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558 results for “dry forest”
Distribution. Amazonian Basin in NE Ecuador (Orellana Province), NE Peru (Loreto Department), E Colombia (Vaupés Department), S & W Venezuela, the Guianas, and N Brazil (Amazonas, Amapa, and Para states), with one additional record from Atlantic Dry Forest of SE Brazil (Sâo Paulo State). in Emballonuridae
Distribution. Amazonian Basin in NE Ecuador (Orellana Province), NE Peru (Loreto Department), E Colombia (Vaupés Department), S & W Venezuela, the Guianas, and N Brazil (Amazonas, Amapa, and Para states), with one additional record from Atlantic Dry Forest of SE Brazil (Sâo Paulo State).
Data from: Drought legacies are short, prevail in dry conifer forests and depend on growth variability.
<ul> <li>The negative impacts of drought on forest growth and productivity last for several years generating legacies, although the factors that determine why such legacies vary across sites and tree species remain unclear.</li> <li>We used an extensive network of tree-ring width (RWI, ring-width index) records of 16 tree species from 567 forests, and high-resolution climate and NDVI datasets across Spain during the common period 1982‒2008 to test the hypothesis that climate conditions and growth features modulate legacy effects of drought on forests. Legacy effects of drought were calculated as the differences between detrended-only RWI and NDVI series (i.e. after removing long-term growth trends) and pre-whitened RWI and NDVI series predicted by a model including drought intensity. Superposed epoch analysis (SEA) was used to estimate whether legacy effects differed from random. Finally, legacy effects were related to water balance, growth persistence and variability, and tree species identity.</li> <li>We found a widespread occurrence of drought legacy effects in both RWI and NDVI, but they were seldom significant. According to SEA, first-year drought legacies were negative and different from random in 9% and 5% of the RWI and NDVI series, respectively. The number of significant second- and third-year legacies was substantially lower. Differences between RWI and NDVI legacies indicate that canopy greenness and radial-growth responses to drought are decoupled. We found variations in legacies between tree species with gymnosperms presenting larger first-year drought legacies than angiosperms, which were exposed to less severe droughts. Greater growth variability can explain the presence of first-year RWI legacies in gymnosperms from dry sites despite the relationship between growth variability and legacies was complex.</li> </ul> <p><i>"Synthesis"</i> Accounting for species and site responses to drought provides a better understanding of the magnitude and duration of drought legacies on forest growth and productivity. Despite the widespread occurrence of growth reductions in the years during and after drought occurrence, significant legacies were not very common, mostly lasted one year and were more widespread in gymnosperms. These are relevant factors to be considered in the future when studying the consequences of drought on forest productivity and tree growth.</p>
Data from: Limitations to recovery following wildfire in dry forests of southern Colorado and northern New Mexico, USA
Climate warming is contributing to increases in wildfire activity throughout the western U.S., leading to potentially long-lasting shifts in vegetation. The response of forest ecosystems to wildfire is thus a crucial indicator of future vegetation trajectories, and these responses are contingent upon factors such as seed availability, interannual climate variability, average climate (e.g., 30-year normals), and other components of the physical environment. To better understand variation in forest resilience to fire across vulnerable dry forests, we performed field surveys of conifer seedling abundance in 15 recent (1988-2010) wildfires and characterized temporal variation in seed cone production and seedling establishment. We then modeled post-fire seedling abundances for each species at a 30 m resolution using downscaled climate data, monthly water balance models, and canopy cover of surviving mature conifers. Widespread ponderosa pine (Pinus ponderosa) seed cone production occurred at least twice following each fire surveyed and pulses of conifer seedling establishment coincided with years of above-average moisture availability. Ponderosa pine and Douglas-fir (Pseudotsuga menziesii) seedling abundances were higher on more mesic sites and adjacent to surviving trees, though there were also important interspecific differences, likely attributable to drought- and shade-tolerance. We estimated that 41.8% (for ponderosa pine) and 68.5% (for Douglas-fir) of the total area burned did not meet tree density thresholds consistent with historical densities for each species. Spatial models demonstrated that the availability of seed trees (particularly in the interior of large, high-severity patches) limited seedling abundances in many areas, but 30-year average actual evapotranspiration and climatic water deficit also limited abundances on marginal sites. A better understanding of the limitations to post-fire recovery is likely to aid in developing adaptation and mitigation strategies through the improvement of models of future ecosystem change throughout the western U.S.
