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Mountains provide an interesting context in which to study the many facets of biodiversity in response to macroclimate, since environmental conditions change rapidly due to elevation. Although the decrease in biodiversity with increasing elevation is generally accepted, our understanding of the variation of functional diversity along altitudinal gradients is still poorly known. The partitioning of diversity into spatial components can help to understand the processes that influence the distribution of species, and these studies are urgently needed in face of the increasing threats to mountain environments throughout the world. We describe the distribution of dung beetle diversity along an altitudinal gradient on a tropical mountain in southeastern Brazil, including the spatial partitioning of taxonomic and functional diversities. The altitudinal gradient ranged from 800 up to 1400 m a.s.l. and we collected dung beetles at every 100 m of altitude. We used the Rao Index to calculate γ, α and β diversity for taxonomic and functional diversity of dung beetles. Climatic, soil and vegetation variables were used to explain variation in community attributes along the altitudinal gradient. Dung beetle richness declined with altitude and was related to climatic and vegetation variables, but functional diversity did not follow the same pattern. Over 50% of γ taxonomic diversity was caused by among altitudes diversity (β), while almost 100% of functional diversity was due to the α component. Contrasting β taxonomic with β functional diversity, we suggest that there is ecological redundancy among communities and that the environment is filtering species in terms of the Grinnellian niche, rather than the Eltonian niche. β taxonomic diversity is caused mainly by the turnover component, reinforcing the hypothesis of environmental filtering. Global warming may have strong effects on mountain communities due to upslope range shifts and extinctions, and these events will lead to an even larger than previously expected loss of diversity as dung beetles γ taxonomic diversity is caused mainly by the β component.

Gradient of stressful conditions affect plant physiological and morphological traits. Previous studies have shown that plants located at higher altitudes might exhibit higher levels of both fluctuating asymmetry and leaf thickness. Although it is expected that higher fluctuating asymmetry levels should be accompanied by higher leaf consumption by herbivores, lower herbivory could be expected for elevated leaf thickness. Aiming to investigate this contradiction our objective was to determine the effects of altitude on fluctuating asymmetry and leaf thickness, and evaluate the importance of these two morphological traits on herbivory levels of Tibouchina granulosa Cogn. (Melastomatecea) in Brazilian Atlantic Forest. The study was conducted in southern Brazil, along a continuous altitudinal gradient raging from 1275 to 1950 m, where we measured fluctuating asymmetry, leaf thickness and herbivory from leaves of 29 individuals of T. granulosa . There was a positive effect of altitude on both fluctuating asymmetry and leaf thickness but only fluctuating asymmetry was related to herbivore. Our results suggest that as altitude increases plants face more stressful conditions, leading to higher fluctuating asymmetry. This may lead to a higher nutritional quality of leaves and herbivores may use leaf asymmetry as a cue for plant quality. The lack of a relationship between leaf thickness and herbivory gives us evidence that, in the studied location, leaf thickness is not primarily used as plant defense and probably has other functions related, for example, to water, solar radiation, and nutrient stresses. These results may be considered a baseline for the understanding on how altitudinal stress and potential herbivory pressure influence plant populations.

Biodiversity loss and anthropogenic environmental changes are known to impact ecosystem functions and services. However, there are still some uncertainties such as confounding environmental factors other than community attributes that affect ecosystem functioning. Our goal was to understand what factors influence the performance of Scarabaeinae dung beetle functions, testing the hypothesis that both community attributes and environmental variables influence the performance. Toward this aim, we collected dung beetles along an elevational gradient (800–1400 m a.s.l.) in the Espinhaço mountain range (Brazil) and quantified dung beetle functions, that is, dung removal, soil excavation and secondary seed dispersal. We recorded data on environmental factors related to climate, soil and vegetation and evaluated their effects on dung beetle functions. Dung beetle ecological functions declined with elevation and the decrease was more pronounced than richness, indicating that there are other factors involved in functions performance besides diversity of beetles. Indeed, we found that the ecological functions measured were dependent on both dung beetle community attributes and environmental factors. Climate, soil and vegetation influenced dung beetle function performance as much as richness, abundance and body size. Dung beetle functional diversity did not explain any of the functions measured. Our study demonstrates that ecological functions are directly influenced by both community attributes and environmental variables and confirms the link between biodiversity, environment and ecosystem functioning.

