Aim Anurans' sensitivity to hydric stress has driven adaptive changes in multiple traits, potentially displaying geographical clines, as is the case with body size. A longstanding body of research suggests that skin resistance to water loss may also vary geographically in response to water loss. We build upon biophysical first principles to test for the existence of this yet elusive global-level cline in skin resistance to dehydration that alternates with body size across the aridity gradient.Location Worldwide.Time Period Current.Major Taxa Studied Amphibian anurans.Methods We combined mechanistic biophysical modelling with a phylogenetic comparative approach within a model-selection framework. We estimated species' sensitivity to variations in body mass and resistance to dehydration using biophysical equations for species worldwide. We then integrated these sensitivities into a weighted phylogenetic comparative approach with model selection to test the effect of the aridity index on trait variation.Results We provide the first evidence of a global-level geographic gradient in skin resistance. Skin resistance varies with aridity gradients and alternates with body size along this gradient, as predicted by theory. These clines interact with microhabitat use, with clines in skin resistance predominating in ground-dwelling species with low skin resistance. In contrast, body size variation is more pronounced in arboreal, small-bodied species with higher skin resistance.Main Conclusions Our findings highlight how multiple functional traits can follow distinct adaptive routes under shared environmental pressures, thereby accounting for the lack of universality of ecogeographical rules. This study underscores the value of mechanistic models in generating and testing hypotheses about trait evolution and ecogeographical rules.
Biological invasions are a major driver of global biodiversity loss, yet predictive frameworks remain underdeveloped, particularly in underexplored ecosystems such as the Caatinga dry forest in Brazil. Here, we evaluated the factors influencing the naturalization and invasion of 159 non-native plant species in the Caatinga using machine learning (ML) classification models. We aimed to identify the key ecological, evolutionary, and environmental predictors most strongly associated with each invasion stage and to assess their global and local influence using Shapley additive explanation (SHAP) values. We compiled 49 predictors, including functional traits, phylogenetic distances, niche-similarity metrics, and distribution-model outputs, to classify species into non-native, naturalized, or invasive categories. Separate models were developed for naturalization and invasion transitions, and their performance was evaluated using multiple metrics. Naturalization models had lower accuracy, with height, seed mass, and rainfall-related variables emerging as the most influential predictors. In contrast, invasion models performed well, with climatic niche dissimilarity (pseudo-F), phylogenetic similarity (MPDw), and predicted distribution area as key predictors. SHAP values revealed nonlinear effects and misclassifications that, in some cases, aligned with known ecological behaviors. Our findings highlight the importance of functional similarity, broad climatic tolerance, and niche position in shaping plant invasions in the Caatinga. Despite limitations in predicting naturalization, integrating ML and SHAP provides a promising framework for the early detection and management of invasive species in dryland ecosystems.
ABSTRACT Studying niche evolution becomes central to understanding the processes driving species diversification along latitudinal gradients. Octodontoidea rodents serve as a model group for understanding how the colonisation of extratropical regions has shaped the climatic niche evolution of species. We analyse the time and mode of climatic niche evolution among different Octodontoidea lineages to understand how niche evolutionary processes operate across the spatial gradient of the Neotropical region. We constructed ecological niche models for living Octodontoidea species to assess the timing and mode of climatic niche evolution across tropical and extratropical lineages. We estimated niche similarity and correlated it with species divergence times, and estimated the rate of climatic niche diversification across lineages. Our results show a trend of greater niche overlap in more recent lineages and lower niche overlap in older lineages. However, extratropical lineages exhibit lower climatic niche overlaps. From diversification analysis, we detected that the Ctenomyidae group shows higher rates of niche diversification, whereas the tropical Echimyidae group exhibits the lowest rates of climatic niche diversification. Our results support the idea that the lineages restricted to tropical regions tend towards niche conservatism. However, some tropical lineages have successfully colonised extratropical regions, and this colonisation has been accompanied by strong selective pressures, leading to higher rates of niche diversification and lower climatic niche overlap among species.
