Isotopic niche variation from the Holocene to today reveals minimal partitioning and individualistic dynamics among four sympatric desert mice

1.Species interact with each other and their environment over a range of temporal scales, yet our understanding of resource partitioning and the mechanisms of species coexistence is largely restricted to modern time-scales of years to decades. Furthermore, the relative magnitudes of inter- versus intraspecific variation in resource use are rarely considered, despite the potential for the latter to influence a species’ ability to cope with changing environmental conditions. 2.Modern desert rodent communities are thought to be strongly structured by competitive interactions, with niche partitioning of food resources hypothesized to explain the coexistence of multiple sympatric granivores. Yet the stability of niche dynamics over extended temporal scales within desert rodent communities is unknown. 3.I examined the isotopic niche dynamics of four common sympatric desert mice (three granivores: Chaetodipus formosus, Perognathus longimembris, and Reithrodontomys megalotis, and one omni...1. 物种会在一系列时间尺度上彼此发生相互作用，并与环境产生关联；然而当前学界对资源分隔（resource partitioning）与物种共存机制的认知，大多仅局限于数年至数十年的现代时间尺度。此外，尽管种内变异具备影响物种应对环境变化能力的潜力，但资源利用中的种间与种内变异的相对幅度却极少被纳入研究考量。 2. 现有研究普遍认为，现代沙漠啮齿动物群落的结构主要由竞争相互作用塑造，而食物资源的生态位分隔被假说认为是多种同域分布食谷动物得以共存的核心机制。但目前学界仍未明确，沙漠啮齿动物群落的生态位动态在扩展的长时间尺度下是否具备稳定性。 3. 本研究针对四种常见的同域分布沙漠小鼠的同位素生态位动态展开了分析，其中三种为食谷动物：Chaetodipus formosus、Perognathus longimembris以及Reithrodontomys megalotis，另有一种为杂食性动物。