We investigated the patterns of taxonomic (TD) and functional (FD) α and β‐diversities of ants in a mountainous landscape along three dimensions, namely one temporal (seasonal) and two spatial dimensions: between habitats – grassland and forest habitats (horizontal), and among elevation bands (vertical). In addition, we tested the effects of environmental variables (mean elevation and temperature, and normalised difference vegetation index – NDVI) on taxonomic and functional α‐ and β‐diversities. β diversities among the two spatial dimensions are the main components of TD. Conversely, FD is almost entirely composed by the α‐diversity component, with a very low contribution of β‐diversity. Regarding environmental drivers, the decrease in temperature caused by increased elevations and seasonal variations had a negative effect on taxonomic α‐diversity. There were no effects of environmental variables on ant functional α‐diversity. Despite the high turnover of ant species occurring along spatial dimensions, the communities were functionally redundant. The changes in species richness and composition patterns in this mountain were strongly influenced by variables correlated with elevation and habitat structure. Species composition changed across all dimensions, but the core traits and functions remained unchanged. Differences observed in the composition of ant communities over relatively short geographic distances highlight the importance to conserve the entire mountain, ensuring the maintenance of the ant diversity and associated ecosystem functions.

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We surveyed ant fauna in the leaf litter in an Atlantic Semideciduous forest in the State Park of Rio Doce (PERD). The work aimed to produce basic information about habitat effects on diversity, as well as about how the ant fauna in a such buffered forest habitat, as the litter layer, could respond the climate variation in a short and long term. We sampled two years in two distinct forest physiognomies, which respond to different geomorphologic backgrounds, in dry and rainy seasons. Species composition, richness and abundance of these forests were distinct. However, both forests hosted similar numbers of rare and specialized, habitat demanding species, thus suggesting both are similarly well preserved, despite distinct physiognomies. However, the lower and more open forest was, more susceptible to dry season effects, showing a steeper decline in species numbers in such season, but similar numbers in the wet seasons. The pattern varied between years, which corroborates the hypothesis of a strongly variable community in response to subtle climatic variation among years. The present results are baselines for future long term monitoring projects, and could support protocols for early warnings of global climatic changes effects on biodiversity.

Naturally fragmented landscapes are adequate systems for evaluating patterns and mechanisms that determine species distribution without confounding effects of anthropogenic fragmentation and habitat loss. We aimed to evaluate an ant metacommunity's spatiotemporal patterns in montane forest islands amid a grassland-dominated matrix. We assessed these patterns by deconstructing the ant metacommunity into forest-dependent and habitat generalist species. We sampled twice a year (summer and winter) over 2 years (2014 and 2015), using soil and arboreal pitfall traps, in fourteen forest islands (varying in size, shape, and connectivity) in the Espinhaço Range Biosphere Reserve, Brazil. We evaluated the relationship between ant species richness, composition (β-diversity), and predictor variables of forest island structure (canopy cover and understory density) and landscape structure (forest amount, number of forest islands, and shape). We sampled 99 ant species, 66.7% of which were classified as forest-dependent and 33.3% as habitat generalist species. We found that ant β-diversity was higher in space than in time, and that species composition variation in time (temporal β-diversity) differed between ant species groups. Both ant groups responded differently to forest island and landscape structure characteristics. Landscape structure seems to act as a spatial filter and the forest islands' local characteristics as an environmental filter, which jointly determine the local and regional diversity. We demonstrate the importance that forest archipelagos pose to ant metacommunity's structure and dynamics in montane tropical regions. Mountaintop conservation and management strategies must consider the forest island archipelago to maintain the biodiversity and the functioning of these systems.

