Effects of forest conversion on the assemblages’ structure of aquatic insects in subtropical regions

• Published in: Revista brasileira de entomologia Vol. 59; no. 1; pp. 43 - 49
• Main Authors: Bertaso, Tiago R.N., Spies, Marcia R., Kotzian, Carla B., Flores, Maria L.T.
• Format: Journal Article
• Language: English; Portuguese
• Published: Elsevier Editora Ltda 01.01.2015; Sociedade Brasileira de Entomologia
• Subjects: Agricultural land use; Aquatic macroinvertebrates; Ephemeroptera, Plecoptera and Tricoptera taxa; Headwater streams; Parque Estadual do Turvo; Aquatic macroinvertebrates; Parque Estadual do Turvo; Headwater streams; Agricultural land use; Ephemeroptera, Plecoptera and Tricoptera taxa
• ISSN: 0085-5626; 1806-9665
• DOI: 10.1016/j.rbe.2015.02.005

The effects of forest conversion to agricultural land uses on assemblages of aquatic insects were analyzed in subtropical streams. Organisms and environmental variables were collected in six low-order streams: three streams located in a forested area, and three in areas converted to agricultural land uses. We expected that the aquatic insects’ assemblage attributes would be significantly affected by forest conversion, as well as by environmental variables. Streams in converted areas presented lower species richness, abundance and proportion of sensitive insect taxa. The ANOSIM test evidenced strong difference in EPT assemblage structure between streams of forested and converted areas. The ISA test evidenced several EPT genera with high specificity to streams in forested areas and only one genus related to streams in converted areas. Thus, the impacts of the conversion of forested area to agricultural land uses have significantly affected the EPT assemblages, while environmental variables were not affected. We suggest that the effects detected can be influenced by two processes related to vegetation cover: i) lower input of allochthonous material, andii) increased input of fine sediments in streams draining converted areas.