Coyote (Canis latrans) mammalian prey diet shifts in response to seasonal vegetation change

‡ Contribution to the Special Issue “Stable Isotopes in Mammals”.

Abstract

Drylands typically have strong seasonal variation in rainfall and primary productivity. This study examines the effects of seasonal change in grass-derived resource availability on the base of the food chain of a mammalian predator. Seasonal changes in live grass cover were measured in two vegetation types at the Sevilleta National Wildlife Refuge in central New Mexico, USA. Non-invasive genetic sampling of scat was used to identify individuals in the local coyote (Canis latrans) population. Stable carbon and nitrogen isotope analysis of hair removed from scats of 45 different coyotes was used to assess seasonal variation in the diet of mammalian coyote prey that came from C₄ grasses. Live grass cover increased from the spring to the summer and fall; contribution of C₄ grasses to the diet of mammalian coyote prey increased from the summer to the fall and was higher in grassland areas. There were significant differences in the seasonal patterns in the prey diet between grassland and shrubland areas.

Keywords:

• arid ecosystem
• carbon-13
• coyote prey
• food chain
• isotope ecology
• microsatellite; nitrogen-15
• seasonality

Acknowledgements

We thank the following people for their assistance in the field: A. Boutz, K. Bowman, M. Donovan, K. McQuade, and T. Seamster. Thanks to T. Koontz for her help with plant identification, to M. Kreutzian and Y. Matsubara for their assistance, to K. Gebhardt and K. Soderberg for the lab method training that they provided, and to D. Carr for his statistical advice. We greatly appreciate the work done by A. Ouimette at the Stable Isotope Laboratory at the University of New Hampshire in producing the carbon and nitrogen stable isotope data presented here. We also greatly appreciate the coding work done by C. Herrera and thank J. Hopkins for running IsotopeR. We are grateful for the comments made by six anonymous reviewers and the following individuals on earlier drafts of this paper: K. Burke, P. D'Odorico, E. Elton, M. Erwin, J. Hopkins, T. Ransom, and H. Wilbur.

Funding

This research was supported by: the Department of Environmental Sciences at the University of Virginia; a NSF grant to the University of New Mexico for Long-term Ecological Research [DEB-0620482]; and the Sevilleta National Wildlife Refuge.

Supplemental data

for this article can be accessed http://dx.doi.org/10.1080/10256016.2014.930037

Notes

‡ Contribution to the Special Issue “Stable Isotopes in Mammals”.