Abstract Climate change responds to, and in turn modifies, trends in the Earth's top-of-atmosphere albedo. These trends are caused in particular by anthropogenic aerosol-radiation and aerosol-cloud interactions, as well as by non-aerosol feedbacks involving cloudiness and surface albedo. Here, periods of higher albedo and higher aerosol optical depth, and periods of lower albedo and lower aerosol optical depth, are identified in CERES and MODIS satellite retrievals from 2002-2020 over Europe, Eastern North America, Northeastern Asia, and India. Albedo and aerosol optical depth decrease over 2002-2020 in all regions except India, where both increase. A Gradient Boosting regression is then applied to monthly retrieval differences between these periods to decompose regional albedo trends into aerosol, cloud, and other contributions. Changes in cloud fraction are a primary contributor to albedo trends in Europe, Northeastern Asia, and India. At least half of this contribution is related to aerosol trends. In contrast, in Eastern North America, aerosol-related variations in cloud droplet number and aerosol optical depth account for most of the observed trend, with a minimal contribution from cloud fraction changes. In Northeastern Asia, changes in surface albedo also contribute strongly to the albedo trend because of variations in snow cover. Sensitivities of top-of-atmosphere albedo to aerosol optical depth, cloud fraction, liquid water path, droplet number, surface albedo, and surface temperature are calculated regionally and seasonally. These sensitivities can be used to test the magnitude and causes of albedo trends simulated by climate models.

Camouflage is a common plant strategy to avoid herbivory in sparsely vegetated environments. In temperate deciduous forests, leaf mottling is hypothesized to camouflage the nutrient-rich leaves of spring-active understory plants against the sparsely vegetated background of leaf litter. However, tests of this hypothesis remain limited to few species at small spatial scales. I used texture metrics to quantify leaf mottling variation across gradients in canopy cover (as a proxy for leaf background) and deer abundance (as a proxy for herbivore pressure) in five Erythronium species in central and eastern North America. Inter- and intraspecific leaf mottling roughness and evenness were quantified from iNaturalist community science observations. I then used ANOVA and multiple regression to determine whether mottling increased with canopy cover and deer abundance, as expected from the camouflage hypothesis. Mottling roughness and evenness were greatest in Erythronium species known to occur in forests and diminished (i.e., leaves became less mottled) in prairie and woodland species. Mottling also varied intraspecifically for three species (and nearly so for a fourth), tending to increase with greater canopy cover. This mottling-canopy-cover relationship was strongest in areas of high to very high deer abundance. Greater Erythronium leaf mottling with canopy cover and deer abundance indicates that this trait may act as an herbivore avoidance strategy in forests. While mottling has also been hypothesized to facilitate photoprotection in high-light environments, minimal leaf mottling in prairie and woodland species suggests photoprotection is an unlikely mechanism for the genus studied here.

West Nile virus (WNV) and eastern equine encephalitis virus (EEEV) are typically maintained via enzootic cycles between birds and mosquitoes (Diptera: Culicidae). In North America, the blood hosts of mosquitoes involved in pathogen circulation are poorly described for many regions, limiting our ability to predict disease outbreaks. Our objectives were to (i) identify local (Eastern Ontario, Canada) bloodmeal hosts fed on by mosquitoes using DNA barcoding and (ii) investigate if the bloodmeal hosts identified were representative of the entire host community using species accumulation curves and Chao richness estimates. We successfully identified 313 bloodmeal hosts from 292 mosquitoes belonging to the species Aedes cinereus, Aedes vexans, Coquillettidia perturbans, Culex pipiens/restuans, Ochlerotatus stimulans and Ochlerotatus trivittatus, with 257 and 56 bloodmeal hosts identified at the species and genus levels, respectively. Concurrent with the literature, Culex species almost exclusively fed on birds, C. perturbans fed on a mixture of birds and mammals, and the remaining mosquito species fed almost exclusively on mammals. Eastern cottontail rabbits (Sylvilagus floridanus) were the most common mammal species fed on, driven by A. vexans and O. trivittatus. With respect to WNV and EEEV enzootic cycles, Culex species, the main vectors for WNV transmission, were observed to forage on American robins (Turdus migratorius), an amplification host for WNV, highlighting a pathway by which WNV could be maintained in our study region. A. vexans, a potential bridge vector, was also observed to forage on a relatively high frequency of humans (Homo sapiens), suggesting a pathway by which humans could be exposed to WNV. C. perturbans, a potential bridge vector for EEEV transmission, was also observed to forage on both an American Robin (also an amplifying host for EEEV) as well as on humans in a relatively high frequency, illustrating a potential pathway by which EEEV exposure in humans could occur. Our species accumulation curves and Chao estimates of richness with respect to bloodmeal hosts, indicated that the bloodmeal host community was not completely characterized. Together, our results contribute to a better understanding of mosquito bloodmeal hosts in eastern North America and suggest a larger or more directed sampling effort would be needed to characterize the entire bloodmeal host community in our study region.

