VARIATIONS IN THE COVERAGE OF BIOLOGICAL SOIL CRUSTS ALONG A GRADIENT OF ARIDITY IN THE CENTER-WEST OF ARGENTINA

Abstract

The biological soil crusts (biocrust) play a fundamental role in the arid and semiarid areas of South America. However, little attention has been paid to the distribution and coverage of them. In Argentina, studies about biocrust are still scarce. The goal of this contribution is to analyze the coverage of the biocrust and each of the functional component along a gradient of aridity in the center-west of Argentina. The gradient included three differentiated sites: semiarid, arid, and hyperarid sites. The coverage was recorded using the Point-quadrat method on 30 transects through a gradient consisting of three sites: semiarid, arid, and hyper-arid sites. The arid site was the system with the highest coverage of biocrust followed by the hyper-arid site. The semiarid site had the lowest values of coverage and showed significant differences among the three systems were found. Cyanobacterias dominate in the hyper-arid site. On the other hand, cyanobacteria and lichens were dominant in the arid site. The coverage of studied organisms showed variations in the semiarid site. These results support the idea that the coverage has a strong relationship with the features of the studied ecosystem and the environmental factors both at a mesoscale and a microscale in a determined community.