Diversidade genética de Dicypellium caryophyllaceum (Mart.) Ness na Área de Influência Direta da UHE Belo Monte, Altamira, PA

Abstract

The Belo Monte Hydropower Plant is one of the largest initiatives of the Brazilian energy sector. Its installation in Xingu River Basin brings a range of social, economic and environmental consequences. One of the main negative impacts of its installation is threat to biodiversity. Brazilian clove bark (Dicypellium caryophyllaceum, Lauraceae) is an arboreal specie that suffered strong exploitation for centuries for being considered a spice and is currently quite rare in Brazil. Therefore, this study aimed at analyzing the genetic diversity of a natural population of Dicypellium caryophyllaceum present at the Direct Influence Area of Belo Monte Hydropower Plant in Altamira (Para). The analysis was based on 22 ISSR primers. A total of 180 fragments were identified, being 125 polymorphic (69,44%). The number of loci per primer ranged from five to 15, with mean of 8,2 (± 2,68). The number of alleles (Na) and the number of effective alleles (Ne) were, respectively, 1,672 and 1,470. The expected heterozygosity (He) and Shannon index (I) were 0,266 and 0,389 respectively. Spatial genetic structure analysis based on coancestry kinship coefficient was significant (p < 0,05) for a distance of 21 m. The Wilcoxon test for the occurrence of genetic bottleneck showed a significant result (P = 0,03125), indicating that the studied population has recently experienced a reduction in population size. The results of this work showed that although it is an endemic and endangered species, the D. caryophyllaceum population has moderate genetic diversity. Individuals distant from less than 21 m exhibited a trend of family structure and it was observed the population underwent a genetic bottleneck. The strong exploitation of the species occurred in recent centuries leading to the reduction in its population size. Reduction in population size and isolation of populations may lead to inbreeding and genetic drift, which reduce the genetic diversity and increase its risk to extinction.