• Understanding the population dynamics of a high-density ungulate is challenging. • We built an age/sex-structured population model for a moose population. • Our model successfully reproduced changes in abundance and demographic drivers. • We offered a way to build and calibrate complex population models with scarce data. • We identified mechanisms at play in a protected area without hunting and wolves. High-density populations can threaten the ecological integrity of ecosystems through cascading effects. In such cases, management practices must be guided by sufficient knowledge of the biological mechanisms at play. Simulation models are powerful tools for acquiring such knowledge. The moose ( Alces alces americana ) is a species that recently became overabundant in some areas of eastern North America, sometimes requiring specific management measures. While numerous models exist for moose population dynamics, few are adapted to high density populations like the one in Forillon National Park (Quebec, Canada), a protected area in which the moose's apical predator (grey wolf Canis lupus ) is absent. We developed a sex- and age-structured population model respecting these conditions that we parameterized using pattern-oriented modelling to help explain the changes in moose density observed over nearly 4 decades. The most plausible sequence of vital rates identified exhibited negative density dependence in survival, reproduction and dispersal. Predation by alternative predators, black bears ( Ursus americanus ) and coyotes ( Canis latrans ), caused substantial mortality of calves each year. Unlike elsewhere in northeastern North America, winter tick only had a slight effect on calf survival. Variations in the population’s sex ratio were mainly explained by sex-biased dispersal. Our study provides new insights concerning the dynamics of high-density ungulate populations in the absence of their apical predator, and our modelling approach helped reveal new methodological challenges and opportunities. We also present a comprehensive process to build and parameterize a complex population model using scarce data.

Eastern newts (Notophthalmus viridescens) are a ubiquitous member of eastern North America's caudate fauna. Unlike most amphibians, which have two major life stages, their life cycle is typically multiphasic. Eastern newts are also polyphenic, possessing alternative life cycle strategies including an aquatic juvenile stage and a facultatively paedomorphic adult stage that is fully aquatic. Because these salamanders occupy different habitats (terrestrial, semi-aquatic, and fully aquatic) throughout their lives, they likely experience various physical forces on their skeletons, providing a unique model to study musculoskeletal changes across development and ecology. We hypothesized that individuals experiencing terrestrial life stages would exhibit vertebral morphologies constrained by the mechanical demands of terrestrial loading, resulting in similar vertebral shapes between terrestrial juveniles and semi-aquatic adults. In contrast, we predicted that fully aquatic phenotypes would exhibit greater morphological disparity due to relaxed gravitational constraints in buoyant environments. Using micro-computed tomography (μCT) and geometric morphometrics (GMM), we quantified vertebral shape and morphological disparity across life stages (terrestrial juvenile, aquatic juvenile, aquatic paedomorph, semi-aquatic adult) and axial regions (cervical, trunk, sacral, caudal). Our findings reveal that terrestrial life stages exhibit constrained vertebral morphology that persists despite subsequent ontogenetic niche shifts. Unexpectedly, aquatic juveniles and aquatic paedomorphs differed significantly despite shared aquatic habitat, suggesting that developmental pathway plays a larger role than current environment in shaping vertebral morphology. Fully aquatic stages displayed greater morphological disparity, particularly in the caudal region, consistent with relaxed gravitational constraints in buoyant environments.

