Taxonomic composition and feeding habits of Chironomidae in Cerrado streams (Southeast Brazil): impacts of land use changes

Abstract

The Chironomidae family is the most abundant and diverse member of the benthic community in streams, yet their identification is still neglected in many papers. It is considered a family tolerant to environmental impacts and with homogeneous feeding habit. AIM: To compare the richness, abundance and taxonomic composition of Chironomidae in Cerrado streams under different land uses as well as the feeding habit differences between genera of reference areas, sugar cane culture and pasture. METHODS: We selected seven streams in each land use and sampled six units using Surber sampler. The material was transported live for laboratory processing. RESULTS: Our results showed no significant differences in abundance and richness of Chironomidae among different land use, but we observed greater average values of abundance and richness in streams impacted by pasture. We found a distinct taxonomic composition between reference streams and impacted streams, both sugar cane and pasture. Stenochironomus was the most representative genus in reference areas, while Parametriocnemus was in sugar cane culture and Tanytarsus in pastures. The only statistically different feeding pattern found were between Cerrado streams and sugar cane for plant tissues, reflecting the greater abundance of Stenochironomus in Cerrado and among Cerrado streams and pasture for microalgae. CONCLUSIONS: We conclude that the conversion of natural areas in monocultures and pastures directly impact streams by modifying the taxonomic structure of Chironomidae. In contrast we did not observe a clear change in feeding patterns, because in all streams the diet pattern was mostly detritivorous.

Keywords

• insetos aquáticos
• mosquitos
• impactos ambientais
• composição faunística
• grupos funcionais