Geographical variation in ant foraging activity and resource use is driven by climate and net primary productivity

AIM : Foraging activity is critical for animal survival. Comprehending how ecological drivers influence foraging behaviour would benefit our understanding of the link between animals and ecological processes. Here, we evaluated the influence of ecological drivers on ant foraging activity and relative resource use. LOCATION : Six Brazilian biomes: Amazon, Atlantic rainforest, Caatinga, Cerrado, Pampa and Pantanal. TAXON : Formicidae. METHODS : We assessed ant foraging activity and resource use by sampling across 60 sites. We placed baited tubes that contained one of five liquid resources (sugar, lipids, amino acid, sodium and distilled water). We used model selection to assess the influence of ecological drivers (temperature, precipitation, temperature seasonality and net primary productivity) on ant foraging activity and relative resource use. RESULTS : Foraging activity was higher in wetter, more productive and less thermally seasonal environments. The relative use of amino acids increased at higher temperatures while the relative use of lipids decreased. The relative use of sugar increased in drier and less productive environments with high-temperature seasonality while the relative use of amino acid and sodium decreased in those environments. The relative use of lipids was complex: increasing with increasing temperature seasonality and decreasing with increasing precipitation. Furthermore, the relative use of sodium was greater where the foraging activity was high. MAIN CONCLUSIONS : We demonstrate how ecological drivers are correlated with ant foraging activity and resource use in the field across large spatial scales. The search for resources encompasses different interactions involving ants with abiotic and biotic components in the ecosystem. Thus, we suggest that changes in climate and NPP, which influence the intensity and the way that ants search for resources, will result in changes in ant-mediated ecological processes.Chaim J. Lasmar is a Post-doctoral researcher at the Programa de Pós-Graduação em Ecologia Aplicada (Universidade Federal de Lavras, Brazil). This study was part of his Ph. D. work at the Universidade Federal de Lavras with an internship period at the University of Liverpool.DATA AVAILABILITY STATEMENT: All data have been uploaded to Dryad (https://doi.org/10.5061/dryad.6wwpzgmxc).Fundação de Amparo à Pesquisa do Estado de Minas Gerais and Rufford Foundation.http://wileyonlinelibrary.com/journal/jbiam2022Zoology and Entomolog

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

¿Pueden los incendios afectar a las comunidades de hormigas epígeas e hipógeas (Hymenoptera: Formicidae) de Cerrado de la misma manera?

Fire occurrences are a common perturbation in Cerrado ecosystems, and may differently impact the local biodiversity. Arthropods are one of the taxa affected by fires, and among them, ants are known as good bioindicators. We aimed to evaluate the effect of anthropic fires on epigaeic and hypogaeic ant communities (species richness and composition) in Cerrado areas with different post-fire event recovery periods. We conducted the study in four Cerrado areas during two weeks of 2012 dry season: one unburned and three at different post-fire times (one month, one and two years). We sampled ants with pitfall traps in epigaeic and hypogaeic microhabitats. We collected 71 ant morpho-species from 25 genera. In the epigaeic microhabitat we sampled 56 morpho-species and 42 in the hypogaeic microhabitat. The area with the shortest recovery time presented lower epigaeic ant species richness (4.3 ± 2.00) in comparison to the other areas (8.1 ± 2.68 species on one year area; 10.3 ± 2.66 species on two years area; 10.4 ± 2.31 species on control area), but recovery time did not affect hypogaeic ant species richness. Regarding ant species composition, fire did not directly affect hypogaeic ant species, which remained the same even one month after fire event. However, two years were not enough to reestablish ant species composition in both microhabitats in relation to our control group samples. Our study is the first to assess anthropic fire effects upon epigaeic and hypogaeic ants communities; highlighting the importance of evaluating different microhabitats, to more accurately detect the effects of anthropic disturbances in biological communities. We concluded that ant communities are just partially affected by fire occurrences, and epigaeic assemblages are the most affected ones in comparison to hypogaeic ants. Furthermore the study provides knowledge to aid in the creation of vegetation management programs that allow Cerrado conservation.Los incendios son una alteración común en los ecosistemas del Cerrado brasileño y pueden causar diferentes efectos sobre la biodiversidad. Los artrópodos son uno de los taxones comúnmente afectados por el fuego, y entre ellos, se conoce que las hormigas son buenos bioindicadores. El objetivo de este trabajo fue evaluar el efecto de los incendios antrópicos sobre las comunidades de hormigas epígeas e hipógeas (riqueza de especies y composición) en áreas del Cerrado en diferentes tiempos de recuperación. Para ello, el estudio se realizó en cuatro áreas del Cerrado durante la temporada seca del 2012: una área no quemada y otras tres áreas en diferentes momentos post-incendio (un mes, uno y dos años). Las hormigas fueron muestreadas utilizando trampas de caída en los microhábitats epígeo e hipógeo. Fueron recolectadas 71 morfo-especies de hormigas pertenecientes a 25 géneros. En el microhábitat epígeo recolectamos 56 morfo-especies y en el microhábitat hipógeo 42. El área con el menor tiempo de recuperación presentó una menor riqueza de especies de hormigas epígeas (4.3 ± 2.00) en comparación con las otras áreas (8.1 ± 2.68 especies en el área de un año; 10.3 ± 2.66 especies en el área de dos años; 10.4 ± 2.31 especies en el área de control), pero el tiempo de recuperación no afectó riqueza de especies de hormigas hipógeas. En cuanto a la composición de especies, el fuego no afectó directamente a las especies de hormigas hipógeas, la cual se mantuvo igual, incluso un mes después del incendio. Sin embargo, dos años no fueron suficientes para restablecer la composición de especies de hormigas en ambos microhábitats en relación con las muestras del área control. Nuestro estudio es el primero en evaluar los efectos del fuego antrópico sobre las comunidades de hormigas epígeas y hipógeas; se destaca la importancia de la evaluación de diferentes microhábitats para detectar con mayor precisión los efectos de las alteraciones antrópicas en las comunidades biológicas. Las comunidades de hormigas son solo parcialmente afectadas por incendios y las epígeas son las más perjudicadas. Además, este estudio proporciona conocimientos que pueden ayudar a la creación de programas de manejo de la vegetación del Cerrado, lo que permite conservar este importante bioma brasileño