Understanding the seasonal phenology of an insect pest in a specific region on a specific host is fundamental to the timing of management actions. The elongate hemlock scale, Fiorinia externa Ferris (Hemiptera: Diaspididae), is an invasive insect from Japan known to infest various conifer hosts in its invasive range in eastern North America. The phenology of the scale has been studied on hemlock (Tsuga spp.) hosts in its native range and portions of its invasive range in the northeastern and mid-Atlantic regions of the United States; similar studies are lacking for the southeastern region. In the Southern Appalachians, this scale poses a significant management and regulatory challenge for Fraser fir (Abies fraseri [Pursh] Poir.,) Christmas tree production. The objective of this study was to examine the seasonal phenology of the scale in the western North Carolina production region. Biweekly samples were collected from Fraser fir at three sites over 2 years and analyzed for abundance of each life stage. We found all life stages present at all locations throughout the year. Large variability in egg abundance was observed across 2 years. There was little variability in the abundance of life stages between sampling locations. Substantially more scale eggs, crawlers, 2nd instar nymphs and adult females were observed on the 2 most recent years' needles as opposed to older needles. These findings can help optimize the timing of management practices to control the elongate hemlock scale more effectively.

West Nile virus (WNV) is a mosquito-borne zoonotic pathogen with expanding distribution and recurrent outbreaks in Europe and the Americas. WNV transmission depends on interactions between competent avian hosts and mosquito vectors, but empirical data on host competence remain narrow, limiting large-scale assessments of viral hazard. Here, we compile viremia data from experimental infections of birds and develop a trait-based, phylogenetically informed model to predict global avian host competence. We integrate predictions with the habitat distribution of competent Culex vectors to estimate WNV hazard across the Americas and Europe. Our model identified over 4900 avian species as potentially competent hosts for WNV. The Mediterranean Basin and eastern North America showed high host richness-co-occurrence of several predicted host species-and high suitability for Culex vectors. Conversely, several tropical and subtropical regions had high host richness but limited vector suitability at present. These areas represent 'latent' hotspots of hazard, i.e. areas with high potential for future WNV emergence under environmental change. Our results refine the understanding of where WNV transmission is most likely to occur at present and highlight regions at risk of future emergence. This approach can inform risk mapping, surveillance efforts and targeted public health interventions.

Abstract Wild populations of North American cranberry (Vaccinium macrocarpon Aiton) are reservoirs of genetic variation that may contribute to the improvement of breeding-relevant traits. However, the extent to which wild genetic variation is geographically structured and represented in elite germplasm remains unclear. We analyzed 179 wild cranberry accessions from the upper Midwest and Eastern North America to estimate nucleotide diversity (π), population structure, and loci associated with genetic differentiation and environmental variables using a genome-informed targeted genotyping panel. Additionally, 14 demographic scenarios were evaluated using site-frequency-spectrum–based inference to identify historical events that could explain current genetic diversity. We observed extremely low nucleotide diversity within the targeted panel (π = 5 × 10−6). Rare allele distributions strongly influenced π and Tajima’s D values, suggesting constrained diversity in the genomic regions assayed that is not captured by heterozygosity-based estimates alone. However, we interpreted these results as conservative lower bounds on genome-wide neutral diversity because the targeted panel is enriched for genic and conserved regions. A clear separation between the Midwest and East populations was observed, with inbreeding coefficients ranging from -0.13 to 0.15. Furthermore, site frequency spectrum inference from the targeted panel supported a demographic scenario consistent with a significant population reduction ≈15-14 thousand years ago (kya), followed by a divergence between the two regions ≈12 kya, and an asymmetric gene flow ≈1.3 kya. We detected 254 candidate loci showing regional allele-frequency differentiation. Several of these loci colocalized with candidate genes linked to stress response, development, and metabolic processes. To evaluate the representation of geographically differentiated wild alleles in a breeding context, we analyzed Rutgers breeding materials (n = 484) and found that this panel is enriched for common alleles in Eastern wild populations. These findings indicate regionally structured allele-frequency variation in wild cranberry, with potential relevance to environmental response and breeding. This study extends prior wild cranberry population-genetic research by providing targeted-panel estimates of diversity, comparisons of demographic models, and breeding insights on geographically differentiated alleles, while highlighting the importance of conserving wild cranberry germplasm for use in modern breeding programs.

