Multiscale Environmental Drivers of Aquatic Insect Assemblages in Cerrado Streams

Lotic ecosystems are structured by factors operating at multiple spatial scales. We investigated how local and regional environmental variables influence the composition, richness, and abundance of Ephemeroptera, Plecoptera and Trichoptera (EPT) assemblages in streams of the Tocantins–Araguaia basin in the Cerrado (Brazilian savanna) biome, Goiás, Brazil. We sampled aquatic insects and environmental variables in 19 streams. We employed multiple regression analyses to evaluate the impact of spatial and environmental factors on taxonomic richness and abundance. We applied multiscale multivariate codependence analysis (MMCA) to examine the environmental and spatial effects on assemblage composition. Our results revealed that taxonomic richness increased with the percentage of agriculture in the watershed at finer scales, reflecting colonisation by tolerant taxa. Total abundance, in turn, responded to local factors (conductivity and temperature) and watershed areas. The assemblage composition of EPT was primarily structured by broad‐scale spatial gradients (~192 and ~128 km), associated with altitude and pH, respectively. These findings demonstrate that spatial processes (limited dispersal) act together with specific environmental filters to shape assemblages. We conclude that conservation strategies for aquatic biodiversity in the Cerrado must adopt a multiscale perspective that considers both local factors and watershed integrity.