Temperature is a primary driver to define the ecophysiological activity and performance of ectotherms. Thus, thermal tolerance limits have a profound effect in determining geographic ranges. In regions with extreme cold temperatures, lower thermal limits of species are a key physiological trait for survival. Moreover, thermal niche breadth also plays an important role in allowing organisms to withstand climatic variability and confers species with broader potential to establish in new regions. Here we study the evolution of thermal tolerance limits among Collembola (Arthropoda) and explore how they are affected by the colonization of polar environments. In addition, we test the hypothesis that globally invasive species are more eurythermal than non‐invasive ones. Critical thermal limits (CT min and CT max ), classic measurements of thermal tolerance, were compiled from the literature and complemented with experimental assays for springtail species. Genetic data of the mitochondrial gene cytochrome oxidase subunit 1 (COI) was used to assemble a phylogeny. Our results show that polar springtails have lower CT min and lower CT max compared to species from temperate and tropical regions, consistent with the Polar pressure hypothesis. We found no phylogenetic signal for CT max , but low values of phylogenetic signal for CT min . Globally invasive species do not have significantly broader thermal tolerance breadth (CT range ) than non‐invasive ones, thus not supporting the predictions of the Eurythermality hypothesis. We conclude that polar springtails have evolved their thermal niches in order to adapt to extremely cold environments, which has led to decreasing both upper and lower thermal tolerance limits.
Snakebite envenoming poses a significant public health challenge on a global basis, affecting millions of people annually and leading to complications that may result in fatalities. Brazil stands as one of the countries most impacted by snakebite envenoming, with snakes of the Bothrops genus being responsible for most bites. The current study aimed to identify the determinants of Bothrops snakebite incidence across different regions of Brazil. An ecological study was conducted using municipality-aggregated data, with snakebite incidence as the dependent variable. The study period comprised the years 2015-2021. We constructed Species Distribution Models (SDMs) for Bothrops species, and information was collected on precipitation, runoff, maximum and minimum temperatures, native forest, historical forest loss, agriculture, and pasture in each Brazilian municipality. These data were employed to assess the association between snakebite incidence and biotic, climatic, and landscape factors. The data were analyzed using Generalized Least Squares (GLS) regression. The SDMs demonstrated good performance. The average annual snakebite incidence during the study period ranged from zero to 428.89 per 100,000 inhabitants, depending on the municipality. Higher incidence rates were concentrated primarily in municipalities in the northern region of the country. In this study, we found that nationwide, areas with extensive native forests and those that have historically experienced significant loss of forest cover exhibited higher snakebite incidence rates. Additionally, areas with higher temperatures and precipitation levels, as well as greater climatic suitability for the species B. jararaca, showed significantly higher snakebite incidence rates in the South and Southeast of Brazil, respectively. These associations may be linked to increased snake abundance and active behavior, as well as to engagement in activities favoring human-snake contact in these areas. The findings of this study can contribute to the improvement of prevention and control strategies for this public health issue in Brazil.
Aim: We studied the niche evolution and diversification modes in transisthmian Alpheus shrimps by examining the interplay between environmental niche divergence and conservatism in allopatric sister species. In a broader perspective, the current study analysed the evolution of climatic niche and the role of the environment in species diversification of Alpheus transisthmian shrimp. Location: Atlantic and Eastern-Pacific oceans. Taxon: Alpheus shrimps (Caridea: Alpheidae). Methods: We assembled georeferenced occurrences for 33 species of Alpheus (with 24 sister species) from a time-calibrated molecular phylogeny. We modelled their ecological niches and assessed niche overlap through pairwise comparisons. Additionally, we performed phylogenetic reconstructions of the ancestral environmental niche, for each niche axis. Results: Our results demonstrate that thermal tolerances, food availability and hydrodynamic forces were relevant environmental axes in evolutionary processes in transisthmian species of Alpheus. Among the 528 paired comparisons, we found that most niches were divergent, including in 12 clades formed by pairs of sister species (in only two of these clades were the niches fully equivalent). Phylogenetic reconstructions of ancestral niches showed an initial niche conservatism in all axes, with divergences intensifying in the last 12 million years. Main Conclusions: We found evidence that confirms the relevance of the environmental changes that occurred in the West Atlantic and East Pacific for niche evolution in transisthmian Alpheus species, as well as for the emergence of some lineages. Our findings provide evidence for different modes of Alpheus species speciation in a period consistent with the closure of the Isthmus of Panama.
