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...