Hierarchical multi-grain models improve descriptions of species’ environmental associations, distribution, and abundance

The characterization of species’ environmental niches and spatial distribution predictions based on them are now central to much of ecology and conservation, but implicitly requires decisions about the appropriate spatial scale (i.e. grain) of analysis. Ecological theory and empirical evidence suggest that range-resident species respond to their environment at two characteristic, hierarchical spatial grains: (i) response grain, the (relatively fine) grain at which an individual uses environmental resources, and (ii) occupancy grain, the (relatively coarse) grain equivalent to a typical home range. We use a multi-grain (MG) occupancy model, aided by fine-grain remotely sensed imagery, to simultaneously estimate species-environment associations at both grains, conduct grain optimization to measure response grain, and apply this analysis framework to an example species: a medium-sized bird (Tockus deckeni) in a heterogeneous East African landscape. Based on home range analysis of movement ...

物种生态位的特征刻画及其基于该刻画的空间分布预测，现已成为生态学与保护生物学领域的核心研究内容，但此类研究隐含着需要确定分析的适宜空间尺度（即空间粒度（grain））。生态学理论与实证研究表明，定居物种会在两个具有层级特征的典型空间粒度下对环境做出响应：(1) 响应粒度（response grain），即个体利用环境资源时所对应的相对精细的空间粒度；(2) 占用粒度（occupancy grain），即对应典型活动家域的相对粗粒的空间粒度。本研究采用多粒度占用模型（multi-grain occupancy model, MG），结合高分辨率遥感影像，同时估算两个空间粒度下的物种-环境关联，开展粒度优化以量化响应粒度，并将该分析框架应用于一个示例物种：东非异质性景观中的中型鸟类——德氏弯嘴犀鸟（Tockus deckeni）。基于移动活动家域分析……