Effects of environmental factors on community structure of Leptophlebiidae (Insecta, Ephemeroptera) in Cerrado streams, Brazil

Abstract

ABSTRACT. We analyzed the effects of environmental factors on abundance, species richness, and functional group richness of Leptophlebiidae in 16 sampling points along four Cerrado streams. Across three periods of 2005, we collected 5,492 larvae from 14 species in stream bed substrate. These species belong to three functional feeding groups: scrapers, filtering collectors and shredders. The abundance and species richness were not affected by water quality, but habitat quality related to presence of riparian vegetation had positive effects on the abundance of shredders. Our results add important information on the natural history of the species and functional groups of aquatic insects and also provide relevant data for the monitoring and conservation of streams in the Brazilian Cerrado.KEYWORDS. Aquatic insects; functional feeding groups; environmental changes. RESUMO. Efeito de fatores ambientais sobre Leptophlebiidae (Insecta: Ephemeroptera) em córregos de Cerrado, Brasil. O efeito de fatores ambientais sobre a abundância, riqueza de espécies e grupos funcionais alimentares de Leptophlebiidae foi analisado em 16 locais pertencentes a quatro córregos de Cerrado, a partir de coletas de substrato em três períodos de 2005. Foram amostradas 5.492 larvas distribuídas em 14 espécies, classificadas em três grupos funcionais alimentares: raspadores, coletores-filtradores e fragmentadores. A abundância e riqueza de espécies não foram afetadas por nenhum dos fatores ambientais investigados, mas a integridade dos hábitats exerceu efeito positivo sobre a abundância dos fragmentadores, consequência da intrínseca interação desses organismos com a mata ciliar. Dessa forma, acreditamos que este trabalho agrega informações bioecológicas sobre as espécies e grupos funcionais de insetos aquáticos e poderá contribuir no monitoramento e conservação de riachos do Cerrado.

The effects of environmental integrity on the diversity of mayflies, Leptophlebiidae (Ephemeroptera), in tropical streams of the Brazilian Cerrado

“…Dias-Silva et al (2010) found a reduction in the species richness of Gerromorpha (Heteroptera) with decreasing habitat integrity, for example, while Silva-Pinto et al (2012), detected morphometric asymmetries in odonates. Pereira et al (2012) recorded alterations in the species composition of an assemblage of Trichoptera, while Carvalho et al (2013) observed a shift in the species richness of odonates, and Brasil et al (2013) recorded a reduction in the abundance of shredder leptophlebiids. Leptoblebiids have also been shown to be good indicators in other parts of the world.…”

“…The final index varies from zero to one, with the highest scores referring to the most intact environments. The index has been used in a number of studies of environmental impact, and has produced good results for the analysis of the communities of a number of taxonomic groups of aquatic insects across different regions (e.g., Dias-Silva et al, 2010;Silva et al, 2010;Souza et al, 2011;Pereira et al, 2012;Silva-Pinto et al, 2012;Brasil et al, 2013;Carvalho et al, 2013).…”

“…These changes may alter the balance of nutrients, sediments, debris, and substrates, which is essential to the trophic structure of a community (Allan, 2004;Yoshimura, 2012). In particular, a reduction in riparian forest cover, generally results in a decrease in the abundance of shredders -due to a decline in the supply of dead leaves and an increase in sunlight penetration -while the abundance of scrapers expands (Brasil et al, 2013).…”

“…These mayflies tend to be abundant and widely distributed, and are found in rhithral and potamal lotic habitats, as well as semi-lotic environments, such as rhithral impoundments or flooded forests (Da Silva et al, 2010). These organisms are also crucial to nutrient cycling in aquatic ecosystems due to their functional roles as scrapers, filterers and shredders of organic matter (Baptista et al, 2006;Bello and Cabrera, 2001;Shimano et al, 2012;Brasil et al, 2013).…”

“…They are normally found in well-preserved or only slightly impacted habitats (Shimano et al, 2010) and are useful indicators of environmental quality (Brasil et al, 2013).…”