Changes in Monte desert plant communities induced by a subterranean mammal.

CAMPOS CLAUDIA; GIANNONI STELLA; BORGHI CARLOS

JOURNAL OF ARID ENVIRONMENTS

Año: 2001 vol. 47 p. 339 - 345

0140-1963

Herbivory by medium-sized rodents is of great importance in Monte Desertcommunities. In this paper we study changes in the plant cover, plant compositionand diversity in two creosotebush communities of the Monte Desertinduced by the herbivorous subterranean rodent Ctenomys sp. (tuco-tuco). Westudied two sites: a community where only Larrea divaricata is dominant(site 1), and a mixed community dominated by L. cuneifolia and L. divaricata(site 2). On both sites we studied two types of areas: highly disturbed byCtenomys, and less disturbed by this species. In the highly disturbed areas, herbcover decreased in both plant communities (6·4 vs. 14·1%, and 15·1 vs. 32·4%,respectively), whereas shrub cover diminished significantly only in site 1. Theforaging activity of this herbivore affected the cover of Pappophorumcaespitosum, Aristida sp. and Digitaria sp. Herb diversity was significantlydifferent between highly and less disturbed areas in both communitiesconsidered, although it was higher in the less disturbed area on site 1, and in thehighly disturbed area on site 2. Shrub diversity did not vary significantlybetween highly and less disturbed areas.