Freshwater ecosystems are among the most important in the world and provide essential functions and services to humans. In this study, we examine the roles of environmental and historical factors in explaining contemporary patterns of species richness. We investigated spatial patterns of species richness of freshwater crabs by compiling geographic distribution maps for 1271 species. We employed six environmental variables slightly correlated and non-collinear to test environmental hypotheses. At a global scale, we identified three regions characterized by particularly high species richness: in northern South America (Neotropical biogeographic realm), in the Western Ghats and Sri Lanka (Oriental), and southwestern China (Oriental). The best-fitting model that explained global richness variation included environmental hypotheses: Temperature-Speciation, Resource Availability, Habitat Heterogeneity and Anthropic Impact. We also observed a historical influence on the pattern of richness, with distinct sets of environmental predictors of richness across taxa and biogeographic realms. Our models suggest that freshwater crab richness is associated with by varying processes occurring within specific environmental and historical scenarios. In general, we documented a concentration of freshwater crab richness in areas heavily impacted by human activities. These findings hold implications for the conservation of this taxonomic group.
BackgroundClimate change is expected to have profound effects on the distribution of venomous snake species, including reductions in biodiversity and changes in patterns of envenomation of humans and domestic animals. We estimated the effect of future climate change on the distribution of venomous snake species and potential knock-on effects on biodiversity and public health.MethodsWe built species distribution models based on the geographical distribution of 209 medically relevant venomous snake species (WHO categories 1 and 2) and present climatic variables, and used these models to project the potential distribution of species in 2070. We incorporated different future climatic scenarios into the model, which we used to estimate the loss and gain of areas potentially suitable for each species. We also assessed which countries were likely to gain new species in the future as a result of species crossing national borders. We integrated the species distribution models with different socioeconomic scenarios to estimate which countries would become more vulnerable to snakebites in 2070.FindingsOur results suggest that substantial losses of potentially suitable areas for the survival of most venomous snake species will occur by 2070. However, some species of high risk to public health could gain climatically suitable areas for habitation. Countries such as Niger, Namibia, China, Nepal, and Myanmar could potentially gain several venomous snake species from neighbouring countries. Furthermore, the combination of an increase in climatically suitable areas and socioeconomic factors (including low-income and high rural populations) means that southeast Asia and Africa (and countries including Uganda, Kenya, Bangladesh, India, and Thailand in particular) could have increased vulnerability to snakebites in the future, with potential effects on public human and veterinary health.InterpretationLoss of venomous snake biodiversity in low-income countries will affect ecosystem functioning and result in the loss of valuable genetic resources. Additionally, climate change will create new challenges to public health in several low-income countries, particularly in southeast Asia and Africa. The international community needs to increase its efforts to counter the effects of climate change in the coming decades.FundingGerman Research Foundation, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, German Centre for Integrative Biodiversity Research, Ministerio de Ciencia e Innovación de España, European Regional Development Fund.
