Using stable isotopes to detect responses to environmental change in parapatric ctenomyid rodents

MILLER, M.J.; DAWSON, T.E.; TAKENAKA, RISA; LACEY, EILEEN A.; TAMMONE, MAURO N.

Minneapolis

Congreso; 96th annual meeting of the American Society of Mammalogists; 2016

Understanding how interspecific differences in a community play out in response to historicalenvironmental changes provides a useful foundation for predicting the evolutionary and conservationoutcomes of future changes in environmental conditions. Ecological studies have increasingly utilizedstable isotopes to gain insights into the diets, and hence, the floristic composition that historicalpopulations of mammals utilized. Here, we report on the use of stable isotope analyses of rodent teeth toexplore the potential role that interspecific differences in response to past environmental changes haveplayed in shaping observed differences in genetic structure between two parapatric species of ctenomyidrodents. Previous research has revealed that both abundance and genetic diversity have declined overthe last 12,000 years for C. sociabilis, a group-living habitat specialist, but not for C. haigi, a solitaryhabitat generalist. We analyzed the carbon and oxygen stable isotope composition of molars frommodern and paleontological specimens of C. sociabilis and C. haigi. Our data indicate that the floristiclandscape in this region of Patagonia has changed markedly over the past 12,000 years, and as it did C.sociabilis and C. haigi shifted their diet in response to this change. Based on these findings we suggestthat future studies explore potential interspecific differences in response to the same environmentalvariables, to understand observed temporal differences in abundance and genetic diversity in the studyspecies.