Spatial genetic structure of Cavanillesia arborea K. Schum. (Malvaceae) in seasonally dry tropical forest: implications for conservation

Abstract

Worldwide, Seasonally Dry Tropical Forests (SDTF) are among the least known and most degraded vegetation types. Cavanillesia arborea (Malvaceae) is an endemic dry forest tree that is bat-pollinated and the seeds are wind-dispersed. The present study sought to characterize the spatial genetic structure (SGS) in natural populations of C. arborea growing in SDTF fragments in Minas Gerais State, Brazil, using ISSR molecular markers. Seven ISSR primers generated 81 polymorphic loci in 175 individuals. In three populations (FU, MO and PC), we found random distributions of genotypes, while two populations (JAN and MV) showed SGS in their first distances classes (171 m and 17 m, respectively), with significant kinship (Sp) values (0.0189 and 0.0005 respectively; P < 0.05). Sp values for these populations indicate that the effects of kinship can be minimized by collecting seeds from distance classes beyond the species' first distance class. The continuous anthropogenic impacts on remnant tree populations, low species densities, and the observed genetic structure, all indicate the need to preserve large areas of dry forest vegetation for conservation purposes.