The combined effects of climate and landscape change are likely to be contributing to widespread and pervasive declines in forest bird populations. Individual species responses vary across climatic niches and habitat requirements, but bird communities and populations in montane systems may be particularly vulnerable to climate anomalies. Previous syntheses have reviewed evidence for impacts of climate change on bird species in general, in temperate regions and in Holarctic mountain ranges. Here, we propose that the Appalachian Mountains of eastern North America serve as an instructive case study due to their distinct combination of extensive temperate broadleaf forest cover, predominantly northeast–southwest orientation that bridges two major biomes and a bird assemblage that contains trailing‐edge populations of species that predominantly breed in the boreal forest. Our goal was to review the contemporary and potential future effects of both climate and land cover change on forest birds breeding in the Appalachian Mountains. Specifically, we focused on synthesizing documented and predicted changes in bird species distributions, populations and communities in response to changes in climate and land cover across this mountain range. We further compared our findings with trends from other mountain ranges across the world to assess commonalities and differences. Although there was limited literature from the Appalachian Mountains that incorporated both climate and land cover variables in models of forest bird responses, several results were consistent with studies from other montane systems, including vulnerability of cold‐associated species to warming temperatures and stronger effects predicted for future scenarios with higher greenhouse gas emissions. In addition, there were no prevailing trends that differed greatly from other mountain ranges, but potential extirpations of cold‐associated species varied along latitudinal gradients within the Appalachian Mountains region, and there was nuance in how changes in land cover and habitat conditions modified forest bird responses to climate change. We concluded our review by identifying key knowledge gaps, suggesting future directions for research and highlighting the conservation implications for forest birds in the Appalachian Mountains.

Harmful cyanobacterial blooms dominated by Microcystis aeruginosa represent an escalating threat to freshwater ecosystems and public health worldwide, driven by climate change and eutrophication. This study employs maximum entropy (MaxEnt) modeling to project the global distribution of suitable habitat for M. aeruginosa under current and future climatic conditions. We compiled 395 occurrence records from the Global Biodiversity Information Facility and field surveys, integrating them with six bioclimatic variables selected through rigorous multicollinearity filtering: Annual Mean Temperature (bio_1), Temperature Seasonality (bio_4), Maximum Temperature of Warmest Month (bio_5), Mean Temperature of Warmest Quarter (bio_10), Precipitation of Driest Month (bio_14), and Precipitation of Driest Quarter (bio_17). The MaxEnt model demonstrated excellent predictive performance (AUC = 0.91, TSS = 0.82), identifying temperate and subtropical regions across central Europe, eastern North America, East Asia, and southern Australia as current high-suitability zones. Limiting factor analysis revealed Temperature Seasonality as the dominant constraint on global distribution, emphasizing the critical role of inter-annual climatic variability in governing bloom dynamics. Projections under Representative Concentration Pathways RCP 2.6 and RCP 8.5 for 2050 and 2070 indicate substantial northward expansion of suitable habitat, particularly under high-emission scenarios. By 2070 under RCP 8.5, suitable habitat is projected to increase by 8.4% globally, with pronounced gains in high-latitude regions of Canada, northern Europe, and Russia, while some currently suitable subtropical areas experience habitat contraction due to intensified drought stress. These findings identify regions where future climatic conditions may become increasingly suitable for M. aeruginosa occurrence, providing a basis for prioritizing monitoring and precautionary water resource management strategies.

ABSTRACT Atmospheric blocking over the northern North Pacific–Alaska sector has a central role in shaping winter weather variability and cold‐air outbreaks across central and eastern North America. Motivated by recent high‐impact Alaskan ridge events, this study examines the climatological characteristics of Alaskan atmospheric blocking and its downstream temperature response based on reanalysis data during January–February (JF) 1979–2023. The meridional gradient of potential vorticity (PVy) is used here as a physically motivated dynamical index in which a reduced PVy is associated with zonal wind reversal and weakened westerly winds and conditions favourable for ridge amplification. The PVy index exhibits spatial structures and temporal evolution similar to the traditional Tibaldi–Molteni blocking index. Negative‐PVy anomalies over the Bering Sea occur in most winters, typically persisting for several days to one week. Composites based on negative PVy show a robust atmospheric circulation pattern characterised by enhanced ridging over Alaska and a downstream trough over North America, accompanied by negative near‐surface temperature anomalies over the central and eastern United States and positive anomalies over Alaska and the Pacific Arctic. Although negative‐PVy conditions are common in winter, prolonged blocking episodes spanning much of a month are rare, consistent with the transient nature of blocking events. Selected winters (1979, 1986, 1988 and 2018) are illustrative case studies that demonstrate the range of circulation structures and surface‐temperature responses, embedded within a long‐term climatological relationship. These results highlight the important meteorological role of Alaskan blocking and identify PVy as a simple, physically interpretable diagnostic of background‐flow conditions associated with North American winter temperature variability.

