Functional and taxonomic diversity of aquatic insects (EPT) in an urban river of the Colombian plains

Abstract

The Ocoa river is important for development of the municipality of Villavicencio, but it is subjected to different types of anthropogenic activities along its course; they affect the diversity of bioindicator aquatic insects. The objective of this research was to determine the response of the functional and taxonomic diversity of aquatic insects (EPT) to land use in the Ocoa river. Water samples were taken to measure 19 ex situ physicochemical and bacteriological variables at 12 stations with different land uses (urban and industrial, agriculture, natural, fish farming, livestock) and the organisms were collected using Surber net. They were determined until genus and their respective functional traits were recorded. The effective numbers of species, functional diversity indices, redundancy and RLQ analysis were used. The assemblages were dominated by the genera Smicridea (Trichoptera), Lumahyphes and Americabaetis (Ephemeroptera); and the frequent functional traits corresponded to slow development, breathing through gills, soft and non-aerodynamic medium bodies with habit of clinging. The stations in the middle zone of the river, corresponding to the land use urban and industrial, presented low to no taxonomic and functional diversity. The functional traits presented characteristics associated with the type of substrate; trophic habits were mainly related to organic matter (coarse and fine). In contrast, the stations of the upper and lower zone presented the highest values of taxonomic and functional diversity, which were characterized by natural land use, livestock and agriculture.