Habitat split as a driver of disease in amphibians.

Anthropogenic habitat disturbance is fundamentally altering patterns of disease transmission and immunity across the vertebrate tree of life. Most studies linking anthropogenic habitat change and disease focus on habitat loss and fragmentation, but these processes often lead to a third process that is equally important: habitat split. Defined as spatial separation between the multiple classes of natural habitat that many vertebrate species require to complete their life cycles, habitat split has been linked to population declines in vertebrates, e.g. amphibians breeding in lowland aquatic habitats and overwintering in fragments of upland terrestrial vegetation. Here, we link habitat split to enhanced disease risk in amphibians (i) by reviewing the biotic and abiotic forces shaping elements of immunity and (ii) through a spatially oriented field study focused on tropical frogs. We propose a framework to investigate mechanisms by which habitat split influences disease risk in amphibians, focusing on three broad host factors linked to immunity: (i) composition of symbiotic microbial communities, (ii) immunogenetic variation, and (iii) stress hormone levels. Our review highlights the potential for habitat split to contribute to host-associated microbiome dysbiosis, reductions in immunogenetic repertoire, and chronic stress, that often facilitate pathogenic infections and disease in amphibians and other classes of vertebrates. We highlight that targeted habitat-restoration strategies aiming to connect multiple classes of natural habitats (e.g. terrestrial-freshwater, terrestrial-marine, marine-freshwater) could enhance priming of the vertebrate immune system through repeated low-load exposure to enzootic pathogens and reduced stress-induced immunosuppression.

Adapt conservation biology teaching to address eco-anxiety in students.

The fear of environmental doom (eco-anxiety) is a new and growing source of mental distress that could particularly affect the next generation of conservation biologists. With care and empathy, educators can help to prevent worsening the mental health of students.

Signatures of functional bacteriome structure in a tropical direct-developing amphibian species.

BACKGROUND: Host microbiomes may differ under the same environmental conditions and these differences may influence susceptibility to infection. Amphibians are ideal for comparing microbiomes in the context of disease defense because hundreds of species face infection with the skin-invading microbe Batrachochytrium dendrobatidis (Bd), and species richness of host communities, including their skin bacteria (bacteriome), may be exceptionally high. We conducted a landscape-scale Bd survey of six co-occurring amphibian species in Brazil's Atlantic Forest. To test the bacteriome as a driver of differential Bd prevalence, we compared bacteriome composition and co-occurrence network structure among the six focal host species. RESULTS: Intensive sampling yielded divergent Bd prevalence in two ecologically similar terrestrial-breeding species, a group with historically low Bd resistance. Specifically, we detected the highest Bd prevalence in Ischnocnema henselii but no Bd detections in Haddadus binotatus. Haddadus binotatus carried the highest bacteriome alpha and common core diversity, and a modular network partitioned by negative co-occurrences, characteristics associated with community stability and competitive interactions that could inhibit Bd colonization. CONCLUSIONS: Our findings suggest that community structure of the bacteriome might drive Bd resistance in H. binotatus, which could guide microbiome manipulation as a conservation strategy to protect diverse radiations of direct-developing species from Bd-induced population collapses.

The trade-off between color and size in lizards' conspicuous tails.

A tail of conspicuous coloration is hypothesized to be an advantageous trait for many species of lizards. Predator attacks would be directed to a non-vital, and autotomizable, body part, increasing the chance of survival. However, as body size increases it also increases the signaling area that could attract predators from greater distances, increasing the overall chance of predation. Here, we test the hypothesis that there is a trade-off between tail color and size, affecting predation probabilities. We used plasticine replicas of lizards to study the predation patterns of small and large lizards with red and blue tails. In a natural environment, we exposed six hundred replicas to the attacks of free-ranging predators. Large red-tailed replicas were more attacked by birds. Mammals and unidentified predators showed no preference for any size or colors. The attacks were not primarily directed to conspicuous tails when compared to the bodies/heads of our replicas. Our study suggests that red color signals in large lizards could enhance their detection by visually oriented predators (i.e., birds). The efficacy of conspicuous tails as a decoy may rely on associated behavioral displays, which are hard to test with static replicas.

Climatic suitability, isolation by distance and river resistance explain genetic variation in a Brazilian whiptail lizard.

Spatial patterns of genetic variation can help understand how environmental factors either permit or restrict gene flow and create opportunities for regional adaptations. Organisms from harsh environments such as the Brazilian semiarid Caatinga biome may reveal how severe climate conditions may affect patterns of genetic variation. Herein we combine information from mitochondrial DNA with physical and environmental features to study the association between different aspects of the Caatinga landscape and spatial genetic variation in the whiptail lizard Ameivula ocellifera. We investigated which of the climatic, environmental, geographical and/or historical components best predict: (1) the spatial distribution of genetic diversity, and (2) the genetic differentiation among populations. We found that genetic variation in A. ocellifera has been influenced mainly by temperature variability, which modulates connectivity among populations. Past climate conditions were important for shaping current genetic diversity, suggesting a time lag in genetic responses. Population structure in A. ocellifera was best explained by both isolation by distance and isolation by resistance (main rivers). Our findings indicate that both physical and climatic features are important for explaining the observed patterns of genetic variation across the xeric Caatinga biome.

