Partitioning taxonomic diversity of aquatic insect assemblages and functional feeding groups in neotropical savanna headwater streams

Biological diversity can be divided into: alpha (alpha local), beta (beta, difference in assemblage composition among locals), and gamma (gamma, total diversity). We assessed the partitioning of taxonomic diversity of Ephemeroptera, Plecoptera and Trichoptera (EPT) and of functional feeding groups (FFG) in neotropical savanna (southeastern Brazilian cerrado) streams. To do so, we considered three diversity components: stream site (alpha), among stream sites (beta(1)), and among hydrologic units (beta(2)). We also evaluated the association of EPT genera composition with heterogeneity in land use, instream physical habitat structure, and instream water quality variables. The percentage of EPT taxonomic alpha diversity (20.7%) was smaller than the beta(1) and beta(2) diversity percentages (53.1% and 26.2%, respectively). The percentage of EPT FFG collector-gatherer a diversity (26.5%) was smaller than that of 131 diversity (55.8%) and higher than the beta(2) (17.7%) diversity. The collector-gatherer FFG was predominant and had the greatest beta diversity percentage among stream sites (beta(1), 55.8%). Our findings support the need for implementing regional scale conservation strategies in the cerrado biome, which has been degraded by anthropogenic activities. (C) 2016 Elsevier Ltd. All rights reserved.