Urbanization is a major driver of environmental change that shapes the evolution of populations. However, the environmental differences amongst cities and their effects on neutral and adaptive evolution are less well understood. We investigated the contribution of city-level variation to patterns of genetic evolution in Impatiens capensis, a native wildflower found in parks and green spaces in many cities across eastern North America. While the mixed mating system and flexible pollination requirements of I. capensis likely contribute to its resilience to urbanization, microenvironmental differences among cities may shape how this species evolves in cities. We used genotype-by-sequencing to evaluate genetic variation, contemporary demographic history, and genetic signatures of local adaptation in plants sampled from urban and rural sites across 10 cities in Ontario, Canada. Urbanization and city size shaped the amount of genetic diversity present at sites and were associated with fine-scale spatial genetic structure. We identified a signal of repeated population bottlenecks across all cities, corresponding to the timing of rapid urban expansion in the region. City size was the environmental predictor most strongly associated with multilocus selection, highlighting the contribution of city variation to adaptive genomic evolution. Our findings provide one of the first examples of parallel demographic shifts in response to urbanization in plants and offer insights into why a native wildflower like I. capensis may be particularly resilient to urbanization. Taken together, our results emphasize the role that urban parks can play in maintaining genetic diversity and facilitating adaptation, suggesting that prioritizing greenspace conservation is critical for promoting urban biodiversity.

Hop (Humulus lupulus) production in the eastern United States has increased in recent years, prompting the need to understand emerging fungal pathogens in this region. This study is the first population genetics analysis of Diaporthe humulicola, a recently described pathogen causing halo blight. A total of 71 D. humulicola isolates from Michigan, NewYork, Minnesota, and Canada were sequenced and analyzed using Illumina 150× 150-bp reads with 10× coverage. Single-nucleotide polymorphisms were discovered and filtered using the Genome Analysis Toolkit. After filtering and clone correction, 63 isolates remained for downstream analysis. Population structure was determined to have three clusters and was supported using STRUCTURE, principal component analysis, and discriminant analysis of principal components. Analyses showed that Michigan isolates closely clustered with isolates from Canada and NewYork, as well as one isolate from Minnesota. The rest of the Minnesota isolates clustered in an independent cluster. Minnesota isolates appear to have high levels of population differentiation when compared with the different populations exhibiting a high fixation index, a measure of population differentiation and low nucleotide diversity. Mating type was determined for each isolate, with Mat1-2-1 present in 61.9% of the whole population. We also detected signals of recombination in each of the fungal populations, with higher levels in Michigan and Canada. These findings highlight the genetic complexity and regional differentiation of D. humulicola populations, with implications for disease management and hop breeding programs.

ABSTRACT Aim Warmer range limits of species distributions offer a window into the ecological and evolutionary processes associated with long‐term warming, as they often harbour relicts of refugial populations from the last glaciation. However, warm‐edge populations vary in their refugial, evolutionary, and climatic histories, complicating their use as models. Here, we characterise this variation at the warmer range limit of the North American herb Campanula americana . Location Eastern North America. Taxon Campanula americana . Methods We evaluated the warmer range limit using species distribution model hindcasting, range‐wide analyses of population structure, effective migration, and phylogenetic relationships. Results Warm‐edge populations vary in their refugial history; most are relicts of historic refugial populations (i.e., rear edge), but some result from southward postglacial colonisation. Within the rear edge, populations exhibit pronounced genetic structure, forming highly isolated clusters despite contiguous geography and only modest landscape barriers. Distinct rear‐edge clusters varied in climate history and gene flow among populations, with more southern populations experiencing greater habitat decline, fragmentation and isolation. Finally, only rear‐edge populations from northern refugial areas contributed to postglacial range expansion. Main Conclusions Our study highlights the challenges of using warm‐edge populations as ecological and evolutionary models of response to climate change. Even in a geographically simple setting, warm‐edge populations exhibit refugial, genetic, and climatic heterogeneity. Characterising this variation is essential for accurately identifying rear‐edge populations and inferring their evolutionary history. Knowledge of the contribution of warm‐edge populations to range‐wide genetic variation is key when considering how these populations may inform studies of adaptation to future climate change.