Influence of sea turtle nesting on hunting behavior and movements of jaguars in the dry forest of northwest Costa Rica
Jaguars (Panthera onca) are opportunistic predators that prey on large profitable prey items, such sea turtles at nesting beaches. Here we use jaguar and sea turtle track count surveys, combined with satellite telemetry of one jaguar, to evaluate whether jaguar hunting behavior and movements are influenced by seasonal sea turtle nesting in the Sector Santa Rosa of Área de Conservación Guanacaste in northwest Costa Rica. We used Generalized Linear Models to evaluate the effect of moon phase and sea surface temperature on olive ridley (Lepidochelis olivacea) and green turtle (Chelonia mydas) nesting abundance, as well as the combination of these predictors on the frequency of jaguar predation activity (proximity to nesting beaches) and movements. For home range size and location analyses, we calculated Kernel Density Estimates for each season at three different temporal scales. Sea turtle nesting season influenced jaguar activity patterns, as well as sea turtle abundance was related to jaguar locations and predation events, but jaguar home range size (88.8 km2 overall) did not differ between nesting seasons or among temporal scales. Environmental conditions influenced sea turtle nesting and, as a consequence, also influenced jaguar movements and foraging activity. Our study defined the home range of a female jaguar in the tropical dry forest and its relationship to seasonally abundant turtles. Additional information related to the effect of tourism on jaguar-sea turtle interactions would improve conservation of these species at unique nesting beaches in the area.
Data from: Genetic diversity of the rain tree (Albizia saman) in Colombian seasonally dry tropical forest for informing conservation and restoration interventions
<p><i>Albizia saman</i> is a multipurpose tree species of seasonally dry tropical forests (SDTFs) of Mesoamerica and northern South America typically cultivated in silvopastoral and other agroforestry systems around the world, a trend that is bound to increase in light of multimillion hectare commitments for forest and landscape restoration. The effective conservation and sustainable use of <i>A. saman</i> requires detailed knowledge of its genetic diversity across its native distribution range of which surprisingly little is known to date. We assessed the genetic diversity and structure of <i>A.saman</i> across twelve representative locations of SDTF in Colombia, and how they may have been shaped by past climatic changes and human influence. We found four different genetic groups which may be the result of differentiation due to isolation of populations in pre-glacial times. The current distribution and mixture of genetic groups across STDF fragments we observed might be the result of range expansion of SDTFs during the last glacial period followed by range contraction during the Holocene and human-influenced movement of germplasm associated with cattle ranching. Despite the fragmented state of the presumed natural <i>A. saman</i> stands we sampled we did not find any signs of inbreeding, suggesting that gene flow is not jeopardized in humanized landscapes. However, further research is needed to assess potential deleterious effects of fragmentation on progeny. Climate change is not expected to seriously threaten the <i>in situ</i> persistence of <i>A. saman</i> populations and might present opportunities for future range expansion. However, the sourcing of germplasm for tree planting activities needs to be aligned with the genetic affinity of reference populations across the distribution of Colombian SDTFs. We identify priority source populations for i<i>n situ</i> conservation based on their high genetic diversity, lack or limited signs of admixture and/or genetic uniqueness.</p>
Data from: Landscape genetics of leaf-toed geckos in the tropical dry forest of northern Mexico
Habitat fragmentation due to both natural and anthropogenic forces continues to threaten the evolution and maintenance of biological diversity. This is of particular concern in tropical regions that are experiencing elevated rates of habitat loss. Although less well-studied than tropical rain forests, tropical dry forests (TDF) contain an enormous diversity of species and continue to be threatened by anthropogenic activities including grazing and agriculture. However, little is known about the processes that shape genetic connectivity in species inhabiting TDF ecosystems. We adopt a landscape genetic approach to understanding functional connectivity for leaf-toed geckos (Phyllodactylus tuberculosus) at multiple sites near the northernmost limit of this ecosystem at Alamos, Sonora, Mexico. Traditional analyses of population genetics are combined with multivariate GIS-based landscape analyses to test hypotheses on the potential drivers of spatial genetic variation. Moderate levels of within-population diversity and substantial levels of population differentiation are revealed by FST and Dest. Analyses using STRUCTURE suggest the occurrence of from 2 to 9 genetic clusters depending on the model used. Landscape genetic analysis suggests that forest cover, stream connectivity, undisturbed habitat, slope, and minimum temperature of the coldest period explain more genetic variation than do simple Euclidean distances. Additional landscape genetic studies throughout TDF habitat are required to understand species-specific responses to landscape and climate change and to identify common drivers. We urge researchers interested in using multivariate distance methods to test for, and report, significant correlations among predictor matrices that can impact results, particularly when adopting least-cost path approaches. Further investigation into the use of information theoretic approaches for model selection is also warranted.
