The search for ecological indicators: is it possible to biomonitor forest system degradation caused by cattle ranching activities in Argentina?

Cattle ranching is a typical disturbance factor in the North Patagonian forests. The selection of modal areas having similar natural environmental conditions enabled the analysis of the response of the system to exploitation.Different structural parameters in the vegetal community were studied and secondary data on fire frequency and livestock censuses were compiled. An area gradient showing different degrees of degradation was defined, which was presumed to show the stages an area goes through when under livestock farming. Three ecological indicators were defined: key species, as indicators of the occurrence of a degradation process, vegetal cover, as an indicator of the stage a degradation process is going through and vegetal biovolume, as an indicator of when the degradation process has become critical. These indicators must be used together in order to obtain a good diagnosis of the state of the area under exploitation.