The genus Triantha (Tofieldiaceae) consists of four species, two of which, Triantha glutinosa and Triantha racemosa, have populations that are found in eastern North America. T. glutinosa has a primary distribution across Canada and into the northern United States, and is found in marshes, wet meadows, and on calcareous soil. T. racemosa primarily occurs on the Gulf Coast and in the southeastern United States in boggy areas, pine barrens, and savannas with acidic soils. The distribution of T. racemosa has never been known to extend beyond southern New Jersey. In the past, populations of Triantha found in New Jersey were identified as Triantha racemosa, though these plants have also been noted to exhibit some morphological characteristics associated with T. glutinosa. It has previously been hypothesized that the New Jersey populations are actually hybrids of T. glutinosa and T. racemosa, and that the two species may have had overlapping ranges at some point in the past. New Jersey populations are currently isolated from the nearest T. glutinosa and T. racemosa localities by hundreds of miles, too distant for gene flow to occur. Sequence analyses of the trnH-psbA intergenic spacer and matK gene region of chloroplast DNA (cpDNA), and the internal transcribed spacer (ITS) of nuclear ribosomal DNA and PCR-RFLP confirm the unique genetic identity of New Jersey populations of Triantha. Due to their unique genetic sequences, unique morphology, and a distribution that is isolated from extant T. glutinosa and T. racemosa populations, a new nothospecies, Triantha × novacaesariensis, is described for New Jersey populations of Triantha.

Deer keds (Diptera: Hippoboscidae: Lipopteninae) are blood-feeding ectoparasitic flies that usually feed on deer and other Cervidae but sometimes bite humans. Two species are found in eastern North America: introduced European deer keds (Lipoptena cervi L.) and native Neotropical deer keds (L. mazamae Rondani). While historically dismissed as potential vectors of diseases, half a dozen tick-borne pathogens, including species pathogenic to humans, have been sequenced from deer keds over the last 15 years. In response to growing concerns that deer keds may transmit pathogens, efforts have been made recently to determine the distribution of deer keds in North America. Herein, we present new state records for Illinois, Kentucky, Michigan, and Nebraska, as well as 146 new county records from these and other states. We also discuss the relationship of hippoboscids to CO2-baited mosquito traps and review the impact of the community science platforms iNaturalist.org and BugGuide.net.

Swede midge, Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae), is an invasive pest of canola (Brassica napus Linnaeus, Brassica juncea Linnaeus, Brassica rapa Linnaeus) and other Brassicaceae crops that causes significant damage in eastern North America. Contarinia nasturtii has the potential to invade the Canadian Prairies, which represents North America’s largest canola growing region. This study examined host plant range, female oviposition preference, and larval development of C. nasturtii on selected weed, cultivated, and model Brassicaceae species. We also examined potential host plant resistance using a diverse panel of B. napus lines and developed a novel measure of larval performance using the proportion of third instar larvae as a proxy for larval development. All tested weed species, except Descurainia sophia Linnaeus, supported C. nasturtii development and 5 new host plants (Lepidium densiflorum Schrad., Neslia paniculata (Linnaeus) Desv., Diplotaxis muralis (Linnaeus) DC., Camelina sativa (Linnaeus) Crantz, and Erysimum cheiranthoides Linnaeus) were identified. Notably, we provide the first evidence that Arabidopsis thaliana Linnaeus can be a host for C. nasturtii, establishing a novel model system for gall midge–plant interaction studies. Evaluation of B. napus lines found slight variation in oviposition but no strong resistance, suggesting the need to investigate resistance sources outside of B. napus. These findings expand our knowledge on the host range of C. nasturtii, introduce A. thaliana as a tractable experimental model system, and underscore the need for investigation of host plant resistance and the development of integrated pest management strategies for C. nasturtii to mitigate threats to North American canola production.