Data from: Modeling seasonal surface temperature variations in secondary tropical dry forests
Secondary tropical dry forests (TDFs) provide important ecosystem services such as carbon sequestration, biodiversity conservation, and nutrient cycle regulation. However, their biogeophysical processes at the canopy-atmosphere interface remain unknown, limiting our understanding of how this endangered ecosystem influences, and responds to the ongoing global warming. To facilitate future development of conservation policies, this study characterized the seasonal land surface temperature (LST) behavior of three successional stages (early, intermediate, and late) of a TDF, at the Santa Rosa National Park (SRNP), Costa Rica. A total of 38 Landsat-8 Thermal Infrared Sensor (TIRS) data and the Surface Reflectance (SR) product were utilized to model LST time series from July 2013 to July 2016 using a radiative transfer equation (RTE) algorithm. We further related the LST time series to seven vegetation indices which reflect different properties of TDFs, and soil moisture data obtained from a Wireless Sensor Network (WSN). Results showed that the LST in the dry season was 15–20 K higher than in the wet season at SRNP. We found that the early successional stages were about 6–8 K warmer than the intermediate successional stages and were 9–10 K warmer than the late successional stages in the middle of the dry season; meanwhile, a minimum LST difference (0–1 K) was observed at the end of the wet season. Leaf phenology and canopy architecture explained most LST variations in both dry and wet seasons. However, our analysis revealed that it is precipitation that ultimately determines the LST variations through both biogeochemical (leaf phenology) and biogeophysical processes (evapotranspiration) of the plants. Results of this study could help physiological modeling studies in secondary TDFs.
Functional organization of woody plant assemblages along precipitation and human disturbance gradients in a seasonally dry tropical forest
<p>Chronic anthropogenic disturbances (CAD) and rainfall are important drivers of plant community assembly, but little is known about the role played by inter and intraspecific trait variation as communities respond to these pervasive forces. Here we examined the hypothesis that lower precipitation and higher CAD reduce both intra and interspecific trait variation in Caatinga dry forests. We sampled woody plants across 15 plots along precipitation and CAD gradients and measured resource-use traits. Effects of precipitation and CAD on RaoQ functional diversity were decomposed into species turnover and intraspecific variability. We used "T-statistics" to assess the trait sorting from the regional pool to local communities (i.e. external filtering), and within-community forces leading to low trait overlap (i.e. internal filtering) at individual- and species-level. Intraspecific variability explained at least one third of the total trait variation and 46% of variation in multitrait diversity across communities. Increasing disturbance reduced multitrait diversity, while precipitation affected some particular traits, such as wood density. Overall, precipitation determined species sorting across communities, while disturbance relaxed internal filters, leading to higher trait overlap within communities due to higher intraspecific variability.<b> </b>Our results suggest that<b> </b>the woody Caatinga flora contains a substantial amount of both inter and intraspecific trait variation. This variation is not randomly distributed within and across communities, but varies according to rainfall conditions and disturbance intensity. These findings reinforce the emerging idea that human-disturbances can reorganize plant communities at multiple scales and highlight trait variability as a key biological asset for the resilience of dry forests.</p>
Data from: Strong spatial structure, Pliocene diversification and cryptic diversity in the Neotropical dry forest spider Sicarius cariri
The Brazilian Caatinga is part of the seasonally dry tropical forests, a vegetation type disjunctly distributed throughout the Neotropics. It has been suggested that during Pleistocene glacial periods, these dry forests had a continuous distribution, so that these climatic shifts may have acted as important driving forces of the Caatinga biota diversification. To address how these events affected the distribution of a dry forest species, we chose Sicarius cariri, a spider endemic to the Caatinga, as a model. We studied the phylogeography of one mitochondrial and one nuclear gene and reconstructed the paleodistribution of the species using modelling algorithms. We found two allopatric and deeply divergent clades within S. cariri, suggesting that this species as currently recognized might consist of more than one independently evolving lineage. Sicarius cariri populations are highly structured, with low haplotype sharing among localities, high fixation index and isolation by distance. Models of paleodistribution, Bayesian reconstructions and coalescent simulations suggest that this species experienced a reduction in its population size during glacial periods, rather than the expansion expected by previous hypotheses on the paleodistribution of dry forest taxa. In addition to that, major splits of intraspecific lineages of S. cariri took place in the Pliocene. Taken together, these results indicate S. cariri has a complex diversification history dating back to the Tertiary, suggesting the history of dry forest taxa may be significantly older than previously thought.
