Estimating spatial structure and population turnover using presence-absence data with false negatives: Investigating mechanisms driving crustacean metapopulations.
Wilcox, Chris*,1, 1 The Ecology Centre, Brisbane, QLD, Australia
ABSTRACT- Habitat spatial structure plays a central role in determining species and community dynamics, particularly in cases where metapopulations may play a role. However, for many species, such as invertebrates and plants, dormancy introduces observation errors, or false absences, which make analysis of habitat effects using presence-absence patterns at the landscape scale difficult. I investigated the spatial structure and population turnover of two putative crustacean metapopulations (Linderiella occidentalis and Branchinecta lynchi) that inhabit seasonal wetlands in the Central Valley of California. I used both frequentist and Bayesian approaches to compensate for observation errors in this system. I estimated the observation error in this system using an evolutionary model linked with a hydrologic model. Despite morphological and life history similarities between these species, their populations show significantly different spatial structures and turnover patterns. Differences in dispersal appear to provide the best explanation for the differences between the two species. Life history and habitat preferences of the fairy shrimp species interact to bias L. occidentalis toward dispersal via avian predation on gravid female shrimp, resulting in more over-dispersed and longer distance dispersal.
Key words: false negative, wetland, metapopulation, dormancy
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