Background Incomplete species inventories for Antarctica represent a key challenge for comprehensive ecological research and conservation in the region. Additionally, data required to understand population dynamics, rates of evolution, spatial ranges, functional traits, physiological tolerances and species interactions, all of which are fundamental to disentangle the different functional elements of Antarctic biodiversity, are mostly missing. However, much of the fauna, flora and microbiota in the emerged ice -free land of the continent have an uncertain presence and/or unresolved status, with entire biodiversity compendia of prokaryotic groups (e.g. bacteria) being missing. All the available biodiversity information requires consolidation, cross -validation, re -assessment and steady systematic inclusion in order to create a robust catalogue of biodiversity for the continent. New information We compiled, completed and revised eukaryotic species inventories present in terrestrial and freshwater ecosystems in Antarctica in a new living database: terrANTALife (version 1.0). The database includes the first integration in a compendium for many groups of eukaryotic microorganisms. We also introduce a first catalogue of amplicon sequence variants (ASVs) of prokaryotic biodiversity. Available compendia and literature to date were searched for Antarctic terrestrial and freshwater species, integrated, taxonomically harmonised and curated by experts to create comprehensive checklists of Antarctic organisms. The final inventories comprises 470 animal species (including vertebrates, freeliving invertebrates and parasites), 306 plants (including all Viridiplantae: embryophytes and green algae), 997 fungal species and 434 protists (sensu lato). We also provide a first account for many groups of microorganisms, including non-lichenised fungi and multiple groups of eukaryotic unicellular species (Stramenophila, Alveolata and Rhizaria (SAR), Chromists and Amoeba), jointly referred to as "protists". In addition, we identify 1753 bacterial (obtained from 348117 ASVs) and 34 archaeal genera (from 1848 ASVs), as well as, at least, 14 virus families. We formulate a basic tree of life in Antarctica with the main lineages listed in the region and their "known-accepted-species" numbers.
Grasses (Family Poaceae) are among the most successful invasive plants in the world. Here we evaluate phylogenetic and biogeographic patterns of emergence of naturalized and invasive species among grasses globally. In our data, circa 19% of the grasses are currently catalogued as invasive and almost 38% are listed as naturalized; these are among the highest ratios for single families of organisms. Remarkably, most tribes of grasses contain numerous naturalized and invasive species, suggesting that the invasion success is rooted broadly in ancestral traits in the Poaceae. Moreover, the probability of invasiveness is positively related to the diversification rates in the family also suggesting a link with recent radiation events. The phylogenetic distribution of the invasive condition is neither strongly conserved nor purely random. Phylogenetic clumping levels also vary between Poaceae subclades. We postulate that this diffuse clumping could be partially attributed to the expression of labile traits that contribute to species invasiveness. In addition, floristic regions (biomes and biogeographic realms) have different proportions of invasive species, with the temperate Palearctic region having the highest ratio of invasive vs. non-invasive species. The phylodiversity of aliens across regions is also variable in space. Comparison of alien phylodiversity levels across biogeographic realms and biomes reveals regions producing highly restricted invasive lineages and others where the diversity of aliens exported is no different from global mean diversity levels in grasses. Elucidating the evolutionary patterns and drivers of invasiveness is useful for understanding and managing invasions, with the low phylogenetic structure of alien grasses warning of their overall high invasiveness potential.
Climate change is affecting the distribution of marine organisms worldwide, including venomous marine gastropods that offer risks to human health, but also potential pharmacological resources, such as Conus sp. Species Distribution Models (SDMs) are valuable tools for predicting species distribution under climate change. The objective of our study was to evaluate the potential distribution of Conus geographus and C. textile in the Indo-Pacific region under different climate change scenarios for 2050 and 2090. We constructed SDMs with MaxEnt for each species, using bioclimatic variables from Bio-ORACLE and NOAA, and occurrence data from GBIF. We projected the best-fit model for the present and different future climate change scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5). We obtained high accuracy SDMs for C. geographus and C. textile, with Temperature and Primary Productivity as the main explanatory variables. Our future projections reveal that both species may react differently to climate change. Southeast Asia and Micronesia will continue to provide a climatically appropriate environment for both species; however, they may become more suitable for C. geographus and less suitable for C. textile. This may lead to a higher risk of human envenomation by C. geographus, but a lower risk by C. textile. A decreased suitability for C. textile may also lead to the loss of potential pharmacological resources among its range. Our study emphasizes how SDMs can be used to assess the future distribution of species with human health implications, which can aid in the monitoring of venomous marine species.
