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Specimen‐based data have played a central role in documenting body‐size shifts as a possible response to global warming over the last century. Identification of the drivers and patterns of these trends requires comparisons across taxa, often through meta‐analyses; however, a lack of repeatability within and interoperability (i.e. the potential for a dataset to be augmented for future research) among published studies is a major obstacle.We reviewed published studies on mammal body‐size changes in the Anthropocene, focusing on those that used museum specimens to analyse body‐size trends over time in at least one species. We assessed these papers for repeatability and interoperability with the following criteria: raw data and specimen identifiers were published and accessible, measurements were unambiguously defined, and potential sex‐ and age‐based size differences among individuals were accounted for.Most published body‐size studies have low potential for replication or augmentation; only one of 27 met all of our criteria. Although these 27 papers collectively generated an estimated 51,790 new body‐size measurements, only 1.25% (649) could be repeated or readily used in further investigations, as the remainder did not include raw data and/or specimen identifiers.Based on these findings, we recommend the following best practices in the study of body‐size trends. First, authors should explicitly define and justify all measures of size and quantify measurement error and publish all data, including measurements and specimen catalogue numbers. In addition to complying with the fundamental scientific tenet of repeatability, this minimizes redundant handling and the concomitant risk of damage to irreplaceable and often fragile museum specimens. Second, authors should test and account for the effects of demography, as some dimensions can change throughout an individual's life. Adopting these practices will improve the quality of body‐size studies, enhance the utility of extended specimen data from natural history collections, and enable researchers to conduct more expansive investigations of size trends over time. [ABSTRACT FROM AUTHOR]

Ecologists have long debated the relative importance of biotic interactions versus species‐specific habitat preferences in shaping patterns of ecological dominance. In western North America, cycles of fire disturbance are marked by transitions between North American deermice (Peromyscus maniculatus), which predominate after wildfires, and southern red‐backed voles (Myodes gapperi), which gradually replace deermice 3–4 years postfire and maintain dominance as forests mature. While this shift has been frequently documented, the processes that mediate this turnover are debated. One possibility is competitive release, which predicts a reduction in vole competition may contribute to niche expansion and population growth in deermice. Alternatively, turnover in both species may be shaped by differences in their preferred habitat and resource base, as predicted by optimum foraging theory. We evaluate these hypotheses using stable isotopes and spatial mark–recapture of deermouse and vole populations sampled prior to and following a fire as part of a longitudinal study in the Greater Yellowstone Ecosystem. Fire disturbance was associated with a 94% decrease in vole abundance but a 102% increase in deermice. Even after accounting for microhabitat, vole and deermouse populations were negatively correlated spatially and temporally (R = −0.45), and competitor abundance was more important prefire than postfire. When vole abundance was high (prefire), vole dietary niche space was seven times broader than that of deermice. Postfire, deermouse dietary niche nearly tripled and was enriched in 13C (i.e., more C4 plants), while voles occupied a slightly reduced dietary niche (79% of prefire breadth). Our results suggest deermice are experiencing ecological release due to a reduction in vole competition but vole shifts are largely driven by habitat preferences. [ABSTRACT FROM AUTHOR]

Understanding the historical contributions of differing glacial refugia is key to evaluating the roles of microevolutionary forces, such as isolation, introgression, and selection in shaping genomic diversity in present‐day populations. In Europe, where both Mediterranean and extra‐Mediterranean (e.g., Carpathian) refugia of the bank vole (Clethrionomysglareolus) have been identified, mtDNA indicates that extra‐Mediterranean refugia were the main source of colonization across the species range, while Mediterranean peninsulas harbor isolated, endemic lineages. Here, we critically evaluate this hypothesis using previously generated genomic data (>6,000 SNPs) for over 800 voles, focusing on genomic contributions to bank voles in central Europe, a key geographic area in considering range‐wide colonization. The results provide clear evidence that both extra‐Mediterranean (Carpathian) and Mediterranean (Spanish, Calabrian, and Balkan) refugia contributed to the ancestry and genomic diversity of bank vole populations across Europe. Few strong barriers to dispersal and frequent admixture events in central Europe have led to a prominent mid‐latitude peak in genomic diversity. Although the genomic contribution of the centrally located Carpathian refugium predominates, populations in different parts of Europe have admixed origins from Mediterranean (28%–47%) and the Carpathian (53%–72%) sources. We suggest that the admixture from Mediterranean refugia may have provisioned adaptive southern alleles to more northern populations, facilitating the end‐glacial spread of the admixed populations and contributing to increased bank vole diversity in central Europe. This study adds critical details to the complex end‐glacial colonization history of this well‐studied organism and underscores the importance of genomic data in phylogeographic interpretation. [ABSTRACT FROM AUTHOR]

