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

¹ Programa de Pós Graduação em Ecologia e Conservação – Universidade do Estado de Mato Grosso (UNEMAT) – Br 158, Km 655 – Cep. 78690-000 Caixa postal 08, Nova Xavantina, MT, USA
² Laboratório de Ecologia e Conservação, Instituto de Ciências Biológicas – Universidade Federal do Pará (UFPA) – Rua Augusto Correia, no 1, Bairro Guamá, Cep 66075-110, Belém, PA, USA

^* Corresponding author: brasil_biologia@hotmail.com

Received: 9 July 2014
Accepted: 9 October 2014

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.