干旱区生态环境知识资源中心

Several ecological features make ants important elements in the functioning of arid and semi-arid ecosystems. However, knowledge about these insects in semiarid environments of Venezuela is poor. Hence, ant diversity was evaluated in three semiarid vegetation formations in the northen Paraguana peninsula: thorn woodland, cactus scrub and desert. Since the vegetation of these formations exhibits structural differences, resident ant assemblages are expected to be susceptible to such variations and, thus, show differences in their species richness and abundance. Fifty pitfall traps were installed and 6 hrsman were invested in direct collections for each vegetation unit (total of 150 traps and 18 hrsman). Forty eight species, 21 genera and seven subfamilies of ants were registered. The thorn woodland exhibited greater richness of species (42) in relation to the other vegetation formations (30), with Solenopsis geminata and Dorymyrmex biconis being the most abundant ones. Significant variations were detected between the thorn woodland ant assemblage and those in the other vegetation formations. Diversity, indicator species and guild analysis showed relevant information about ant assemblage properties of each vegetation type. We discuss how the biogeographic insular features of the peninsula affect regional ant composition and, hence, diminish species turnover, and suggest how changes in vegetation explain specific richness and abundance variations in the ant assemblages at local scale.