Intra- and interspecific variation in home-range size in sympatric tuco-tucos, Ctenomys australis and C. talarum

CUTRERA A. P.; MORA M.; ANTENUCCI C. D.; VASSALLO A. I.

JOURNAL OF MAMMALOGY

ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS

Año: 2010 vol. 91 p. 1425 - 1434

0022-2372

Despite the fundamental nature of the home range to the biology of a species, assessing aspects of its size, shape and structure remains elusive in certain groups, such as subterranean rodents. These rodents, characterized by limited individual mobility and a patchy distribution of local populations, generally defend multi-purpose territories in which breeding and foraging take place, increasing the chances for trade-offs among factors of habitat quality. The present study assessed the home-range size and shape of two species of tuco-tucos, C. australis (300-600 g) and C. talarum (100-180 g), using radiotelemetry in an area where they occur in sympatry, and explored the factors that could influence space use in these subterranean rodents. Home-range size of C. australis (1282.22 ± 1014.83 m2) was ~24 times larger than that of C. talarum (66.69 ± 22.34 m2). The area covered daily by C. australis only represented about 9 % of the total home-range size estimated by radiotelemetry in this study, and was 2 times larger than that of C. talarum, while the area covered by the latter species represented an average 35 % of its total home-range size. Total, aerial and subterranean plant biomass, plant cover and soil hardness were significantly higher in the habitat occupied by C. talarum. Contrary to expected, body size was not the predominant factor explaining inter and intraspecific variation in home–range size. We discuss instead, how variation in food availability in space and time and differences in the intensity of polygyny could be more important factors shaping home-range size in this genus of subterranean rodents.