Data from: Can terrestrial laser scanners (TLSs) and hemispherical photographs predict tropical dry forest succession with liana abundance?
Tropical dry forests (TDFs) are ecosystems with long drought periods, a mean temperature of 25 °C, a mean annual precipitation that ranges from 900 to 2000 mm, and that possess a high abundance of deciduous species (trees and lianas). What remains of the original extent of TDFs in the Americas remains highly fragmented and at different levels of ecological succession. It is estimated that one of the main fingerprints left by global environmental and climate change in tropical environments is an increase in liana coverage. Lianas are non-structural elements of the forest canopy that eventually kill their host trees. In this paper we evaluate the use of a terrestrial laser scanner (TLS) in combination with hemispherical photographs (HPs) to characterize changes in forest structure as a function of ecological succession and liana abundance. We deployed a TLS and HP system in 28 plots throughout secondary forests of different ages and with different levels of liana abundance. Using a canonical correlation analysis (CCA), we addressed how the VEGNET, a terrestrial laser scanner, and HPs could predict TDF structure. Likewise, using univariate analyses of correlations, we show how the liana abundance could affect the prediction of the forest structure. Our results suggest that TLSs and HPs can predict the differences in the forest structure at different successional stages but that these differences disappear as liana abundance increases. Therefore, in well known ecosystems such as the tropical dry forest of Costa Rica, these biases of prediction could be considered as structural effects of liana presence. This research contributes to the understanding of the potential effects of lianas in secondary dry forests and highlights the role of TLSs combined with HPs in monitoring structural changes in secondary TDFs.
Data from: Scale-dependent variation in nitrogen cycling and soil fungal communities along gradients of forest composition and age in regenerating tropical dry forests
Rates of ecosystem nitrogen (N) cycling may be mediated by the presence of ectomycorrhizal fungi, which compete directly with free‐living microbes for N. In the regenerating tropical dry forests of Central America, the distribution of ectomycorrhizal trees is affected by succession and soil parent material, both of which may exert independent influence over soil N fluxes. In order to quantify these interacting controls, we used a scale‐explicit sampling strategy to examine soil N cycling at scales ranging from the microsite to ecosystem level. We measured fungal community composition, total and inorganic N pools, gross proteolytic rate, net N mineralization and microbial extracellular enzyme activity at multiple locations within 18 permanent plots that span dramatic gradients of soil N concentration, stand age and forest composition. The ratio of inorganic to organic N cycling was correlated with variation in fungal community structure, consistent with a strong influence of ectomycorrhiza on ecosystem‐scale N cycling. However, on average, > 61% of the variation in soil biogeochemistry occurred within plots, and the effects of forest composition were mediated by this local‐scale heterogeneity in total soil N concentrations. These cross‐scale interactions demonstrate the importance of a spatially explicit approach towards an understanding of controls on element cycling.
Data from: Canopy height variation and environmental heterogeneity in the tropical dry forests of coastal Oaxaca, Mexico
Despite its importance for carbon storage and other ecosystem functions, the variation of vegetation canopy height is not yet well understood. We examined the relationship between this community attribute and environmental heterogeneity in a tropical dry forest of southern Mexico. We sampled vegetation in 15 sites along a 100-km coastal stretch of Oaxaca State, and measured the heights of all woody plants (excluding lianas). The majority of the ca. 4000 individuals recorded concentrated in the 4–8 m height range. We defined three plant sets to describe overall community canopy height at each site: a set including all plants, a set made up by the tallest plants representing 10 percent of all individuals, and a set comprising the 10 tallest plants. For each site we computed maximum height and the mean and median heights of the three sets. Significant collinearity was observed between the seven resulting height variables, but null distributions constructed through bootstrap revealed their different behaviors as functions of species richness and density of individuals. Through linear modeling and a model selection procedure, we identified 21 models that best described the variation of canopy height variables. These models pointed out to soil (measured as PC1 of a principal component analysis performed on 10 soil variables), water stress, and elevation as the main drivers of canopy height variation in the region. In the event of increasing water stress resulting from global climate change, the studied tropical dry forests could become shorter and thus decrease their carbon storage potential.
