Pollution tolerance, flight capacity and natural history explain metacommunity structure in high-altitude stream insects

Abstract

Aim To test how different taxonomic and functional groups of aquatic insects from high-altitude streams respond to environmental and spatial gradients at multiple scales in Southeast of Brazil. Methods Specimens were collected in 26 high-altitude streams distributed over a gradient of previously defined environmental quality. The taxonomic identification was made at the genus level and the functional classification was based on traits of flight capacity and pollution tolerance compiled from specific literature. We obtained local in situ data (limnological, sediments, and organic matter), as well as calculated land use at the riparian and drainage basin scale. A variation partitioning approach was used to explain species composition based on different response matrices deconstructed by both taxonomic groups and functional traits. The explanatory matrices encompassed environmental variables at three spatial scales and spatial variables extracted from Principal Components of Neighbor Matrices analysis. A linear model was applied to verify the possible correlation between spatial and environmental components. Results The contribution of the spatial and environmental components varied strongly between taxonomic and functional groups. For taxonomic groups, the pure environmental component was more important for Odonata and Trichoptera, while spatial variables were more important for Diptera (non-Chironomidae) and Chironomidae, Coleoptera, Ephemeroptera, Plecoptera and Megaloptera. The sensitive groups with good flight capacity showed a greater environmental signature while the tolerant groups with low flight capacity had a greater spatial signature. Moreover, the important variables for explaining community variation were from different spatial scale (local, riparian and watershed) depending either on the analyzed taxonomic or on functional groups. However, a general effect of forests was found in several groups. Conclusions It is necessary to consider the joint effect of evolutionary natural history of groups, as well as their functional traits in the structuring of metacommunities, since only taxonomic resolutions may not be sufficient to detect assembly processes at multiple spatial scales.

Opiliofauna (Arachnida, Opiliones) de campos de Altitude no município de Poços de Caldas, Minas Gerais, Brasil

“…O inventário foi conduzido em uma área de campos de altitude no Morro do Ferro (21°53'31" S; 46°32'57" O), associado a capão de mata (Figura 1), que se encontra fortemente impactado pelo cultivo de Eucalyptus sp. (Myrtaceae) (SANTOS et al, 2020). Na imagem aérea (Figura 1) é possível notar que a área de coleta dos opiliões encontra-se cercada por monocultivo de eucaliptos à direita, monocultivos de espécies rotativas à esquerda, além de pastagens e campos naturais.…”