Efeito da forma das parcelas na riqueza, diversidade e estrutura de espécies arbóreas em uma floresta de terra firme e de várzea no estado do Pará

Abstract

The influence of plot shape has been little explored in tropical studies and few studies have been conducted to test differences in plant community richness, diversity and structure in relation to plot shape. The objective of this study is to test whether plot shape influences the patterns of richness, diversity and structure in two types of forest in the eastern Amazon, Pará State: one area located in the Gunma Ecological Park (PEG) located in the municipality of Santa Barbara, and another in the Ama fruit, located in the municipality of Ananindeua. In the PEG, 15 hectares were used in the terra firme forest, each hectare consisting of 25 plots of 20 x 20 m. Within each hectare, a square plot (60 x 60 m) and a rectangular plot (20 x 180 m) were chosen, totaling 15 square and 15 rectangular plots. In the Amafruta area, three 100 x 500 m blocks were used in a floodplain forest, each block consisting of 200 10 x 25 m plots. Within each block, three square plots (50 x 50 m) and three rectangular plots (10 x 250 m) were chosen, totaling 12 square and 12 rectangular plots. To test for differences in species richness, species diversity, number of rare or common species, density, and basal area of the plots (dependent variables) in relation to plot shape (square or rectangular) (factor) in the two forest types analyzed in this study, Student's t-test was used. The test showed that there was no significant difference in richness, diversity, number of rare and common species, density and basal area of trees between square and rectangular plots in Gunma State Park and in the floodplain forest of the Amafruta area. Thus, due to the lower cost of implementation and maintenance, rectangular plots should be prioritized in botanical and forestry surveys or permanent plots for monitoring the structure of the plant community.