Seasonally dry tropical forest temporal patterns are marked by floristic stability and structural changes

Abstract

We have aimed to characterize the Seasonally Dry Tropical Forests (SDTF) dynamic in floristic and structural changes, evaluating changes in dynamic rates and structural attributes such as richness, number of trees and biomass. We have hypothesized the SDTF fragments present the dynamic patterns characterized by temporal fluctuations, describing an instability pattern, in according to the already found for others tropical forests. The work was carried out based on the data of 42 plots of 400 m² in three fragments, measured in 2005 2010, 2015 in the Brazilian Arboreal Caatinga. We evaluated temporal changes in richness, species composition, trees density, biomass and rates of Mortality and Recruitment and Biomass gain and loss using Mixed Generalized Linear Models (GLMM). The results suggest floristic composition stability, but changes in structure and dynamics. There was a density reduction conditioned by constant mortality and by recruitment decrease, and biomass increase due to losses reduction and gain increase. The biomass increase was concentrated in a small set of species that are the most representative of the community temporal patterns. The results are probably related to the community dynamic processes and to the main SDTF characteristics such as climatic seasonality that influences the local ecological processes.