Grupos funcionales alimentarios de insectos acuáticos en quebradas andinas afectadas por agricultura y minería

Abstract

Aquatic insects are ecological indicators of human disturbance and currently there is the tendency to use the functional approach as a potential tool to evaluate water quality. Insects can change the food acquisition mode and the type according to environmental conditions. This study aims to evaluate the influence of the agricultural and mining impacts upon the diversity and dominance of aquatic insect feeding functional groups and trophic guilds found upstream in the Chinchiná River (Caldas, Colombia). Two localities were selected, one with mining and one with agriculture activities, in each locality we evaluated a reference and an impacted creek. A total of 8239 individuals were collected using a Surber net; these are grouped into eight orders, 36 families and 71 morphospecies (Ĉn=100%). The intestinal content of the specimens whom belong to the nine most abundant genera of aquatic insects was analyzed and classified as: shredders, collectors, predators, scrapers, and filterers. No changes were noted regards to the diet between impacted and reference areas, possibly due to resource availability. Agricultural activity presented the strongest negative effect on the diversity of the group. This result may be linked to the complete loss of riparian vegetation due the immediate proximity of the crops to the studied streams, and to the use of agrochemicals.