Graydon Gillies MSc Student, Eckert Lab Metapopulation structure and dynamics may maintain a species’ range edge Species range limits may be enforced by various evolutionary and ecological processes.
It is thought that many range limits are imposed by low fitness beyond a species’ range or the inability to disperse to suitable habitat beyond the range. However, transplant experiments and geographic surveys often find that these hypotheses fail to adequately explain species ranges, requiring the use of a more comprehensive framework. The metapopulation-hypothesis outlines how changes in habitat patch colonization rates, extinction rates, and habitat availability may cause metapopulation collapse and the generation of an abrupt range limit. Using coastal dune plant Camissoniopsis cheiranthifolia, I evaluated the metapopulation-hypothesis by conducting a multi-year survey across the species’ northern range. I found that patch structure, including the frequency, size, isolation, and quality of patches, changes towards the northern range edge. Furthermore, I found that colonization rates and habitat availability decline towards the range edge, while extinction rates increase non-significantly. With this survey, I provide the first empirical estimates of metapopulation parameters towards a species’ range edge and demonstrate that metapopulation dynamics may contribute to the maintenance of species’ range limits. Comments are closed.
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April 2024
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