Population dynamics of the fossorial rodent Ctenomys talarum (Rodentia: Octodontidae)

Abstract

As part of a study on the ecological strategies related to adaptation to the subterranean habitat of genus Ctenomys (tuco-tucos), a natural population of C. talarum was live-trapped at Necochea (Buenos Aires Province, Argentina) with the aim of providing information on its population ecology. Population size was consistently low throughout the study and was related to the low habitat productivity. Mortality rates were low, although for juveniles the estimations were higher than for adults. Individuals have an average life expectancy of 22-25 months, but some individuals lived at least three years. Reproductive activity started by July and ended by March, when last known pregnancies were recorded. This long reproductive season allowed a gradual incorporation of young over an extended period of time, with a restricted period of recruitment lacking. Sex ratio did not depart from 1:1 and appears to be density dependent. The spatial distribution of individuals was clumped and corresponded to the patchy distribution of suitable habitats. The results are compared and contrasted with those from previous demographic studies performed in other conspecifics as well as in other subterranean rodents.