AmphiBIO, a global database for amphibian ecological traits.

Current ecological and evolutionary research are increasingly moving from species- to trait-based approaches because traits provide a stronger link to organism's function and fitness. Trait databases covering a large number of species are becoming available, but such data remains scarce for certain groups. Amphibians are among the most diverse vertebrate groups on Earth, and constitute an abundant component of major terrestrial and freshwater ecosystems. They are also facing rapid population declines worldwide, which is likely to affect trait composition in local communities, thereby impacting ecosystem processes and services. In this context, we introduce AmphiBIO, a comprehensive database of natural history traits for amphibians worldwide. The database releases information on 17 traits related to ecology, morphology and reproduction features of amphibians. We compiled data from more than 1,500 literature sources, and for more than 6,500 species of all orders (Anura, Caudata and Gymnophiona), 61 families and 531 genera. This database has the potential to allow unprecedented large-scale analyses in ecology, evolution, and conservation of amphibians.

Estimating synchronous demographic changes across populations using hABC and its application for a herpetological community from northeastern Brazil.

Many studies propose that Quaternary climatic cycles contracted and/or expanded the ranges of species and biomes. Strong expansion-contraction dynamics of biomes presume concerted demographic changes of associated fauna. The analysis of temporal concordance of demographic changes can be used to test the influence of Quaternary climate on diversification processes. Hierarchical approximate Bayesian computation (hABC) is a powerful and flexible approach that models genetic data from multiple species, and can be used to estimate the temporal concordance of demographic processes. Using available single-locus data, we can now perform large-scale analyses, both in terms of number of species and geographic scope. Here, we first compared the power of four alternative hABC models for a collection of single-locus data. We found that the model incorporating an a priori hypothesis about the timing of simultaneous demographic change had the best performance. Second, we applied the hABC models to a data set of seven squamate and four amphibian species occurring in the Seasonally Dry Tropical Forests (Caatinga) in northeastern Brazil, which, according to paleoclimatic evidence, experienced an increase in aridity during the Pleistocene. If this increase was important for the diversification of associated xeric-adapted species, simultaneous population expansions should be evident at the community level. We found a strong signal of synchronous population expansion in the Late Pleistocene, supporting the increase of the Caatinga during this time. This expansion likely enhanced the formation of communities adapted to high aridity and seasonality and caused regional extirpation of taxa adapted to wet forest.

Integrating data-deficient species in analyses of evolutionary history loss.

There is an increasing interest in measuring loss of phylogenetic diversity and evolutionary distinctiveness which together depict the evolutionary history of conservation interest. Those losses are assessed through the evolutionary relationships between species and species threat status or extinction probabilities. Yet, available information is not always sufficient to quantify the threat status of species that are then classified as data deficient. Data-deficient species are a crucial issue as they cause incomplete assessments of the loss of phylogenetic diversity and evolutionary distinctiveness. We aimed to explore the potential bias caused by data-deficient species in estimating four widely used indices: HEDGE, EDGE, PDloss, and Expected PDloss. Second, we tested four different widely applicable and multitaxa imputation methods and their potential to minimize the bias for those four indices. Two methods are based on a best- vs. worst-case extinction scenarios, one is based on the frequency distribution of threat status within a taxonomic group and one is based on correlates of extinction risks. We showed that data-deficient species led to important bias in predictions of evolutionary history loss (especially high underestimation when they were removed). This issue was particularly important when data-deficient species tended to be clustered in the tree of life. The imputation method based on correlates of extinction risks, especially geographic range size, had the best performance and enabled us to improve risk assessments. Solving threat status of DD species can fundamentally change our understanding of loss of phylogenetic diversity. We found that this loss could be substantially higher than previously found in amphibians, squamate reptiles, and carnivores. We also identified species that are of high priority for the conservation of evolutionary distinctiveness.

Speciation with gene flow in whiptail lizards from a Neotropical xeric biome.

