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Aim: Vegetation structure is a key determinant of animal diversity and species distributions. The introduction of Light Detection and Ranging (LiDAR) has enabled the collection of massive amounts of point cloud data for quantifying habitat structure at fine resolution. Here, we review the current use of LiDAR‐derived vegetation metrics in diversity and distribution research of birds, a key group for understanding animal–habitat relationships. Location: Global. Methods: We review 50 relevant papers and quantify where, in which habitats, at which spatial scales and with what kind of LiDAR data current studies make use of LiDAR metrics. We also harmonize and categorize LiDAR metrics and quantify their current use and effectiveness. Results: Most studies have been conducted at local extents in temperate forests of North America and Europe. Rasterization is currently the main method to derive LiDAR metrics, usually from airborne laser scanning data with low point densities (<10 points/m2) and small footprints (<1 m diameter). Our metric harmonization suggests that 40% of the currently used metric names are redundant. A categorization scheme allowed to group all metric names into 18 out of 24 theoretically possible classes, defined by vegetation part (total vegetation, single trees, canopy, understorey, and other single layers as well as multi‐layer) and structural type (cover, height, horizontal variability and vertical variability). Metrics related to canopy cover, canopy height and canopy vertical variability are currently most often used, but not always effective. Main conclusions: Light Detection and Ranging metrics play an important role in understanding animal space use. Our review and the developed categorization scheme may facilitate future studies in the selection, prioritization and ecological interpretation of LiDAR metrics. The increasing availability of airborne and spaceborne LiDAR data and the development of voxel‐based and object‐based approaches will further allow novel ecological applications, also for open habitats and other vertebrate and invertebrate taxa. [ABSTRACT FROM AUTHOR]

Aim: Species distribution models (SDMs) have emerged as essential tools in the equipment of many ecologists, useful to explore species distributions in space and time and answering an assortment of questions related to biogeography, climate change biology and conservation biology. Historically, most SDM research concentrated on well‐known organisms, especially vertebrates. In recent years, these tools are becoming increasingly important for predicting the distribution of understudied invertebrate taxa. Here, we reviewed the literature published on main terrestrial arthropod predators (ants, ground beetles and spiders) to explore some of the challenges and opportunities of species distribution modelling in mega‐diverse arthropod groups. Location: Global. Methods: Systematic mapping of the literature and bibliometric analysis. Results: Most SDM studies of animals to date have focused either on broad samples of vertebrates or on arthropod species that are charismatic (e.g. butterflies) or economically important (e.g. vectors of disease, crop pests and pollinators). We show that the use of SDMs to map the geography of terrestrial arthropod predators is a nascent phenomenon, with a near‐exponential growth in the number of studies over the past ten years and still limited collaborative networks among researchers. There is a bias in studies towards charismatic species and geographical areas that hold lower levels of diversity but greater availability of data, such as Europe and North America. Conclusions: Arthropods pose particular modelling challenges that add to the ones already present for vertebrates, but they should also offer opportunities for future SDM research as data and new methods are made available. To overcome data limitations, we illustrate the potential of modern data sources and new modelling approaches. We discuss areas of research where SDMs may be combined with dispersal models and increasingly available phylogenetic and functional data to understand evolutionary changes in ranges and range‐limiting traits over past and contemporary time‐scales. [ABSTRACT FROM AUTHOR]

Information about species distributions is lacking in many regions of the world, forcing resource managers to answer complex ecological questions with incomplete data. Information gaps are compounded by climate change, driving ecological bottlenecks that can act as new demographic constraints on fauna. Here, we construct greater sandhill crane (Antigone canadensis tabida) summering range in western North America using movement data from 120 GPS‐tagged individuals to determine how landscape composition shaped their distributions. Landscape variables developed from remotely sensed data were combined with bird locations to model distribution probabilities. Additionally, land‐use and ownership were summarized within summer range as a measure of general bird use. Wetland variables identified as important predictors of bird distributions were evaluated in a post hoc analysis to measure long‐term (1984–2022) effects of climate‐driven surface water drying. Wetlands and associated agricultural practices accounted for 1.2% of summer range but were key predictors of occurrence. Bird distributions were structured by riparian floodplains that concentrated wetlands, and flood‐irrigated agriculture in otherwise arid and semi‐arid landscapes. Findings highlighted the role of private lands in greater sandhill crane ecology as they accounted for 78% of predicted distributions. Wetland drying observed in portions of the range from 1984 to 2022 represented an emerging ecological bottleneck that could limit future greater sandhill crane summer range. Study outcomes provide novel insight into the significance of ecosystem services provided by flood‐irrigated agriculture that supported nearly 60% of wetland resources used by birds. Findings suggest greater sandhill cranes function as a surrogate species for agroecology and climate change adaptation strategies seeking to reduce agricultural water use through improved efficiency while also maintaining distinct flood‐irrigation practices supporting greater sandhill cranes and other wetland‐dependent wildlife. We make our wetland and sandhill crane summering distributions available as interactive web‐based mapping tools to inform conservation design. [ABSTRACT FROM AUTHOR]

Geographic patterns of species distributions and the factors contributing to species endangerment are necessary for the development of integrative conservation strategies. Freshwater mussels Unionidae have among the highest levels of imperilment recorded in North America. This paper describes the biogeography and diversity of Unionidae along climate and habitat gradients in Texas, evaluates human impact, and identifies the hot spots of diversity and endemism that should be targeted for conservation. Texas, North America. Unionids were surveyed in all major Texas river basins in 2003-2009. Multivariate statistics were used to test for differences in environmental parameters and among unionid assemblages in different bioprovinces, and to determine to what extent the multivariate pattern of species distribution was affected by environmental factors. To estimate human impact, we examined the relationship between human population density and the proportion of rare species, as well with the proportion of historically present species that persist in the watershed. Correlation between biotic and environmental similarity matrices indicated concordance in the differences among unionid assemblages and environmental factors that could cause these differences. Lake surface evaporation rate and percentage of forest cover in the watershed were among the most important parameters explaining the differences in unionid assemblages. Human population density was negatively correlated with the proportion of rare species. The proportion of species found live relative to the total number of live and relic species found in our surveys and to the number of historically known species decreased with the increase in human population density. Climate, landscape, geology, and land use type were important factors influencing unionid distribution patterns among biotic provinces. Increased human population density was associated with the loss of rare species over several decades, but this loss was not recognized because of a lack of assessing the conservation status of unionids. [ABSTRACT FROM AUTHOR]

Pollen reconstructions of tree genera in North America since glaciation are available, but species distributions predicted for paleoclimate based on tree inventories may inform knowledge gaps. Here I examined the distributions of 25 species or species groups from 20 000 years ago (ka) to 5 ka to give potential paleoecological ranges of boreal and temperate tree species. I also assessed the effects of correlated climate variables on species distribution models for current and past climate, which were modeled with the non‐linear random forests classifier. Climate change alone was enough to create unique, species‐specific paths that did not run directly north. At 20 ka, black spruce (Picea mariana) occurred as far north as the ice sheet and most boreal species generally may have extended as far south as 32°N, or the northern southeastern United States. Temperate eastern species may have extended as far north as 39°N in low‐elevation locations and temperate eastern species displayed both continuous and clustered distributions across the southeastern United States. Rate of movement was 5.5 km per century between 20 and 14 ka, 13.3 km per century between 14 and 10 ka, and 3.25 km per century between 10 and 5 ka. Species retreated southward between 7 and 5 ka. Regarding correlation, models with all variables had greater accuracy than models with the two most important variables, which had greater accuracy than models with two variables of intermediate importance, demonstrating both reduced accuracy with omission of relevant variables and isolation of important variables that improve accuracy in models with correlated climate variables. Models from different climates identified the same two most important variables and ranked the remaining variables similarly, revealing robustness in the models over time. Distribution models agreed with pollen reconstructions regarding timing and rate of change, while generating detailed species‐specific information about movement trajectories and velocities, latitudinal extents, and distribution continuities. [ABSTRACT FROM AUTHOR]