The history of repeated northern glacial cycling and southern climatic stability has long dominated explanations for how genetic diversity is distributed within temperate species in Eurasia and North America. However, growing evidence indicates the importance of cryptic refugia for northern colonization dynamics. An important geographic region to assess this is Fennoscandia, where recolonization at the end of the last glaciation was restricted to specific routes and temporal windows. We used genomic data to analyse genetic diversity and colonization history of the bank vole (Myodes glareolus) throughout Europe (>800 samples) with Fennoscandia as the northern apex. We inferred that bank voles colonized Fennoscandia multiple times by two different routes; with three separate colonizations via a southern land‐bridge route deriving from a "Carpathian" glacial refugium and one via a north‐eastern route from an "Eastern" glacial refugium near the Ural Mountains. Clustering of genome‐wide SNPs revealed high diversity in Fennoscandia, with eight genomic clusters: three of Carpathian origin and five Eastern. Time estimates revealed that the first of the Carpathian colonizations occurred before the Younger Dryas (YD), meaning that the first colonists survived the YD in Fennoscandia. Results also indicated that introgression between bank and northern red‐backed voles (Myodes rutilus) took place in Fennoscandia just after end‐glacial colonization. Therefore, multiple colonizations from the same and different cryptic refugia, temporal and spatial separations and interspecific introgression have shaped bank vole genetic variability in Fennoscandia. Together, these processes drive high genetic diversity at the apex of the northern expansion in this emerging model species. [ABSTRACT FROM AUTHOR]

In their paper entitled "Course-based undergraduate research to advance environmental education, science, and resource management", Messager I et al i . By introducing real-world data collected by students across a broad geographic range into classrooms, educators can expand not only how our students interpret and understand ecological data, but also the degree to which those data may inform them about the world around us. We would like to highlight other opportunities provided by several recently developed CURE networks that offer resources for collecting ecological data in undergraduate courses, efficiently assimilating and disseminating course data, and supporting instructors in these endeavors. [Extracted from the article]

Aim: Quantitatively evaluate the similarity of genomic variation and geography in five different alpine small mammals in Alaska, and use this quantitative assessment of concordance as a framework for refining hypotheses about the processes structuring population genetic variation in either a species-specific or shared manner. Location: Alaska and adjacent north-western Canada. Methods: For each taxon we generated 3500-7500 single-nucleotide polymorphisms and applied a Procrustes analysis to find an optimal transformation that maximizes the similarity between principal components analysis maps of genetic variation and geographical maps of sample locations. We generate stability maps using projected distributions from ecological niche models of the Last Glacial Maximum and the present. Results: Significant similarity between genes and geography exists across taxa. However, the extent to which geography is predictive of patterns of genetic variation not only differs among taxa, but the correspondence between genes and geography varies over space. Geographical areas where genetic structure aligns poorly with the geographical coordinates are of particular interest because they indicate regions where processes other than isolation by distance (IBD) have influenced genetic variation. The clustering of individuals according to their sample location does not support suppositions of admixture, despite the presumed high vagility of some species (e.g. arctic ground squirrels). Main conclusions: Genomic data indicate a more nuanced biogeographical history for the taxa than suggested by previous studies based on mtDNA alone. These include departures from IBD that are shared among taxa, which suggest some shared processes structuring genetic variation, including new potential ancestral source populations. In addition, some regions fit expectations of IBD where incremental migration and gene flow play a strong role in population structure, despite any ecological difference among taxa. Differences in dispersal capabilities do not result in different species-specific local patterns of population structure, at least at the sampling scale examined here. We highlight how the general fit to, as well as departures from, expectations for patterns of genetic variation based on the Procrustes analyses can be used to generate hypotheses about the underlying processes. [ABSTRACT FROM AUTHOR]

Identifying the genetic structure of a species and the factors that drive it is an important first step in modern population management, in part because populations evolving from separate ancestral sources may possess potentially different characteristics. This is especially true for climate-sensitive species such as pikas, where the delimitation of distinct genetic units and the characterization of population responses to contemporary and historical environmental pressures are of particular interest. We combined a restriction site-associated DNA sequencing ( RADSeq) data set containing 4156 single nucleotide polymorphisms with ecological niche models ( ENMs) of present and past habitat suitability to characterize population composition and evaluate the effects of historical range shifts, contemporary climates and landscape factors on gene flow in Collared Pikas, which are found in Alaska and adjacent regions of northwestern Canada and are the lesser-studied of North America's two pika species. The results suggest that contemporary environmental factors contribute little to current population connectivity. Instead, genetic diversity is strongly shaped by the presence of three ancestral lineages isolated during the Pleistocene (~148 and 52 kya). Based on ENMs and genetic data, populations originating from a northern refugium experienced longer-term stability, whereas both southern lineages underwent population expansion - contradicting the southern stability and northern expansion patterns seen in many other taxa. Current populations are comparable with respect to generally low diversity within populations and little-to-no recent admixture. The predominance of divergent histories structuring populations implies that if we are to understand and manage pika populations, we must specifically assess and accurately account for the forces underlying genetic similarity. [ABSTRACT FROM AUTHOR]