Two main hypotheses have been proposed to explain the diversification of the Caatinga biota. The riverine barrier hypothesis (RBH) claims that the São Francisco River (SFR) is a major biogeographic barrier to gene flow. The Pleistocene climatic fluctuation hypothesis (PCH) states that gene flow, geographic genetic structure and demographic signatures on endemic Caatinga taxa were influenced by Quaternary climate fluctuation cycles. Herein, we analyse genetic diversity and structure, phylogeographic history, and diversification of a widespread Caatinga lizard (Cnemidophorus ocellifer) based on large geographical sampling for multiple loci to test the predictions derived from the RBH and PCH. We inferred two well-delimited lineages (Northeast and Southwest) that have diverged along the Cerrado-Caatinga border during the Mid-Late Miocene (6-14 Ma) despite the presence of gene flow. We reject both major hypotheses proposed to explain diversification in the Caatinga. Surprisingly, our results revealed a striking complex diversification pattern where the Northeast lineage originated as a founder effect from a few individuals located along the edge of the Southwest lineage that eventually expanded throughout the Caatinga. The Southwest lineage is more diverse, older and associated with the Cerrado-Caatinga boundaries. Finally, we suggest that C. ocellifer from the Caatinga is composed of two distinct species. Our data support speciation in the presence of gene flow and highlight the role of environmental gradients in the diversification process.

O relacionamento entre pessoas e serpentes no leste de Minas Gerais, sudeste do Brasil / The relationship between people and snakes in eastern Minas Gerais, southeastern Brazil

O conhecimento popular sobre as serpentes, incluindo as práticas adotadas em casos de acidentes ofídicos, foi abordado neste estudo etnozoológico realizado na região de Araponga e entorno da Serra do Brigadeiro, Mata Atlântica do Estado de Minas Gerais, região Sudeste do Brasil. Entre agosto e novembro de 2008 foram realizadas entrevistas com 50 moradores da zona rural de Araponga e 20 funcionários do Parque Estadual da Serra do Brigadeiro (PESB). Em relação ao perfil cultural e social, os grupos avaliados diferiram entre si somente quanto ao nível de escolaridade (maior entre os funcionários do parque), apresentando as mesmas distribuições em relação a idade e religião. Também se verificou menor nível de escolaridade entre os indivíduos mais velhos. Em geral, ambos os grupos de entrevistados demonstraram conhecimento adequado sobre prevenção e procedimentos em casos de acidente ofídico (78,2 por cento afirmaram procurar atendimento médico em caso de ofidismo). A utilização de substâncias da medicina popular para tratamento de acidentes ofídicos mostrou-se uma prática em desuso, relatada por aproximadamente 21 por cento dos entrevistados. A maioria dos entrevistados (57,14 por cento) afirmou não saber diferenciar uma serpente peçonhenta de uma não peçonhenta, e 66,67 por cento demonstraram reconhecer o período chuvoso como aquele com maior frequência no encontro com serpentes. O grupo "Araponga" mostrou-se mais hostil em relação a encontros com serpentes, com 43 por cento dos indivíduos afirmando matarem o animal, contra apenas 5 por cento do grupo "PESB". A escolaridade do entrevistado foi decisiva no tipo de atitude tomada diante das serpentes, sendo menos hostis os indivíduos mais instruídos. Pessoas com menos escolaridade apresentaram maior tendência a considerar todas as serpentes como perigosas, e estas se mostraram também mais hostis com estes animais. O maior contato com atividades científicas e educativo-ambientais parece ter sido decisivo para a maior tolerância com as serpentes por parte do grupo "PESB". A realização de atividades de educação-ambiental com a população das comunidades de Araponga pode ampliar a conscientização quanto à importância das serpentes, instruindo aqueles que ainda as consideram indiscriminadamente nocivas.

The popular knowledge about snakes, including the practices adopted in cases of snakebite, was analysed in this ethnozoological study performed in Araponga region and vicinities of Serra do Brigadeiro (Brigadeiro Mountain Range), Atlantic Forest of Minas Gerais state, southeastern Brazil. Between August and November 2008, interviews were conducted with 50 residents of rural areas of Araponga, and 20 employees of the Serra do Brigadeiro State Park (PESB). In relation to social and cultural profile, these two groups differed only on the level of education (higher among the park staff), with the same distributions for age and religion. There was also a lower level of education among older individuals, a possible reflection of improvements in the social conditions in that region, which would have provided greater access to schools in recent decades. In general, both groups demonstrated adequate knowledge about prevention and procedures in cases of snakebite (78.2 percent reported seeking medical attention in case of snakebite). The use of folk medicine for treatment of snakebite proved to be a practice falling into disuse, reported by approximately 21 percent of respondents. Most respondents (57.14 percent) said they did not know the difference between a poisonous and a non-poisonous snake, and 66.67 percent showed adequate knowledge of the season when snake encounters are more likely to happen. The "Araponga" group was more hostile concerning to possible encounters with snakes, with 43 percent of people saying they would kill the animal, against 5 percent in the "PESB" group. The educational level of the respondents was decisive in determining the kind of attitude taken against snakes, and those with higher levels of education showed to be the less hostile ones. People with lower educational levels were more likely to consider all snakes as dangerous, and they also proved to be more hostile to these animals. More contact with scientific and environmental education activities seems to have been decisive for the higher tolerance to snakes by the "PESB" group. The implementation of activities of environmental education for the population of Araponga can increase the awareness of the importance of snakes, instructing those who still consider them intrinsically harmful.