Aim: Decades of research on species distributions has revealed geographic variation in species‐environment relationships for a given species. That is, the way a species uses the local environment varies across geographic space. However, the drivers underlying this variation are contested and still largely unexplored. Niche traits that are conserved should reflect the evolutionary history of a species whereas more flexible ecological traits could vary at finer scales, reflecting local adaptation. Location: North America. Methods: We used mammal observations during a 5‐year period from the iNaturalist biodiversity database and a local ensemble modelling approach to explore spatial variation in American black bear (Ursus americanus) relationships with eight ecological correlates. We tested four biologically driven hypotheses to explain the patterns of local adaptation. We evaluated non‐stationarity in ecological relationships using a Stationarity Index and tested predictive performance using an independent, national‐level animal occurrence data set. Results: We documented considerable spatial non‐stationarity in all eight environmental relationships, with the greatest spatial variation occurring in bear's relationship to climatic factors. Notably, the greatest variation in environmental relationships tended to occur along the current boundaries of the species' range, potentially representing the ecological limits to the species geographic range. We additionally documented that spatial variation in relationships with land cover and anthropogenic factors were best explained by niche conservatism at the subspecies level, whereas climatic relationships were better explained by local adaptation. Main Conclusions: Based on these results, we propose that the current distribution of American black bear is determined by an evolutionary legacy of habitat relationships unique to each subspecies combined with more fine‐scale local adaptation to climatic conditions. This result suggests that black bears should be adaptable to climatic changes over the 21st century and that management of habitat and human‐bear relationships could be considered at the subspecies level. [ABSTRACT FROM AUTHOR]

Aim: Understanding speciation mechanisms requires disentangling processes that promote and erode population‐level divergence. Three hypotheses are raised that contemporary population structure is mainly shaped by refugial isolation, gene flow or both. Testing these hypotheses requires range‐wide phylogeography and integrative analyses across scales. Here we aimed to (1) re‐estimate the previously unresolved nuclear divergence within a widespread bat; (2) test the above three phylogeographical hypotheses and (3) inform conservation management under climatic change. Location: North America including the Caribbean. Taxon: The big brown bat (Eptesicus fuscus). Methods: We collected range‐wide samples and genome‐wide markers using restriction site‐associated DNA sequencing. Population structure was analysed by clustering methods and spatial estimations. Nuclear phylogeographical divergence was estimated using tree methods (concatenation and coalescence) and network analyses (TreeMix). Phylogeographical hypotheses were tested by comparing alternative evolutionary scenarios using demographic modelling. Species distribution modelling was used to help identify Pleistocene refugia and predict future range shifts under climatic change. Results: We identified three populations in the Caribbean, eastern and western North America. The western population further split into three phylogeographical clades: Pacific, southwestern North America and Mexico. Discordance among mitochondrial and nuclear topologies reflected strong impacts of gene flow without sex bias. Demographic modelling supported scenarios of historical isolation followed by secondary gene flow and estimated Holocene divergence times. Species distribution was essentially continuous during glaciation with possible regional isolation, and northward range shifts were predicted under future climatic change. Main Conclusions: Contemporary population divergence of big brown bats was shaped by both historical isolation and secondary gene flow, supporting the third phylogeographical hypothesis. While climatic change likely triggered initial divergence, ongoing gene flow has largely impacted the dynamic within‐species evolution and generated population divergence without speciation. [ABSTRACT FROM AUTHOR]

Aim: The distribution of Yersinia pestis, the pathogen that causes plague in humans, is reliant upon transmission between host species; however, the degree to which host species distributions dictate the distribution of Y. pestis, compared with limitations imposed by the environmental niche of Y. pestis per se, is debated. We test whether the present‐day environmental niche of Y. pestis differs between its native range and an invaded range and whether biotic factors (host distributions) can explain observed discrepancies. Location: North America and Central Asia. Major taxa studied: Yersinia pestis. Methods: We use environmental niche models to determine whether the current climatic niche of Y. pestis differs between its native range in Asia and its invaded range in North America. We then test whether the inclusion of information on the distribution of host species improves the ability of models to capture the North American niche. We use geographical null models to guard against spurious correlations arising from spatially autocorrelated occurrence points. Results: The current climatic niche of Y. pestis differs between its native and invaded regions. The Asian niche overpredicted the distribution of Y. pestis across North America. Including biotic factors along with the native climatic niche increased niche overlap between the native and invaded models, and models containing only biotic factors performed better than the native climatic niche alone. Geographical null models confirmed that the increased niche overlap through inclusion of biotic factors did not, with a couple of exceptions, arise solely from spatially autocorrelated occurrences. Main conclusions: The current climatic niche in Central Asia differs from the current climatic niche in North America. Inclusion of biotic factors improved the fit of models to the Y. pestis distribution data in its invaded region better than climate variables alone. This highlights the importance of host species when investigating zoonotic disease introductions and suggests that climatic variables alone are insufficient to predict disease distribution in novel environments. [ABSTRACT FROM AUTHOR]

Premise: Populations of species with large spatial distributions are shaped by complex forces that differ throughout their ranges. To maintain the genetic diversity of species, genepool‐based subsets of widespread species must be considered in conservation assessments. Methods: The population genetics of the lichenized fungus Lobaria pulmonaria and its algal partner, Symbiochloris reticulata, were investigated using microsatellite markers to determine population structure, genetic diversity, and degree of congruency in eastern and western North America. Data loggers measuring temperature and humidity were deployed at selected populations in eastern North America to test for climatic adaptation. To better understand the role Pleistocene glaciations played in shaping population patterns, a North American, range‐wide species distribution model was constructed and hindcast to 22,000 years before present and at 500‐year time slices from then to the present. Results: The presence of two gene pools with minimal admixture was supported, one in the U.S. Pacific Northwest and one in eastern North America. Western populations were significantly more genetically diverse than eastern populations. There was no evidence for climatic adaptation among eastern populations, though there was evidence for range‐wide adaptation to evapotranspiration rates. Hindcast distribution models suggest that observed genetic diversity may be due to a drastic Pleistocene range restriction in eastern North America, whereas a substantial coastal refugial area is inferred in the west. Conclusions: Taken together the results show different, complex population histories of L. pulmonaria in eastern and western North America, and suggest that conservation planning for each gene pool should be considered separately. [ABSTRACT FROM AUTHOR]

Aim: The fungal pathogen Pseudogymnoascus destructans and resultant white‐nose syndrome (WNS) continues to advance across North America, infecting new bat hibernacula. Western North America hosts the highest bat diversity in the United States and Canada, yet little is known about hibernacula and hibernation behaviour in this region. An improved understanding of the distribution of suitable hibernacula is critical for land managers to anticipate conservation needs of WNS‐susceptible species in currently uninfected regions. Location: United States, Canada. Taxon: Bats. Methods: We estimated suitability of potential winter hibernaculum sites across five bat species' ranges. We estimated winter survival capacity from a mechanistic survivorship model based on bat bioenergetics and climate conditions. We then used boosted regression trees to relate these estimates, along with key landscape attributes, to bat occurrence data in a hybrid correlative‐mechanistic approach. Results: Winter survival capacity, topography, land cover and access to subterranean features were important predictors of winter hibernaculum selection, but the shape and relative importance of these relationships varied amongst species. This suggests that the occurrence of bat hibernacula can, in part, be predicted from readily mapped above‐ground features, not just below‐ground characteristics for which spatial data are lacking. Furthermore, our mechanistic estimate of winter survivorship was, on average, the third strongest predictor of winter occurrence probability across focal species. Main conclusions: Winter distributions of North American bat species were driven by their physiological capacity to survive winter conditions and duration in a given location, as well as selection for topographic and other landscape features but in species‐specific ways. The influence of winter survivorship on several species' distributions, the underlying influence of climate conditions on winter survivorship and the anticipated influence of WNS on bats' hibernation physiology and survivorship together suggest that North American bat distributions may undergo future shifts as these species are exposed not only to WNS but also to climate change. [ABSTRACT FROM AUTHOR]

