Home range size and survival probability of two major rodents (Rhabdomys dilectus and Lophuromys aquilus) on slopes of Mount Kilimanjaro, Tanzania

Abstract

Home range and survival are important parameters influencing abundance and distribution of rodent species. Therefore, understanding the factors affecting them is crucial for conservation and management of the species. This study was aimed to determine home range size and survival probabilities of two dominant rodent species (Lophuromys aquilus and Rhabdomys dilectus) found in western slopes of Mount Kilimanjaro, Tanzania. Trapping was done in moorland and fallow habitats across both dry and wet seasons, using Sherman live traps in four CMR grids. Home range size of Rhabdomys dilectus was influenced by habitat type. It was significantly higher in moorland than in fallow habitat. Whereas, home range size of Lophuromys aquilus was influenced by the variations in habitat, season and sex. It was significantly higher in moorland than in fallow. Also, male L. aquilus had larger home range size than females but the difference was not significant. Moreover, there were significant differences in survival of the two species and sex. Survival of L. aquilus was higher than that of R. dilectus indicating that L. aquilus could be more adapted to live on Mt. Kilimanjaro than R. dilectus. This was evident from its lower capture probability compared to R. dilectus. Low capture probability indicates trap shy behavior which could serve as a mechanism of predator avoidance. Furthermore, for both species female’s survival was higher than that of males. This was probably due to that females spend most of their time inside the nest during breeding season, hence reduces the risk to encounter predators. The study concludes that, species type, sex, habitat type and quality influence home range size and survival probability of rodents, which are attributed to variations in resources availability, mating behavior and reproductive fitness. Therefore, rodent conservation and management interventions should be species and sex specific taking other factors into consideration.