Estrutura populacional de Butia purpurascens Glassman (Arecaceae) em duas áreas de Cerrado sensu stricto no estado de Goiás

Abstract

This study aimed at describing and comparing the structure of Butia purpurascens (palmeirajataí) populations in two sites of Cerrado sensu stricto (Lajeado and 41st Brazilian Military Zone), both located in Jataí, Goiás, Brazil. For each site, we marked a 1-ha sample plot, subdivided in 100 m2 and 400 m2 plots, in which we registered the number of individuals, their height, and the circumference at 30 cm from the ground level of those presenting exposed stem. The populations were divided into four height classes: 0.1-1.0 m; 1.1-2.0 m; 2.1-3.0 m; > 3.0 m. In Lajeado, the age distribution showed an exponential decrease, while the 41st Military Zone had a higher number of individuals and more adults. The spatial distribution determined by the Morisita index indicated an aggregated pattern for both populations studied, although in the 41st Military Zone this pattern was more evident, suggesting some limitation in the dispersion processes. Factors such as tree density, fire, presence of cattle, competition with alien grasses, and extraction of palm leaves may have been contributing to the demographic differences of the species registered in both sites under study.