Great environmental changes may affect the survival capability of a variety of organisms. Testudinidae is the most diverse family of terrestrial chelonians within the whole order (Testudines). Interestingly, however, the number of extinct species overcome the extant ones. In order to understand better how the diversification process of this family occurred, this work used the PyRate software, which estimates both the preservation and diversification processes in a continuous time interval. For such, the software used a list of fossil occurrences obtained from the Paleobiology Database whereas the extant species list was obtained from Catalogue of Life. This way, the software was able to infer the probability of the ancestral clade having resulted in these species during its evolutionary history. The analyses generated graphs containing the diversification, extinction and speciation curves and their respective associated 95% credibility intervals. A great rise in the extinction rate was observed starting 6 million years ago. This rise is believed to be related to the drop of atmospheric CO2 all over the globe at the end of the Miocene, about 8-6 million years ago. This event led to a turnover of the vegetation composition on the warmer areas of the planet, with plants that used C3 metabolism giving way to C4 plants. In terms of landscape, grasses and herbal vegetation, such as savannas, started dominating. As for other animal groups, those herbivores with grazing habits were more successful than those used to only browsing or that did not have enough flexibility of choice.
The foreseen global changes of the next decades will modify human and livestock interactions with venomous animals throughout the planet. Advancing the knowledge about the distribution of venomous animal species and their possible impact in humans and livestock will be essential not only to prevent and treat envenomings but also to conserve the planet's biodiversity.
Understanding the success factors underlying each step in the process of biological invasion provides a robust foundation upon which to develop appropriate biosecurity measures. Insights into the processes occurring can be gained through clarifying the circumstances applying to non-native species that have arrived, established and, in some cases, successfully spread in terrestrial Antarctica. To date, examples include a small number of vascular plants and a greater diversity of invertebrates (including Diptera, Collembola, Acari and Oligochaeta), which share features of pre-adaptation to the environmental stresses experienced in Antarctica. In this synthesis, we examine multiple classic invasion science hypotheses that are widely considered to have relevance in invasion ecology and assess their utility in understanding the different invasion histories so far documented in the continent. All of these existing hypotheses appear relevant to some degree in explaining invasion processes in Antarctica. They are also relevant in understanding failed invasions and identifying barriers to invasion. However, the limited number of cases currently available constrains the possibility of establishing patterns and processes. To conclude, we discuss several new and emerging confirmatory methods as relevant tools to test and compare these hypotheses given the availability of appropriate sample sizes in the future.
Body size and shape fundamentally determine organismal energy requirements by modulating heat and mass exchange with the environment and the costs of locomotion, thermoregulation, and maintenance. Ecologists have long used the physical linkage between morphology and energy balance to explain why the body size and shape of many organisms vary across climatic gradients, e.g., why larger endotherms are more common in colder regions. However, few modeling exercises have aimed at investigating this link from first principles. Body size evolution in bats contrasts with the patterns observed in other endotherms, probably because physical constraints on flight limit morphological adaptations. Here, we develop a biophysical model based on heat transfer and aerodynamic principles to investigate energy constraints on morphological evolution in bats. Our biophysical model predicts that the energy costs of thermoregulation and flight, respectively, impose upper and lower limits on the relationship of wing surface area to body mass (S-MR), giving rise to an optimal S-MR at which both energy costs are minimized. A comparative analysis of 278 species of bats supports the model’s prediction that S-MR evolves toward an optimal shape and that the strength of selection is higher among species experiencing greater energy demands for thermoregulation in cold climates. Our study suggests that energy costs modulate the mode of morphological evolution in bats—hence shedding light on a long-standing debate over bats’ conformity to ecogeographical patterns observed in other mammals—and offers a procedure for investigating complex macroecological patterns from first principles.
Species distribution models (SDMs), the most prominent tool in modern biogeography, rely on the assumptions that (i) species distribution is in equilibrium with the environment and (ii) that climatic niche has been conserved throughout recent geological time. These issues affect the spatial and temporal transferability of SDMs, limiting their reliability for applications such as when studying effects of past climate change on species distribution and extinctions. The integration of paleontological and neontological data for a multitemporal calibration and validation of SDMs has been suggested for improving SDMs flexibility. Here, we provide an empirical test for a multitemporal calibration, employing virtual species (i.e., with perfectly-known distributions) and comparing them directly with monotemporal SDMs (i.e., SDM calibrated in a single time layer). We used 1kyr-interval scenarios throughout the last 22 kyr BP for two ecologically different species in South America (a "hot and wet" species and a "cold and dry" species). Models with multitemporal calibration performed similarly to models with monotemporal calibration, regardless of species, sample sizes, and time frame. However, multitemporal calibration performed better when dealing with non-analogous climates among time layers. By improving the temporal SDMs transferability, multitemporal calibration opens new avenues for integrating fossil and recent occurrence data, which may substantially benefit biogeography and paleoecology.
