Clinton Hart Merriam

Abstract The Montane Shrew, Sorex monticola, is a common and wide-ranging mammal throughout western North America. Previous studies identified multiple mitochondrial lineages, but limited geographic sampling constrained our understanding of distributional limits, phylogeographic variation, and biogeographic history. We used range-wide sampling and multi-model phylogenetic analyses to examine mitochondrial phylogeographic variation, evaluate niche differentiation, and test historical biogeographic hypotheses. We examined cytochrome b gene sequences from 462 individuals and 277 localities across the distribution of S. monticola and related species, including the first specimens from the Sierra Nevada (California, United States) and Sierra Madre Occidental (Durango and Chihuahua, Mexico). Estimated genealogical relationships, divergence times, and delimitation approaches identified 3 well-supported, deeply divergent, geographically structured clades consistent with previous estimates (Coastal, Southern, Northern). Sorex monticola was paraphyletic with S. sonomae and all species of North American water shrews. We also identified minimal divergence between Coastal S. monticola and 2 nominal species, S. pacificus and S. bairdii, that are sympatric in the Pacific Northwest. Demographic tests indicated that some lineages represent stable and isolated island and montane populations, while others represent populations that experienced demographic expansion since the Last Glacial Maximum. Niche differentiation tests revealed that each clade occupies distinctive environmental conditions, with projections of future conditions suggesting that populations isolated in southern mountains may face extirpation associated with warming climate and aridification. This range-wide assessment of geographic genetic variation lays a foundation for selecting samples from key populations for expanded genome-level investigations into evolutionary relationships and taxonomic limits, enabling tests of hypotheses related to Pleistocene climatic drivers of biotic diversification processes across western North America.

Distributions of plants are expected to change in response to climate change, but the relative probability of that change is often unknown. Curl-leaf mountain mahogany (Cercocarpus ledifolius), an important browse species used by ungulates as forage and cover across the western US, is thought to be moderately to highly vulnerable to climate change this century, and a reduction in curl-leaf mountain mahogany occurrence may negatively impact ungulates reliant upon it. A combination of probability density estimation and vector analysis was used to predict curl-leaf mountain mahogany distribution across the species range relative to climate space and how that relationship would affect curl-leaf mountain mahogany at a local scale. Locally, we used the curl-leaf mountain mahogany population at the Bighorn Canyon National Recreation Area (BICA) in Montana and Wyoming for comparison. We modeled the probability of curl-leaf mountain mahogany occurrence across its distribution using water balance data to spatially and temporally assess the vulnerability of a population at a local scale. Modeled probabilities of occurrence and vector analysis indicated the species to remain in some areas within BICA but will be vulnerable in others given the predicted changes in temperature and precipitation in BICA if historical trajectories continue. This information allows managers to direct limited resources to other management actions by using the best available science to inform decisions. Other curl-leaf mountain mahogany populations currently inhabiting wetter, drier sites may follow a similar trajectory as the effects of climate change manifest. The approach used serves as a model to assess the predicted trend for species-specific plant communities of concern that may be adversely affected by climate change.

The need for renewable energy has become increasingly evident in response to the climate change crisis, presenting a paradoxical challenge to biodiversity conservation. The Southwest United States is desirable for large-scale solar energy development (SED) due to its high global horizontal irradiance (GHI) values and vast open landscapes. However, this region is also rich in unique ecological and biological diversity. Several distinct species have garnered special attention as human population growth, habitat alteration, and climate change have accelerated in recent decades (i.e., LeConte’s Thrasher (Toxostoma lecontei), Bendire’s Thrasher (Toxostoma bendirei), Sonoran Desert Tortoise (Gopherus morafkai), Mojave Desert Tortoise (Gopherus agassizii), and the Southwestern population of the Burrowing Owl (Athene cunicularia). As the United States prepares to increase its development in renewable energies, particularly solar energy, there has been a growing concern about how this development will further impact these species. In this study, we propose a novel combined approach to find areas of high habitat suitability for endangered species within areas of high SED potential. Specifically, we employed species distribution modeling (SDM) to identify areas with suitable habitats and likely species presence, and we conducted a site suitability analysis for potential SED locations within the Southwest. As a result, we found significant overlap between potential SED locations and the high-priority habitats of all target species, thus underlining the importance of prioritizing conservation efforts as more solar projects are reviewed in these Southwestern states. Our study aims to inform conservationists and developers in making sustainable decisions for the region’s future development.