Data from: Unraveling the mechanisms underlying pulse dynamics of soil respiration in tropical dry forests
Tropical dry forests are already undergoing changes in the quantity and timing of rainfall, but there is great uncertainty over how these shifts will affect belowground carbon (C) cycling. While it has long been known that dry soils quickly release carbon dioxide (CO2) upon rewetting, the mechanisms underlying the so-called 'Birch effect' are still debated. Here, we quantified soil respiration pulses and their biotic predictors in response to simulated precipitation events in a regenerating tropical dry forest in Costa Rica. We also simulated the observed rewetting CO2 pulses with two soil carbon models: a conventional model assuming first-order decay rates of soil organic matter, and an enzyme- catalyzed model with Michaelis–Menten kinetics. We found that rewetting of dry soils produced an immediate and dramatic pulse of CO2, accompanied by rapid immobilization of nitrogen into the microbial biomass. However, the magnitude of the rewetting CO2 pulse was highly variable at fine spatial scales, and was well correlated with the size of the dissolved organic C pool prior to rewetting. Both the enzyme-catalyzed and conventional models were able to reproduce the Birch effect when respiration was coupled directly to microbial C uptake, although models differed in their ability to yield realistic estimates of SOC and microbial biomass pool sizes and dynamics. Our results suggest that changes in the timing and intensity of rainfall events in tropical dry forests will exert strong influence on ecosystem C balance by affecting the dynamics of microbial biomass growth.
Data from: An extensive suite of functional traits distinguishes wet and dry Hawaiian forests and enables prediction of species vital rates
1. The application of functional traits to predict and explain plant species' distributions and vital rates has been a major direction in functional ecology for decades, yet numerous physiological traits have not yet been incorporated into the approach. 2. Using commonly measured traits such as leaf mass per area (LMA) and wood density (WD), and additional traits related to water transport, gas exchange and resource economics, including leaf vein, stomatal, and wilting traits, we tested hypotheses for Hawaiian wet montane and lowland dry forests (MWF and LDF respectively): (1) forests would differ in a wide range of traits as expected from contrasting adaptation; (2) trait values would be more convergent among dry than wet forest species due to the stronger environmental filtering; (3) traits would be inter-correlated within "modules" supporting given functions; (4) relative growth rate (RGR) and mortality rate (m) would correlate with a number of specific traits, with (5) stronger relationships when stratifying by tree size, and (6) RGR and m can be strongly explained from trait-based models. 3. The MWF species' traits were associated with adaptation to high soil moisture and nutrient supply and greater shade tolerance whereas the LDF species' traits were associated with drought tolerance. Thus, on average, MWF species achieved higher maximum heights than LDF species and had leaves with larger epidermal cells, higher maximum stomatal conductance and CO2 assimilation rate, lower vein lengths per area, higher saturated water content and greater shrinkage when dry, lower dry matter content, higher phosphorus concentration, lower nitrogen to phosphorus ratio, high chlorophyll to nitrogen ratio, high carbon isotope discrimination, high stomatal conductance to nitrogen ratio, less negative turgor loss point, and lower WD. Functional traits were more variable in the MWF than LDF, were correlated within modules, and predicted species' RGR and m across forests, with stronger relationships when stratifying by tree size. Models based on multiple traits predicted vital rates across forests (R2 = 0.70-0.72; P < 0.01). 4. Our findings are consistent with a powerful role of broad suites of functional traits in contributing to forest species' distributions, integrated plant design, and vital rates.
