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Atropelamentos de vertebrados silvestres no semiárido brasileiro: dinâmica temporal, hotspots e fatores ambientais

Mon, 20 Jul 2026 00:00:00 GMT

Título: Atropelamentos de vertebrados silvestres no semiárido brasileiro: dinâmica temporal, hotspots e fatores ambientais Autor(es): Silva, João Gabriel Santos Abstract: The road network plays an important role in the movement of people and the transportation of goods between regions of the country. However, roads are responsible for a series of negative environmental impacts, such as wildlife roadkills. In general, these roadkills occur in clustered patterns along specific road segments, known as hotspots, and may be influenced by adjacent landscape characteristics and seasonal factors, such as precipitation. Therefore, the present study analyzed wild vertebrate roadkills along a 112-km stretch of the SE-230 highway, located in a Caatinga area in the state of Sergipe, northeast of Brazil, characterizing the affected fauna, its temporal dynamics, the spatial distribution of hotspots, and the influence of landscape and precipitation on these events. Monitoring was conducted biweekly between January and December 2025 by two observers traveling in a motorized vehicle at 50 km/h, during which information regarding specimen identification, date, and geographic coordinates was recorded. Circular analyses (Rayleigh and Mardia–Watson–Wheeler tests) were used to evaluate the temporal distribution of roadkills, while Ripley’s K 2D and 2D HotSpot Identification tests were applied to identify hotspots. In addition, logistic regression models were used to investigate the influence of landscape and precipitation. A total of 524 individuals belonging to 63 vertebrate species were recorded. Amphibia showed the highest number of records (37.79%), followed by Aves (24.62%), Mammalia (24.04%), and Reptilia (13.55%). Circular analyses indicated a non-uniform distribution of roadkills for amphibians, reptiles, and mammals, whereas birds showed a uniform distribution throughout the year, with differences in the temporal distribution of roadkills among vertebrate classes. The location of hotspots varied between dry and rainy months, showing low spatial similarity among taxonomic groups. Logistic regression models indicated that landscape variables influenced roadkills as urban areas and use mosaics. Furthermore, precipitation had a positive effect on amphibians and birds. The results demonstrate that vertebrate roadkills in the Caatinga exhibit temporal and spatial variation. Thus, this study contributes to expanding knowledge about the impacts of roads in semiarid regions and provides support for the implementation of mitigation measures aimed at wildlife conservation.

Determinantes ambientais da diversidade genética da fauna marinha brasileira: uma meta-análise

Fri, 24 Jul 2026 00:00:00 GMT

Título: Determinantes ambientais da diversidade genética da fauna marinha brasileira: uma meta-análise Autor(es): Castro, Juliano Guerra de Abstract: Genetic diversity is a fundamental dimension of biodiversity, playing a key role in species evolution and in the resilience of populations to global climate change. This study aimed to conduct a systematic review of the scientific literature on population genetics of Brazilian shallow waters marine fauna and to synthesize its results using linear mixed models (LMMs) and meta-regressions, to evaluate the influence of environmental variables on genetic diversity. Studies were included if they measured, or allowed the measuring of, haplotype diversity (h) and nucleotide diversity (3,14) in at least three populations with five or more individuals of Brazilian marine species distributed along the coast and oceanic islands, based on mitochondrial molecular markers. The literature search was conducted in the Web of Science, Scopus, PubMed, and Periódicos CAPES databases on December 2, 2025, yielding 1,210 records, of which 63 were included, comprising 64 species and 375 populations. Data synthesis was performed using LMMs, including a spatial autocovariate as a fixed effect to consider the spatial dependence between populations. Results robustness to evolutionary dependence between species as assessed through phylogenetic models (pGLMMs). Model robustness to h and r precision was assessed through sensitivity analyses restricted to populations with 25 or more individuals. Risk of bias in the meta-regressions was evaluated using funnel plots, Egger’s test, Rosenthal’s Failsafe-N, and leave-one-out analyses. The LMMs revealed a weak but consistent positive effect of mean annual sea surface temperature (SST) on h (Estimate = 0.04; p = 0.001), whereas no robust effect was observed for 3,14. This pattern suggests that temperature primarily influences recent demographic events, with no evidence of detectable differences in mutation rates among environments. Meta-regressions conducted using Fisher’s Z-transformed correlation coefficients (Zr) for 40 species with four or more populations corroborated this result (Zr = 0.464; CI = 0.28–0.65; p < 0.0001). The effect was consistent across the most represented phyla and independent of the methodological approaches employed. Robustness analyses found no evidence of publication bias and supported consistency in the results. Limitations of this study include the exclusive use of mitochondrial markers, representing only a fraction of the genome, as well as taxonomic and geographic bias. Overall, the results reinforce that the phylogeographic patterns in Brazilian marine fauna genetic diversity emerge from the interaction between environmental variables, life history and evolutional processes. Therefore, more integrative conservation strategies, aided by high resolution genomic approaches, could highly benefit the understanding and preservation of Brazilian marine biodiversity.