Acanthotomicus suncei is a newly discovered bark beetle in China that significantly threatens the American sweetgum Liquidambar styraciflua. In recent years, this pest has spread from its original habitat to many surrounding cities, causing substantial economic and ecological losses. Considering the wide global distribution of its host, Liquidambar styraciflua, this pest is likely to continue to spread and expand. Once the pest colonizes a new climatically suitable area, the consequences could be severe. Therefore, we employed the CLIMEX and Random Forests model to predict the potential suitable distribution of A. suncei globally. The results showed that A. suncei was mainly distributed in Southern China, in South Hokkaido in Japan, Southern USA, the La Plata Plain in South America, southeastern Australia, and the northern Mediterranean; these areas are located in subtropical monsoon, monsoonal humid climates, or Mediterranean climate zones. Seasonal rainfall, especially in winter, is a key environmental factor that affects the suitable distribution of A. suncei. Under future climates, the total suitable area of A. suncei is projected to decrease to a certain extent. However, changes in its original habitat require serious attention. We found that A. suncei exhibited a spreading trend in Southwest, Central, and Northeast China. Suitable areas in some countries in Southeast and South Asia bordering China are also expected to show an increased distribution. The outward spread of this pest via sea transportation cannot be ignored. Hence, quarantine efforts should be concentrated in high-suitability regions determined in this study to protect against the occurrence of hosts that may contain A. suncei, thereby avoiding its long-distance spread. Long-term sentinel surveillance and control measures should be carried out as soon as A. suncei is detected, especially in regions with high suitability. Thus, our findings establish a theoretical foundation for quarantine and control measures targeting A. suncei.

AbstractPremiseTo survive climate change and habitat loss, plants must rely on phenotypic changes in response to the environment, local adaptation, or migration. Understanding the drivers of intraspecific variation is critical to anticipate how plant species will respond to climate change and to inform conservation decisions. Here we explored the extent of local adaptation and phenotypic plasticity in Heteromeles arbutifolia, toyon, a species endemic to the California Floristic Province.MethodsWe collected leaves from 286 individuals across toyon's range and used seeds from 37 individuals to establish experimental gardens in the northern and southern parts of toyon's range. We measured leaf functional traits of the wild‐collected leaves and functional and fitness traits of the offspring grown in the experimental gardens. We then investigated the relationships between traits and source environment.ResultsMost traits we investigated responded plastically to the environment, and some traits in young seedlings were influenced by maternal effects. We found strong evidence that variation in leaf margins is a result of local adaptation to variation in temperature and temperature range. However, the source environment was not related to fitness traits or survival in the experimental gardens.ConclusionsOur findings reiterate the adaptive role of toothed leaf margins in colder and more seasonally variable environments. Additionally, we provide evidence that fitness of toyon is not dependent on where they are sourced, and thus toyon can be sourced across its range for restoration purposes.

Abstract After many decades of effective control of stem rust caused by the Puccinia graminis f.sp. tritici, (hereafter Pgt) the reported emergence of race TTKSK/Ug99 of Pgt in Uganda reignited concerns about epidemics worldwide because ∼90% of world wheat cultivars had no resistance to the new race. Since it was initially detected in Uganda in 1998, Ug99 variants have now been identified in thirteen countries in Africa and the Middle East. Stem rust has been a major problem in the past, and concern is increasing about the risk of return to Central and East Asia. Whilst control programs in North America and Europe relied on the use of resistant cultivars in combination with eradication of barberry (Berberis spp.), the alternate host required for the stem rust pathogen to complete its full lifecycle, the focus in East Asia was principally on the use of resistant wheat cultivars. Here, we investigate potential airborne transmission pathways for stem rust outbreaks in the Middle East to reach East Asia using an integrated modelling framework combining estimates of fungal spore deposition from an atmospheric dispersion model, environmental suitability for spore germination, and crop calendar information. We consider the role of mountain ranges in restricting transmission pathways, and we incorporate a representation of a generic barberry species into the lifecycle. We find viable transmission pathways to East Asia from the Middle East to the north via Central Asia and to the south via South Asia and that an initial infection in the Middle East could persist in East Asia for up to three years due to the presence of the alternate host. Our results indicate the need for further assessment of barberry species distributions in East Asia and appropriate methods for targeted surveillance and mitigation strategies should stem rust incidence increase in the Middle East region.

