Abstract
AIMS: In this study, the diversity of Ephemeroptera, Plecoptera, Trichoptera and Coleoptera communities was surveyed in the Toropi River basin, a watershed localized in a slope region, in southernmost Brazil. The influence of some local abiotic factors on the most common genera was also analyzed. METHODS: Samplings were conducted at 40 sites in 1st-4th order streams, along a short elevation gradient (70-500 m), with a Surber sampler. Water physico-chemical factors, as well as substrate type, were obtained at each site. RESULTS: At all, 5,320 specimens were collected, belonging to 18 families and 52 genera. The caddisflies Austrotinodes and Celaenotrichia, and an undescribed Elmidae, Genus M, are new records for the region. The caddisfly Smicridea was the most frequent genus in the study area. The mayflies Camelobaetidius, Paracloeodes and Americabaetis were influenced by stream order. Smicridea was related to air temperature, while the mayfly Thraulodes was influenced by high levels of electrical conductivity. CONCLUSIONS: The high diversity found in the study area, compared to other Brazilian regions, reflects the environmental heterogeneity in the region. These data show that hydrographic basins in slope areas from extreme Southern Brazil sustain high levels of diversity of aquatic insect communities.
Highlights
Rivers and streams are one of the most threatened ecosystems worldwide, due to human pressure on water sources (Allan and Castillo, 2007; Maloney et al, 2011)
It is very important to survey aquatic insect community diversity in rivers and streams in Rio Grande do Sul, before many of them are extirpated, hindering obtain data related to the protection of lotic ecosystems environmental integrity
This study presents the results of an inventory of EPTC genera in montane streams from southern Brazil
Summary
Rivers and streams are one of the most threatened ecosystems worldwide, due to human pressure on water sources (Allan and Castillo, 2007; Maloney et al, 2011). It is very important to survey aquatic insect community diversity in rivers and streams in Rio Grande do Sul, before many of them are extirpated, hindering obtain data related to the protection of lotic ecosystems environmental integrity. Aquatic insects such as Ephemeroptera, Plecoptera and Trichoptera (EPT), as well as some coleopteran (hereafter C) families such as Elmidae and Psephenidae, are important components in lotic ecosystems, and generally predominate at these environments, for they are diverse and broad distributed insects. This study provides important information for stream conservation and environmental assessment programs
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