SEASONAL ACTIVITY PATTERNS OF THE MENDOCINO TUCO-TUCO, CTENOMYS MENDOCINUS, IN THE MONTE DESERT, ARGENTINA

PABLO CUELLO AND RICARDO A. OJEDA

Mendoza, Argentina

Congreso; Xth International Mammalogical Congress; 2009

International Federation of Mammalogists

    Activity patterns in fossorial rodents result from the interplay of their biology (i.e. physiology), environment (e.g. temperature, humidity), topographic features (eg. soil hardness), and availability of resources. We tested the association of these variables with the activity of the mendocino tuco-tuco, Ctenomys mendocinus in the Monte desert.  The study was conducted at the MaB Ñacuñan Reserve located in the central Monte desert, Argentina.  We sample 3 habitats during 4 seasons, Larrea shrubland, mesquite forest and sand dunes. We quantified the number of active burrows, soil humidity and food availability, whereas temperature was compared seasonally. Our results showed that the peak of activity (number of burrows) was in autumn and that it varied seasonally in all habitats (p<0.0001). The habitat with the highest activity was the sand dune, followed by the mesquite forest and Larrea shrubland, however we found non significant differences. Temperature and humidity showed seasonal variations, with the highest values recorded in summer and the lowest in winter.  Food availability (e.g. grasses, herbs and shrubs) was constant throughout the year.  We found that the peak of activity was associated with intermediate levels of temperature and soil humidity. Our results are in accordance with the energetic hypothesis, where soil properties and intermediate values of temperature and soil humidity in autumn would provide the optimum energetic conditions for burrowing (Partially supported by CONICET, PIP 5944,  and AGENCIA, PICT 1176).