Population Characteristics of Virginia Opossum in the Cross Timbers During Raccoon Reduction

• Published in: The American midland naturalist Vol. 151; no. 1; pp. 154 - 163
• Main Authors: Kasparian, MA, Hellgren, E C, Ginger, S M, Levesque, L P, Clark, JE, Winkelman, D L, Engle, D M
• Format: Journal Article
• Language: English
• Published: 01.01.2004
• Subjects: Didelphis virginiana; Procyon lotor; USA, Oklahoma
• ISSN: 0003-0031
• DOI: 10.1043/0003-0031(2004)151(0154:PCOVOI)2.0.CO;2

Mesopredator populations are increasing because of habitat fragmentation and elimination of keystone predators. An increase of mesopredators, such as the raccoon (Procyon lotor) and Virginia opossum (Didelphis virginiana), may change competitive interactions within the trophic level of medium-sized carnivores and omnivores. We conducted live-trapping during 1998-2001 in north-central Oklahoma and compared population parameters of opossums living in areas with and without reduction of raccoons during 2000-2001. The equivalent of 6.2 raccoons/km2 was removed from the treatment area. Capture rates of opossums were higher in the non-removal area for most of the study period, but population estimates and density did not vary by treatment. Survival rates of opossums varied by sex and season, but not by treatment according to modeling of opossum survival. Habitat partitioning, prey switching by opossum predators, food supply, study scale, and environmental and demographic stochasticity may have masked effects of interspecific competition on population dynamics of opossums on the study site.