Effect of silica sand extraction on the structure and species composition of two pine forest sites in the western region of Pinar del Río

Abstract

The effect of the practices of silica sand mining in the structure and species composition at two sites (San Ubaldo and Sabanalamar) of pine forests of western Pinar del Río was evaluated. A floristic inventory is from 24 square plots of 20 x 20 m (400 m2) by simple random sampling in areas with and without silica sand mining. Structural parameters, value index of ecological, alpha and beta diversity are determined. It was found that the current state of natural pine forests is unfavorable, with a more marked effect in San Ubaldo, determined by the bulk of silica sand mining. The area was poor floristically and differentiation between the study sites, according to hierarchical clustering, where Sabanalamar presented richest flora dominate families Asteraceae, Euphorbiaceae, Eriocaulaceae and Xyridaceae. The pine forest is characterized by a heterogeneous structure with alterations in diameter classes. The most ecologically important species were found to be: acoelorrhaphe, Pinus caribaea var. caribaea, Chrysobalanus icaco, Colpothrinax wrightii and Anacardium occidentale. The analysis corresponding of the sampling units and the degree of intervention indicated strong gradient with a high ratio of silica sand mining and distribution of species, proving that the intensity of harvesting practices directly influenced the floristic composition the pine forests of white sand.