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

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, and ii) increased input of fine sediments in streams draining converted areas.

Extension of the geographical distribution of two anuran species for Rio Grande do Sul State, Brazil, with comments on natural history / Extensão da distribuição geográfica de duas espécies de anuros para o Estado do Rio Grande do Sul, Brasil, com comentários sobre história natural

We record for the first time Crossodactylus schmidti (Anura: Hylodidae) and Proceratophrys avelinoi (Anura: Cycloramphidae) from Rio Grande do Sul State, Brazil, based on individuals captured in an area of Mesophytic Semideciduous Forest, the Parque Estadual do Turvo, located in the northwest region of the state. These records extend the geographical range for both species in about 60 km from the nearest known locality, the Municipality of San Vicente, Misiones, Argentina. We provide a characterization of the calling site used by males of Crossodactylus schmidti, and we also determined the niche breadth of P. avelinoi regarding to the use of water bodies.

Reportamos o primeiro registro de Crossodactylus schmidti (Anura: Hylodidae) e Proceratophrys avelinoi (Anura: Cycloramphidae) para o Estado do Rio Grande do Sul, Brasil, com base em indivíduos coletados em área de Floresta Estacional Semidecidual, Parque Estadual do Turvo, região noroeste do estado. Estes registros ampliam a área de distribuição das duas espécies em aproximadamente 60 km a partir da localidade mais próxima conhecida, o Município de San Vicente, Misiones, Argentina. Fornecemos, ainda, uma caracterização do sítio de vocalização de C. schmidti e determinamos a amplitude de nicho de P. avelinoi quanto ao uso de corpos d'água.