Although least chipmunks (Neotamias minimus) are a widely distributed North American species of least concern, the southernmost population, N. m. atristriatus (Peñasco least chipmunk), is imperiled and a candidate for federal listing as a subspecies. We conducted a phylogeographic analysis across the N. minimus range to assess genomic differentiation and distinctiveness of the N. m. atristriatus population. Additionally, we leveraged the historical component of sampling to conduct a temporal analysis of N. minimus genetic diversity and also considered climate change effects on range persistence probability by projecting a species distribution model into the IPCC5 RCP 2.6 and 8.5 scenarios. We identified three geographically structured groups (West, North, and South) that were supported by both mitochondrial and nuclear data. N. m. atristriatus grouped within a unique South subclade but were not reciprocally monophyletic from N. m. operarius, and nuclear genome analyses did not separate N. m. atristriatus, N. m. caryi, and N. m. operarius. Thus, while least chipmunks in the Southwest represent an evolutionary significant unit, subspecies distinctions were not supported and listing of the Peñasco population as a Distinct Population Segment of N. m. operarius may be warranted. Our results also support consideration of populations with North and West mitogenomes as two additional evolutionary significant units. We found that N. minimus genetic diversity declined by ~87% over the last century, and our models predicted substantial future habitat contraction, including the loss of the full contemporary ranges of N. m. atristriatus, N. m. arizonensis, and N. m. chuskaensis. [ABSTRACT FROM AUTHOR]

Aim: Abiotic, biotic and dispersal factors interact to shape species distributions. At broad geographic extents, abiotic factors are thought to exert the greatest influence on the distribution, while biotic and dispersal factors strongly influence the distribution regionally and locally. We test whether reproductive traits relating to biotic and dispersal factors explain differences between estimated potential and occupied geographic distributions for 21 species of Trillium. Location: Eastern North America. Methods: Fundamental niches and associated predicted suitable distributions were estimated using climate‐calibrated ecological niche models. We defined occupied distributions as the intersection between known ranges and predicted suitable areas (PSAs). Proportional occupancy of the predicted suitable distribution (PO) was calculated by dividing the area of the occupied distribution by the PSA. We related reproductive traits (ovule number, seed set, number of seeds/plant, seed mass, adult biomass, flower type: sessile/pedicellate) to PO using beta regression models. AICc was used to assess model fit. Results: There was considerable variation in PO across species (1.1%–96%, mean = 51%). Eighty‐five percent of species with PO < 60% were sessile; 88% of species with PO > 60% were pedicellate. The best‐fit beta regression (pseudo R2 =.70) yielded significantly lower PO for sessile‐flowered species; ovule number and seed mass were also significant predictors of PO. Main conclusions: Variation in PO among study species can be explained by flower type, ovule number and seed mass—biotic traits related to dispersal ability. We posit that variation in dispersal potential stemming from primary and long‐distance dispersers is related to occupancy of the predicted suitable distribution in Trillium. We exemplify a scenario in which life history traits explain why some species are range‐restricted when their close relatives are widespread. Our methodology constitutes a powerful comparative framework that can be applied to diverse biological systems to inform conservation of rare species. [ABSTRACT FROM AUTHOR]

Aim: Based upon species distribution models (SDMs), many studies have predicted that climate change will cause regional extinctions of tree species within the next 50–100 years. SDM‐based predictions have been challenged on procedural and theoretical grounds, but for tree species they are largely beyond the practical reach of direct experimental validation. Here we report the experimental consequences of moving seedlings from ~50 natural populations of each of two ash (Fraxinus) species to experimental sites spanning a range of 10°C colder to 10°C warmer (mean annual temperature) than home environments. Location: Eastern North America. Methods: We measured population‐by‐test‐site survival percentages and mean trunk diameters at an average age of 35 years. We then used linear, mixed‐effect models to develop transfer functions for each species and predict survival and mean annual growth as functions of fixed and random effects including, especially, the climatic distance (CD) between test site and home environment. Results: Survival and growth were highest at CD ≈ 0 and declined as populations were moved to warmer or colder environments, indicating that survival and growth were optimal when populations were in home‐like climates. However, variance around the model fit was substantial, and we could not statistically detect, even at α =.50, elevated mortality following displacements into environments 3.5°C (white ash) and 4.1°C (green ash) warmer in mean annual temperature. Survival rates of 80%–100% were common even within populations subjected to warming conditions greater than those predicted to cause meso‐scale extinctions in this century. We show that within‐population genetic variance, phenotypic plasticity and idiosyncratic aspects of the non‐climatic environment and its interaction with genotype each likely contributed to these unexpected responses to climatic displacement. Main conclusions: Results emphasize the uncertainty that underlies predictions of climate‐induced extinctions of long‐lived woody plants over time frames of 50 to perhaps 100 years into the future. [ABSTRACT FROM AUTHOR]

Aim: MaxEnt has been widely used to model species' geographic distributions as functions of environmental variables and to predict changes in distributions in response to environmental change. Here, we test the predictive ability of MaxEnt models through time by modelling colonizations and extinctions. Location: North America. Methods: Using data for 21 species from the North American Breeding Bird Survey, we first related avian species' geographic distributions to the spatial variation in environmental conditions. Then, we modelled site‐specific colonizations and extinctions between 1979 and 2009 as functions of MaxEnt‐estimated habitat suitability and neighbourhood occupancy. Results: We found that colonization and extinction probabilities were related to spatial variation in habitat suitability, and to neighbourhood occupancy, in the expected directions. However, change in habitat suitability (which is much smaller through time than through space) is a weak predictor of extinction and worse for colonization. This is because a) for most species and most sites, climatic suitability did not change dramatically between 1979 and 2009, and b) the relationship between colonization or extinction probability and change in climatic variables is very weak (r2 = 0.02). Most colonizations and extinctions are apparently unrelated to climate change. Main conclusions: MaxEnt models apparently capture a real effect of habitat suitability on North American bird species' distributions, but over short and medium time scales, occupancy of neighbouring sites by conspecifics predicts changes in occupancy as well as, or better than changes in climatic habitat suitability, as characterized by MaxEnt. One would not expect species' distributions to track climate change closely. Prediction of species' responses to climate change should 1) recognize that the process of colonization and extinction are not equally well predicted by species distribution models and 2) account for the spatial structure of species' distributions. [ABSTRACT FROM AUTHOR]

Aim: Dynamic range models are proposed to investigate species distributions and to project range shifts under climate change. They are based upon the Hutchinsonian niche theory, specifying that the occurrence of a species in an environmental space should be limited to positions where the intrinsic growth rate is positive. Evaluating population growth rate is, however, difficult for physiologically structured populations, such as forest stands, owing to size‐induced individual variation in performance. Therefore, we still have a limited understanding of which aspect of tree demography contributes the most to their geographical range limit. We develop an index of demographic performance for size‐structured populations and study its variation across a climatic gradient. We then investigate the relationship between the demographic performance index and species distribution. Location: North America (57–124° W, 26–52° N). Time period: 1963–2010. Major taxa studied: Fourteen tree species. Methods: We represent forest dynamics with a size‐structured population model and neighbourhood competition with the perfect plasticity approximation. We then derive the lifetime reproduction per individual, R0, in the absence of density dependence. Using forest inventory data, we assess how tree demography for each species varies with climate. We test the model by comparing R0 and the probability of occurrence within species ranges. Results: We find that both growth and mortality rates vary across species distributions, but climate explains little of the observed variation. Individual size and neighbourhood competition are the primary explanatory variables of tree demography. Finally, we find that R0 relates weakly to the probability of occurrence, with no systematic decline in population growth rates towards the range limits. Main conclusions: Spatial and size‐induced variation in tree growth and mortality do not explain range limits and are insufficient to enable an understanding of tree dynamics. We propose that phenomena perceived mostly at the metapopulation scale should also be considered. [ABSTRACT FROM AUTHOR]

