Caracterización de la fauna de macroinvertebrados bentónicos en la cuenca del río Orbigo (León)

Abstract

This paper has pretended to analyze different groups of bentonic macroinvertebrates that you can find in the Órbigo river and its flowing respect to the physico-chemical and geomorphological variations of the basin. This work has been done with all the dates from 1987 that is the reason that all of plecoptera, ephemeroptera, trichoptera, diptera, odonata and mollusca taxonomic groups have been selected. From Principal Components Analysis results, it is possible to observe that respect to the macroinvertebrates, the second factorial axis is corresponded with a variation tendence relationated whit an increment of aquatic vegetation; Tanytarsus brundini, Brillia modesta, Potthastia gaedii, species are situated on the positive coordinates while, the species from stony substratum and the flowing speed are located on the oppossite outmost, such as Ancylus fluviatilis and Onychogomphus uncatus. The variation tendency, represented by the third axis, is depending on the temperature. On the positive utmost, the estenothennes species, are founded for instance Glossosoma privatum, Sericostoma sp. and Rhyacophila mocsari tredosensis, while on the negative plot it is associated to thermophilous species pro example Caenis luctosa, Choroterpes picteti, Hydropsyche exocellata and Rheocricotopus sp. In relation to the samples station, the first axis differences the temporary rivers. The second axis is relationated whith the lithology. The limestone subbasin is situated in the positive utmost while the siliceus is ubicated on the opposite side. The third axis, express in a progresive way the eutrophic degree putting away lengthwise the river; there is one exception the points of the sample which have been translated of the hurnan actuation of use and profit, have been translated towards the pothamon areas.