Refuge strategies and habitat segregation in two sympatric rodents Otomys unisulcatus and Parotomys brantsii

The possibility of different refuge strategies resulting in habitat segregation in two sympatric rodents, the bush Karoo rat, O. unisulcatus and the whistling rat, P. brantsii was investigated. The rodents' habitats were characterized by using the multivariate analysis procedures: ordination diagrams and hierarchical classification. The most important environmental variables were identified. Otomys unisulcatus was restricted to areas with high percentage plant cover (60.6%) and dense foliage compared to P. brantsii habitat (plant cover=34.8%). The high percentage plant cover is necessary for nest construction. Parotomys brantsii habitat was characterized by deep Soil (76.9+15cm) with larger soil particles (0.31+0.2mm) compared to 47.5+30.3 cm soil depth and 0.15+0.1 mm soil particles in O. unisulcatus habitat. A suitable substratum therefore determines distribution of P. brantsii. The different refuge strategies result in habitat segregation and may be an important means of partitioning resources between these two sympatric rodents which have comparable body sizes, adtivitym dietary and thermoregulatory patterns.