Modelagem de nicho ecológico e diversidade genética de Copernicia prunifera (Miller) H.E. Moore (Arecaceae): implicações para a conservação

Abstract

Copernicia prunifera (Miller) H.E. Moore is a native palm tree from northeastern Brazil, it has multiple forms of use, its main product being the ceriferous powder. Due to the extractivism carried out over the years in the natural populations of the species, studies on the geographical distribution and genetic diversity of their populations are increasingly necessary. The present study aimed to study the geographic distribution of Copernicia prunifera as a basis in ecological niche modeling (MNE) and to analyze the genetic diversity among natural populations of the species. The ecological niche models were constructed based on 80 species occurrence points and on 19 environmental variables. The results suggest that the potential distribution model of Copernicia prunifera was concentrated in the states of Ceará, Rio Grande do Norte, southwest of Pernambuco, north of Bahia and the valley of the São Francisco River, north and southwest of Piauí and north of Maranhão. The environmental variable that contributed most to the MNE was the rainfall of the driest quarter. In the study of genetic diversity 180 individuals were sampled in 11 natural populations in the states of Rio Grande do Norte and Ceará. Seven ISSR primers were used and provided 100 locus with 99.09% polymorphism. The Polymorphic Information Content (PIC) of each primer was considered to be medium to informative. The genetic diversity of Nei (He) ranged from 0.071 to 0.288 and the Shannon Index (I) ranged from 0.103 to 0.418. AMOVA indicated greater genetic variation among individuals within populations (58.11%) than among populations (41.89%). The Mantel test revealed a positive and significant correlation (r = 0.423; P = 0.006) between the genetic and geographic distances, suggesting isolation by distance. The highest value of gene flow occurred among the populations of AR1 and AR2 (Nm = 29), as well as the greatest genetic similarity. Bayesian analysis revealed that the genotypes were divided into three distinct groups (K = 3). Most populations presented genetic bottleneck populations. Most populations presented genetic bottleneck populations. The results suggest that the populations of Copernicia prunifera are losing their genetic diversity, being necessary measures of conservation of their populations in order to minimize the loss of important alleles, contributing to the maintenance of the species.