Efeitos da relação filogenética e da similaridade funcional na invasibilidade de plantas na Caatinga

Fri, 09 Feb 2024 00:00:00 GMT

Título: Efeitos da relação filogenética e da similaridade funcional na invasibilidade de plantas na Caatinga Autor(es): Almeida, Thieres Santos Abstract: One of the main questions in biological invasions studies is the reason why numerous species are introduced, but only some become invasive. This shift in status has been justified by the phylogenetic relationship and functional similarity between exotic and native species. However, these patterns have not been explored in semi-arid environments like the Caatinga. Thus, the aim of this work is to test how phylogenetic and functional similarity between exotic and native plants in the Caatinga affect invasion status and distribution of invasive species. To achieve this, we constructed a list of exotic plants and obtained their respective invasion statuses in the Caatinga. We gathered occurrence data for these species and native plants. Additionally, a functional database was constructed for these species, including Leaf Area (LA), Height (H), and Seed Mass (SM) attributes. Using the occurrences, we created diversity fields for exotic species, representing the composition of native species that co-occur with each exotic species and calculated phylogenetic metrics for the focal species' distance to its field. Binomial GLMs were employed to assess whether changes in status from exotic to naturalized and from naturalized to invasive are influenced by phylogenetic relationships and functional attributes. For invasive species, we tested if observed phylogenetic distance values differ from those expected by chance. Lastly, we analyzed if there are functional similarities between the statuses of exotic species and native plants. We found that plants phylogenetically closer to Caatinga natives are more likely to become naturalized and invasive. Smaller plants also have a higher probability of becoming naturalized. Among invasive species with a phylogenetic relationship different from what is expected by chance, there is a prevalence of species phylogenetically closer to natives in their field. In comparing statuses, naturalized and invasive plants were found to be shorter and have smaller leaves and seeds than native plants in the Caatinga. The results indicate that Caatinga's environmental filter appears to favor species more similar to natives. The observed functional differences suggest that naturalized and invasive species are competitive, adopting strategies similar to native plants of Caatinga, such as seed bank formation and dense populations during a specific period of the year.

Determinantes de padrões espaciais, ambientais e evolutivos das lacunas hutchinsonianas de serpentes (Squamata: serpentes)

Wed, 11 Feb 2026 00:00:00 GMT

Título: Determinantes de padrões espaciais, ambientais e evolutivos das lacunas hutchinsonianas de serpentes (Squamata: serpentes) Autor(es): Lima, Luiz Antônio Gonzaga de Abstract: Knowledge of the different dimensions of biodiversity is marked by gaps and biases that unevenly affect data availability, being strongly influenced by geographic, historical, and phylogenetic factors. Among these gaps, the Hutchinsonian shortfall—related to the lack of knowledge about tolerance limits to abiotic factors—stands out as particularly relevant in the context of rapid climate change, since the absence of information on thermal tolerance compromises our understanding of species vulnerability, persistence, and future distributions. In this study, we investigated the magnitude of the Hutchinsonian shortfall associated with thermal biology traits of snakes, assessing the distribution and biases of available knowledge across geographic, phylogenetic, and climatic spaces. To this end, we integrated thermal biology data from the literature with spatial, phylogenetic, and environmental analyses. We compiled morphological, physiological, and climatic information from global databases and a systematic review, including data on thermal tolerance, evapotranspiration, and climatic niche under current conditions and future scenarios. Knowledge representativeness was evaluated using niche overlap tests, spatial autocorrelation analyses, and the phylogenetic aggregation index (NRI), in addition to analyses of changes in climatic conditions projected until 2100 under the SSP585 scenario. Our results demonstrate that knowledge of snake thermal biology is limited, strongly biased, and structured across phylogenetic, environmental, and geographic spaces, characterizing a multifaceted Hutchinsonian shortfall. Data are concentrated in a few clades and temperate regions, incompletely representing the group’s climatic niche, particularly for traits associated with minimum thermal tolerance and water balance. This pattern results in extensive portions of climatic space—especially in tropical regions—being systematically underrepresented. Projections of future climate scenarios indicate climatic rearrangements and the emergence of non-analog conditions, increasing uncertainty and limiting ecological inferences and realistic predictions about snake responses to global climate change.