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

Abstract

-Aquatic insects are widely distributed, and are especially diverse and abundant in tropical streams, where they play an important role in the food chain due to their diversity of feeding strategies, and the potential for the transfer of energy between aquatic and terrestrial environments. The intimate relationship found between these insects and environmental variables means that they are often used as bioindicatorss in environmental studies. We tested the hypothesis that the loss of environmental integrity in tropical streams will lead to a loss of species and a decline in the abundance of mayflies (Leptophlebiidae), in addition to a change in species composition, and the dynamics of population. Collect immature leptophlebiids in 18 streams representing different degrees of conservation, in the Brazilian Cerrado. The environmental integrity of the sites was assessed using a Habitat Integrity Index (HII), which generates values of zero (degraded) to one (preserved), based on soil use, the extension and conservation of riparian forest, as well as morphological features of the stream. A total of 4945 immature leptophlebiids were collected and identified as belonging to 16 species or morphospecies. On an average, a reduction of 0.1 in the value of the HII led to the loss of five specimens and one species. The composition of the communities varied systematically along the environmental gradient, with more sensitive species being found only when the index was above a threshold of 0.6. The importance of the riparian vegetation for the aquatic biota, especially its role in the mitigation of impacts from the surrounding matrix, supports the universal conservation of this type of habitat.

Assessment of ecological water quality along a rural to urban land use gradient using benthic macroinvertebrate-based indexes

“…Moreover, the absence of riparian vegetation, more frequent in the urban streams of the Uberabinha river catchment (BORGES et al, 2006;GUIMARÃES-SOUTO et al, 2011), increases vulnerability to runoff and excessive loading of nutrients and sediments, and reduces dissolved oxygen concentration (OMETTO et al, 2004). These impacts reduce the spectrum of conditions that most of the taxa are able to live within (RESH et al, 1988), reducing taxa richness to a few tolerant and generalist groups (COUCEIRO et al, 2007) and produces shifts in abundance patterns (BRASIL et al, 2014).…”

Cold/Warm stenothermic freshwater macroinvertebrates along altitudinal and latitudinal gradients in Western South America: A modern approach to an old hypothesis with updated data

“…They parallel changes operating at the community level as a whole. Consequently, their assemblages can be used as indicators of anthropogenic global environmental change in the community structure including patterns of spatial variation (Brasil, Juen, & Cabette, ; Firmiano et al., ; Jackson & Blois, ; Souza, Cabette, & Juen, ). Importantly, it is necessary to assess quantitatively the relevance of such changes, differentiating minor/random signals from critical, meaningful changes.…”

The role of spatial and environmental variables in shaping aquatic insect assemblages in two protected areas in the transition area between Cerrado and Amazônia

“…Under a similar spatial configuration, Brasil et al (2018) found the composition of adult odonate communities, a group of aquatic insects with greater dispersion potential than EPT, to be biogeographically congruent among different regions. Although integrity measured by the Habitat Integrity Index (Nessimian et al 2008) has been the most important environmental predictor for EPT in Cerrado streams (Brasil et al 2013;Brasil et al 2014;Souza et al 2011;Pereira et al 2012;, it varied little in the present study.…”