Aim: Climatic equilibrium is a foundational principle in ecological theory and models used in conservation, but has been challenged by growing evidence of disequilibrium, particularly for long‐lived, sessile organisms like trees. Here, we calculated range filling for North American trees to detect the degree to which trees are filling their potential climatic niches, and to assess climatic and non‐climatic drivers of underfilling. Location: North America (22°N–72°N). Taxon: Trees and shrubs. Methods: We modelled the potential ranges of 447 North American tree and shrub species with species distribution models using bioclimatic variables, and calculated the occupied proportion of each potential range. Results were compared to a null model using simulated ranges generated by a spreading‐dye algorithm. We further used range shape ratios (latitude/longitude) to detect the drivers of disequilibrium. Results: The potential ranges of North American trees and shrubs are broadly underfilled (mean = 48%). Furthermore, range filling is positively correlated with geographic range size. Large‐ranged species have higher range filling than the null model, and shape ratios indicative of climatic restrictions. Small‐ranged species showed a stronger influence of dispersal limitation. Main conclusions: Climate explains only about half of tree species' ranges, and the signal of climatic equilibrium increases with range size. Small‐range species show high levels of climatic disequilibrium, which is likely be driven by combinations of dispersal lags, and undetected environmental factors or biotic interactions. These results highlight the importance of conserving small‐ranged species and the difficulty of forecasting how their distributions will shift in the coming centuries. [ABSTRACT FROM AUTHOR]

Aim: Species distribution models (SDMs) are widely used to forecast potential range expansion of invasive species. However, invasive species occurrence datasets often have spatial biases that may violate key SDM assumptions. In this study, we examined alternative methods of spatial bias correction and multiple methods for model evaluation for seven invasive plant species. Location: North America. Taxon: Common Tansy (Tanacetum vulgare), Wild Parsnip (Pastinaca sativa), Leafy Spurge (Euphorbia virgata), Common Teasel (Dipsacus fullonum), Brown Knapweed (Centaurea jacea), Black Swallowwort (Vincetoxicum nigrum) and Dalmatian Toadflax (Linaria dalmatica). Methods: We employed bias‐correction measures for both occurrence sampling and background sampling inputs in a factorial design for Maxent resulting in six potential models for each species. We evaluated our models for complexity, model fit and using commonly employed evaluation metrics: AUC, partial AUC, the continuous Boyce index and sensitivity. We then developed a structured process for model selection. Results: Models developed without occurrence or background bias correction often were overly complex and did not transfer well to expanding range fronts. Conversely, models that employed occurrence and/or background bias‐correction measures were less complex, had better AICc scores and had greater projection into incipient areas. These simpler models were also more likely to be selected when evaluated using a process that integrated multiple evaluation metrics. We found that invasion history (e.g. established versus incipient) was associated with the effectiveness of spatial bias correction techniques. Main Conclusions: While challenges exist in building climate‐based correlative species distribution models for invasive species, we found that methods relying on maximizing AUC performed poorly for invasive species. We advocate for the use of multiple and diverse metrics for model evaluation. Users of species distribution models need to incorporate explicit consideration of model discrimination, model fit and model complexity into their decision‐making processes if they are to build biologically realistic models. [ABSTRACT FROM AUTHOR]

The endangered Silver Chub (Macrhybopsis storeriana, Kirtland 1844) is native to North America and primarily riverine, with the only known large‐lake population in Lake Erie. Once a major component of the Lake Erie fish community, it declined and became nearly extirpated in the mid‐1900s. Recent collections in western Lake Erie suggest that Silver Chub may be able to recover, but their habitat and distribution are poorly known. A recent work showed an extensive area of western Lake Erie with the potential to support large numbers of Silver Chub, but was based on a geographically limited dataset. We developed a neural network‐based species distribution model for the Silver Chub in western Lake Erie, improved by new synoptic data and using habitat variables resistant to anthropogenic activities. The Potential model predictions were compared with a model that included anthropogenic‐sensitive variables. The Potential model used 10 habitat variables and performed well, explaining > 99% of data variation and had generally low error rates. Predictions indicated that a large area of the waters approximately 2–9 m deep contained Appropriate habitat and the highest abundances should be supported by habitat in a wide arc through the western end of the basin. The model indicated that Appropriate Silver Chub habitat was associated with relatively deep water, near coastal wetlands, where effective fetch is less than average. Disturbance model predictions were similar, but predicted poorer Silver Chub habitat in more areas than that predicted by the Potential model. Our Potential model reveals Appropriate habitat conditions for Silver Chub and its spatial distribution, indicating that extensive areas of western Lake Erie could support Silver Chub. Comparisons with Disturbance model predictions demonstrate that Potential model predictions may be used in conjunction with analyses of degrading conditions in the system to better conserve and manage for this endangered species. [ABSTRACT FROM AUTHOR]

Most spatial conservation planning for wide‐ranging or migratory species is constrained by poor knowledge of species' spatiotemporal dynamics and is only based on static species' ranges. However, species have substantial variation in abundance across their range and migratory species have important spatiotemporal population dynamics. With growing ecological data and advancing analytics, both of these can be estimated and incorporated into spatial conservation planning. However, there is limited information on the degree to which including this information affects conservation planning. We compared the performance of systematic conservation prioritizations for different scenarios based on varying the input species' distributions by ecological metric (abundance distributions versus range maps) and temporal sampling resolution (weekly, monthly, or quarterly). We used the example of a community of 41 species of migratory shorebirds that breed in North America, and we used eBird data to produce weekly estimates of species' abundances and ranges. Abundance distributions at a monthly or weekly resolution led to prioritizations that most efficiently protected species throughout the full annual cycle. Conversely, spatial prioritizations based on species' ranges required more sites and left most species insufficiently protected for at least part of their annual cycle. Prioritizations with only quarterly species ranges were very inefficient as they needed to target 40% of species' ranges to include 10% of populations. We highlight the high value of abundance information for spatial conservation planning, which leads to more efficient and effective spatial prioritization for conservation. Overall, we provide evidence that spatial conservation planning for wide‐ranging migratory species is most robust and efficient when informed by species' abundance information from the full annual cycle. [ABSTRACT FROM AUTHOR]

The North American crop wild relatives (CWR) of lettuce (Lactuca L.) represent an underexplored pool of genetic diversity of potential value to breeding programs. The 10 species belong to three different groups: a native clade including at least six allotetraploid species [L. biennis (Moench) Fernald, L. canadensis L., L. floridana (L.) Gaertn., L. graminifolia Michx., L. hirsuta Muhl. ex Nutt., and L. ludoviciana (Nutt.) Riddell], a diploid clade with one species [L. tatarica (L.) C. A. Mey. subsp. pulchella (Pursh) Stebbins], and a clade related to the cultivated taxon (L. sativa L.) with three non‐native species (L. saligna L., L. serriola L., and L. virosa L.). In this review, we examine the role of herbarium and genebank holdings in taxonomic and other foundational studies, as well as for germplasm exploration and use. We compile the state of knowledge on the ranges of lettuce CWR in North America, modeling the potential distributions of the species and assessing their ex situ and (for native species) in situ conservation status. We categorize seven of the species as high priority for further conservation and three as medium priority, with none currently considered low priority or sufficiently conserved. Further, we review morphological, phenological, genetic diversity, and pest and disease information with regard to North American species. We conclude by outlining the critical gaps and describing a way forward for addressing challenges in the conservation and use of North American wild lettuce germplasm. [ABSTRACT FROM AUTHOR]

