ABSTRACT
The aquatic macroinvertebrate community reflects the ecological status of a river. Typically, some extraction methods have been implemented, but the capture and preservation of organisms are necessary. The techniques of digital image processing applied to ecology have become innovative tools for the characterization of aquatic macroinvertebrates. This research implements a methodology for the processing and classification of four aquatic macroinvertebrates genera Thraulodes, Traverella (Ephemeroptera), Anacroneuria (Plecoptera), and Smicridea (Trichoptera) present in three rivers in Antioquia (Colombia), which includes two phases. The first of these was the collection and capture of organisms to obtain a database of the most abundant genera, at laboratory scale. The second was the use of simulations that allow the classification of data through a process of selection and extraction of characteristics using the bag of visual words technique. Of all the classifiers tested, Gaussian vector support machines obtained a percentage of success in the recognition up method of four organisms to the genus level of 97.1 %. The training and computational processing for classification enabled the standardization of an appropriate methodology that will serve as a starting point for aquatic biomonitoring and inventory in Colombia and internationally.
Subject(s)
Ecosystem , Invertebrates , Animals , Colombia , Environmental Monitoring , RiversABSTRACT
RESUMEN El embalse La Nitrera se encuentra localizado a 2140 m.s.n.m. en el municipio de Concordia, departamento de Antioquia (Colombia) y es la única fuente de abastecimiento de agua del municipio. La operación de un embalse sobre un sistema lótico afecta la estructura y ensamblaje de sus ecosistemas acuáticos. Esta investigación tuvo como propósito analizar la distribución de la biomasa de los macroinvertebrados acuáticos antes y después del embalse, con el fin de determinar el impacto de este sobre las comunidades hidrobiológicas. Para tal fin, se analizaron las variables hidrobiológicas en época seca, de lluvia y en diferentes periodos de transición entre el año 2016 y 2017. Se investigaron cuatro estaciones de monitoreo, realizando la determinación, conteo y definiendo el rol trófico de los macroinvertebrados acuáticos, además de un análisis termogravimétrico (TGA) de la biomasa. Con la información obtenida, se construyó un modelo trófico y se calculó la pérdida de energía calórica disponible de la biomasa (TGA). Los resultados evidenciaron que las comunidades de macroinvertebrados acuáticos presentan una modularidad similar entre ellas en las estaciones antes del embalse, y una modularidad diferente en la estación después del embalse. A través del índice de modularidad (modelo Ghepi) y el análisis TGA, se logró establecer que el embalse altera la cadena trófica de las comunidades de macroinvertebrados acuáticos.
ABSTRACT The reservoir La Nitrera is located at 2140 m.a.s.l. in Concordia's town, in the Antioquia's department (Colombia) and is the only source of water supply in the municipality. The operation of a reservoir on a lotic system generates affectations in the structure and assembly of aquatic ecosystems. The purpose of this research was to analyze the distribution of biomass of aquatic macroinvertebrates before and after of the reservoir to determine the impact of it on the hydrobiological communities. For this purpose, the hydrobiological variables were analyzed in dry season, rain season and in different periods of transition between 2016 and 2017 in four monitoring stations, making the determination, counting and defining the trophic role of aquatic macroinvertebrates, in addition to a thermogravimetric analysis (TGA) of the biomass. With the obtained information, a trophic model and an analysis of the loss of the available caloric energy of the biomass (TGA) was made. The results showed that the communities of aquatic macroinvertebrates had a similar modularity between them in the stations before the reservoir and different modularity in the station after the reservoir. Through the modularity index (Ghepi model) and the TGA analysis, it could be established that the reservoir generates an alteration in the trophic chain of aquatic macroinvertebrate communities.
