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Partitioning taxonomic diversity of aquatic insect assemblages and functional feeding groups in Neotropical Savanna headwater streams
Ferreira, W., L. Hepp, R. Ligeiro, D. Macedo, R. Hughes, Phil Kaufmann, AND M. Callisto. Partitioning taxonomic diversity of aquatic insect assemblages and functional feeding groups in Neotropical Savanna headwater streams. ECOLOGICAL INDICATORS. Elsevier Science Ltd, New York, NY, 72:365-373, (2017).
Using adaptations of the US EPA’s National Aquatic Resource Survey (NARS) designs and methods, Ferreira and colleagues examined the distribution of taxonomic and functional diversity of aquatic insects among basins, stream sites within basins, and within stream sample reaches. They sampled 160 low-order stream reaches, 40 in each of four major drainage basins within the subtropical Cerrado biome of southeastern Brazil. They found the greatest diversity among stream sites, followed by lesser diversity among basins, and least diversity within individual stream sample sites. Each individual stream site contributed only a small part of the total diversity, but variation among streams was very large. Understanding the distribution of taxonomic and functional diversity of aquatic organisms at different scales is an important step for selecting ecological indicators for biodiversity conservation and environmental quality assessments. Furthermore, an understanding how organisms are distributed spatially and how they interact with their habitats is essential for designing successful measures for ecosystem conservation and biodiversity preservation. These will help focus sampling efforts for future surveys of biodiversity and biointegrity at local and regional scales. Similar adaptations of NARS designs, field methods, and approaches for assessing ecological condition have been applied in state and basin stream surveys throughout the U.S. and internationally, but have been especially innovative in Brazil. These applications are not only valuable tests of the NARS approaches, but contribute to environmental science, resource management, and conservation of biodiversity through new understandings of natural and anthropogenic controls on biota and physical habitat in streams. This paper contributes to SSWR 3.01.
Biological diversity can be divided into: alpha (α, local), beta (β, difference in assemblage composition among locals), and gamma (γ, 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 (α), among stream sites (β1), and among hydrologic units (β2). We also evaluated the association of EPT genera composition with heterogeneity in land use, instream physical habitat structure, and instream water quality variables. The percent of EPT taxonomic α diversity (20.7%) was lower than the β1 and β2 diversities (53.1% and 26.2%, respectively). The EPT FFG α diversity (26.5%) was lower than the β1 diversity (55.8%) and higher than the β2 (17.7%) diversity. The collector-gatherer FFG was predominant and had the greatest β diversity among stream sites (β1, 55.8%). Our findings support the need for implementing regional scale conservation strategies in the Cerrado biome, which has been degraded by anthropogenic activities.