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74 results for “Neotropical savanna”
Data from: Variations in bark structural properties affect both water loss and carbon economics in neotropical savanna trees in the Cerrado region of Brazil
<p><span>Even after complete stomatal closure, plants lose water through the leaf cuticles and bark. This residual water conductance of leaves (g<sub>leaf-res</sub>) and stems (g<sub>bark</sub>) can negatively impact plant water balance and affect plant survival in seasonally dry environments. However, little is known about the costs and benefits associated with such water leaks, especially on stem level. </span></p> <p><span>Here, we characterized the structural and functional determinants of the variability in g<sub>bark</sub> across tropical savanna species to elucidate how variations in this trait are related to contrasting growth strategies. </span></p> <p><span>The high variability in g<sub>bark</sub> across species was associated with morphoantomical properties of the outer bark (thickness, density, and lenticel investment), and such characteristics influenced both stem transpiration and respiration, suggesting the existence of a trade-off between water conservation and oxygen permeability, which reflected contrasting growth and dehydration tolerance strategies</span><span>. For instance, species with higher g<sub>bark</sub> and g<sub>leaf-res</sub> presented a fast resource acquisition strategy but were more prone to drought-induced mortality by hydraulic failure. However, model simulations revealed that the relative contribution of g<sub>leaf-res</sub> and g<sub>bark</sub> to overall water balance depended on whether leaves were less or more resistant to cavitation than the stems. </span></p> <p><span>Synthesis. By combining correlative studies, experimental results, and a modeling exercise, we provide a new understanding of the costs and benefits associated with the variability in g<sub>bark</sub> across tropical savanna species, and a new perspective for studies of water relations and carbon economics in species from a hyperdiverse savanna. </span></p>
A comparative phylogenomic analysis of birds reveals heterogeneous differentiation processes among Neotropical Savannas
<p>The main objective of this study is to evaluate biogeographic hypotheses of diversification and connection between isolated savannas north (Amazonian savannas) and south (Cerrado core) of the Amazon River. To achieve our goal, we employed genomic markers (genotyping by sequencing) to evaluate the genetic structure, population phylogenetic relationships, and historical range shifts of four Neotropical passerines with peri-Atlantic distributions: the Narrow-billed Woodcreeper (<em>Lepidocolaptes angustirostris</em>), the Plain-crested Elaenia (<em>Elaenia cristata</em>), the Grassland Sparrow (<em>Ammodramus humeralis</em>), and the White-banded Tanager (<em>Neothraupis fasciata</em>). The population genetic analyses indicated that landscape (e.g., geographic distance, landscape resistance, and percentage of tree cover) and climate metrics explained divergence among populations in most species, but without indicating a differential role between current and historical factors. Our results did not fully support the hypothesis that isolated populations at Amazonian savannas have been recently derived from the Cerrado core domain. Intraspecific phylogenies and gene flow analyses supported multiple routes of connection between the Cerrado and Amazonian savannas, rejecting the hypothesis that the Atlantic corridor explains the peri-Atlantic distribution. Our results reveal that the biogeographic history of the region is complex and cannot be explained by simple vicariant models.</p>
Data from: The role of habitat simplification and seasonality in shaping interactions between ants, plants and herbivores in a Neotropical savanna
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Data from: Isolation by instability: historical climate change shapes population structure and genomic divergence of treefrogs in the Neotropical Cerrado savanna
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Data from: Functional richness shows spatial scale dependency in Pheidole ant assemblages from Neotropical savannas
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Data from: Sugar-rich resources mediate geographic morphological variation in a dominant, neotropical savanna ant
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Temporal consistency in interactions among birds, ants, and plants in a neotropical savanna
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Data from: Variations in bark structural properties affect both water loss and carbon economics in neotropical savanna trees in the Cerrado region of Brazil
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Evolutionary history of Neotropical savannas geographically concentrates species, phylogenetic and functional diversity of lizards
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Taxonomic, functional, and phylogenetic diversity of anuran assemblages across habitats and seasons in a Neotropical savanna
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A comparative phylogenomic analysis of birds reveals heterogeneous differentiation processes among Neotropical Savannas
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Development of a benthic macroinvertebrate multimetric index (MMI) for Neotropical Savanna headwater streams. Appendix C
<p>Appendix C. Metric Screening<br> </p>
FIGURES 9–13 in A new species of Aricoris Westwood, 1851 (Lepidoptera: Riodinidae) from the Neotropical Cerrado savanna
FIGURES 9–13. Male and female genitalia of Aricoris emeryi sp. nov.: Male genitalia in lateral (9) and ventral (10) views (paratype DZ 16.348, Pirenópolis, Goiás, Brazil) (red arrow in fig. 9 indicates the pointed projection at the upper medial region of valvae and in fig. 10 indicates the lateral spine-shaped projection of valvae). Female genitalia, ventral view, sterigma in lateral view (11), details of the sterigma (12) and corpus bursae (13) in ventral view (paratype DZ 16.348, Cachoeira das Andorinhas, Goiás, Goiás, Brazil). Legend: PA, papillae anales; ST, sterigma; DB, ductus bursae; CB, corpus bursae; LP, lamella postvaginalis; LA, lamella antevaginalis; SI, signum; SP, spermatophore. Asterisks represent the most sclerotized area of the lamella antevaginalis. Scale bars = 1 mm (Figs 9–10), 2 mm (Fig. 11) and 0.2 mm (Figs. 12–13).
