Tree Species Composition in Tropical Forest Remnants of Highly Deforested Regions: The

Deforestation and fragmentation of tropical forest are the most serious threats to biodiversity. In the lowlands of the Huasteca Potosina region, Mexico, more than 95,000 ha of tropical forest have disappeared. This paper analyses tree species composition in tropical forest patches of this highly deforested region, located in northeast of Mexico. At present, only 57 remnants of arboreal vege-tation larger than ten hectares still remain standing, which cover 6117 ha. These decreasing frag-ments host 140 floristic species, representing 42 families and 85 genera. Compared with previous inventories, these data show a sharp drop in species composition. Most of the forest remnants contain less than 50 % of the floristic diversity recorded by previous surveys, particularly in the medium subperennial tropical forest