Diez Jeffrey M, Pulliam H Ronald
Institute of Ecology, University of Georgia, Athens, Georgia 30602, USA.
Ecology. 2007 Dec;88(12):3144-52. doi: 10.1890/07-0047.1.
Abiotic and biotic processes operate at multiple spatial and temporal scales to shape many ecological processes, including species distributions and demography. Current debate about the relative roles of niche-based and stochastic processes in shaping species distributions and community composition reflects, in part, the challenge of understanding how these processes interact across scales. Traditional statistical models that ignore autocorrelation and spatial hierarchies can result in misidentification of important ecological covariates. Here, we demonstrate the utility of a hierarchical modeling framework for testing hypotheses about the importance of abiotic factors at different spatial scales and local spatial autocorrelation for shaping species distributions and abundances. For the two orchid species studied, understory light availability and soil moisture helped to explain patterns of presence and abundance at a microsite scale (<4 m2), while soil organic content was important at a population scale (<400 m2). The inclusion of spatial autocorrelation is shown to alter the magnitude and certainty of estimated relationships between abundance and abiotic variables, and we suggest that such analysis be used more often to explore the relationships between species life histories and distributions. The hierarchical modeling framework is shown to have great potential for elucidating ecological relationships involving abiotic and biotic processes simultaneously at multiple scales.
非生物和生物过程在多个空间和时间尺度上发挥作用，塑造了许多生态过程，包括物种分布和种群统计学。目前关于基于生态位的过程和随机过程在塑造物种分布和群落组成方面的相对作用的争论，部分反映了理解这些过程如何跨尺度相互作用的挑战。忽略自相关和空间层次结构的传统统计模型可能会导致对重要生态协变量的错误识别。在这里，我们展示了一个层次建模框架的效用，用于检验关于非生物因素在不同空间尺度和局部空间自相关对塑造物种分布和丰度的重要性的假设。对于所研究的两种兰花物种，林下光照可用性和土壤湿度有助于解释微生境尺度（<4平方米）上的存在和丰度模式，而土壤有机含量在种群尺度（<400平方米）上很重要。纳入空间自相关被证明会改变丰度与非生物变量之间估计关系的大小和确定性，并且我们建议更频繁地使用这种分析来探索物种生活史与分布之间的关系。层次建模框架显示出在阐明涉及非生物和生物过程同时在多个尺度上的生态关系方面具有巨大潜力。