Data from: Topography, more than land cover, explains genetic diversity in a Neotropical savanna treefrog
<p><b><span>Aim</span></b><span>: </span>Effective conservation policies rely on information about population genetic structure and the connectivity of remnants of suitable habitat. The interaction between natural and anthropogenic discontinuities across landscapes can uncover the relative contributions of different barriers to gene flow, with direct consequences for decision-making in conservation. Therefore, we aimed t<span>o quantify the relative roles of land cover and topographic variables on the population genetic differentiation and diversity of a stream-breeding savanna treefrog (<i>Bokermannohyla ibitiguara</i>) across its range.</span></p> <p><b><span>Location</span></b><span>: Serra da Canastra mountain range, Cerrado of Minas Gerais State, Brazil.</span></p> <p><b><span>Methods</span></b><span>: We collected and extracted DNA samples from 12 populations within and outside a strictly protected park, and used 17 microsatellite markers to assess genetic structure, among-population differentiation, and within-population diversity measures. We incorporated landscape data derived from digital models and satellite images to create connectivity matrices to correlate with genetic differentiation using Mantel tests. We used generalized linear models and path analyses to assess the roles of each landscape variable in shaping genetic diversity in this species.</span></p> <p><b><span>Results</span></b><span>: </span>Populations within and outside the park boundaries belonged to four genetic clusters. Most populations showed evidence of limited gene flow, with significant genetic differentiation, except for those within the park, which also had higher levels of allelic richness and heterozygosity. However, genetic differentiation among populations in this landscape was primarily explained by topographic complexity. Likewise, within-population genetic measures were best explained by models including elevation and topographic complexity, and not the amount of natural habitat or gallery forests.</p> <p><b><span>Main conclusions</span></b><span>: </span>Our results underscore that topography may be a strong historical factor shaping genetic structure among amphibian populations. Therefore, effective conservation strategies for endangered amphibians should avoid focusing exclusively on habitat suitability, and incorporate topographic complexity, which seems to be a key factor for the fauna of the extremely threatened Brazilian savanna.</p>
Data from: Do an ecosystem engineer and environmental gradient act independently or in concert to shape juvenile plant communities? Tests with the leaf-cutter ant Atta laevigata in a Neotropical savanna
Background. Ecosystem Engineers are species that transform habitats in ways that influence other species. While the impacts of many engineers have been well described, our understanding of how their impact varies along environmental gradients remains limited. Although disentangling the effects of gradients and engineers on biodiversity is complicated – the gradients themselves can be altered by engineers – doing so is necessary to advance conceptual and mathematical models of ecosystem engineering. We used leaf-cutter ants (Atta spp.) to investigate the relative influence of gradients and environmental engineers on the abundance and species richness of woody plants. Methods. We conducted our research in South America's Cerrado. With a survey of plant recruits along a canopy cover gradient, and data on environmental conditions that influence plant recruitment, we fit statistical models that addressed the following questions: (1) Does A. laevigata modify the gradient in canopy cover found in our Cerrado site? (2) Do environmental conditions that influence woody plant establishment in the Cerrado vary with canopy cover or proximity to A. laevigata nests? (3) Do A. laevigata and canopy cover act independently or in concert to influence recruit abundance and species richness? Results. We found that environmental conditions previously shown to influence plant establishment in the Cerrado varied in concert with canopy cover, but that ants are not modifying the cover gradient or cover over nests. However, ants are modifying other local environmental conditions, and the magnitude and spatial extent of these changes is consistent across the gradient. In contrast to prior studies, we found that ant-related factors (e.g., proximity to nests, ant changes in surface conditions), rather than canopy cover, had the strongest effect on the abundance of plant recruits. However, the diversity of plants was influenced by both the engineer and the canopy cover gradient. Discussion. Atta laevigata in the Cerrado modify local conditions in ways that have strong but spatially restricted consequences for plant communities. We hypothesize that ants indirectly reduce seedling establishment by clearing litter and reducing soil moisture, which leads to seed and seedling desiccation. Altering soil nutrients could also reduce juvenile growth and survivorship; if so these indirect negative effects of engineering could exacerbate their direct effects of harvesting plants. The effects of Atta appear restricted to nest mounds, but they could be long-lasting because mounds persist long after a colony has died or migrated. Our results support the hypothesis that leaf-cutter ants play a dominant role in Cerrado plant demography. We suggest the ecological and economic footprint of these engineers may increase dramatically in coming decades due to the transformation of the Cerrado by human activities.
