Population and community ecology of small rodents in Montane forest of western Mexico

This study reports results of a 14-month live-trap study of small-rodent co mmunities in 2 habitats, cloud forest and disturbed areas, at Las Joyas Sci entific Station of the Sierra de Manantlan Biosphere Reserve, western Mexic o. Seven taxa of 2 families (Muridae, Heteromyidae) of small rodents were c aptured (Hodomys alleni, Liomys pictus, Oryzomys couesi, Peromyscus aztecus , Reithrodontomys fulvescens, R. sumichrasti, and Sigmodon alleni). Informa tion about age structure, population dynamics, biomass, and reproduction we re obtained with mark-recapture techniques for the most abundant species (P . aztecus and R. fulvescens) in both habitats. These species comprised 80.3 % of the 707 captures in the cloud forest (P. aztecus, 51.2%; R, fulvescens , 29.1%), whereas, in the disturbed areas, R. fulvescens represented 81.7% of the 916 captures. Species varied in population density, relative abundan ce, and timing of reproduction, which was seasonal. Reproductive activity f or P. aztecus peaked in the middle of the wet season (September 1995) in th e cloud forest and in the wet season and middle of the dry-cold season (Jan uary 1996) in the disturbed areas. R. fulvescens showed reproductive activi ty in the wet season (July-October 1995) in both habitats, Density fluctuat ed annually for P. aztecus in both habitats, with a peak in January and Feb ruary 1996; R. fulvescens showed the same patterns of density in both habit ats with the highest values at the end of the wet season.