CHANGES IN THE SAVANNHA VEGETATION RESULTING FROM THE INTRODUCTION OF PINUS CARIBAEA IN YICHADA, COLOMBIA

Abstract

The savanna is a natural ecosystem of the low tropics, of character very seasonal, with a continuous level of grasses and sedges and a discontinuous level of low trees or shrubs. Over these,in the Centro Las Gaviotas (Vichada), was established a plantation of Caribbean pine (Pinus caribaea var. hondurensis), originally a species of the Caribbean and Central America. In order to evaluate the effect of the pine implantation on the natural vegetation of the savanna, six vegetation inventories were carried out in the dry lands savannas on soils of the series Gaviotas, one dedicated to extensive cattle and 5 planted with caribbean pine of 4, 7, 10, 12 and 15 years ago. With comparisons, analysis of structural variables and composition of the vegetation beetwen the locations, a substantial change in plant composition, phisionomy and structure of the dry lands savannas is demonstrated as consequence of the plantation. The principal changes in pine plantations are: decrease of the number of species and coverage of grasses and sedges and legumes, increase of the number of species and coverage of melastomatáceas, dilleniáceas, rubiáceas and hypericáceas and appearance of four levels of vegetation (herbaceous, shrubby, subtree and tree) rather than the herbaceous one of savanna 186 species, 80 in savanna and 159 in plantations between 4 and 15 years, were found.