Data from: Spatial-temporal dynamics of Neotropical velvet ant (Hymenoptera: Mutillidae) communities along a forest-savanna gradient
Understanding how and why biological communities are organized over space and time is a major challenge and can aid biodiversity conservation in times of global changes. Herein, spatial-temporal variation in the structure of velvet ant communities was examined along a forest-savanna gradient in the Brazilian Cerrado to assess the roles of environmental filters and interspecific interactions upon community assembly. Velvet ants were sampled using 25 arrays of Y-shaped pitfall traps with drift fences for one year along an environmental gradient from cerrado sensu stricto (open canopy, warmer, drier) to cerradão (closed canopy, cooler, moister). Dataloggers installed on each trap recorded microclimate parameters throughout the study period. The effects of spatial distances, microclimate parameters and shared ancestry on species abundances and turnover were assessed with canonical correspondence analysis, generalized dissimilarity modelling and variance components analysis. Velvet ant diversity and abundance were higher in the cerrado sensu stricto and early in the wet season. There was pronounced compositional turnover along the environmental gradient, and temporal variation in richness and abundance was stronger than spatial variation. The dry season blooming of woody plant species fosters host abundance and, subsequently, velvet ant captures. Species were taxonomically clustered along the gradient with Sphaeropthalmina (especially Traumatomutilla spp.) and Pseudomethocina more associated, respectively, with cerrado sensu stricto and cerradão. This suggests a predominant role of environmental filters on community assemble, with physiological tolerances and host preferences being shared among members of the same lineages. Induced environmental changes in Cerrado can impact communities of wasps and their hosts with unpredictable consequences upon ecosystem functioning and services.
Data from: Short-term effects of elevated precipitation and nitrogen on soil fertility and plant growth in a Neotropical savanna
Increasing nitrogen (N) deposition and changing precipitation patterns in Neotropical savannas could alter plant growth, reproduction, and nutrients by altering soil nutrient and water availability. We examined the potential for simulated N deposition and increased dry season precipitation to have interactive effects on reproduction and growth of two abundant native Cerrado (Brazilian savanna) grasses – Loudetiopsis chrysothrix and Tristachya leiostachya – via feedbacks with soil nutrient status. Plant growth and reproduction responses consistently varied by species. Water addition led to more consistent increases in both growth and reproduction than nitrogen addition and the two treatments did have significant interactive effects. We expected that both treatments would affect plant growth and reproduction via positive effects on soil and plant N. Instead, we found that plant responses were linked to species-specific treatment effects on soil and foliar phosphorus (P). Structural equation models (SEM) confirmed that changes in soil P - rather than changes in soil N or increasing soil acidity - explained plant response to treatments. Our results imply that N deposition and precipitation change could impact Cerrado plant growth and reproduction via subtle effects on plant and soil phosphorus.
Data from: Ant diversity in Neotropical savannas: hierarchical processes acting at multiple spatial scales
1. Understanding what creates and maintains macroscale biodiversity gradients is a central focus of ecological and evolutionary research. Spatial patterns in diversity are driven by a hierarchy of factors operating at multiple scales. Historical and climatic factors drive large-scale patterns of diversity by affecting the size of regional species pools, while habitat heterogeneity or microhabitat characteristics further influence species coexistence at small scales. 2. We tested the degree to which the species-energy, historical factors, habitat heterogeneity and local environment hypotheses explain observed patterns of ant diversity across hierarchical spatial scales. 3. We sampled ground-dwelling ants at 29 sites within a Neotropical savanna region, the Brazilian Cerrado. We measured species density – an abundance-dependent diversity metric – and rarefied species richness – an abundance-independent metric – at spatial scales with varying grain sizes. For each hypothesis, two correlates were used to predict ant diversity patterns: i) species-energy: rainfall and productivity; ii) historical factors: historical variation in rainfall and refugial areas; iii) habitat heterogeneity: heterogeneity in greenness and diversity of land cover; iv) local factors: contents of sand and coarse fragments in the soil. 4. Ant diversity patterns correlated to net primary productivity and to the proportion of coarse fragments in the soil, corroborating the species-energy and local environment hypotheses, respectively. Soil negatively influenced species density, but not rarefied species richness, which was positively influenced by productivity. We found scale dependencies in the effects of soil/productivity on species density; productivity best predicted species density patterns at large scales, since sampling completeness offset the abundance-driven effects of soil. 5. Considering abundance differences may help to discern the mechanisms underlying the relationship between macroscale diversity patterns and its ecological drivers. Plant productivity affected ant diversity independently of abundance, possibly by limiting the size of regional species pools. On the other hand, soil properties had an abundance-dependent effect on ant diversity, indicating a sampling mechanism. Our findings are consistent with predictions of the hierarchical theory of diversity. Large-scale patterns of productivity limit regional diversity, an effect that cascades down to finer spatial scales, where soil properties influence the number of coexisting species.