Aim: The species abundance distribution (SAD) is a fundamental pattern in macroecology. Understanding how SADs vary spatially, and identifying the variables that drive any change, is important from a theoretical perspective because it enables greater understanding of the factors that underpin the relative abundance of species. However, precise knowledge on how the form of SADs varies across large (continental) scales is limited. Here, we use the shape parameter of the gambin distribution to assess how meta‐community‐scale SAD shape varies spatially as a function of various climatic variables and dataset characteristics. Location: Eastern North America (ENA). Time period: Present day. Major taxa studied: Trees. Methods: Using an extensive continental‐scale dataset of 863,930 individual trees in plots across ENA sampled using a standardized method, we use a spatial regression framework to examine the effect of temperature and precipitation on the form of the SAD. We also assess whether the prevalence of multimodality in the SAD varies spatially across ENA as a function of temperature and precipitation, in addition to other sample characteristics. Results: We found that temperature, precipitation and species richness can explain two‐thirds of the variation in tree SAD form across ENA. Temperature had the largest effect on SAD shape, and it was found that increasing temperature resulted in more logseries‐like SAD shapes (i.e. SADs with a relatively higher proportion of rarer species). We also found spatial variation in SAD multimodality as a function of temperature and species richness. Main conclusions: Our results indicate that temperature is a key environmental driver governing the form of ENA tree meta‐community‐scale SADs. This finding has implications for our understanding of local‐scale variation in tree abundance and suggests that niche factors and environmental filtering are important in the structuring of ENA tree communities at larger scales. [ABSTRACT FROM AUTHOR]

The underlying drivers of β‐diversity along latitudinal gradients have been unclear. Previous studies have focused on β‐diversities calculated at a local scale and shed limited light on regional β‐diversity. We tested the much‐debated effects of range size vs. environmental filtering on the β‐gradient using data from the US Forest Inventory Analysis Program. We showed that the drivers of the β‐gradient were scale dependent. At the local scale species spatial patterns contributed little to the β‐gradient, whereas at the regional scale spatial patterns dominated the gradient and a U‐shape latitudinal relationship for the standardised β‐diversity deviation was revealed. The relationship can be explained by spatial variation in climate and soil texture, thus supporting the environmental filtering hypothesis. But it is inconsistent with Rapoport's rule about the effect of range size on β‐gradient. These results resolve the debate on whether species spatial distributions contribute to β‐gradient and attest the importance of environmental filtering in determining regional β‐diversity. [ABSTRACT FROM AUTHOR]

Aim: We aim to determine the relative influence of climate and species interactions on the global distribution of Soricinae and Crocidurinae shrews through the analysis of their distribution, climate niche and evolutionary history. Both subfamilies are partially allopatric in Eurasia, but in North America only Soricinae is present, thus providing a scenario to address the role of potential competition versus competitive release in determining species' realized distributions at a global scale. Location: Global. Taxon: Soricidae, Eulipotyphla. Methods: We obtained climate data from WorldClim, spatial range data for 302 species from the IUCN Red List and 2614 cytb complete sequences from GenBank. We modelled the potential distribution of the subfamilies by computing three environmental niche models using Maxent: one for Crocidurinae, one for American Soricinae and one for Afro‐Eurasian Soricinae. We created matrices for the genetic, spatial and climatic distance between all pairs of species to calculate the average climatic distance between pairs of species within and between subfamilies. We then evaluated this distance against a null model. To assess the effect of phylogeny on the segregation of the subfamilies, we checked for correlation between genetic and spatial distance. Results: The Afro‐Eurasian Soricinae environmental niche model under‐predicted its occurrence in America. The average climatic distance between subfamilies was larger than expected by chance, while the distance within both Crocidurinae and Afro‐Eurasian Soricinae was smaller. The average distance between the American and Afro‐Eurasian Soricinae was also larger than expected. There was no correlation between spatial and genetic distance for genetic distances over 0.14 substitutions per nucleotide site. Main conclusions: Climate significantly influences the distribution of both subfamilies. As expected in a scenario of competitive release, the climatic range of the Soricinae in America is larger than in Afro‐Eurasia. Thus, besides climate, competition may play an important role in shaping species' global distributions. [ABSTRACT FROM AUTHOR]

Aim: Recent and rapid warming is reorganizing terrestrial vegetation, creating novel species assemblages, and shifting range limits. Relative to the evergreen species that currently dominate much of the boreal forest landscape, Larix (larch) distributions may be particularly responsive to climatic change due to their deciduous habit, and quick growth and reproduction. Here, we amassed data from 83 studies to describe and explain observed patterns of Larix range shifts under contemporary climate change. Location: Northern hemisphere. Taxon: Species of the genus Larix, deciduous gymnosperms. Methods: With 181 observations of Larix range limit dynamics, we used five distribution parameters (tree line advance, stand infilling, tree line recession, stand thinning, no response) and their determinants (climate, land use change, natural disturbance) to describe and explain observed patterns of Larix range shifts under contemporary climate change. We ran a redundancy analysis on the matrix of five distribution parameters considered with other climatic and nonclimatic parameters as explanatory variables. We also characterized the climatic niche of Larix species (temperature and precipitation) and how the niche has changed during the 20th century. Results: Of 173 sites studied over the full distribution of Larix, 63% experienced Larix population increases, 18% had population decreases, and no response was detected at 19% of sites. Latitudinal Larix tree lines in Siberia and North America appear to be infilling and shifting their distributions northward, whereas Larix recession and thinning was more common in southern regions, suggesting southern populations may be experiencing greater drought stress than their northern counterparts. Climatic niches of most Larix species shifted towards warmer and wetter conditions, with tree line advance/forest infilling in cool/dry climate space, and recession/thinning in warm/dry space. Main conclusions: Northern expansion is underway or seems imminent for boreal Larix species, primarily L. laricina in North America. Retraction in southern regions and disappearance of some mountainous populations may be inevitable due to their narrow ecological niches. Species restricted to mountainous habitats may expand locally, though will likely not contribute to broad scale range expansion. These changes will depend on suitable climate, disturbance, and dispersal mechanisms. [ABSTRACT FROM AUTHOR]

The article offers information on the history of terrestrial biogeography and paleobiogeography from 1700–1830s. Topics discussed include species distributions and histories of plant and animal geographies; history of biogeography in North America and works of naturalist Mark Catesby; and works of naturalist Thomas Pennant on bird migration.

