Environmental gradient analysis in arboreal communities in the lower Jacuí river

Central Depression region in the state of Rio Grande do Sul extends across plains and gentle undulated reliefs, with a predominance of gallery forests. This study aimed to analyze remaining tree communities of the seasonal deciduous forest in different positions of the landscape in small tributaries of a watershed in Pantano Grande, RS, Brazil. Surveys were conducted at 40 sampling points equaling 500 m². The analysis pointed to the existence of three ecological groups, spatially correlated with their positions in the landscape, at different stages of preservation, diversity, structure and floristic development. The community groups were named sub-montane (upper plains) and alluvial formations, and the domain area of both formations (FA/FS). TheFA/FS proved to be more diverse than the others, with lower ecological dominance in narrow fragments. Submontane stood out with higher density of individuals in the largest diameter and height classes, with high ecological dominance, determined by a particular species tolerant to shade,Actinostemon concolor . Alluvial formation (FA) was characterized by smaller individual trees and the dominant presence of Sebastiania commersoniana in narrow corridors.

ecology; diversity; subtropical forest; forest soil