Natural history museums (NHM) are important for students' learning and motivation. However, the lack or scarcity of NHMs in countries with emerging markets may hamper the learning process. Virtual 3D models represent an important tool to counterbalance the lack of access of students to NHMs. Our study aims to understand if the use of 3D models may help in the motivation and learning of zoology. The study comprised three groups: (i) control group , where the participants only received classes of frontal teaching; (ii) practice group , where participants received, in addition to traditional classes, practical classes with biological material; (iii) 3D model group , where participants received the traditional class plus practical classes with 3D models of amphibian species. We used pre-questionnaires and post-questionnaires as an educational assessment method. Then we performed a two-way ANOVA test between the experimental groups. All three groups showed equivalent levels of motivation after the classes. Nevertheless, the 3D model and Practice groups showed a significant (p < 0.001) increase in learning performance when compared to the control group, demonstrating the relevance of 3D models in the teaching of zoology especially in institutions distant from large biological collections.
Anion supply in prepartum rations affects the mineral metabolism in primiparous cows. The objective of this study was to evaluate the effect of calcium chloride and dietary calcium sulfate in prepartum heifers’ rations on the composition of colostrum, fat and protein milk content, and total milk production during 305 days of lactation. Forty five Holstein heifers were assigned to three groups (15 per group) 21 days before calving. The heifers received a partially mixed ration (PMR) plus 2.5 kg/cow/day of wheat middlings (CP= 18.5%, neutral detergent fiber= 36.7%). Mineral salts with a dietary cation-anion difference (DCAD) of +200 mEq/kg of dry matter (DM) were added in the control group (TCon); calcium chloride was added in one of the experimental groups (TCICa), Brazilian Journal of Animal and Environmental Research ISSN: 2595-573X 5817 Brazilian Journal of Animal and Environmental Research, Curitiba, v.4, n.4, p. 5816-5828 out./dez.. 2021. and calcium sulfate was added in the other experimental group (TSoCa), both with DCAD= +30 mEq/kg of DM. After calving, they were fed on commercial feed, corn silage, and alfalfa grazing. The content of fat, protein, calcium, phosphorus, and magnesium in the colostrum was not different among the treatments (p>0.05). TClCa cows produced a greater average of milk (kg/day), fat and protein corrected milk (kg/day), fat (kg/day), and net energy of lactation (Mcal/day). The TClCa group had higher milk production, and fat (kg) and protein (kg) content than TCon (p<0.05), with intermediate values for TSoCa. The supply of calcium chloride in the prepartum of heifers produced differences in milk production and composition during the 305 days of lactation.
The order Characiformes is one of the most diverse and widely distributed groups of fishes in cis-Andean basins. That diversity is reflected in the São Francisco River (Brazil), where approximately 1/3 of all described species belong to that order, with many being endemic and/or considered endangered. The great morphological diversity observed in this group has been the focus of several systematic, ecomorphological, and evolutionary studies. Here, we evaluated the morphological patterns of 39 species of Characiformes from the São Francisco River using geometric morphometric and comparative phylogenetic techniques to better understand how ecological factors can modulate morphological diversity. Our data produced a highly supported topology revealing two promoters that drive the diversity of the analyzed forms, one is associated with phylogenetic inheritance, while the other is modulated by habitat, generating similarities between phylogenetically distant species. The absence of any observed relationship between body shape and trophic niche may reflect phylogenetic inertia of food preferences and morphological characteristics. Our data highlights the importance of combined analysis of all available evidences for understanding the evolutionary routes of diverse groups, as is the case of the Characiformes of the São Francisco River.