Habitat conversion is one of the major threats for biodiversity conservation and viability of natural populations. Thus, habitat disturbance alters distinct ecological processes, such as plant reproductive success and diaspore fate. In this study, we determined the effects of seasonally tropical dry forests (STDFs) conversion by anthropogenic disturbance by assessing diaspore fate of Enterolobium contortisiliquum. We compared 20 adult trees present in a STDFs preserved area and 20 adult trees present in a human-converted area. In general, diaspore fates from both areas were similar, i.e., there was no difference in the reproductive success of trees in STDFs and human-converted area. Habitat disturbance did not affect the length or width of fruits; only fruit thickness was larger in trees of STDFs habitat. None of the biometric seed measures differed between different habitat conditions. Likewise, the number of undamaged seeds, aborted seeds, pre-dispersal pre-dated seeds, and seed production were independent of habitat conditions. Besides, we did not observe any effect of habitat disturbance on germination percentage. However, seeds from preserved STDFs germinated faster than seeds from the human-converted area. Even though the effects of human-modified habitats on the diaspore fate have already been studied, tree species exhibit different responses to habitat conversion regarding seed predation, seed dispersal, seed germination, and seedling establishment. Overall, our results show that habitat disturbance does not affect the diaspore fate of E. contortisiliquum. This study also highlights the importance of remnants trees in converted landscapes as the population’s connectors which maintain plant–animal mutualistic and antagonistic interactions that mitigate the effects of habitat disturbance.

Ground-dwelling ants are active foragers that may extend their foraging area into the vegetation, although the factors affecting their diversity in the suspended litter of understorey plants remain overlooked. To evaluate the influence of the distance between strata, litter biomass and plant size on the ant fauna, the litter ant assemblage of the suspended stratum was compared with the ground immediately below the understorey treelet Erythrochiton brasiliensis (Rutaceae) in an Atlantic Forest, south-eastern Brazil. We collected 1364 ants from 26 ant species. The suspended litter ant assemblage represented a subset of the ground-dwelling ants present in soil litter. The beta diversity results primarily from the high ant species turnover among individual suspended-litter samples, and among ground-litter samples, while species turnover among suspended-ground pairs is lower. Additionally, plant height was not important in determining the species turnover between strata. However, plant height positively correlated with ant species richness, probably because of the increased number of microhabitats. These results suggest that suspended litter in the forest understorey can provide the conditions for ground-dwelling ants to forage and nest, functioning as a vertical extension of resources and microhabitat conditions present in the ground litter.

Symbiosis, the living‐together of unlike organisms, underlies every major transition in evolution and pervades most ecological dynamics. Among examples of symbioses, the simultaneous occupation of a termite nest by its builder termites and intruding invertebrate species (so‐called termitophily) provides suitable macroscopic scenarios for the study of species coexistence in confined environments. Current evidence on termitophily abounds for dynamics occurring at the interindividual level within the termitarium, but is insufficient for broader scales such as the community and the landscape. Here, we inspect the effects of abiotic disturbance on termitophile presence and function in termitaria at these broader scales. To do so, we censused the termitophile communities inhabiting 30 termitaria of distinct volumes which had been exposed to increasing degrees of fire‐induced disturbance in a savanna‐like ecosystem in southeastern Brazil. We provide evidence that such an abiotic disturbance can ease the living‐together of termitophiles and termites. Putative processes facilitating these symbioses, however, varied according to the invader. For nonsocial invaders, disturbance seemed to boost coexistence with termites via the habitat amelioration that termitaria provided under wildfire, as suggested by the positive correlation between disturbance degree and termitophile abundance and richness. As for social invaders (ants), disturbance seemed to enhance associational defenses with termites, as suggested by the negative correlation between the presence of ant colonies and the richness and abundance of other termitarium‐cohabiting termitophiles. It is then apparent that disturbance‐modulated distinct symbioses in these termite nests. Fire‐induced disturbance boosted coexistence of termites and non‐social termitophiles via the habitat amelioration that termitaria provided under wildfire. Simultaneously, harsh conditions enhanced termitaria defense by social termitophiles (ants).

