Impacts of climate change and habitat loss on the distribution of the endangered crested capuchin monkey (Sapajus robustus).

The crested capuchin monkey (Sapajus robustus) is endemic to the Atlantic Forest and its transition areas within Cerrado in Brazil. The species is currently threatened by habitat loss and has been classified as endangered by the IUCN Red List of Threatened Species since 2015. We used ecological niche models built with MaxEnt to predict the potential impact of climate change on the distribution of this species. The models were projected onto the reference climate, considering six climate scenarios (three Global Climate Models and two Representative Concentration Pathways) from IPCC for 2050 and 2070. We showed that while the amount of suitable area is expected to change little across the species' range in most evaluated climate scenarios, climatic conditions may significantly deteriorate by 2070 in the pessimistic scenario, especially in currently warmer and dryer areas to the west. As seen on other capuchin monkeys, the potential use of tools by crested capuchins may increase the chances of the species adaptation to novel harsher environmental conditions. The major negative impacts across the species range also include habitat loss and fragmentation so that the conservation of the species relies on the protection of the forest remnants in the center of its distribution, which can harbor populations of the species in current and future climate scenarios.

Genotyping-by-sequencing and ecological niche modeling illuminate phylogeography, admixture, and Pleistocene range dynamics in quaking aspen (Populus tremuloides).

Populus tremuloides is the widest-ranging tree species in North America and an ecologically important component of mesic forest ecosystems displaced by the Pleistocene glaciations. Using phylogeographic analyses of genome-wide SNPs (34,796 SNPs, 183 individuals) and ecological niche modeling, we inferred population structure, ploidy levels, admixture, and Pleistocene range dynamics of P. tremuloides, and tested several historical biogeographical hypotheses. We found three genetic lineages located mainly in coastal-Cascades (cluster 1), east-slope Cascades-Sierra Nevadas-Northern Rockies (cluster 2), and U.S. Rocky Mountains through southern Canadian (cluster 3) regions of the P. tremuloides range, with tree graph relationships of the form ((cluster 1, cluster 2), cluster 3). Populations consisted mainly of diploids (86%) but also small numbers of triploids (12%) and tetraploids (1%), and ploidy did not adversely affect our genetic inferences. The main vector of admixture was from cluster 3 into cluster 2, with the admixture zone trending northwest through the Rocky Mountains along a recognized phenotypic cline (Utah to Idaho). Clusters 1 and 2 provided strong support for the "stable-edge hypothesis" that unglaciated southwestern populations persisted in situ since the last glaciation. By contrast, despite a lack of clinal genetic variation, cluster 3 exhibited "trailing-edge" dynamics from niche suitability predictions signifying complete northward postglacial expansion. Results were also consistent with the "inland dispersal hypothesis" predicting postglacial assembly of Pacific Northwestern forest ecosystems, but rejected the hypothesis that Pacific-coastal populations were colonized during outburst flooding from glacial Lake Missoula. Overall, congruent patterns between our phylogeographic and ecological niche modeling results and fossil pollen data demonstrate complex mixtures of stable-edge, refugial locations, and postglacial expansion within P. tremuloides. These findings confirm and refine previous genetic studies, while strongly supporting a distinct Pacific-coastal genetic lineage of quaking aspen.