Diferentes usos da terra determinam a ocorrência de espécies vegetais exóticas em ambientes campestres do Sul do Brasil

Abstract

Biological invasions represents a threat to the biodiversity and human activities may induce plant invasions, which affects native species, communities and ecosystems. Yet, brazilian pampas lack of studies focused on the investigation of the relation between alien species and land use. Thus, this study investigated the relation between alien species and distincts land uses based on different kinds of disturbance such as roads, agriculture, field with no management and grazing. A 400m transect were performed in the four different areas and the flora was sampled using braun-blanquet method with a meter square subdivided in 100 equal parts every 20 meters amounting to 20 samples per area to determine the coverage of each alien and native species. It was found 13 alien species in our study with significant differences in the abundance of each area (Tukey Test p<0,001) and significant differences in the floristic composition for both alien ( ONE-WAY ANOSIM R=0,56, p<0,0001) and native species (ONE-WAY ANOSIM R=0,52, p<0,0001) in the four different areas. The highest number of alien species was found on the road transects followed by agricultural area. These results suggest that the presence of alien species is directly related to land uses, especially the ones with high impact. Therefore, a correct management of the soil and control over human activities is encouraged to avoid high levels of disturbance and prevent the spread of alien species to new areas.