LTREB: Ecological and Evolutionary Determinants of Habitat Selection and Risk of Nest Predation among Coexisting Species

9707598马丁共存物种的栖息地选择通常被认为反映了生态成本最小化和适应性最大化的选择。共存物种之间的生态过程经常被强调为微生境选择差异的潜在解释。然而，流程和底层流程机制很少被直接测试。捕食可以促进共存物种之间的微栖息地差异，这是一个可以直接测试的过程。然而，作为物种进化史的一个功能，生境选择也可能受到生理耐受性的限制，不同的进化历史或生理耐受性可能为物种之间资源利用的差异提供了另一种解释。这种生物与非生物影响的替代作用在小气候梯度上特别突出，因为物种通常沿着小气候梯度分离。这项研究将解决这个问题，“物种沿着环境梯度的分布是否反映了生理限制或对生态成本（如巢捕食或植被偏好）的反应？”对这一系统和巢址变化的持续长期研究是很重要的，因为这种变化提供了一个前所未有的机会，可以根据潜在环境影响的动态变化，研究生物与非生物影响对栖息地选择和物种共存的潜在作用。这项长期工作的继续将促进我们对巢捕食作为影响栖息地选择、物种共存和亲代活动模式的过程的机制的理解。这些数据将为物种的长期保护提供重要信息；成功繁殖的栖息地要求对保护至关重要，美国林务局目前正在使用本项目收集的数据来影响所研究森林的土地管理决策。

9707598 Martin Habitat selection among coexisting species is generally thought to reflect choices that minimize ecological costs and maximize fitness. Ecological processes among coexisting species are often emphasized as a potential explanation for differences in microhabitat choices. Yet, processes and the mechanisms underlying processes are rarely directly tested. Predation can favor microhabitat differences among coexisting species and is a process that can be tested directly. However, habitat selection also may be constrained by physiological tolerances as a function of the evolutionary history of a species and different evolutionary histories or physiological tolerances may provide an alternative explanation for differences in resource use among species. Such alternative actions of biotic versus abiotic influences are particularly highlighted along microclimate gradients because species commonly segregate along microclimate gradients. This study will address the question, "Does the distribution of species along an environmental gradient reflect physiological constraints or responses to ecological costs such as nest predation or vegetation preferences?" Continued long term study of this system and nest site shifts is important because such shifts provide an unprecedented opportunity to examine the potential role of biotic versus abiotic influences on habitat selection and species coexistence based on dynamic changes in potential environmental influences. Continuation of this long-term work will advance our understanding of mechanisms underlying nest predation as a process influencing habitat selection, species coexistence, and parental activity patterns. These data will provide important information for long-term conservation of species; habitat requirements for successful reproduction are critical for conservation and data being collected under this project is currently being used by the US Forest Service to affect land management decisions on the forests being studied.