Nestedness is widely observed in natural metacommunities, but its underlying mechanisms are still poorly understood. The distribution of habitats in the landscape and differences in dispersal rates of distinct insect taxa can determine the nestedness of the metacommunity. Here, we evaluated how species habitat specialization contributes to metacommunity nestedness in insect groups with different dispersal capacities in a mountaintop landscape in south-eastern Brazil. We sampled ants, butterflies and dung beetles in two main habitats, naturally fragmented forest islands and a grassland matrix (campo rupestre), during both dry and rainy seasons. We classified species according to their degree of habitat specialization (generalists or specialists) based on the relative frequencies and abundances between these two contrasting habitats. Forty of 211 species were classified as habitat specialists, seven as habitat generalists. It was not possible to classify the remaining species. The metacommunity was nested in structure, with habitat generalist species contributing more to nestedness than habitat specialists. Nonetheless, habitat distribution in the landscape did not affect the nestedness of the metacommunity. Our findings reveal that species sorting (for habitat specialists) and mass effects (for habitat generalists) are concurrent processes in the mountaintop forest–grassland mosaic. Our study helps to advance our understanding of the differences in the distribution of generalist and specialist species in a tropical mountaintop landscape and improves our ability to predict and manage the increasingly adverse effects of changes in land use and climate on metacommunities and ecosystem functions.

Aim Ancient tropical mountains are megadiverse, yet little is known about the distribution of their species. We aimed to disentangle the effects of latitudinal and elevational gradients on the distribution of species of Aculeata and to understand the effects of climatic variables across different spatial scales of diversity (α‐, γ‐, and β‐diversity). Location Campo rupestre in the Espinhaço Mountain Range, Southeast Brazil. Taxon Bees, wasps, and ants (Aculeata: Hymenoptera). Methods We used a unique dataset built from sampling species of Aculeata at 24 study sites across 12 mountains, covering 1200 km from south to north and an elevational range of 1000 to 2000 m. We explored the elevational and latitudinal patterns of α‐ (site), γ‐ (mountain), and β‐diversity among samples at each location (βLocal). We also tested the effect of elevational range on β‐diversity in each mountain (βMountain) and, on a larger scale (βRegional), if β‐diversity is influenced by geographical and environmental distances. Finally, we tested whether climatic variables underpin the observed patterns. Results Latitude had no effect on diversity. We found a decrease in both site and mountain diversity and, only for bees, βLocal increased with elevation. Climatic variables (temperature, wind, and precipitation) and their interactions were important drivers of diversity, with temperature being the most important. Finally, βMountain increased with mountain elevation range, and βRegional increased with the geographical and environmental distances. Main conclusions Our results showed that variation in species richness and composition across mountains is strongly associated with elevational gradient, which showed stronger climatic variation than latitudinal gradient. Therefore, despite having narrow elevational ranges, the biogeographical effects of tropical mountains drive high diversity. Facing global climate changes, this limited elevational gradient may limit species range shifts, leading to severe biodiversity losses.

Insect–plant interactions occur in several ways and have considerable environmental and ecological importance. Many feeding strategies have evolved among herbivorous insects, with host–herbivore systems likely being influenced by trophobionts with ants. We investigated how these interactions vary across elevation gradients by evaluating the structure of the herbivorous insect community and ants associated with Baccharis dracunculifolia at three distinct elevations (800, 1100, and 1400 m a.s.l.) on a mountain in southeastern Brazil. Moreover, we evaluated the diversity and specialisation of interactions between herbivores and host plants along the elevational gradient. We sampled herbivores and ants on 60 plants at each elevation (totalling 180 plant individuals). Herbivore species composition differed among elevations, as did interaction diversity and specialisation. Richness and abundance of chewing insects increased with elevation, while β‐diversity among patches of the host plant was higher at the lowest elevation, probably due to the patchy occurrence of B. dracunculifolia. Richness and abundance of sap‐sucking insects were higher at the intermediate elevation, possibly due to local environmental conditions. We observed a positive relationship between ant and herbivore trophobiont richness on B. dracunculifolia. We found that interactions were more specialised and less diverse at higher elevations compared to the lowest elevation. Changes in vegetation and environmental variables shaped species distributions and their ecological interactions along the elevation gradient. Our study demonstrates that increased elevation changes the structure and patterns of interactions of the herbivore insect guilds associated with the host plant B. dracunculifolia. Ant effects depend on the context, the environment, and the species of ants involved, and are essential for the presence of insect trophobionts.