Zoology

The research focus of my laboratory revolves around the effects of anthropogenic disturbances on the ecology of wildlife species. With increasing human populations and landscape fragmentation comes a need to understand vertebrate responses to these pressures. Because of my interests in population and nutritional ecology, my students tend to work on demographic and nutritional responses of mammals and reptiles to manipulations (e.g., burning, grazing, fertilization). Within this applied context, I also study basic ecological questions such as competition, resource partitioning, and life-history variation.

For more information on the research program within the Cooperative Wildlife Research Laboratory and my own research efforts, please see the CWRL webpage.

Recent Publications

Criffield, M. A., E. C. Hellgren, and D. M. Leslie, Jr. 2010. Density estimation and survey validation for swift fox (Vulpes velox) in the Oklahoma Panhandle. Acta Theriologica 55: In press.

Hellgren, E. C.. A. L. Burrow, et al. 2010. The effects of winter burning and grazing on resources and survival of Texas horned lizards in a thornscrub ecosystem. Journal of Wildlife Management 74: In press.

Cooper, J. D. R. Vitalis, P. M. Waser, … E. C. Hellgren, et al. 2009. Quantifying male-biased dispersal among social groups in the collared peccary (Pecari tajacu) using analyses based on mtDNA variation. Heredity: In press.

Van Den Bussche, R. A., … E. C. Hellgren, et al. 2009. Mitochondrial DNA phylogeography of black bears (Ursus americanus) in central and southern North America: Conservation implications. Journal of Mammalogy 90:1075-1082.

Criffield, M. A., M. V. Reichard, E. C. Hellgren, et al. 2009. Parasites of swift fox (Vulpes velox) in the Oklahoma Panhandle. Southwestern Naturalist 54:494-500.

Ganguli, A. C., D. M. Engle, E. C. Hellgren, et al. 2008. Plant community diversity and composition provide little resistance to Juniperus encroachment. Botany (formerly Canadian Journal of Botany) 86:1416-1426.

Disney, M. R., E. C. Hellgren, et al. 2008. Mesopredator abundance and size of oak patches in the cross timbers ecoregion. Southwestern Naturalist 53:214-223.

Wack CL, Fox SF, Hellgren EC, et al. 2008. Effects of sex, age, and season on plasma steroids in free-ranging Texas horned lizards (Phrynosoma cornutum). General and Comparative Endocrinology 155: 589-596.

Endriss DA, Hellgren EC, Fox SF, et al. 2007. Demography of an urban population of the Texas horned lizard (Phrynosoma cohnutum) in central Oklahoma. Herpetologica 63: 320-331.

Downey PJ, Hellgren EC, Caso A, et al. 2007. Hair snares for noninvasive sampling of felids in North America: Do gray foxes affect success? Journal of Wildlife Management 71: 2090-2094.

Onorato DP, Hellgren EC, Van Den Bussche RA, et al. 2007. Genetic structure of American black bears in the desert southwest of North America: conservation implications for recolonization. Conservation Genetics 8: 565-576.

Ilse, L. M., and E. C. Hellgren. 2007. Indirect interactions among dendrophages: Porcupines predispose pinyon pines to bark beetle attack. Forest Ecology and Management 242: 217-226

Hellgren, E. C., and D. C. Ruthven, III. 2007. Progeny sex ratio in a sexually monomorphic ungulate, the collared peccary (Tayassu tajacu). Journal of Mammalogy 88: 124-128.

Hellgren, E. C. S. L. Bales, M. Gregory, D. M. Leslie, Jr., and J. D. Clark. 2007. Testing a Mahalanobis distance model of black bear habitat use in the Ouachita Mountains of Oklahoma. Journal of Wildlife Management 71: 924-928.

Onorato, D. P., E. C. Hellgren, R. A. Van Den Bussche, D. L. Doan-Crider, and J. R. Skiles, Jr. 2006. Genetic structure of America black bears in the desert southwest of North America: conservation implications for recolonization. Conservation Genetics. Published online 28 Sep 2006.

Servello, F. A., E. C. Hellgren, and S. R. McWilliams. 2005. Techniques for wildlife nutritional ecology. Pages 554-590 in C. Braun, editor. Research and management techniques for wildlife and habitats. The Wildlife Society, Bethesda, Maryland

Bales, S. L., E. C. Hellgren, D. M. Leslie, Jr., and J. Hemphill. 2005. Dynamics of a recolonizing population of black bears in the Ouachita Mountains of Oklahoma. Wildlife Society Bulletin 33:1342-1351.

Horncastle, V. J., E. C. Hellgren, P. M. Mayer, A. C. Ganguli, D. M. Engle, and D. M. Leslie, Jr. 2005. Implications of invasion by Juniperus virginiana on small mammals in the southern Great Plains. Journal of Mammalogy 86:1144-1155.

Moeller, B. A., E. C. Hellgren, D. C. Ruthven, III, R. T. Kazmaier, and D. R. Synatzske. 2005. Temporal differences in activity patterns of male and female Texas horned lizards, Phrynosoma cornutum, in southern Texas. Journal of Herpetology 39:336-339.

Parsons, J. L., E. C. Hellgren, E. E. Jorgensen, and D. M. Leslie, Jr. 2005. Neonatal growth and survival of rodents in response to variation in maternal dietary nitrogen: life-history strategy vs. dietary niche. Oikos 110:297-308.

Clark, J. E., E. C. Hellgren, J. L. Parsons, E. E. Jorgensen, D. M. Engle, and D. M. Leslie, Jr. 2005. Nitrogen outputs of small mammals from fecal and urine deposition: implications for nitrogen cycling. Oecologia 144:447-455.

Hellgren, E. C., D. P. Onorato, and J. R. Skiles, Jr. 2005. Dynamics of a black bear population within a desert metapopulation. Biological Conservation 122:131-140.

Onorato, D. P., E. C. Hellgren, R. A. Van Den Bussche, and J. R. Skiles, Jr. 2004. Paternity and relatedness of American black bears recolonizing a desert montane island. Canadian Journal of Zoology 82:1201-1210.

Onorato, D. P., E. C. Hellgren, R. A. Van Den Bussche, and D. L. D. Crider. 2004. Phylogeographic patterns within a metapopulation of black bears (Ursus americanus) in the American Southwest. Journal of Mammalogy 85:140-147.