Estudio de la entomofauna acuática presente en el Río Palmar, Cundinamarca

Abstract

Aquatic insects are the main animal component of freshwater ecosystems, playing important ecological roles in the regulation of organic matter, and they have a high susceptibility to changes such as temperature, substrate and concentration of waste, which has made it possible to use them as a tool for the evaluation of water quality, as a consequence, most of the studies have been directed towards bioindication and the strengthening of systematics, leaving aside the inclusion of environmental variables such as height or if they include it, this is evaluated isolated way in different water channels without reaching a relationship between the different communities that inhabit it. For this reason, the present investigation had as object to establish how the composition of the aquatic entomofauna varies with respect to the altitudinal gradient and to determine the physicochemical conditions that are distributed in the Palmar river, Cundinamarca from its source to its mouth in the Negro river, during the months of September 2018 to February 2019. Three sampling areas were established: Matarredonda Natural Ecological Park at 3,294 meters above sea level, the municipality of Ubaque at 1,958 meters above sea level and the municipality of Guayabetal at 1,090 meters above sea level. In each zone, two quantitative methods were used to capture the individuals, which consisted of a Surber network and a "D" type network, the physicochemical parameters were measured in situ. We analyzed the richness, relative abundance, Shannon diversity index, Pielou's equitability and Simpson's dominance, as well as multivariate analyzes such as ACP and ACM to establish the distribution of the groups in the studied zones and an ACC to relate the aquatic entomofauna to the registered physicochemical variables, likewise, an analysis of similarity, of multidimensional scaling nMDS and an ANOSIM under the Bray-Curtis estimator. A total of 22,361 individuals were collected grouped into 8 orders, 35 families, 72 genera, 5 species and 92 morphospecies of which the orders Díptera and Trichoptera were the most diverse and of greater abundance, with the genera Cricotopus, Onconeura and Mortoniella. On the other hand, the similarity analyzes showed that the zones studied in the Palmar river have notable differences among themselves, sharing only 5 morphospecies. The first report is made for Cundinamarca of the species Americabaetis alphus Lugo-Ortiz and McCafferty, 1996 of the order Ephemeroptera, the genus Austrolimnius Carter and Zeck, 1929 of the order Coleoptera, the genus Anchitrichia Flint, 1970, Cerasmatrichia Flint et al., 1994 and Neotrichia Morton, 1905 of the order Trichoptera and the altitudinal range is increased for the genera Atopsyche Banks, 1905 and Macrelmis Motschulsky, 1859. This research provides data that contribute to the taxonomic and distributional knowledge of aquatic insects from the department of Cundinamarca and it suggests that the height in function of the variation of the physicochemical parameters mainly the temperature, influence in the dynamics of the population composition of the aquatic insects.