Dinâmica florestal e relação com atributos funcionais em uma floresta aluvial

Abstract

Alluvial forests are "wetlands" relevant to the conservation of ecosystems, since they play a key role in stabilizing sediments, filtering pollutants from neighboring areas, supplying organic matter to aquatic systems. These forests have a unique floristic composition. However, they are systems that are severely threatened by anthropic activities. Despite the importance of these forests, long-term studies, such as the forest dynamics associated with the functional traits, are scarce, however they are necessary for understanding the functioning of the vegetation. In this context, the present study had as objectives to quantify the structural changes of vegetation in an alluvial forest for two periods of time (2005-2011, 2011-2017), to describe the functional traits that are driving the forest dynamics and to verify the influence of the anthropic impacts in relation to the dynamics rates. For this purpose, it was proceeded forest inventories in the years of 2005, 2011 and 2017 looking for the analysis of the dynamic. In addition, the following functional traits were evaluated: leaf area, specific leaf area, leaf thickness, petiole length, wood density, crown depth, first bifurcation, presence of lenticels and ramification. It was calculated the diversity index, and using Leopold Matrix, the pre-established anthropic impacts in the area were ranked. The anthropic impacts and the drought recorded in the second period of dynamics (2011-2017) had a direct influence at the calculated rates to the alluvial areas analyzed in which provided a mortality higher than recruitment, and consequently occasioning in a decreasing at tree density. In addition, the study allowed to verify the relation of reduction in diversity with the mortality and decreasing in basal area, as well as a more direct relation from functional characteristics with recruitment and increase in basal area.