We assessed changes in fundamental climate‐niche space for lizard and snake species in western North America under modeled climate scenarios to inform natural resource managers of possible shifts in species distributions. We generated eight distribution models for each of 130 snake and lizard species in western North America under six time‐by‐climate scenarios. We combined the highest‐performing models per species into a single ensemble model for each scenario. Maps were generated from the ensemble models to depict climate‐niche space for each species and scenario. Patterns of species richness based on climate suitability and niche shifts were calculated from the projections at the scale of the entire study area and individual states and provinces, from Canada to Mexico. Squamate species' climate‐niche space for the recent‐time climate scenario and published known ranges were highly correlated (r = 0.81). Overall, reptile climate‐niche space was projected to move northward in the future. Sixty‐eight percent of species were projected to expand their current climate‐niche space rather than to shift, contract, or remain stable. Only 8.5% of species were projected to lose climate‐niche space in the future, and these species primarily occurred in Mexico and the southwestern U.S. We found few species were projected to lose all suitable climate‐niche space at the state or province level, although species were often predicted to occupy novel areas, such as at higher elevations. Most squamate species were projected to increase their climate‐niche space in future climate scenarios. As climate niches move northward, species are predicted to cross administrative borders, resulting in novel conservation issues for local landowners and natural resource agencies. However, information on species dispersal abilities, landscape connectivity, biophysical tolerances, and habitat suitability is needed to contextualize predictions relative to realized future niche expansions.

Coniferous forests are under severe threat of the rapid anthropogenic climate warming. Abies (firs), the fourth‐largest conifer genus, is a keystone component of the boreal and temperate dark‐coniferous forests and harbors a remarkably large number of relict taxa. However, the uncertainty of the phylogenetic and biogeographic history of Abies significantly impedes our prediction of future dynamics and efficient conservation of firs. In this study, using 1,533 nuclear genes generated from transcriptome sequencing and a complete sampling of all widely recognized species, we have successfully reconstructed a robust phylogeny of global firs, in which four clades are strongly supported and all intersectional relationships are resolved, although phylogenetic discordance caused mainly by incomplete lineage sorting and hybridization was detected. Molecular dating and ancestral area reconstruction suggest a Northern Hemisphere high‐latitude origin of Abies during the Late Cretaceous, but all extant firs diversified during the Miocene to the Pleistocene, and multiple continental and intercontinental dispersals took place in response to the late Neogene climate cooling and orogenic movements. Notably, four critically endangered firs endemic to subtropical mountains of China, including A. beshanzuensis, A. ziyuanensis, A. fanjingshanensis and A. yuanbaoshanensis from east to west, have different origins and evolutionary histories. Moreover, three hotspots of species richness, including western North America, central Japan, and the Hengduan Mountains, were identified in Abies. Elevation and precipitation, particularly precipitation of the coldest quarter, are the most significant environmental factors driving the global distribution pattern of fir species diversity. Some morphological traits are evolutionarily constrained, and those linked to elevational variation (e.g., purple cone) and cold resistance (e.g., pubescent branch and resinous bud) may have contributed to the diversification of global firs. Our study sheds new light on the spatiotemporal evolution of global firs, which will be of great help to forest management and species conservation in a warming world.

Aim We examined range‐wide genetic variation in a widespread white oak species in western North America to determine phylogeographic patterns (including possible latitudinal gradients) and investigate their underlying causes.LocationWestern North America.TaxonQuercus garryana (Fagaceae).MethodsWe sampled Q. garryana at 117 locations throughout its range and related species of white oaks in 8 additional populations. We sequenced DNA from four variable intergenic plastid spacers and the ribosomal nuclear ITS region. We constructed haplotype networks and phylogenetic trees, mapped the geographical distributions of plastid haplotypes, and analysed genetic diversity patterns.ResultsWe identified 25 plastid haplotypes that clustered in two major groups, each showing pronounced genetic variation with latitude. In contrast, ITS showed little or no geographical or phylogenetic variation. Quercus garryana shared several plastid haplotypes with related white oaks and was not differentiated from these species by ITS. Plastid haplotype diversity in Q. garryana was highest in the central part of its range and sharply reduced to the north. Two haplotypes (one from each haplotype group) occurred in the northern third of the range, with only one at the northern range limit. Populations at the southern range limit were characterised by distinct haplotypes.Main ConclusionsGenetic patterns of Q. garryana have been shaped both by post‐Pleistocene climate change, interacting with features of the landscape, and by hybridisation with other white oaks. The species contains substantial genetic variation with strong spatial structuring of plastid haplotypes, indicating (1) early divergence of southern (Sierra Nevada) and northern populations, and (2) northward dispersal during the Holocene resulting in greatly reduced genetic diversity in its northern range. Species that can adjust their ranges with changing climates may remain susceptible to loss of genetic variation, potentially affecting their ability to persist in novel conditions at northern range margins.

Myotis is the most diverse genus of bats in Central America, with 10 species currently reported for Guatemala. Here, we present the first record of M. volans (H. Allen, 1866), and third record of M. auriculus Baker & Stains, 1955 in Guatemala, both from the cloud forest of the highlands of Sierra de las Minas Biosphere Reserve. This new locality may serve as one of the southernmost habitats akin to North American ecosystems for these two species. Our record of M. volans increases the number of bats in Guatemala to 105. Our findings underscore the importance of further research to understand patterns of biodiversity in Guatemala and Central America.