From species descriptions to diversity patterns: the validation of taxonomic data as a keystone for ant diversity studies reproducibility and accuracy.

Research findings in natural sciences need to be comparable and reproducible to effectively improve our understanding of ecological and behavioural patterns. In this sense, knowledge frontiers in biodiversity studies are directly tied to taxonomic research, especially in species-rich tropical regions. Here we analysed the taxonomic information available in 470 studies on Brazilian ant diversity published in the last 50 years. We aimed to quantify the proportion of studies that provide enough data to validate taxonomic identification, explore the frequency of studies that properly acknowledge their taxonomic background, and investigate the primary resources for ant identification in Brazil. We found that most studies on Brazilian ant diversity (73.6%) explicitly stated the methods used to identify their specimens. However, the proportion of papers that provide complete data for the repository institutions and vouchered specimens is vanishingly small (5.8%). Additionally, only 40.0% of the studies consistently presented taxon authorities and years of description, rarely referencing taxonomic publications correctly. In turn, the number of specialists and institutions consulted for ant identification in Brazil has increased in the last years, along with the number of studies that explicitly provide their taxonomic procedures for ant identification. Our findings highlight a shift between generations regarding the recognition of taxonomy as fundamental science, deepening our understanding of biodiversity.

Testing the context dependence of ant nutrient preference across habitat strata and trophic levels in Neotropical biomes.

Animals are integrated into the wider ecosystem via their foraging and behavior. The compensation hypothesis predicts that animals target their foraging efforts (i) toward nutrients that are scarce in the environment and (ii) toward nutrients that are not present in the usual diet of species, which varies across trophic levels. Understanding how foraging for resources varies locally, such as across habitat strata, and trophic levels will help to elucidate the links between the local environment and communities to the ecological functions that animals mediate. We examined whether the relative resource use of ants varies consistently along a habitat strata gradient and across trophic levels across Neotropical biomes. We placed 4500 baited tubes, each containing one of five liquid resources (sugar, amino acid, lipid, sodium, and distilled water) in one of three habitat strata (subterranean, epigaeic, and arboreal) across 60 transects in Amazon, Atlantic Forest, Caatinga, Cerrado, Pampa, and Pantanal biomes. We assessed the relative resource use of all ants across the habitat strata and among two different trophic groups across biomes. The relative preference for sugar increased from subterranean to arboreal strata in all biomes, while the relative preference for lipids decreased at this gradient in five biomes. We also found that in general sugar-consuming ants foraged more for sugar and less for lipids than predatory ants across biomes. Conversely, we found no consistency across biomes in nutrient preference of amino acid and sodium across habitat strata or trophic levels. Overall, our results indicate sugar limitation in the arboreal stratum and lipid limitation on the ground across biomes and that the trophic level of ants strongly determines their foraging efforts-possibly because ants try to fix their dietary nutrient imbalances. Hence, our findings suggest strong local niche partitioning of sugar and lipid use across habitat strata and trophic levels and that other large spatial scale processes influence the local amino acid and sodium dynamics.

Os animais se integram nos ecossistemas pelos seus esforços e comportamento de forrageio. A hipótese da compensação prevê que os animais direcionam seus esforços de forrageio para (i) nutrientes que são escassos no ambiente e (ii) para nutrientes que não estão presentes em sua dieta, que variam entre os níveis tróficos. Assim, entender como a busca de recursos varia localmente entre os estratos de habitat e entre níveis tróficos, ajudará a entender as conexões entre o ambiente e suas comunidades com as funções ecológicas mediadas pelos animais. Avaliamos se o uso relativo de recursos das formigas varia consistentemente em um gradiente de estratos de habitat e em diferentes níveis tróficos nos biomas Neotropicais. Disponibilizamos um total de 4.500 tubos contendo um de cinco recursos líquidos (açúcar, aminoácido, lipídio, sódio e água destilada) em três estratos de habitat (subterrâneo, epigéico e arbóreo) em 60 transectos distribuídos nos biomas Amazônia, Mata Atlântica, Caatinga, Cerrado, Pampa e Pantanal. Avaliamos o uso relativo de recursos de todas as formigas ao longo dos estratos de habitat e entre dois grupos tróficos diferentes nos biomas. A preferência relativa por açúcar aumentou do estrato subterrâneo para o arbóreo em todos os biomas, enquanto a preferência relativa por lipídios diminuiu neste gradiente em cinco biomas. Também descobrimos que, em geral, as formigas consumidoras de açúcar procuram mais açúcar e menos lipídios do que as formigas predadoras nos biomas. Por outro lado, não encontramos consistência entre biomas na preferência nutricional de aminoácidos e sódio nos estratos de habitat ou níveis tróficos. No geral, nossos resultados indicam limitação de açúcar no estrato arbóreo e limitação de lipídios no solo em todos os biomas e que o nível trófico das formigas determina fortemente seus esforços de forrageamento - possivelmente porque as formigas tentam corrigir seus desequilíbrios de nutrientes na dieta. Portanto, nossas descobertas sugerem forte partição de nicho local de uso de açúcar e lipídios em estratos de habitat e níveis tróficos e que outros processos de grande escala espacial influenciam a dinâmica local de aminoácidos e sódio.

Diaspore Removal by Ants Does Not Reflect the Same Patterns of Ant Assemblages in Mining and Rehabilitation Areas.

