Comunidades de odonatos (Insecta: Odonata) en tramos de diferentes características hidrotérmicas en la cuenca de río Carrión

Abstract

The diversity of odonata in the area around Velilla del Río Carrión (NW of Palencia) was analyzed in relation to the water temperature and the modification of the water regime by the Compuerto reservoir. The communities along the main axis of the Carrión river were compared in three sections with different dynamics with respect to a section of the Besandino river, not influenced by the presence of a large nearby reservoir. The results contributed the presence of 11 species (6 Zygoptera and 5 Anisoptera) in 23 records obtained between June and September during 2014 and 2015. Due to the release of water for irrigation in summer, the temperature and flow in the river Carrión were inverted below the reservoir and were associated with a decrease in the specific richness of odonata showing evidence of reproduction, indicated by the presence of larvae and exuviae. Downstream from the Compuerto dam, despite being a long and varied section, only one species was found of a specimen observed in flight and with no evidence of reproduction, while in the rest of the areas a larger number of species appeared with signs of reproduction in all of them. The thermal effect of a smaller dam was attenuated and did not restrict the presence of odonata in the same way