Aim Ecological niche theory states that realized niche breadth should increase with population growth. This relationship has been studied extensively in the context of density-dependent habitat selection, and there is evidence that animal populations at higher density occupy a wider range of vegetation types. To our knowledge, no previous studies have investigated the relationship between population growth and climate niche breadth (i.e. the range of climatic conditions occupied). Here we aim to estimate the influence of population trend, as well as changes in distribution, on realized climate niche breadth. Location North America. Methods We estimated changes in realized climate niche breadth and distribution between 1980 and 2012 for 46 bird species using data from the North American Breeding Bird Survey (BBS) and standard ecological niche modelling techniques. We analysed changes in niche breadth in relation to population trends and distributional changes from the BBS for these same species. Results Changes in realized climate niche breadth were significantly and positively associated with population growth, as reflected by BBS population trends, and with changes in distributional extent. Using variance partitioning, we showed that 44.2% of the variation in change in niche breadth can be explained by population trend, and that roughly half of this was independent of changes in distribution. Conclusions Realized climate niche breadth is variable on an ecological time-scale as a function of population trend. Mechanisms associated with changes in distribution and those acting within current species range limits appear to be equally important in driving this relationship. Observed changes in niche breadth may violate distribution modelling assumptions of niche conservatism. Studying how population growth influences realized climate niche breadth is therefore important for understanding dynamic species distributions, responses to climate change and our ability to model future species distributions. [ABSTRACT FROM AUTHOR]

Aim Plasticity in migratory and foraging behaviour allows species to exploit dynamic and novel habitats. This is especially important during seasonal transitions as species track shifting environmental resources and potentially associate with a diversity of habitats. Although land cover associations are thought to vary across seasons for many species, the prevalence of these dynamic relationships across species' distributions are unknown. Our goal was to quantify the extent to which flexibility in seasonal land cover associations exists among forest breeding birds with differing migratory and foraging strategies. Location Eastern United States. Methods We used data on bird occurrence from eBird in conjunction with dynamic species distribution modelling to quantify seasonal plasticity in species land cover associations for 43 forest breeding bird species. We employed a multi-scaled approach relying on adaptive regression models to quantify spatiotemporally varying associations between species' occurrences and land cover diversity and composition. We estimated how these associations varied from spring to autumn and across multiple regions. Results Species demonstrated seasonal shifts in land cover associations and, despite being forest dependent species, were more likely to occur in human-modified landscapes during seasonal transitions. From spring to autumn, Neotropical migrants were more likely to occur in landscapes of lower land cover diversity, but showed the highest seasonal plasticity in land cover associations. Residents and temperate migrants occurred in landscapes with a higher diversity of land cover, but were less variable in their seasonal land cover associations. Following summer, migratory and insectivorous birds took advantage of a wider array of land cover ranging from open to developed landscapes. Main conclusions Species move across landscapes in a seasonally dynamic fashion, and yet concepts of the ecological niche and species-environmental relationships are often considered static. Dynamic species distribution modelling can uncover seasonally complex species-environment relationships, and identify novel aspects of habitat associations critical for supporting full life cycle research and conservation efforts. [ABSTRACT FROM AUTHOR]

The concept of 'natural' populations is a foundation of modern ecology and conservation, with a large body of theoretical literature using these discrete demographic units to understand population dynamics and prioritize conservation strategies. To date, there are currently no objective methods for empirically delineating large-scale population boundaries using demographic data., We present a novel approach for using large-scale, citizen-science monitoring data to quantify geographic structure in trend and abundance and identify distinct natural populations. We demonstrate this approach by delineating populations of eight passerine species using data collected as part of the North American Breeding Bird Survey., Our approach was able to identify geographic structure in both trend and abundance and to delineate distinct populations for all eight species. An independent validation of three species indicated this demographic variation was reflected in underlying vital rates., Synthesis and applications. Natural populations are biologically based alternatives to the traditional geographically defined units that can improve the ability of researchers and managers to quantify spatial variation in population dynamics. Our analysis of natural population structure in breeding songbirds demonstrates that species can show substantial geographic variation in population attributes and underlying demography. We recommend managers define spatial units using natural populations when setting regional population objectives for both single and multispecies conservation plans. [ABSTRACT FROM AUTHOR]

Aim Current interest in forecasting changes to species ranges has resulted in a multitude of approaches to species distribution models ( SDMs). However, most approaches include only a small subset of the available information, and many ignore smaller-scale processes such as growth, fecundity and dispersal. Furthermore, different approaches often produce divergent predictions with no simple method to reconcile them. Here, we present a flexible framework for integrating models at multiple scales using hierarchical Bayesian methods. Location Eastern North America (as an example). Methods Our framework builds a metamodel that is constrained by the results of multiple sub-models and provides probabilistic estimates of species presence. We applied our approach to a simulated dataset to demonstrate the integration of a correlative SDM with a theoretical model. In a second example, we built an integrated model combining the results of a physiological model with presence-absence data for sugar maple ( A cer saccharum), an abundant tree native to eastern North America. Results For both examples, the integrated models successfully included information from all data sources and substantially improved the characterization of uncertainty. For the second example, the integrated model outperformed the source models with respect to uncertainty when modelling the present range of the species. When projecting into the future, the model provided a consensus view of two models that differed substantially in their predictions. Uncertainty was reduced where the models agreed and was greater where they diverged, providing a more realistic view of the state of knowledge than either source model. Main conclusions We conclude by discussing the potential applications of our method and its accessibility to applied ecologists. In ideal cases, our framework can be easily implemented using off-the-shelf software. The framework has wide potential for use in species distribution modelling and can drive better integration of multi-source and multi-scale data into ecological decision-making. [ABSTRACT FROM AUTHOR]

Aim Towards the cold margins of the Northern Hemisphere boreal zone, continuing warming should theoretically provide a longer vegetative season, favouring growth and a northward shift in tree species distribution. The northern distribution of Thuja occidentalis L. (eastern white cedar) is marked by the presence of isolated marginal populations distant from the continuous distribution. If those populations proved to be well adapted to their future local climatic conditions, their expansion could accelerate cedar poleward migration. We tested the hypotheses that (1) there will be a growth increase in cedar northern marginal populations as a result of global warming, and (2) the edaphic conditions and regional precipitation regimes will modulate their response to warming. Location Canadian boreal forest, western Québec (47-50° N, 74-80° W). Methods We investigated radial growth using tree-ring measurements from dominant and co-dominant eastern white cedar trees ( n = 723) distributed along a latitudinal gradient from the species' northern margin to the centre of its natural range. First, low-frequency growth variations were analysed on whole chronologies ( ad 1720-2010). Second, inter-annual growth variations were tested against ad 1953-2010 monthly temperature and precipitation time series with a bootstrapped correlation function. Finally, the impact of environmental variables on the growth-climate relationships was assessed. Results Unexpectedly, a growth decline was observed starting in 1980 in marginal sites. Dendroclimatic analyses revealed that radial growth was not only limited by short growing seasons but also by summer droughts in the marginal zone. This response was exacerbated in sites that received less summer precipitation. Counterintuitively, autumn and spring precipitation negatively impacted on growth, especially in wet soil stands. Main conclusions Northern marginal populations of cedar may have already reached their optimum temperature threshold for radial growth. Our results suggest that they will probably be facing increasing hydric stress selection pressure under the assumptions of climate change. Their responses to future warming will be highly dependent on the seasonality and magnitude of variation in precipitation regimes. [ABSTRACT FROM AUTHOR]

Aim Using survey data for North American birds, we assess how well historical patterns of species richness are explained by stacked species distribution models and macroecological models. We then describe the degree to which projections of future species richness differ, employing both modelling approaches across multiple emissions scenarios. Location USA and Canada. Methods We use Audubon Christmas Bird Count and North American Breeding Bird Survey data to estimate current and future species richness of birds using two distinct approaches. In the first, we model richness by stacking predictions from individual species distribution models. In the second, we model richness directly, ignoring the contributions of specific taxa to richness estimates. Results The two modelling approaches show similar accuracies when validated with historical observations, particularly winter observations, and result in similar patterns of richness when projected onto current and future climate spaces. Patterns of projected change in species richness differed markedly between winter and summer seasons regardless of modelling approach. Our models suggest that bird species richness in winter will increase or remain stable across much of North America. In contrast, species richness in summer is projected to decrease over much of North America, except part of northern Canada, suggesting that climate may constrain many breeding bird species and communities in the future. Main conclusions Stacked species distribution models and macroecological models produce similar estimates of current and future species richness for each of two seasons despite being built on different concepts of community assembly. Our results suggest that, although the mechanisms that shape geographical variation in biodiversity remain uncertain, these limitations do not impede our ability to predict patterns of species richness at broad scales. Congruence of species richness projections across modelling approaches is encouraging for conservation planning efforts that focus on retaining biodiversity into the future. [ABSTRACT FROM AUTHOR]

