Aim Disentangling the effects of climate and historical factors on biodiversity distribution remains a challenge for biogeographers. Here, we provide an analytical framework to discriminate the contributions of contemporary climate and the biogeographical history of taxa to the geographical distributions of phylogenetic lineages. Furthermore, we evaluate the constraint that the biogeographical history of clades exerts on the association between climate and clade distribution, i.e. the historical legacy of climatic effects. As a case study, we analysed the distributions of amphibian lineages across the Americas. Location The Americas. Methods We tallied the number of amphibian species per genus in each of 262 ecoregions. Each ecoregion was described by the composition of phylogenetic lineages using phylogenetic fuzzy weighting. The composition of amphibian genera and phylogenetic clades represented the distributions of shallow and deep phylogenetic nodes, respectively. We characterized each ecoregion by the biogeographical history of amphibian taxa and its current climate, whose influences on shallow and deep phylogenetic nodes were analysed using variation partitioning analysis. Results The association between climate and the distributions of deep phylogenetic nodes showed a strong historical legacy, although the distribution of amphibian genera was mostly associated with climate. Hyloidea were associated with a Gondwanan origin and higher annual mean temperatures, whereas other clades (e.g. Caudata) were related to a Laurasian origin and higher temperature seasonality. Microhylidae were related to occurrence in the Early Jurassic in Gondwana and recent occurrence in the Neotropics. Main conclusions Biogeographical patterns can be thought of as the net outcome of evolutionary, historical and ecological processes. Although temperature is likely to affect the ecology of amphibians, the effects of climate on the distributions of deep phylogenetic nodes were strongly constrained by the biogeographical history of clades. Nevertheless, local, climatically driven processes are likely to influence the distributions of shallow phylogenetic nodes. The historical biogeography of clades might help to explain the interplay between evolutionary and environmental processes in determining assembly patterns found elsewhere.
ABSTRACT. We analyzed the alimentary tract of 66 specimens of Amphisbaena munoai Klappenbach, 1969 from the Serra do Sudeste, state of Rio Grande do Sul, southern Brazil. Forty specimens (60.6%) had prey items in their gut. The diet consisted mainly of small invertebrate prey, such as termites, insect larvae and ants. The most abundant prey item was termites, found in 62.5% of the non empty stomachs. The high number of individual prey items in the majority of stomachs, the small size of the regular prey items, and the absence of gut content in specimens of A. munoai kept alive for about two days, indicate that this species forages very frequently. The predominance of fossorial prey items and the occasional records of nomadic ants lead us to suggest that A. munoai usually feeds underground, and occasionally forages on the surface.KEYWORDS. Amphisbaena munoai, diet, feeding behavior, natural history, southern Brazil. RESUMO. Ecologia alimentar da pequena anfisbaena neotropical Amphisbaena munoai (Amphisbaenidae) no sul do Brasil.Analisamos o trato digestório de 66 exemplares de Amphisbaena munoai Klappenbach, 1969 procedentes da Serra do Sudeste do Rio Grande do Sul, Brasil. Quarenta espécimes (60,6%) possuíam presas. A dieta é composta basicamente de pequenos invertebrados, como térmitas, larvas de insetos e formigas. As presas mais abundantes foram térmitas, encontradas em 62,5% dos estômagos não vazios. O elevado número de presas em cada indivíduo na maioria dos estômagos, o tamanho pequeno de presas regulares e a ausência de itens alimentares em espécimes de A. munoai mantidas vivas por aproximadamente dois dias, indicam que está espécie é forrageadora freqüente. A predominância de itens alimentares fossórios e o encontro ocasional de formigas nômades nos permitem sugerir que A. munoai usualmente se alimenta abaixo da terra e ocasionalmente na superfície.
BackgroundWe evaluated the direct and indirect influence of climate, land use, phylogenetic structure, species richness and endemism on the distribution of New World threatened amphibians.Methodology/Principal FindingsWe used the WWF’s New World ecoregions, the WWFs amphibian distributional data and the IUCN Red List Categories to obtain the number of threatened species per ecoregion. We analyzed three different scenarios urgent, moderate, and the most inclusive scenario. Using path analysis we evaluated the direct and indirect effects of climate, type of land use, phylogenetic structure, richness and endemism on the number of threatened amphibians in New World ecoregions. In all scenarios we found strong support for direct influences of endemism, the cover of villages and species richness on the number of threatened species in each ecoregion. The proportion of wild area had indirect effects in the moderate and the most inclusive scenario. Phylogenetic composition was important in determining the species richness and endemism in each ecoregion. Climate variables had complex and indirect effects on the number of threatened species.Conclusion/SignificanceLand use has a more direct influence than climate in determining the distribution of New World threatened amphibians. Independently of the scenario analyzed, the main variables influencing the distribution of threatened amphibians were consistent, with endemism having the largest magnitude path coefficient. The importance of phylogenetic composition could indicate that some clades may be more threatened than others, and their presence increases the number of threatened species. Our results highlight the importance of man-made land transformation, which is a local variable, as a critical factor underlying the distribution of threatened amphibians at a biogeographic scale.
The red-bellied toads Melanophryniscus dorsalis and M. montevidensis are listed as vulnerable on the IUCN list. Uruguayan populations of M. montevidensis are no longer found near the southern limit of its distribution, and information on the ecology and distribution of both species is still needed. We are proposing consensus models and hotspot analysis to identify priority conservation areas for these toads. Here, we present a consensus model based on three algorithms that use presence-only data (BIOCLIM, GARP and Maximum Entropy). Through consensus models, we used a new OpenModeller implementation called "hotspot", which identifies areas of high environmental suitability. Our results indicated areas of high environmental suitability for both species. Fieldwork validation also indicated their absence from some high-suitability areas identified by the consensus and hotspot models. Five hotspot areas of great interest to preserve both species are proposed
Conservation of small mammals requires knowledge of the genetically and ecologically meaningful spatial scales at which species respond to habitat modifications. Conservation strategies can be improved through the use of ecological niche models and genetic data to classify areas of high environmental suitability. In this study, we applied a Maxent model integrated with genetic information (nucleotide diversity, haplotype diversity and Fu's Fs neutrality tests) to evaluate potential genetic pool populations with highly suitable areas for two parapatric endangered species of tuco-tucos (Ctenomys minutus and C. lami). Our results demonstrated that both species were largely influenced by vegetation and soil variables at a landscape scale and inhabit a highly specific niche. Ctenomys minutus was also influenced by the variable altitude; the species was associated with low altitudes (sea level). Our model of genetic data associated with environmental suitability indicate that the genetic pool data were associated with highly suitable areas for C. minutus. This pattern was not evident for C. lami, but this outcome could be a consequence of the restricted range of the species. The preservation of species requires not only detailed knowledge of their natural history and genetic structure but also information on the availability of suitable areas where species can survive, and such knowledge can aid significantly in conservation planning. This finding reinforces the use of these two techniques for planning conservation actions.
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