Predicting the future of threatened birds from a Neotropical ecotone area.

Climate change affects ecosystems in different ways. These effects are particularly worrying in the Neotropical region, where species are most vulnerable to these changes because they live closer to their thermal safety limits. Thus, establishing conservation priorities, particularly for the definition of protected areas (PAs), is a priority. However, some PA systems within the Neotropics are ineffective even under the present environmental conditions. Here, we test the effectiveness of a PA system, within an ecotone in northern Brazil, in protecting 24 endangered bird species under current and future (RCP8.5) climatic scenarios. We used species distribution modeling and dispersal corridor modeling to describe the priority areas for conservation of these species. Our results indicate that several threatened bird taxa are and will potentially be protected (i.e., occur within PAs). Nonetheless, the amount of protected area is insufficient to maintain the species in the ecotone. Moreover, most taxa will probably present drastic declines in their range sizes; some are even predicted to go globally extinct soon. Thus, we highlight the location of a potentially effective system of dispersal corridors that connects PAs in the ecotone. We reinforce the need to implement public policies and raise public awareness to maintain PAs and mitigate anthropogenic effects within them, corridors, and adjacent areas, aiming to conserve the richness and diversity of these already threatened species.

Discordant patterns of introgression across a narrow hybrid zone between two cryptic lineages of an Iberian endemic newt.

The study of natural hybrid zones can illuminate aspects of lineage divergence and speciation in morphologically cryptic taxa. We studied a hybrid zone between two highly divergent but morphologically similar lineages (south-western and south-eastern) of the Iberian endemic Bosca's newt (Lissotriton boscai) in SW Iberia with a multilocus dataset (microsatellites, nuclear and mitochondrial genes). STRUCTURE and NEWHYBRIDS analyses retrieved few admixed individuals, which classified as backcrosses involving parental individuals of the south-western lineage. Our results show asymmetric introgression of mtDNA beyond the contact from this lineage into the south-eastern lineage. Analysis of nongeographic introgression patterns revealed asymmetries in the direction of introgression, but except for mtDNA, we did not find evidence for nonconcordant introgression patterns across nuclear loci. Analysis of a 150-km transect across the hybrid zone showed broadly coincident cline widths (ca. 3.2-27.9 km), and concordant cline centres across all markers, except for mtDNA that is displaced ca. 60 km northward. Results from ecological niche modelling show that the hybrid zone is in a climatically homogenous area with suitable habitat for the species, suggesting that contact between the two lineages is unlikely to occur further south as their distributions are currently separated by an extensive area of unfavourable habitat. Taken together, our findings suggest the genetic structure of this hybrid zone results from the interplay of historical (biogeographic) and population-level processes. The narrowness and coincidence of genetic clines can be explained by weak selection against hybrids and reflect a degree of reproductive isolation that is consistent with cryptic speciation.

A dynamic continental moisture gradient drove Amazonian bird diversification.

The Amazon is the primary source of Neotropical diversity and a nexus for discussions on processes that drive biotic diversification. Biogeographers have focused on the roles of rivers and Pleistocene climate change in explaining high rates of speciation. We combine phylogeographic and niche-based paleodistributional projections for 23 upland terra firme forest bird lineages from across the Amazon to derive a new model of regional biological diversification. We found that climate-driven refugial dynamics interact with dynamic riverine barriers to produce a dominant pattern: Older lineages in the wetter western and northern parts of the Amazon gave rise to lineages in the drier southern and eastern parts. This climate/drainage basin evolution interaction links landscape dynamics with biotic diversification and explains the east-west diversity gradients across the Amazon.

Delimiting priority areas for the conservation of endemic and threatened Neotropical birds using a niche-based gap analysis.