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 dynamic

Ant community in natural fragments of the Brazilian wetland: species–area relation and isolation

Biogeographic theory has been given much attention for its potential application to biodiversity conservation in areas fragmented through anthropic action. The objective of this study was to determine whether ant community structure established in natural woodland fragments immersed in a matrix of natural grasslands could be explained by this theory. We therefore investigated whether the relationship between species richness and both area and isolation that have previously been found in anthropogenically formed forest fragments are applicable to naturally formed forest fragments. The sampling consisted of eight natural woodland fragments with varying areas and degrees of isolation. Sampling was undertaken proportionally to the fragment size, and each sampling point was spaced at least 10 m apart. Ants were collected from each point through arboreal and epigeic “pitfall” traps. In addition, five epigeic traps were placed 100 m from each sampled fragment in the adjacent grassland. A total of 81 ant species were sampled. Total and epigaeic species richness increased with size of area and fragment isolation. However, arboreal ants responded positively only with respect to increasing area, but not with isolation. Moreover, specialist and generalist species richness had a positive relationship with area, but not with isolation. Biogeographic Theory can only be applied to some of the patterns found in the natural fragments in the present study. This positive relationship of ant richness and isolation suggests that these environments bear unique characteristics and therefore, must be regarded as conservation targets. The results obtained in this study suggest the need for further studies, to reinforce the importance of biodiversity conservation of this characteristic habitat in the Pantanal

Land‐use change in the Amazon decreases ant diversity but increases ant‐mediated predation

Food production in Amazonian traditional societies often occurs through shifting cultivation that uses few pesticides and relies on ecosystem services provided by natural enemies. However, these sustainable agricultural practices are being threatened by increasing livestock and mechanised agriculture. This study aimed to evaluate the effects of the conversion from Amazon Forest to anthropogenic land uses (shifting cultivation and pasture) on α- and β-diversity, functional groups, and ant-mediated predation. Three types of habitats were sampled: forest (eight sites), shifting cultivation (five sites) and pasture (seven sites). The ant assembly of each site was sampled using pitfall traps in the epigeic and hypogeic strata. Beetle larvae were used to evaluate the predation function. Negative effects on epigeic ants and functional groups were found to be greater in sites where anthropogenic land use was more intensive (pasture) than in those where it was less intensive (shifting cultivation). Furthermore, this change increased the predation of insects in shifting cultivation and pasture compared to that in forest. This increase in insect predation was due to high activity of Ectatomma brunneum Smith, 1858, an environmental indicator for shifting cultivation and pasture. The increase in the number of predations in shifting cultivation and pasture may be beneficial from the perspective of biological pest control. However, this relationship needs to be better understood because the high presence and predatory activity of Ectatomma brunneum in these environments may be one mechanism by which α- and β-diversity decrease through antagonistic interactions and dominance

Temperature and productivity distinctly affect the species richness of ectothermic and endothermic multitrophic guilds along a tropical elevational gradient

The diversity of endotherms and ectotherms may be differently affected by ambient temperature and net primary productivity (NPP). Additionally, little is known about how these drivers affect the diversity of guilds of different trophic levels. We assessed the relative role of temperature and NPP in multitrophic guilds of ectothermic (arthropods: ants, ground beetles, spiders, and harvestmen) and endothermic (large mammals) animals along a tropical elevational gradient. We sampled arthropods at eight elevation belts and large mammals at 14 elevation belts in Atlantic rainforest (ranging from 600 to 2450 m.a.s.l.) of Itatiaia National Park, Southeast Brazil. Overall arthropod species richness was more associated with temperature than overall large-mammal species richness, while the latter was more associated with NPP. When separated into trophic guilds, we found that the species richness associated with NPP increased across arthropod trophic levels from herbivores to predators. Conversely, although NPP influenced large-mammal herbivore species richness, its effects did not seem to accumulate across large-mammal trophic levels since the species richness of large-mammal omnivores was more associated with temperature and none of the variables we studied influenced large-mammal predators. We suggest that thermal physiological differences between ectotherms and endotherms are responsible for the way in which arthropods and large mammals interact with or are constrained by the environment. Furthermore, the inconsistency regarding the role of temperature and NPP on species richness across multitrophic guilds of ectotherms and endotherms could indicate that thermal physiological differences might also interfere with energy use and flux in the food web