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Throughout the Plio-Pleistocene, climate change has impacted tropical marine ecosystems substantially, with even more severe impacts predicted in the Anthropocene. Although many studies have clarified demographic histories of seabirds in polar regions, the history of keystone seabirds of the tropics is unclear, despite the prominence of albatrosses (Diomedeidae, Procellariiformes) as the largest and most threatened group of oceanic seabirds. To understand the impact of climate change on tropical albatrosses, we investigated the evolutionary and demographic histories of all four North Pacific albatrosses and their prey using whole-genome analyses. We report a striking concordance in demographic histories among the four species, with a notable dip in effective population size at the beginning of the Pleistocene and a population expansion in the Last Glacial Period when sea levels were low, which resulted in increased potential coastal breeding sites. Abundance of the black-footed albatross dropped again during the Last Glacial Maximum, potentially linked to climate-driven loss of breeding sites and concordant genome-derived decreases in its major prey. We find very low genome-wide (π < 0.001) and adaptative genetic diversities across the albatrosses, with genes of the major histocompatibility complex close to monomorphic. We also identify recent selective sweeps at genes associated with hyperosmotic adaptation, longevity, and cognition and memory. Our study has shed light on the evolutionary and demographic histories of the largest tropical oceanic seabirds and provides evidence for their large population fluctuations and alarmingly low genetic diversities. [ABSTRACT FROM AUTHOR]

The responses of Anatolian plants to global climate change have been poorly investigated. In this study, we aimed to understand how climatic oscillation during the Quaternary period helped to shape the current distribution patterns of the Anatolian endemic Noccaea iberidea , a typical representative of tragacanthic (thorny cushion) steppe communities of Anatolia. We used ecological niche modelling combined with statistical phylogeography, based on nuclear ribosomal ITS and plastidic trnL-F and trnS-ycf9 regions. Both the structure of the haplotype networks and the results of the extended Bayesian skyline plot analysis clearly indicated that N. iberidea has been through a recent population expansion. This interpretation was also supported by ecological niche modelling analysis, which showed that the availability of areas of high suitability expanded from the Last Interglacial to the Last Glacial Maximum, suggesting that N. iberidea might have expanded its range during the glacial periods. In conclusion, the study improves our understanding of the demographic history and responses of steppe plant communities of Anatolia to global climate changes through the Late Quaternary glacial–interglacial cycles, which in turn might aid in the development of future conservation strategies. [ABSTRACT FROM AUTHOR]

Many species that occupy high latitudes of North America were historically restricted to relatively small refugia during the Last Glacial Maximum (LGM). The geographic ranges of many of these species then expanded widely across the continent after glacial ice receded. In contrast, species whose LGM distributions spanned lower (relatively ice-free) latitudes may have been less likely to experience demographic and geographic retraction during glacial periods, or expansion during interglacial periods. For example, species in North America's Intermountain West occupied a topographically complex landscape across which widespread patches of suitable habitat could have helped maintain a relatively stable range-wide effective population size even if local populations fluctuated in response to shifting climates. We test for these alternative demographic signals in southern versus northern species by comparing patterns of genetic diversity of the more southern yellow-bellied marmot (Marmota flaviventris) with those of the more northern hoary marmot (M. caligata). Our data reveal high diversity but no deep structure across the distribution of yellow-bellied marmots. In contrast, hoary marmots have previously been shown to exhibit a deep divergence between regional mitochondrial clades of relatively low diversity. We suggest that these differences reflect differences in habitat availability through time, with hoary marmots persistently isolated in small glacial refugia and yellow-bellied marmots more broadly distributed across the Intermountain West through both glacial and interglacial periods. Our results highlight the importance of historical patterns of habitat availability as key drivers of current genetic structure. [ABSTRACT FROM AUTHOR]