Aim To understand the relative importance of ecological and historical factors in structuring terrestrial vertebrate assemblages across the Australian arid zone, and to contrast patterns of community phylogenetic structure at a continental scale. Location Australia. Methods We present evidence from six lineages of terrestrial vertebrates (five lizard clades and one clade of marsupial mice) that have diversified in arid and semi-arid Australia across 37 biogeographical regions. Measures of within-lineage community phylogenetic structure and species turnover were computed to examine how patterns differ across the continent and between taxonomic groups. These results were examined in relation to climatic and historical factors, which are thought to play a role in community phylogenetic structure. Analyses using a novel sliding-window approach confirm the generality of processes structuring the assemblages of the Australian arid zone at different spatial scales. Results Phylogenetic structure differed greatly across taxonomic groups. Although these lineages have radiated within the same biome - the Australian arid zone - they exhibit markedly different community structure at the regional and local levels. Neither current climatic factors nor historical habitat stability resulted in a uniform response across communities. Rather, historical and biogeographical aspects of community composition (i.e. local lineage persistence and diversification histories) appeared to be more important in explaining the variation in phylogenetic structure. While arid-zone assemblages show an overall tendency towards phylogenetic clustering, this pattern was less pronounced at finer spatial scales. Main conclusions By focusing within different taxonomic groups and between those groups within regions, we show that although the vertebrate lineages we examined exhibited high diversity and low turnover across the arid zone, the underlying phylogenetic structure differs between regions and taxonomic groups, suggesting that taxon-specific histories are more important than habitat stability in determining patterns of phylogenetic community relatedness. [ABSTRACT FROM AUTHOR]

Aim Pikas ( Ochotona spp.) are alpine specialists that show considerable morphological and genetic variation structured along latitudinal and elevational gradients. Recent studies of North American and Asian pikas have uncovered phylogeographical partitioning among separate mountain ranges and drainages, driven by Quaternary climate fluctuations. We tested the prediction that collared pikas ( O. collaris) exhibit lower genetic diversity and less structure than other species of pika due to lower long-term habitat stability. Location Eastern Beringia ( Alaska and north-western Canada). Methods We examined phylogeographical variation in the collared pika ( O. collaris) throughout much of its known range using the mitochondrial cytochrome b gene. Population divergence and genetic diversity were compared within and between mountain ranges. Genetic diversity was contrasted with current and Pleistocene habitat fragmentation inferred from ecological niche models. Results Low but significant differentiation was evident between most populations of O. collaris, with little haplotype sharing among populations and a single phylogeographical break separating a genetically distinct haplogroup in the south-eastern part of its range. Variation was mostly structured within populations (as opposed to between populations or mountain ranges). When within-species nucleotide diversity in O. collaris, O. princeps and O. curzoniae was compared, genetic diversity was found to decline with increasing latitude. Main conclusions Populations of O. collaris are less geographically structured and exhibit less variability than populations of either O. princeps or O. curzoniae. This pattern is better explained by the amount of available Pleistocene habitat predicted for each species than by current predicted habitat or population discontinuity. Collared pikas are currently considered to be a common species at low risk of extinction, but their habitat specificity, population subdivision, and low genetic variation may have consequences for their continued viability in a warming world. [ABSTRACT FROM AUTHOR]

Aim  Pleistocene climatic cycles have left marked signatures in the spatial and historical genetic structure of high-latitude organisms. We examine the mitochondrial (cytochrome b) genetic structure of the singing vole, Microtus miurus (Rodentia: Cricetidae: Arvicolinae), a member of the Pleistocene Beringian fauna, and of the insular vole, Microtus abbreviatus, its putative sister species found only on the St Matthew Archipelago. We reconstruct the phylogenetic and phylogeographical structure of these taxa, characterize their geographical partitioning and date coalescent and cladogenetic events in these species. Finally, we compare the recovered results with the phylogenetic, coalescent and spatial genetic patterns of other eastern Beringian mammals and high-latitude arvicoline rodents. Location  Continental Alaska (alpine and arctic tundra) and the St Matthew Archipelago (Bering Sea). Methods  We generated and analysed cytochrome b sequences of 97 singing and insular voles ( M. miurus and M. abbreviatus) from Alaska. Deep evolutionary structure was inferred by phylogenetic analysis using parsimony, maximum likelihood and Bayesian approaches; the geographical structure of genetic diversity was assessed using analysis of molecular variance and network analysis; ages of cladogenetic and coalescent events were estimated using a relaxed molecular clock model with Bayesian approximation. Results  Regional nucleotide diversity in singing voles is higher than in other high-latitude arvicoline species, but intra-population diversity is within the observed range of values for arvicolines. Microtus abbreviatus specimens are phylogenetically nested within M. miurus. Molecular divergence date estimates indicate that current genetic diversity was formed in the last glacial (Wisconsinan) and previous interglacial (Sangamonian) periods, with the exception of a Middle Pleistocene split found between samples collected in the Wrangell Mountains region and all other singing vole samples. Main conclusions  High levels of phylogenetic and spatial structure are observed among analysed populations. This pattern is consistent with that expected for a taxon with a long history in Beringia. The spatial genetic structure of continental singing voles differs in its northern and southern ranges, possibly reflecting differences in habitat distribution between arctic and alpine tundra. Our phylogenetic results support the taxonomic inclusion of M. miurus in its senior synonym, M. abbreviatus. [ABSTRACT FROM AUTHOR]