DIVERSITY AND ABUNDANCE OF SMALL MAMMALS IN DEGRADED TROPICAL DRY FOREST OF NORTHERN COLOMBIA

An area of highly disturbed tropical dry forest in Cordoba Department, northern Colombia was censused by live-trapping for 17 months to exam ine diversity, abundance, and population dynamics of opossums and rode nts in this habitat type. Three sampling transects were established al ong narrow corridors of second-growth vegetation extending into an agr icultural landscape. An initial census was conducted in October 1993, and monthly censuses were conducted from August 1994 through December 1995. Two species of opossums (Didelphis marsupialis and Marmosa robin soni) and five species of rodents (Sciurus granatensis, Heteromys anom alus, Oecomys concolor, Zygodontomys brevicauda, and Proechimys canico llis) were captured during the study. Relative abundances of D. marsup ialis, H. anomalus, and Z. brevicauda were extremely high during the i nitial census and at the beginning of the monthly censuses but decline d dramatically thereafter and fluctuated erratically through the remai nder of the study. These results suggest that the disturbed habitat su pports a small-mammal fauna of low diversity. However, several of the species appear to have benefitted from forest clearance and agricultur al activities and may occasionally reach extremely high numbers. While abundances may be very high, populations are not stable and may exibi t large-scale fluctuations in abundance.