Mining is responsible for drastic ecosystem changes and rehabilitation is used to promote the return of functions after these impacts. In this scenario, we investigated the responses of ant assemblages and diaspore removal by ants to the transformations caused by mining and rehabilitation predicting that (a) the increase in plant density (a proxy for mining intensity) led to an increase in ant richness, percentage of diaspores removed, and changes in species composition that in turn are correlated with changes in environmental variables; (b) the increase in vegetation structure (a proxy for rehabilitation ages) led to an increase in ant richness, percentage of diaspores removed, and changes in species composition that in turn are correlated with changes in environmental variables. Additionally, we also verified which functional groups were primarily responsible for diaspore removal. We sampled arboreal and epigeic ants, diaspore removal by ants, and environmental variables. We found that ant richness and diaspore removal in mining intensity gradient are positively correlated to plant density. Although vegetation structure is positively correlated with ant richness, we found no changes in diaspore removal in rehabilitation gradient. Epigeic omnivore and epigeic generalist predator ants were the most responsible for diaspore removal. Then, we observed that mining decreases ant richness, altering ant assemblages and their functions, and rehabilitation with exotic plants is ineffective to promote the colonization by the main diaspore-removing ants.

Similar alpha and beta diversity changes in tropical ant communities, comparing savannas and rainforests in Brazil and Indonesia.

Local biodiversity can be expected to be similar worldwide if environmental conditions are similar. Here, we hypothesize that tropical ant communities with different types of regional species pools but at similar habitat types in Brazil and Indonesia show similar diversity patterns at multiple spatial scales, when comparing (1) the relative contribution of alpha and beta diversity to gamma diversity; (2) the number of distinct communities (community differentiation); and (3) the drivers of ß-diversity (species replacement or species loss/gain) at each spatial scale. In both countries, rainforests and savannas (biome scale) were represented by three landscapes (landscape scale), each with four transects (site scale) and each transect with 10 pitfall traps (local scale). At the local scale, α-diversity was higher and ß-diversity lower than expected from null models. Hence, we observed a high coexistence of species across biomes. The replacement of species seemed the most important factor for ß-diversity among sites and among landscapes across biomes. Species sorting, landscape-moderated species distribution and neutral drift are potential mechanisms for the high ß-diversity among sites within landscapes. At the biome scale, different evolutionary histories produced great differences in ant community composition, so the replacement of species is, at this scale, the most important driver of beta diversity. According to these key findings, we conclude that distinct regional ant species pools from similar tropical habitat types are similarly constrained across several spatial scales, regardless of the continent considered.

What is the effect of soil use on ant communities?

Studies on ant communities in agroecosystems have contributed to the knowledge of the effect of agricultural activities on biological communities. The aim of this study is to explain the effect of soil use on ant communities. We tested the hypothesis that there was a decrease in ant species richness and a change in the species composition at habitats with more intense soil use. We collected ants using sardine baits, subterranean traps and direct sampling at four habitats with different soil use (secundary forest, Acacia forestry, initial stage of succession and mixed crops). The ant species richness did not decrease with intensity of soil use. In successional habitat the species numbers collected using sardine baits and subterranean traps were significantly different. Species composition of communities had a pronounced variation, with the epigaeic and hypogaeic ant faunas of the habitat with high intense soil use (mixed crops) had low similarity with ant communities of the three other habitats. The predator species were restricted to habitats with low intensity of soil use. Then, species composition could better reflect the functional changes on ant communities than species richness. Our data can help to choose the component of ant community that better reflect the response of biodiversity to agricultural impacts.

What is the effect of soil use on ant communities? / Qual é o efeito do uso do solo sobre as comunidades de formigas?

Studies on ant communities in agroecosystems have contributed to the knowledge of the effect of agricultural activities on biological communities. The aim of this study is to explain the effect of soil use on ant communities. We tested the hypothesis that there was a decrease in ant species richness and a change in the species composition at habitats with more intense soil use. We collected ants using sardine baits, subterranean traps and direct sampling at four habitats with different soil use (secundary forest, Acacia forestry, initial stage of succession and mixed crops). The ant species richness did not decrease with intensity of soil use. In successional habitat the species numbers collected using sardine baits and subterranean traps were significantly different. Species composition of communities had a pronounced variation, with the epigaeic and hypogaeic ant faunas of the habitat with high intense soil use (mixed crops) had low similarity with ant communities of the three other habitats. The predator species were restricted to habitats with low intensity of soil use. Then, species composition could better reflect the functional changes on ant communities than species richness. Our data can help to choose the component of ant community that better reflect the response of biodiversity to agricultural impacts.

Estudos sobre as comunidades de formigas em agroecossistemas têm contribuído para o conhecimento do efeito das práticas agrícolas sobre as comunidades biológicas. O objetivo deste trabalho foi avaliar o efeito do uso do solo nas comunidades de formigas. Foi testada a hipótese de que há um decréscimo na riqueza de espécies de formigas e uma mudança na composição de espécies em habitats com uso mais intenso do solo. As formigas foram amostradas com iscas de sardinhas, armadilhas subterrâneas e por coleta direta em quatro habitats com diferentes usos do solo (mata secundária, início de sucessão vegetal, reflorestamento com Acacia e cultivo misto). A riqueza não diminuiu com a intensidade de uso do solo. Na área em início de sucessão vegetal, o número de espécies coletadas por iscas de sardinha foi significativamente diferente do obtido pelas armadilhas subterrâneas. A composição de espécies teve uma pronunciada variação, sendo que a fauna de formigas epigéica e hipogéica do habitat com maior intensidade de uso do solo (cultivo misto) mostrou baixa similaridade com as comunidades de formigas dos outros três habitats. As espécies predadoras restringiram-se aos habitats com baixa intensidade de uso do solo (mata secundária e sucessão vegetal). Assim, a composição de espécies refletiu melhor as mudanças funcionais nas comunidades de formigas ao uso do solo do que a riqueza de espécies. Os resultados podem ajudar a escolher o componente das comunidades de formigas mais adequado e que melhor corresponde à resposta da biodiversidade aos impactos causados pelas atividades agrícolas.