Population ecology of Proechimys guairae (Rodentia : Echwiyidae)

An ecological study of Proechimys guairae in Venezuela was made based on ma rking and recapturing of individuals at 225 trapping stations distributed o ver 9 ha. The trappability of individuals was >50% in most sampling events; there was no difference in capture rate between marked or unmarked individ uals, or males and females. Adult individuals were present throughout the s ampling period, but juveniles appeared at the beginning of the rainy season and disappeared in the dry season. Pregnant or lactating females were obse rved during most sampling periods. Most reproductive activity was concentra ted from the middle of the dry season through the wet period. Estimated den sity was 1-3.5 individuals/ha; that variation appeared to be related to wea ther fluctuation and resource availability. Estimated effective population size (N-e) was 3-20 individuals/ha. Estimated home ranges value were signif icantly different for females and males. Adult females had no overlap of th eir home range, suggesting female territoriality. Home range of males did o verlap. Data were compared with those of other species. Some ecological con ditions that might have favored speciation guided by chromosomal mutations characterize P. guairae.