Microhabitat Selection by Tuco Tuco (Ctenomys sp.) in ecosystems disturbed by Fire and Grazing.

VELAZQUEZ BARLOA, NADIA, CÉSAR MARIO ROSTAGNO, GONZALO BOQUÉ, LINA VIDELA Y ALICIA TOYOS

Mendoza, Pcia. de Mendoza

Congreso; The 10 th International Mammalogical Congress, Mendoza, Argentina; 2009

In southern Argentine, the subterranean rodents known as tuco tuco, inhabit different ecosystems. Fire and sheep grazing increase the ecosystem spatial heterogeneity through the modification of the vegetation structure and consequently they influence the activity of tuco tuco and its microhabitat selection. Objectives We studied the microhabitat  selection by tuco tuco in two ecosystems: one belongs to the Monte phytogeographical province and the other to the Patagonian province. Both are characterized by a microtopography of mounds associated with shrubs and mound interspaces areas.   Materiasl & Methods We determined the number of tumuli  (T) and openings (O) on mounds and in the mound interspaces, using 150-m2 plots, in 4 areas in the ecosystem located in the Patagonian province: unburned-ungrazed (UU), burned-ungrazed (BU), grazed-unburned (GU) and grazed and burned (GB) and a BU area in the ecosystem of the Monte province. Results &  Discussion The mean cover of mounds for the five studied areas was between 10 and 30%. In the Patagonian ecosystem, the higher activity of tuco tuco was in the Burned and Ungrazed treatment (BU) and the lower activity in the Grazed and Unburned (GU) area (36 T and 101 O and 8 T y 5 O, respectively). In this ecosystem the higher quantity of tumuli was found on the mounds in the 4 treatments (63% UU, 56% BU, 80% GU, 60% GB). The higher number of openings was also found on the mounds, except in the BU area where the higher number occurred in the mound interspaces. A similar result was found in the Monte ecosystem, where 71% of tumuli were found on mounds. In conclusion, the activity of tuco tuco was strongly influenced by fire and grazing. Mounds represented the most selected microhabitat in the five areas, either for tumuli or openings formation, with the exception of the burned and ungrazed treatment (BU) where we found more openings in the mound interspaces.