行为在种群动态中的作用。

The total impact of predators on prey populations includes the killing of prey and the less conspicuous costs associated with antipredator behavior. These costs often affect prey survival or reproduction and can be an important part of population dynamics in experiments. However, uncovering the costs of these behaviors in the wild is difficult because predation risk tends to vary unpredictably over time and space. Federal wolf reintroduction and conservation programs have resulted in rapidly growing and widely expanding populations in several areas of North America. These new wolf populations have generated several highly publicized controversies, especially in landscapes where animals preyed upon by wolves provide an important source of recreation and revenue for local communities. In the Gallatin Canyon of Montana, elk population size and recruitment showed significantly depressed levels immediately following recolonization by wolves, and direct predation appears only partly responsible. Although winter survival may be involved, pregnancy rates and calf survival suggest elk reproduction might also be influenced by the recent arrival of wolves. This study has shown that elk will break into smaller groups, spend more time in conifer forest, move to higher elevations, increase their level of vigilance, and decrease grazing in open areas when wolves are nearby. Thus, costs associated with avoiding wolves likely exist and are probably an important factor for elk populations. This study will record foraging behavior, diet composition, and dietary nutrition in three separate herds of elk as wolves move across the Gallatin Canyon throughout the winter. Daily wolf locations and frequency of kills will be monitored so that behavioral and nutritional data for each elk herd can be linked to differing levels of predation risk. Finally, differences in condition, survival, and reproductive success between elk herds will be associated with behavioral responses to wolves. In addition to providing financial support for a graduate student to complete the work and an educational experience for undergraduates, these data will contribute substantially to our understanding of the role of antipredator behavior in population dynamics under natural variation in risk.