Extinction-immigration dynamics lag behind environmental filtering in shaping the composition of tropical dry forests within a changing landscape
The impact of rapid habitat loss and fragmentation on biodiversity is a major issue. However, we still lack an integrative understanding of how these changes influence biodiversity dynamics over time. In this study, we investigate the effects of these changes in terms of both niche-based and neutral dynamics. We hypothesize that habitat loss has delayed effects on neutral immigration-extinction dynamics, while edge effects and environmental heterogeneity in habitat patches have rapid effects on niche-based dynamics. We analyzed taxonomic and functional composition of 100 tree communities in a tropical dry forest landscape of New-Caledonia subject to habitat loss and fragmentation. We designed an original, process-based simulation framework, and performed Approximate Bayesian Computation to infer the influence of niche-based and neutral processes. Then, we performed partial regressions to evaluate the relationships between inferred parameter values of communities and landscape metrics (distance to edge, patch area, and habitat amount around communities), derived from either recent or past (65 yrs ago) aerial photographs, while controlling for the effect of soil and topography. We found that landscape structure influences both environmental filtering and immigration. Immigration rate was positively related to past habitat amount surrounding communities. In contrast, environmental filtering was mostly affected by present landscape structure and mainly influenced by edge vicinity and topography. Our results highlight that landscape changes have contrasting spatio-temporal influences on niche-based and neutral assembly dynamics. First, landscape-level habitat loss and community isolation reduce immigration and increase demographic stochasticity, resulting in slow decline of local species diversity and extinction debt. Second, recent edge creation affects environmental filtering, incurring rapid changes in community composition by favoring species with edge-adapted strategies. Our study brings new insights about temporal impacts of landscape changes on biodiversity dynamics. We stress that landscape history critically influences these dynamics and should be taken into account in conservation policies.
Data from: Ecological and phylogenetic predictors of mobbing behavior in a tropical dry forest
Mobbing represents a well-known anti-predatory behavior, where potential prey display aggressively against a predator. Despite considerable experimental and descriptive work, no models predict species participation in mobbing assemblages. Here, we aimed to understand why some bird species engage in this behavior, while others do not, and what factors can be used to predict mobbing engagement within an avian community. We investigated whether certain functional traits, such as body size, foraging guild, foraging mode, and strata, as well species abundance and evolutionary relatedness, are important mobbing predictors. To address these goals, we simulated the presence of the Ferruginous Pygmy-Owl (Glaucidium brasilianum) by broadcasting its voice in 230 experiments conducted in 115 points, systematically distributed in a dry forest of northeastern Brazil. We compared these results to 162 avian surveys (point counts) conducted in the same area. Our avian surveys detected 108 bird species (local avian community), whereas our playback experiments attracted 72 species (mobbing assemblage). In general, small, canopy insectivorous or frugivorous birds dominated the mobs. The best mobbing predictors were body mass and guild, whereas species abundance, foraging mode, and strata were not retained in the best models. We found a strong phylogenetic component in body mass and mobbing propensity (almost 90% of the species and individuals participating in the mobs were passerines). At the community level, we found significant differences in the functional and phylogenetic structure of the mobbing assemblage in relation to the avian community. Our results suggest that mobbing behavior is tightly associated to predation risk and the capacity of individual species to find and detect predators, and that functional and phylogenetic features can predict species participation in this complex animal behavior.
Data from: AFLP diversity and spatial structure of Calycophyllum candidissimum (Rubiaceae), a dominant tree species of Nicaragua's critically endangered seasonally dry forest
The Central American seasonally dry tropical (SDT) forest biome is one of the worlds' most endangered ecosystems, yet little is known about the genetic consequences of its recent fragmentation. A prominent constituent of this biome is Calycophyllum candidissimum, an insect-pollinated and wind-dispersed canopy tree of high socio-economic importance, particularly in Nicaragua. Here, we surveyed amplified fragment length polymorphisms across 13 populations of this species in Nicaragua to elucidate the relative roles of contemporary vs historical factors in shaping its genetic variation. Genetic diversity was low in all investigated populations (mean HE=0.125), and negatively correlated with latitude. Overall population differentiation was moderate (ΦST=0.109, P<0.001), and Bayesian analysis of population structure revealed two major latitudinal clusters (I: 'Pacific North'+'Central Highland'; II: 'Pacific South'), along with a genetic cline between I and II. Population-based cluster analyses indicated a strong pattern of 'isolation by distance' as confirmed by Mantel's test. Our results suggest that (1) the low genetic diversity of these populations reflects biogeographic/population history (colonisation from South America, Pleistocene range contractions) rather than recent human impact; whereas (2) the underlying process of their isolation by distance pattern, which is best explained by 'isolation by dispersal limitation', implies contemporary gene flow between neighbouring populations as likely facilitated by the species' efficient seed dispersal capacity. Overall, these results underscore that even tree species from highly decimated forest regions may be genetically resilient to habitat fragmentation due to species-typical dispersal characteristics, the necessity of broad-scale measures for their conservation notwithstanding.
