Efectos de la regulación sobre los macroinvertebrados en el río Segura (S.E. España)

Abstract

In order lo study the effects of the hydric regulation on the benthic macroinvertebrate communities, two close areas, with similar characteristics, were selected, one of them is regulated by an electric power factory. In these areas a monthly sampling was done. Samples from benthos and measurements of several physical and chemical parameters were taken. Obtained data were treated statistically in order to determine wether or not there is a relationship between the environmental conditions and the macroinvertebrate community. The global changes along the time of macroinvertebrates density have been clearly more uniform in the non regulated river comunity. The hydric regulation cause an increase on the relative significance to some taxons, like Tricoptera, Simulidae and Quironomidae, and this efect is due to the reofile quality of the area. However the efect of hydric regulation on Ephemeroptera, Coleoptera, Hydracarina and Plecoptera, are contrary to fore taxons, so they are more abundant in the non regulate river. Also, the zoobenthic of the regulate river occur an abundancy decrease of Plecoptera and Ephemeroptera. The most important effect observed of the hydrologic regulation on the physical river conditions is a substrate homogeneity, which produces a decrease of the habitat diversity for the invertebrates. So, in the regulated river a poorer community, with a lower diversity, has been observed.