Rock outcrops enhances plant diversity in Patagonian landscape

SPEZIALE, K. L. Y EZCURRA, C.

San Carlos de Bariloche, Argentina

Congreso; VI SOUTHERN CONNECTION CONGRESS; 2010

Rock outcrops usually support unique communities also acting as refuge for species that cannot survive in the surroundings due to overgrazing, fire or climate change among other disturbs. We studied plant communities associated to 50 outcrops along a diverse longitudinal gradient from shrubland to steppe habitats in north-western Patagonia. We recorded every plant species in each outcrop and mounted a temperature and humidity sensor (north and south face). We also characterized the outcrops respect to their morphological variables. We compared species composition and richness within outcrops (north vs. south face), between outcrops and between each outcrop and its surrounding matrix. Correspondence analysis separated shrubland, steppe and outcrop plots. Within outcrops composition of north faces was different from those of the south face. Differences in species composition and richness were related to microsite variables. Our results suggest that rock outcrops could be acting as refuges for species that cannot be found in the surrounding matrix. In this way outcrops could be enhancing biodiversity in north-western Patagonia.