Water flow gradients have been linked to phenotypic differences and swimming performance across a variety of fish assemblages. However, the extent to which water motion shapes patterns of phenotypic divergence within species remains unknown. We tested the generality of the functional relationship between swimming morphology and water flow by exploring the extent of fin and body shape polymorphism in 12 widespread species from three families (Acanthuridae, Labridae, Pomacentridae) of pectoral-fin swimming (labriform) fishes living across localized wave exposure gradients. The pectoral fin shape of Labridae and Acanthuridae species was strongly related to wave exposure: individuals with more tapered, higher aspect ratio (AR) fins were found on windward reef crests, whereas individuals with rounder, lower AR fins were found on leeward, sheltered reefs. Three of seven Pomacentridae species showed similar trends, and pectoral fin shape was also strongly related to wave exposure in pomacentrids when fin aspect ratios of three species were compared across flow habitats at very small spatial scales (,100 m) along a reef profile (reef slope, crest, and back lagoon). Unlike fin shape, there were no intraspecific differences in fish body fineness ratio across habitats or depths. Contrary to our predictions, there was no pattern relating species' abundances to polymorphism across habitats (i.e., abundance was not higher at sites where morphology is better adapted to the environment). This suggests that there are behavioral and/or physiological mechanisms enabling some species to persist across flow habitats in the absence of morphological differences. We suggest that functional relationships between swimming morphology and water flow not only structure species assemblages, but are yet another important variable contributing to phenotypic differences within species. The close links between fin shape polymorphism and local water flow conditions appear to be important for understanding species' distributions as well as patterns of diversification across environmental gradients. [ABSTRACT FROM AUTHOR]

Aim We aimed to quantify the relative contributions of trait-based selection and the flow of individuals across space created by differences in species abundance, i.e. mass effects, in determining local-scale species relative abundance ( SRA) at 0.07 ha, 1° grid cell and subregion grains. Location The eastern USA. Methods We coupled a maximum entropy model ( MaxEnt) with nine species-specific plant traits and a continental-scale forest inventory dataset to perform our analyses. Mass effects were estimated using the next grain size up as the metacommunity (or the eastern USA at the subregion grain, and also at the 1° grid cell grain in a fourth analysis). Permutation tests were conducted to test the significance of trait constraints. The Kullback- Leibler divergence index was used to decompose the information content in each assemblage SRA. Results Trait constraints were significant in predicting community structures at coarse scales, but were largely not significant at fine or medium scales. At the 0.07 ha grain little of the variation in local SRA can be explained by either trait constraints or a regional SRA. At the 1° grain c. 61% of the variation could be accounted for by a regional SRA represented by subregions. At the subregion grain c. 74% of the variation could be accounted for by trait constraints and the SRA of the entire study area. Main conclusions Our results suggest that the relative importance of community assembly processes is scale dependent. Estimated mass effects predominated at small spatial scales where environmental gradients were weak. Trait-based selection was hard to detect at small scales and was strongest at large scales where environmental gradients are stronger. The fact that, at all scales, mass effects accounted for more variation in assemblage SRA than trait-based selection in our analyses suggests that regional processes are important in determining community structures more locally. [ABSTRACT FROM AUTHOR]

The new world screwworm [ Cochliomyia hominivorax (Coquerel)] was eradicated in North America, Libya and other locations using the sterile insect technique ( SIT)., To examine the role of weather in its eradication, a physiologically-based demographic model was developed and used to characterize its range of year-round persistence. Published data on developmental times, fecundity and mortality rates on temperature were used to parameterize the model. The lower and upper thermal thresholds for development are 14.5 and 43.5 °C, and the optimal temperature for survival is 27.2 °C. An index of favourability based on annual rainfall was used as an approximate estimate of the limiting effects of moisture in arid areas., The open source geographical information system software grass was used to map the simulation results, as well as county level myiasis incidence data for Texas for the 1962-1983 SIT eradication programme., Winter temperature and rainfall are shown to have a strong influence on screwworm outbreaks and in facilitating eradication in North America and Libya. Prospective analysis for the Mediterranean Basin suggests that eastern areas are most favourable for screwworm establishment (e.g. the Nile River area of Egypt)., The SIT eradication programme and its possible extension into South America are discussed., Expected +2 °C climate warming is predicted to increase the potential year-round range of screwworm in the southeast U.S.A. [ABSTRACT FROM AUTHOR]

Aim Species distribution models have often been hampered by poor local species data, reliance on coarse-scale climate predictors and the assumption that species-environment relationships, even with non-proximate predictors, are consistent across geographical space. Yet locally accurate maps of invasive species, such as the Africanized honeybee ( AHB) in North America, are needed to support conservation efforts. Current AHB range maps are relatively coarse and are inconsistent with observed data. Our aim was to improve distribution maps using more proximate predictors (phenology) and using regional models rather than one across the entire range of interest to explore potential differences in drivers. Location United States of America. Methods We provide a generalized framework for regional and local species distribution modelling with our more nuanced and spatially detailed forecast of potential AHB spread using multiple habitat modelling techniques and newly derived remotely sensed phenology layers. Results Variable importance did differ between the two regions for which we modelled AHB. Phenology metrics were important, especially in the south-east. Main conclusions Results demonstrate that incorporating a combination of both climate drivers and vegetation phenology information into models can be important for predicting the suitable habitat range of these pollinators. Regional models may provide evidence of differing drivers of distributions geographically. This framework may improve many local and regional species distribution modelling efforts. [ABSTRACT FROM AUTHOR]

Identifying factors affecting species distribution is a longstanding goal in ecology and evolution that is accentuated by our need to anticipate climate change impacts. We sought to test whether any phylogenetic effect can be detected in either the environmental characteristics or range attributes of North American trees, and to explore the existence of a general interspecific pattern in the environmental factors influencing species range size. To do so we tested prevailing hypotheses relating climatic and edaphic characteristics to species range size in the North American arboflora (n = 598), using spatial null models to test for the relevance of observed patterns. We found that interspecific variation in the range area of North American trees is strongly related to the environmental regimes characteristic of the species range. Linear models and phylogenetic regressions involving six environmental characteristics explained 83% of the variance in species range area, and affirmed a positive relationship between niche breadth and range size. Tree species that can tolerate a larger variability in local climatic conditions, deal with harsher edaphic conditions, and weak levels of environmental energy tend to have larger range area; this can account for the greater geographic range of species at higher latitudes, the Rapoport effect. There is a significant phylogenetic signal for both range area and limits in North American trees, and for climatic limits, but not for energy or edaphic characteristics associated with species range. These findings highlight the possibility that species with small geographic ranges may be more sensitive to the effects of climate change. [ABSTRACT FROM AUTHOR]