Knowledge of spatiotemporal distribution of biodiversity is still very incomplete in the tropics. This is one of the major problems preventing the assessment and effectiveness of conservation actions. Mega-diverse tropical regions are being exposed to fast and profound environmental changes, and the amount of resources available to describe the distribution of species is generally limited. Thus, the tropics is losing species at unprecedented rates, without a proper assessment of its biodiversity. Species distribution models (SDMs) can be used to fill such biogeographic gaps within a species' range and, when allied with systematic conservation planning (e.g. analyses of representativeness, gap analysis), help transcend such data shortage and support practical conservation actions. Within the Neotropics, eastern Amazon and northern Cerrado present a high variety of environments and are some of the most interesting ecotonal areas within South America, but are also among the most threatened biogeographic provinces in the world. Here, we test the effectiveness of the current system of Protected Areas (PAs), in protecting 24 threatened and endemic bird species using SDMs. We found that taxa with wider distributions are potentially as protected as taxa with smaller ranges, and larger PAs were more efficient than smaller PAs, while protecting these bird species. Nonetheless, Cerrado PAs are mostly misallocated. We suggest six priority areas for conservation of Neotropical birds. Finally, we highlight the importance of indigenous lands in the conservation of Neotropical biodiversity, and recommend the development of community management plans to conserve the biological resources of the region.

Molecular evidence for cryptic candidate species in Iberian Pelodytes (Anura, Pelodytidae).

Species delineation is a central topic in evolutionary biology, with current efforts focused on developing efficient analytical tools to extract the most information from molecular data and provide objective and repeatable results. In this paper we use a multilocus dataset (mtDNA and two nuclear markers) in a geographically comprehensive population sample across Iberia and Western Europe to delineate candidate species in a morphologically cryptic species group, Parsley frogs (genus Pelodytes). Pelodytes is the sole extant representative of an ancient, historically widely distributed anuran clade that currently includes three species: P. caucasicus in the Caucasus; P. punctatus in Western Europe, from Portugal to North-Western Italy; and P. ibericus in Southern Iberia. Phylogenetic analyses recovered four major well-supported haplotype clades in Western Europe, corresponding to well demarcated geographical subdivisions and exhibiting contrasting demographic histories. Splitting times date back to the Plio-Pleistocene and are very close in time. Species-tree analyses recovered one of these species lineages, corresponding to P. ibericus (lineage B), as the sister taxon to the other three major species lineages, distributed respectively in: western Iberian Peninsula, along the Atlantic coast and part of central Portugal (lineage A); Central and Eastern Spain (lineage C); and North-eastern Spain, France and North-western Italy (lineage D). The latter is in turn subdivided into two sub-clades, one in SE France and NW Italy and the other one from NE Spain to NW France, suggesting the existence of a Mediterranean-Atlantic corridor along the Garonne river. An information theory-based validation approach implemented in SpedeSTEM supports an arrangement of four candidate species, suggesting the need for a taxonomic revision of Western European Pelodytes.

Cryptic patterns of diversification of a widespread Amazonian woodcreeper species complex (Aves: Dendrocolaptidae) inferred from multilocus phylogenetic analysis: implications for historical biogeography and taxonomy.

Inferring evolutionary relationships between recently diverged taxa is still challenging, especially taking into account the likely occurrence of incomplete lineage sorting and/or introgression. The Xiphorhynchus pardalotus/ocellatus species complex includes between two to three polytypic species and eight to nine subspecies distributed throughout most of lowland Amazonia and the foothills of the eastern Andes. To understand its historical diversification and address the main unsettled issues of phylogenetic relationships and taxonomy, we apply several approaches using data from two mitochondrial (Cyt b and ND2) and three nuclear genes (ß-fibint7, CPZint3 and CRYAAint1) for all described species and most subspecies of this complex. We compared single gene trees with a multilocus concatenated tree and Bayesian species tree inferred under a coalescent framework ((*)BEAST). Our results showed a general pattern of incongruence among gene trees and multilocus trees. Despite of this, the coalescent-based species tree analysis supports the sister-taxa relationship of X. ocellatus and X. chunchotambo, while X. pardalotus comes out as the basal taxon. With exception of the last, our results revealed within both X. ocellatus and X. chunchotambo high levels of genetic differentiation (p-distances 0.5-5.5%) with well-supported lineages. Our phylogenetic analyses showed several incongruences with current subspecies taxonomy, revealing that X. o. ocellatus is paraphyletic relative to X. o. perplexus, and the currently recognized subspecies X. c. napensis corresponds to two distinct evolutionary lineages, which are not supported as sister-lineages. In addition, the deep level of genetic divergence between X. o. beauperthuysii and the extant subspecies of X. ocellatus is more consistent with species-level differences found in this complex. Divergence time estimates were consistent with a historical scenario of intense population subdivision and speciation during the Early-mid Pleistocene. The spatial pattern and timing of diversification overlap broadly with that reported for other Amazonian vertebrate lineages.