Diversity of aquatic Entomofauna in three rivers from the Darién Ecoregion, Chocó (Colombia).

Abstract

There are few studies on insect diversity from rivers and streams of coastal areas, particularly within the Chocó biogeographic area.In this study we conducted a spatially explicit inventory of insects from three freshwater bodies in the Darien Ecoregion (located in theColombian Caribbean). To establish the aquatic insect spatial patterns of richness, multiple habitats were sampled at seven stations from threestreams located between the flat and mountainous parts. Also some physicochemical parameters were measured and each sampling station wascharacterized according to the quality of riparian cover and habitat heterogeneity following rapid assessment protocols such as Quality Indexof Riparian forest (QBR) and Fluvial Habitat Index (IHF), respectively. To describe the macroinvertebrate assemblage, Shannon Diversity andPielou Equity indices, and Jaccard similarity were calculated and a non Parametric Multidimensional Scaling (NMDS) performed; the numberof groups used in the clusters and the dendrogram were determined by the k -means partition method (k -Means Partitioning). Clusteringpatterns were interpreted based on the riparian cover condition and the physicochemical variables. A total of 3399 individuals were collectedand identified to family level, most abundant insect families were Leptophlebiidae, Chironomidae and Hydropsychidae. Differences betweensampling stations were found where Carolina Middle and High Capurganà sections had the higher richness values with 31 and 30 familiesrespectively. The most diverse station was the medium reach El Regalo and less diverse was the high reach La Carolina, which separated fromthe other stations by the similarity analysis. The clustering pattern found could partially respond to similarities in riparian coverage, habitatheterogeneity and the particular characteristics provided by these parameters, since they have an indirect effect on other variables such astemperature which has a strong influence on the presence and / or establishment of the insect population.