Data from: Biotic-drivers of seedling establishment in Neotropical savannas: selective granivory and seedling herbivory by leaf-cutter ants as an ecological filter
Herbivory has been shown to have prominent top-down effects on vegetation in Paleotropical savannas, where consumers of early stages of life history act as demographic bottlenecks. Such impact has been largely ignored in Neotropical savannas, however, despite insect consumption being linked to reduced recruitment of woody species. We hypothesize that Atta leaf-cutter ants – the prevalent herbivores in the Neotropics – alter the establishment of woody plant seedlings in the Brazilian Cerrado by reducing seed availability and seedling survival. We also hypothesize that the demographic effects will be species-specific. To test these hypotheses, we experimentally (i) compared seed removal in areas with and without Atta foraging and (ii) compared the survivorship of seedlings exposed to or protected from Atta foraging. Both experiments were performed with the same common Cerrado species which allowed us to evaluate the potential net effects of consumers at the population and community levels. Overall seed removal rates in sites with Atta foraging were greater than those where ants were absent (59.2% and 39.2% of seeds removed, respectively). There were differences in removal for 10 of the 12 tested species, with per species removal 1.1- to 3.8-fold greater in areas with Atta foraging. On transplanted plants, 45% of seedlings exposed to Atta were attacked, resulting in a survival 7.6% lower than that of protected seedlings. Seedling survival was 11.8–31.5% lower in five species, with the largest differences in survival between treatments during the dry season. Taken together, these results support the hypothesis that consumers can lead to demographic bottlenecks in Neotropical savanna plant species, with effects varying among life-history stages and between species. Synthesis. Granivory by ants has been linked to reduced seedling recruitment of woody species in the Brazilian Cerrado. Our results show that leaf-cutter ants may largely limit early seedling establishment of woody species by reducing seed availability and seedling survival with differential species-specific effects. Atta ants may therefore be acting as an ecological filter, which coupled with potential selectivity in foraging on reproductive life-history stages, may ultimately influence the relative abundance of different species and hence the structure and composition of Cerrado vegetation.
Data from: Habitat diversity associated with island size and environmental filtering control the species richness of rock-savanna plants in neotropical inselbergs
Disentangling the multiple factors controlling species diversity is a major challenge in ecology. Island biogeography and environmental filtering are two influential theories emphasizing respectively island size and isolation, and the abiotic environment, as key drivers of species richness. However, few attempts have been made to quantify their relative importance and investigate their mechanistic basis. Here, we applied structural equation modelling, a powerful method allowing test of complex hypotheses involving multiple and indirect effects, on an island-like system of 22 French Guianan neotropical inselbergs covered with rock-savanna. We separated the effects of size (rock-savanna area), isolation (density of surrounding inselbergs), environmental filtering (rainfall, altitude) and dispersal filtering (forest-matrix openness) on the species richness of all plants and of various ecological groups (terrestrial versus epiphytic, small-scale versus large-scale dispersal species). We showed that the species richness of all plants and terrestrial species was mainly explained by the size of rock-savanna vegetation patches, with increasing richness associated with higher rock-savanna area, while inselberg isolation and forest-matrix openness had no measurable effect. This size effect was mediated by an increase in terrestrial-habitat diversity, even after accounting for increased sampling effort. The richness of epiphytic species was mainly explained by environmental filtering, with a positive effect of rainfall and altitude, but also by a positive size effect mediated by enhanced woody-plant species richness. Inselberg size and environmental filtering both explained the richness of small-scale and large-scale dispersal species, but these ecological groups responded in opposite directions to altitude and rainfall, that is positively for large-scale and negatively for small-scale dispersal species. Our study revealed both habitat diversity associated with island size and environmental filtering as major drivers of neotropical inselberg plant diversity and showed the importance of plant species growth form and dispersal ability to explain the relative importance of each driver.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
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The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
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OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.