The family Brassicaceae is agriculturally and economically important. However, ecological knowledge gaps persist for some wild species, even in parts of the world that have broadly well-studied flora, like eastern North America. Knowledge gaps for two eastern North American species, Cardamine concatenata and C. diphylla, are concerning for two reasons. First, these species have known associations with rare, specialist insects. Second, the threat posed by the introduction and spread of noxious invasive confamilial garlic mustard (Alliaria petiolata) within their shared native range. Because C. concatenata and C. diphylla have a short phenological window for seasonal development and reproduction they are at increased risk for mutualism disruption via global change pressures. We aim to evaluate the potential for pollination interference by A. petiolata. We compared pollinator visitation and floral phenology in sympatric wild populations of C. concatenata, C. diphylla, and A. petiolata in northeast Ohio. Pollinator counts and morphotype identifications were recorded during in situ pollinator observations. To supplement morphotype identifications, we collected pollinator specimens and identified them to genus or family in the lab. We found overlap in flowering phenology between A. petiolata and C. diphylla. Fourteen pollinator taxa were observed visiting at least one of the focal plant species; of these, seven taxa were recorded visiting all three plant species. Alliaria petiolata is likely disrupting pollination for the native C. diphylla in our sites because flowering phenology overlaps and pollinator taxa are shared. Future studies should focus on range-wide phenological observation and modelling for all three plant species, and pollen load analysis of native plant stigmas in invaded habitats.

Brook trout Salvelinus fontinalis is a popular sportfish native to North America and introduced worldwide, as well as an indicator of environmental quality. We review published studies and synthesize a view of how geomorphological, climatological, and ecological factors gave rise to the current distribution of brook trout and the geographic patterning of its population genetic diversity. Phylogenetic studies show that the center of diversity for charrs – i.e., members of Genus Salvelinus – is east Asia and northwestern North America and that divergence of most Salvelinus species occurred during the Miocene Epoch. Members of the Salvelinus lineage dispersed throughout northern Canada and eastern North America, the contemporary natural distribution of brook trout, perhaps with the opening of the Bering Strait at ~5.3 mya near the end of the Miocene Epoch or perhaps earlier through the Paleo-Bell River system. The contemporary population genetic structure of brook trout was patterned by retreat to refugia from Pleistocene glaciation, followed by Holocene recolonization of eastern North America. That is, contemporary populations of brook trout represent the descendants of fish from Acadian, Mid-Atlantic, or Mississippian refugia and from recent mixing upon secondary contact. Population genetic variation mostly conforms to watershed boundaries, a finding that informs fisheries and conservation management strategies. A growing body of research provides insights into local adaption of brook trout populations. The future viability of many populatons of brook trout will depend upon implementation of well-considered, conservation-oriented management actions. • Fossil salmonids date to 50 Ma in the Pacific Northwest of North America. • Brook trout arose around 9 Ma, and colonized eastern North America via the Bering Strait or the Paleo-Bell River system. • Neutral genetic variation reflects expansion of populations from three glacial refugia. • Recent research demonstrates adaptive genetic variation within and among brook trout populations.

ABSTRACTCoyotes (Canis latrans) expanded across eastern North America in the last century and are ecological generalists capable of thriving across diverse habitats. Broad genetic surveillance has reported little spatial genetic patterning for this highly dispersive species. Here, we explore the genome‐wide signatures of spatial patterns found in a 10‐year study of 1199 coyotes from northeastern United States, with a temporal analysis of Pennsylvania coyotes. Despite their broad dispersal capability, we detected subtle but significant population structure, with two genetic clusters that have a weak clinal transition zone. This partitioning aligned qualitatively with patterns of human population density and activity. We inferred that gene flow between these genetic groups was associated with two different demographic expansions of coyotes eastward, south along the Great Lakes and separately along the northern Lakes towards northeastern United States. We identify Pennsylvania as a recent contact zone. Morphometric analyses revealed only modest differentiation between clusters and no robust temporal shifts, though a weak trend of increased body mass was noted in southwestern males. Collectively, our findings demonstrate that anthropogenic features likely influence fine‐scale cryptic population structure, even in a highly dispersing and widespread mesopredator.