Climate conditions tend to differ along an altitudinal gradient, resulting in some species groups' patterns of lower species richness with increasing altitude. While this pattern is well understood for tropical mountains, studies investigating possible determinants of variation in beta-diversity at its different altitudes are scarce. We sampled bee and wasp communities (Hymenoptera: Aculeata) along an altitudinal gradient (1,000-2,000 m.a.s.l.) in a tropical mountainous region of Brazil. Trap nests and Moericke traps were established at six sampling points, with 200 m difference in altitude between each point. We obtained average climate data (1970-2000) from Worldclim v2 for altitudes at each sampling site. Nest traps captured 17 bee and wasp species from six families, and Moericke traps captured 124 morphospecies from 13 families. We found a negative correlation between altitude and species richness and abundance. Temperature, precipitation, water vapor pressure, and wind speed influenced species richness and abundance, and were correlated with altitude. β-diversity was primarily determined by species turnover as opposed to nestedness, and Aculeate community similarity was higher for more similar altitudinal ranges. Moericke traps seem to be more efficient for altitudinal surveys compared to nest traps. We found high occurrence of singleton and doubleton species at all altitudes, highlighting the need for long-term studies to efficiently assess hymenopteran diversity in these environments.

The foraging behavior and survivorship of termites are modified by the presence of wood-inhabiting fungi. Nonetheless, it is not clear if these interactions are beneficial, negative, or neutral for termites. We conducted a meta-analytical review to determine if the presence of wood-inhabiting fungi affects the foraging behavior and survivorship of termites. Overall, the presence of wood-inhabiting fungi in a resource used by termites was positive, increasing resource consumption by 120%, and aggregation behavior by 81%. The presence of fungi also increased termite trail-following by approximately 200% and increased survival by 136%. The results varied, however, according to the type of fungi evaluated. Decay fungi and sap-stain fungi elicited positive responses in termites, whereas molds did not affect the consumption of cellulose by termites. Amongst the decay fungi group, white-rot fungi caused the strongest and most positive response in all termite behaviors evaluated, although brown-rot fungi is known to be preferred by termites. The results of our study, therefore, suggest that wood-inhabiting fungi are potential facilitators of the foraging behavior and survivorship of termites. These results have great implications for termite biocontrol, as well as for knowledge of the ecological aspects of termite–fungi interactions.

Bark and the ambrosia beetles dig into host plants and live most of their lives in concealed tunnels. We assessed beetle community dynamics in tropical dry forest sites in early, intermediate, and late successional stages, evaluating the influence of resource availability and seasonal variations in guild structure. We collected a total of 763 beetles from 23 species, including 14 bark beetle species, and 9 ambrosia beetle species. Local richness of bark and ambrosia beetles was estimated at 31 species. Bark and ambrosia composition was similar over the successional stages gradient, and beta diversity among sites was primarily determined by species turnover, mainly in the bark beetle community. Bark beetle richness and abundance were higher at intermediate stages; availability of wood was the main spatial mechanism. Climate factors were effectively non-seasonal. Ambrosia beetles were not influenced by successional stages, however the increase in wood resulted in increased abundance. We found higher richness at the end of the dry and wet seasons, and abundance increased with air moisture and decreased with higher temperatures and greater rainfall. In summary, bark beetle species accumulation was higher at sites with better wood production, while the needs of fungi (host and air moisture), resulted in a favorable conditions for species accumulation of ambrosia. The overall biological pattern among guilds differed from tropical rain forests, showing patterns similar to dry forest areas.

Understanding the interactions among plants, hemipterans, and ants has provided numerous insights into a range of ecological and evolutionary processes. In these systems, however, studies concerning the isolated direct and indirect effects of aphid colonies on host plant and other herbivores remain rare at best. The aphid Uroleucon erigeronensis forms dense colonies on the apical shoots of the host plant Baccharis dracunculilfolia (Asteraceae). The honeydew produced by these aphids attracts several species of ants that might interfere with other herbivores. Four hypotheses were tested in this system: (1) ants tending aphids reduce the abundance of other herbivores; (2) the effects of ants and aphids upon herbivores differ between chewing and fluid-sucking herbivores; (3) aphids alone reduce the abundance of other herbivores; and (4), the aphid presence negatively affects B. dracunculifolia shoot growth. The hypotheses were evaluated with ant and aphid exclusion experiments, on isolated plant shoots, along six consecutive months. We adjusted linear mixed-effects models for longitudinal data (repeated measures), with nested spatial random effect. The results showed that: (1) herbivore abundance was lower on shoots with aphids than on shoots without aphids, and even lower on shoots with aphids and ants; (2) both chewing and fluid-sucking insects responded similarly to the treatment, and (3) aphid presence affected negatively B. dracunculifolia shoot growth. Thus, since aphids alone changed plant growth and the abundance of insect herbivores, we suggest that the ant–aphid association is important to the organization of the system B. dracunculifolia -herbivorous insects.