Effect of woody plant removal in herb-subshrub communities in preserved and disturbed Brazilian Chaco areas

ABSTRACT

The impacts caused on Chaco plant communities by the removal of woody species, together with the effects on the composition and functional structure of herbaceous plants, are still unknown. Therefore, this study aimed to assess the effects of anthropization on herb-subshrub communities in preserved and disturbed Chaco areas. Specifically, we examined differences and similarities in species diversity, composition and proportion of life forms in eight areas of Brazilian Chaco. Samples were taken from herb-subshrub communities using 800 1x1m² plots located in disturbed and preserved areas. Among 130 recorded species, 46 were exclusive to disturbed areas. The composition of species differed between preserved and disturbed areas (PERMANOVA; p = 0.001). PCoA ordination analysis showed greater aggregation of the plots in disturbed areas than in preserved areas. In preserved areas, an analysis of indicator species showed Hemicryptophytes species as the most representative life form. In disturbed areas, the proportion of life forms among indicator species was Hemicryptophytes, followed by Therophytes and Chamaephytes. Our study shows evidence that alterations in species composition, structure, and diversity, as well as sets of indicator species, occur in herb-subshrub communities. The removal of trees and bushes leads to a new configuration of this component in Chaco environments.

Keywords:
anthropization; Chaco vegetation; functional structure; herbaceous plants; indicator species; life form; plant communities; richness; thorn forest