Spatial variation in the density of ectotherms

变温动物密度的空间变化

• 批准号: RGPIN-2018-04234
• 负责人: BlouinDemers, Gabriel
• 金额: $ 3.42万
• 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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=645645
• 关键词: Spatial; variation; density; ectotherms

Within species, abundance (population density) varies markedly in space and in time. Accordingly, explaining spatial and temporal patterns in the abundance of species is one of the major goals of ecology. The abundant center hypothesis posits that species should be most abundant near the center of their geographic ranges, but the empirical data do not support it. Thus, there is a clear need for alternative hypotheses to predict better the spatial patterns in the abundance of animals.******Predicting spatial patterns in the abundance of animals has important theoretical and applied implications. On the theoretical side, a better prediction of spatial patterns in abundance may help determine what drives broad spatial patterns in biodiversity. On the applied side, a better ability to predict spatial patterns will help define critical habitats for species at risk.******Abundance at broad spatial scales is largely dictated by climate. Within the geographical range of species, however, habitat selection can strongly influence the distribution and abundance of individuals. The spatial heterogeneity of resource distribution provides an opportunity for organisms to maximize their fitness by choosing the highest quality habitat available. The suitability of a habitat is determined by the mean success rate of individuals that occupy the habitat, and depends on factors such as food abundance, shelter availability, and density of competitors.******Much of the habitat selection theory assumes that animals are limited by their ability to harvest limited resources. But what happens if animals are limited by their ability to process resources? Most animals are ectotherms, and in ectotherms the total amount of energy available may be more strongly influenced by thermal constraints on resource assimilation than by resource acquisition. My working hypothesis is that the primary driver of abundance in ectotherms is their ability to process resources, not their ability to acquire resources.******The long-term objective of my research program is to determine what dictates spatial patterns of abundance in ectotherms. To meet this objective, I document patterns of abundance in space and I test hypotheses about mechanisms that could generate these spatial patterns. My objective over the next grant cycle is to determine whether it is the ability to acquire, or the ability to process, resources that best predicts abundance of ectotherms. I will address this objective at three spatial scales: at the scale of the geographical range (variation in abundance across the range), at the scale of the landscape (variation in abundance across habitat gradients), and at the scale of the individual home ranges (variation in fitness between home ranges varying in quality).

在物种内部，丰度（种群密度）在空间和时间上存在显着差异。因此，解释物种丰富度的时空模式是生态学的主要目标之一。丰富中心假说认为，物种在其地理范围的中心附近应该是最丰富的，但经验数据并不支持这一点。因此，显然需要替代假设来更好地预测动物丰度的空间模式。******预测动物丰度的空间模式具有重要的理论和应用意义。从理论上讲，更好地预测丰富的空间模式可能有助于确定驱动生物多样性广泛空间模式的因素。在应用方面，更好的预测空间模式的能力将有助于确定面临风险的物种的关键栖息地。******广泛空间尺度上的丰富度很大程度上取决于气候。然而，在物种的地理范围内，栖息地选择可以强烈影响个体的分布和丰度。资源分布的空间异质性为生物体提供了通过选择最高质量的栖息地来最大化其适应性的机会。栖息地的适宜性取决于占据该栖息地的个体的平均成功率，并取决于食物丰富度、庇护所可用性和竞争者密度等因素。******大部分栖息地选择理论都假设动物受到其获取有限资源的能力的限制。但是，如果动物处理资源的能力受到限制，会发生什么呢？大多数动物是变温动物，在变温动物中，可用能量总量可能更受资源同化的热限制的影响，而不是资源获取的影响。我的工作假设是，外温动物丰度的主要驱动因素是它们处理资源的能力，而不是获取资源的能力。********我的研究计划的长期目标是确定外温动物丰度空间模式的决定因素。为了实现这一目标，我记录了空间中的丰富模式，并测试了有关可以生成这些空间模式的机制的假设。我在下一个资助周期的目标是确定是否是获取资源的能力或处理资源的能力最能预测变温动物的丰度。我将在三个空间尺度上实现这一目标：地理范围的尺度（整个范围内丰度的变化）、景观的尺度（栖息地梯度上的丰度的变化）以及个体栖息地的尺度（不同质量的栖息地之间的适应性变化）。