Changes in a Puna desert plant community induced by a subterranean mammal

N LARA; P. L. SASSI; C. E. BORGHI

Mendoza

Jornada; XVI Jornadas Argentinas de Mastozoología; 2001

Herbivory is of great importance in South America desert communities. We study changes in the plant cover and plant composition in one community of the Puna desert, induced by the herbivorous subterranean rodent Ctenomys sp. (tuco-tuco). We sampled five sites in a community where the dominant shrub was Lycium chanar. The effect of tuco-tucos on vegetation was quantified on 300 samples of 2 m2 taken along 30 transects. On each sites we studied two types areas: highly disturbed by Ctenomys, and less disturbed by this species. Highly disturbed plots had a mean of 0.9 mounds/m2, and less disturbed plots had a mean of 0.13 mounds/m2. In each site we sampled plant cover, number of plants, number of seedlings, soil mound cover, number of burrow holes and number of dead plants. In the highly disturbed areas, plant cover decreased significanly (11.6 vs. 21.8%). The foraging activity of tuco-tuco affected significantly almost all plant species. Also, seedling abundance and number of dead plants was significantly higher in disturbed plots