Explaining geographical variation in the isotope composition of mouse lemurs (
Aim We sought to quantify geographical variation in the stable isotope values of mouse lemurs (Microcebus) and to determine whether this variation reflects trophic differences among populations or baseline isotopic differences among habitats. If the latter pattern is demonstrated, then Microcebus can become a proxy for tracking baseline habitat isotopic variability. Establishing such a baseline is crucial for identifying niche partitioning in modern and ancient communities.
Location We studied five species of Microcebus from eight distinct habitats across Madagascar.
Methods We compared isotopic variation in C3 plants and Microcebus fur within and among localities. We predicted that carbon and nitrogen isotope values of Microcebus should: (1) vary as a function of abiotic variables such as rainfall and temperature, and (2) covary with isotopic values in plants. We checked for trophic differences among Microcebus populations by comparing the average difference between mouse lemur and plant isotope values for each locality. We then used multiple regression models to explain spatial isotope variation in mouse lemurs, testing a suite of explanatory abiotic variables.
Results We found substantial isotopic variation geographically. Ranges for mean isotope values were similar for both Microcebus and plants across localities (carbon 3.5–4.0‰; nitrogen 10.5–11.0‰). Mean mouse lemur and plant isotope values were lowest in cool, moist localities and highest in hot, dry localities. Rainfall explained 58% of the variation in Microcebus carbon isotope values, and mean plant nitrogen isotope values explained 99.7% of the variation in Microcebus nitrogen isotope values. Average differences between mouse lemur and plant isotope values (carbon 5.0‰; nitrogen 5.9‰) were similar across localities.
Main conclusions Isotopic data suggest that trophic differences among Microcebus populations were small. Carbon isotope values in mouse lemurs were negatively correlated with rainfall. Nitrogen isotope values in Microcebus and plants covaried. Such findings suggest that nitrogen isotope values for Microcebus are a particularly good proxy for tracking baseline isotopic differences among habitats. Our results will facilitate future comparative research on modern mouse lemur communities, and ecological interpretations of extinct Holocene communities.
Document Type: Research Article
Affiliations: 1: Institute of Zoology, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany 2: Department of Anthropology, Machmer Hall, 240 Hicks Way, University of Massachusetts, Amherst, MA 01003, USA 3: Duke University Program in Ecology, Box 90338, Nicholas School of the Environment, Durham, NC 27708, USA 4: Institute of Biotechnology, Viikki Biocenter, PO Box 56, 00014 University of Helsinki, Helsinki, Finland 5: Department of Anthropology, 19 Russell Street, University of Toronto, Toronto, ON M5S2S2, Canada 6: California University of Pennsylvania, Department of Biological and Environmental Sciences, 250 University Ave – Box 45, California, PA 15419, USA 7: School of Biological Sciences, University of Queensland, Brisbane, Qld 4072, Australia 8: Department of Anthropology, Stony Brook University, Circle Road, Social and Behavioral Science Building, Stony Brook, NY 11794-4364, USA 9: Department of Earth and Planetary Sciences, 1156 High Street, University of California, Santa Cruz, CA 95064, USA
Publication date: 2011-11-01