Predator-prey interactions in anurans of the tropical dry forests of the Colombian Caribbean: a functional approach
<p>Anuran prey selection might be mediated by traits, either by mismatches in predator and prey traits (preventing interactions) or by predator selection of prey traits (encouraging interactions). These effect traits could be summarized in two contrasting foraging strategies: "active" and "sit-and-wait" foragers. We evaluated whether anurans could be classified in groups of species sharing traits associated to their diet, and what is the relation between particular effect traits of anurans and their prey. We collected anurans and identified their stomach contents once during dry, minor and major rain seasons in six dry forest sites in the Colombian Caribbean. For each of the 19 anuran species and 436 prey items, we registered six effect traits. We applied RLQ and Fourth-corner methodologies to relate predator and prey traits through their interaction matrix. Predators were assigned to five groups according to their differences in locomotion, body shape, proportion of the jaw width, mode of tongue protrusion, and strata preferred. Regarding preys, species were assigned to four groups according to their gregariousness, body shape and hardness, defensive traits, and mobility. Body size of both, predators and prey, had a minor contribution in the group assignment. We found that predators using active search target low mobility preys, whereas species using sit-and-wait strategy target highly nutritive prey that are difficult to manipulate. By linking amphibian diet with foraging strategies, we hope to contribute to the understanding of mechanisms behind anuran-prey food web patterns and to build more realistic models of functional response to changing environments.<span> </span></p>
Data from: Re-growing a tropical dry forest: functional plant trait composition and community assembly during succession
A longstanding goal of ecology and conservation biology is to understand the environmental and biological controls of forest succession. However, the patterns and mechanisms that guide successional trajectories, especially within tropical forests, remain unclear. We collected leaf functional trait and abiotic data across a 110-year chronosequence within a tropical dry forest in Costa Rica. Focusing on six key leaf functional traits related to resource acquisition and competition, along with measures of forest stand structure, we propose a mechanistic framework to link species composition, community trait distributions, and forest structure. We quantified the community-weighted trait distributions for specific leaf area, leaf dry matter concentration, leaf phosphorus concentration, leaf carbon to nitrogen ratio, and leaf stable isotopic carbon and nitrogen. We assessed several prominent hypotheses for how these functional measures shift in response to changing environmental variables (soil water content, bulk density and pH) across the chronosequence. Increasingly, older forests differed significantly from younger forests in species composition, above ground biomass and shifted trait distributions. Early stages of succession were uniformly characterized by lower values of community-weighted mean specific leaf area, leaf stable nitrogen isotope, and leaf phosphorus concentration. Leaf dry matter concentration and leaf carbon to nitrogen ratio were lower during earlier stages of succession, and each trait reached an optimum during intermediate stages of succession. The leaf carbon isotope ratio was the only trait to decrease linearly with increasing stand age indicating reduced water use efficiency in older forests. However, in contrast to expectations, community-weighted trait variances did not generally change through succession, and when compared to null expectations were lower than expected. The observed directional shift in community-weighted mean trait values is consistent with the 'productivity filtering' hypothesis where a directional shift in water and light availability shifts physiological strategies from 'slow' to 'fast'. In contrast to expectations arising from niche based ecology, none of the community trait distributions were over-dispersed. Instead, patterns of trait dispersion are consistent with the abiotic filtering and/or competitive hierarchy hypotheses.
Data from: Latitude drives diversification in Madagascar's endemic dry forest rodent, Eliurus myoxinus (sub-family Nesomyinae)
Numerous hypotheses have been proposed for the historical processes governing the rich endemism of Madagascar's biodiversity. The 'watershed model' suggests that drier climates in the recent geological past have resulted in the contraction of forests around major watersheds, thereby defining areas of endemism. We test whether this hypothesis explains phylogeographical patterns in a dry forest-dependent rodent, Eliurus myoxinus, an endemic species widely distributed through western Madagascar. We sequenced the mitochondrial cytochrome b locus and nuclear introns of the β-fibrinogen and the growth hormone receptor genes for E. myoxinus. Using a parametric bootstrapping approach, we tested whether the mitochondrial gene tree data fit expectations of local differentiation given the watershed model. We additionally estimated population differentiation and historical demographic parameters, and reconstructed the spatial history of E. myoxinus to highlight spatial and temporal patterns of differentiation. The data do not support the watershed model as a clear explanation for the genetic patterns of diversity within extant E. myoxinus populations. We find striking patterns of latitudinal genetic structure within western Madagascar, and indicate possible roles for environmental and ecological gradients along this axis in generating phylogeographical diversity.
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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.
International Brain Laboratory public data
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.
OpenNeuro
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.