We performed phylogeographic and genetic structure analyses of Neothraupis fasciata joined with species distribution modelling to evaluate whether: (1) the distribution of genetic variability shows a pattern expected by the isolation-by-distance model; (2) the influence of the Pleistocene climate changes on species distribution; and (3) climate/climatic stability (hypothesis of climatic stability) as a predictor of population genetic diversity. Based on two molecular datasets (ND2 and FIB-5), the isolation-by-distance hypothesis was not supported. The mitochondrial haplotype network indicated the existence of historically isolated populations at the southern range of the species distribution, and recent population expansion was identified by both neutrality tests and extended Bayesian skyline plot analysis. Thus, the climatic changes during the Pleistocene might have promoted the reconnection of the partially isolated southern populations, which may have persisted in the plateaus during the cycles of savanna contractions. Subsequently, this species (re)colonized northern areas of the species present distribution, following the continuous vegetation on the São Francisco and Central plateaus about 60 kyr, and also reached the Amazonian savannas likely via the central corridor. Thus, our results indicated that the intrinsic relationship between the relief heterogeneity (plateaus and depressions) and the climatic fluctuations, mainly in the Pleistocene, promoted population reconnection and demographic expansion of N. fasciata.

Knowledge of the frequency and occurrence of macroinvertebrates throughout landscapes may clarify the effects of anthropic impacts on aquatic systems and help guide conservation actions for watersheds. We evaluated macroinvertebrate α and β diversity in streams in four different subtropical phytophysiognomies: highland grasslands with arboreal riparian vegetation, highland grasslands without arboreal riparian vegetation, mixed ombrophilous forest and silviculture. We also evaluated how environmental factors influence α diversity. We sampled macroinvertebrate communities (by Surber sampler), litter input (by nets) and physicochemical variables of the water (by multiparameter and chemical analysis) at 10 sites in riparian zones of a highland system. A total of 2124 individuals were sampled representing 41 taxa, with high α and β diversity in mixed ombrophilous forest. The results indicate that environmental heterogeneity increases food resource availability, as well as macroinvertebrate diversity. Furthermore, the β diversity was found to increase with distance among the unconnected streams. Areas of silviculture had the highest density values among the sampled areas due high organic material stock in the soil. Therefore, higher leaf litter input may decrease the toxicity effect of secondary compounds released by leaf plant decomposition compared to environments with low systemic leaf litter input, such as highland grasslands. The presence of arboreal riparian vegetation drives canopy openness, water temperature, dissolved oxygen, and orthophosphate in streams, which control the frequency and occurrence of benthic macroinvertebrates. Homogeneous systems, as naturally observed in highland grasslands, plus high canopy openness decrease macroinvertebrate richness and density. The naturally low richness of highland grasslands, although with endemic species, may be an important guideline for legislation on anthropic impacts, management, and conservation of streams in this specific subtropical zone.