LATE PLEISTOCENE FOSSILS RECONTEXTUALIZE THE ECOLOGY OF INTRODUCED TURKEYS IN CALIFORNIA

Managing invasive species is a central challenge in conservation biology given the constraints of limited funds and the potential for unanticipated ecological consequences. New techniques in conservation paleobiology that bring Quaternary fossil records and zooarchaeological assemblages into such discussions are revealing that many introduced species have unexpected histories, and may in fact represent ecological and/or taxonomic substitutes for extirpated or extinct species lost historically or in the Late Pleistocene. Wild turkeys (Meleagris gallopavo) are a non-native, potentially invasive species in California introduced in the 1900s as a game animal, but they are congeneric with the California turkey (Meleagris californica), an endemic species that went extinction at the end of the Pleistocene. Previous research has suggested a role of changing precipitation patterns in driving the extinction of the native California turkey, and it is conspicuously absent from archaeological middens. To assess the potential ecological overlap of these two closely related species and thus provide a currently unaccounted for baseline of turkey ecology in California, we developed a species distribution model (SDM) for M. californica based on bioclimatic data and fossil localities from the Last Glacial Maximum. We then projected this model into current landscapes using present-day climatic data as a counterfactual of this extinct species distribution as if it never went extinct. We compared this projection to an SDM for extant M. gallopavo generated using observation records from citizen science datasets. Quantitative indices of model overlap and variable importance strongly suggest that M. gallopavo in California today largely occupies geographic and environmental spaces similar to those used by M. californica. Future analyses using various techniques, including morphological and stable isotope analyses, may be needed to crystallize the precise ecological effects of M. gallopavo in California and confirm the species’ role as an ecological substitute.