Fitness consequences of habitat selection in terrestrial ectotherms

陆地变温动物栖息地选择的适应性后果

• 批准号: 261260-2013
• 负责人: BlouinDemers, Gabriel
• 金额: $ 2.4万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=547701
• 关键词: Fitness; consequences; habitat; selection; terrestrial

Within species, the abundance of individuals varies in space. The geographic range is a function of abundance: its limits are set where population density declines to zero. Abundance is largely a function of local individual survival and reproduction, which together dictate population mean fitness. Therefore, the pattern of spatial variation in abundance is intimately tied to the pattern of spatial variation in population mean fitness. In vertebrates there is a plethora of papers describing habitat use, but surprisingly few tackle the central issue of quantifying the fitness consequences of habitat selection. Terrestrial ectothermic vertebrates offer a unique opportunity to bridge the gap between habitat use and fitness because their organismal performance varies with body temperature which is regulated largely via habitat selection. We thus have an explicit mechanistic link between habitat use and fitness in this group. Much of the habitat selection theory has been developed with vertebrate endotherms in mind and assumes that animals are limited by their ability to harvest resources. But what happens if animals are not limited by their ability to harvest resources, but rather by their ability to process resources? Most vertebrates are ectotherms, and in ectotherms the total amount of energy utilized may be more strongly influenced by thermal constraints on resource acquisition and assimilation than by resource availability. My working hypothesis in this proposal is that, contrary to vertebrate endotherms, the primary driver of population mean fitness in terrestrial vertebrate ectotherms is their ability to process resources, not their ability to acquire resources. This hypothesis can be operationalized at the species range scale (variation in population mean fitness across the geographic range of species), at the landscape scale (variation in population mean fitness across local sites that vary in temperature and resource availability), or at the individual scale (variation in individual fitness as a function of the thermal quality and resource availability within the home range). I propose to conduct tests at all 3 spatial scales using correlative and manipulative field studies of lizards.

在物种中，个人的丰度在空间上有所不同。地理范围是丰度的函数：将人口密度降至零的限制设置。丰度在很大程度上是当地个体生存和繁殖的函数，这共同决定了人口平均适应性。因此，丰度空间变化的模式与人口平均适应性的空间变异模式密切相关。在脊椎动物中，有很多描述栖息地的论文，但令人惊讶的是，很少有人解决量化栖息地选择的适应性后果的核心问题。陆地式脊椎动物提供了一个独特的机会来弥合栖息地使用和健身之间的差距，因为它们的有机性能随体温而变化，这在很大程度上通过栖息地选择受到调节。因此，我们在该组中的栖息地使用和适应性之间有明确的机械联系。大部分栖息地选择理论是在考虑到脊椎动物的吸热剂的情况下发展的，并假设动物受到收获资源的能力的限制。但是，如果动物不受收获资源的能力而是它们处理资源的能力限制，会发生什么呢？大多数脊椎动物是屈光度，而在阶段中，所用的总能量可能比资源获取和同化的热约束更强烈地影响了资源可用性。我在此提案中的工作假设是，与脊椎动物吸入器相反，陆地脊椎动物的平均适应性的主要驱动力是它们的能力，而不是他们获得资源的能力。该假设可以在物种范围的量表（物种地理范围的种群平均健身范围的变化），景观量表（在温度和资源可用性方面变化）或个体量表（个体适应性的变化作为众多范围内的热质量和资源可用性的函数变化））。我建议使用蜥蜴的相关和操纵性现场研究在所有3个空间尺度上进行测试。