Aim Aridification of western North America from the Miocene to the Recent has spurred plant migrations, as species invaded and/or diversified into newly formed floristic regions. The 51 species of Mentzelia section Bartonia (Loasaceae) inhabit most of these regions, providing an opportunity to investigate lineage-specific diversification among the western floras. Lineage-specific formation of the modern western North American flora was investigated by applying statistical phylogenetic methods to molecular data. Location Western North America, including the intermountain region, south-western deserts, Rocky Mountains and North American Prairies Province. Methods Internal and external transcribed spacer region data for all taxa in section Bartonia and outgroups were analysed with maximum likelihood and Bayesian inference methods for phylogenetic relationships. Distribution and phylogenetic data were then analysed by Bayesian, maximum likelihood, parsimony, and stochastic mapping optimization methods for inference of biogeographical transitions among floristic regions. Model fitting was used to assess the symmetry of transitions from mesic to arid environments. Results Multiple transitions were inferred, especially those associated with the Colorado Plateau and the Rocky Mountains. The ancestral area for section Bartonia was estimated equivocally to be all regions except the Great Basin in parsimony reconstructions, but to be the Colorado Plateau with highest probability with the Bayesian approach. Throughout these regions, transitions between mesic to arid habitats were consistent with expectations under a null model, suggesting no directional bias in transitions. In section Bartonia, within-region diversification occurred in all areas except the Great Basin and Sonoran Desert, the diversity of which is explained as the result of movement into these regions. Main conclusions The floristic regions of western North America have exchanged numerous migrants throughout their history. Among them, the Colorado Plateau, Great Basin and Rocky Mountains were particularly important floristic sources and recipients of migrants. Although previous studies have revealed a strong association among the south-western deserts, these results suggest that the plant diversities in these deserts can be influenced more by adjacent provinces than by each other. [ABSTRACT FROM AUTHOR]

A new approach to habitat distribution modeling is presented and tested with data on North American plants. The relative frequency function (RFF) algorithm compares the relative frequencies of a species' sample points to that of random points or absence points on the landscape to compute a frequency ratio. The relative frequency ratio r is smoothed across the range of values using moving, overlapping windows. The ratio of frequencies at a sample point for each variable is used to compute the geometric mean score for all data with non-missing values. Variables are added using a forward stepwise method. Confidence intervals are computed with bootstrap resampling. The method was tested with artificial and species habitat and geographic range data. The RFF method in all cases gave results comparable to other methods tested. For the species with good geographic range maps, the results were consistent with known biogeography. The RFF method is particularly well-suited to irregularly shaped distributions and can classify sample points even when the data contain missing values. The method is extremely simple to use and comes with a free software tool, does not require a large sample size, does not require absence data, and is more interpretable and portable than certain other methods. [ABSTRACT FROM AUTHOR]

Underpinning the International Union for Conservation of Nature (IUCN) Red List is the assessment of extinction risk as determined by the size and degree of loss of populations. The IUCN system lists a species as Critically Endangered, Endangered, or Vulnerable if its population size declines 80%, 50%, or 30% within a given time frame. However, effective implementation of the system faces substantial challenges and uncertainty because geographic scale data on population size and long-term dynamics are scarce. I develop a model to quantify extinction risk using a measure based on a species' distribution, a much more readily obtained quantity. The model calculates the loss of the area of occupancy that is equivalent to the loss of a given proportion of a population. It is a very simple yet general model that has no free parameters and is independent of scale. The model predicted well the distributions of 302 tree species at a local scale and the distributions of 348 species of North American land birds. This area-based model provides a solution to the long-standing problem for IUCN assessments of lack of data on population sizes, and thus it will contribute to facilitating the quantification of extinction risk worldwide. [ABSTRACT FROM AUTHOR]

Aim To investigate the phylogeographic patterns among populations of the wide-ranging velvet ant Sphaeropthalma arota to (1) examine the biogeographic patterns within this species, and (2) associate major genetic divergences to historical vicariance events in order to gain insight into the processes that drove diversification in arid-adapted organisms. Location Western North America. Methods Phylogenetic relationships were determined by analysing the two ribosomal DNA internal transcribed spacers (ITS1 and ITS2) in M rB ayes. Divergence dates were estimated for major nodes using two different molecular dating analyses: a penalized likelihood approach to rate smoothing using the program r8s, and a Bayesian MCMC averaging approach to rate smoothing using the program beast. Both analyses were calibrated using fossils from Dominican amber. Haplotype networks were estimated using tcs. Ecological niche models (ENMs) were developed using six bioclimatic variables from the WorldClim data set in the program M axent. Results The phylogenetic reconstructions indicate that S. arota can be split into four deeply divergent lineages that probably represent distinct species. No morphological characters were found that can be used to identify these four species, making the S. arota species complex the first documented cryptic species complex in the family Mutillidae. Ecological niche models provide estimated distributions, which indicate that each of the four species inhabits a distinct niche. Divergence date estimates suggest that major diversification events occurred in the late Neogene. Main conclusions Sphaeropthalma arota is composed of four genetically distinct species that cannot be distinguished morphologically based on current methods. We suggest that the members of this group be identified as the S. arota species complex. Major diversification events in this species complex can be linked to late Neogene mountain building and aridification events, specifically the uplift of the mountain ranges in southern California and the expansion of the Bouse Sea. [ABSTRACT FROM AUTHOR]

Aim Geographic variation in species richness is a well-studied phenomenon. However, the unique response of individual lineages to environmental gradients in the context of general patterns of biodiversity across broad spatial scales has received limited attention. The focus of this research is to examine relationships between species richness and climate, topographic heterogeneity and stream channel characteristics within and among families of North American freshwater fishes. Location The United States and Canada. Methods Distribution maps of 828 native species of freshwater fishes were used to generate species richness estimates across the United States and Canada. Variation in species richness was predicted using spatially explicit models incorporating variation in climate, topography and/or stream channel length and stream channel diversity for all 828 species as well as for the seven largest families of freshwater fishes. Results The overall gradient of species richness in North American freshwater fishes is best predicted by a model incorporating variables describing climate and topography. However, the response of species richness to particular climate or landscape variables differed among families, with models possessing the highest predictive ability incorporating data on climate, topography and/or stream channel characteristics within a region. Main conclusions The correlations between species richness and abiotic variables suggest a strong influence of climate and physical habitat on the structuring of regional assemblages of North American freshwater fishes. However, the relationship between these variables and species richness varies among families, suggesting the importance of phylogenetic constraints on the regulation of geographic distributions of species. [ABSTRACT FROM AUTHOR]

Aim North America harbours the most diverse freshwater mussel fauna on Earth. This fauna has high endemism at the continental scale and within individual river systems. Previous faunal classifications for North America were based on intuitive, subjective assessments of species distributions, primarily the occurrence of endemic species, and do not portray continent-wide patterns of faunal similarity. The aim of this study is to provide an analytical portrayal of patterns of mussel diversity in a hierarchical framework that informs the biogeographical history of the fauna. Location The study considered the mussel fauna of North America from the Rio Grande system northwards. Methods Patterns of mussel faunal similarity in 126 river systems or lake watersheds across North America were examined. The dataset was developed from the literature and consisted of recent species presence/absence (282 species) in each drainage unit; subspecies were not included. Patterns of mussel diversity were examined with hierarchical cluster analysis, based on a pairwise distance matrix between all drainage units. Results Cluster analysis revealed 17 faunal provinces within four major faunal regions: Mississippian, Atlantic, Eastern Gulf and Pacific. The Mississippian Region dominates the North American fauna with 11 provinces, including five not recognized by previous classifications: Mississippi Embayment, Upper Mississippi, Great Plains, Ohioan and Pontchartrain–Pearl–Pascagoula. Within the Eastern Gulf Region (containing three provinces), the Escambia–Choctawhatchee Province is distinctive from the Apalachicolan Province, under which it was previously subsumed. Patterns of diversity in the Atlantic Region (two provinces) and Pacific Region (one province) were similar to previous classifications. Main conclusions The classification proposed in this study largely corroborates earlier schemes based on the occurrence of endemic species but identifies additional heterogeneity that reflects unique assemblages of widely distributed species. The study proposes a hierarchical structure that illustrates relationships among these provinces. Although some provinces in the Mississippian Region have high endemism, all Mississippian provinces share a group of widely distributed species. The Atlantic and Eastern Gulf regions have distinctive, endemic faunas suggesting limited past connectivity with the Mississippian Region. The Pacific Region is the most distinct fauna in North America and bears close affinity to the Eurasian mussel fauna. [ABSTRACT FROM AUTHOR]

The textbook version of sympatric host race formation in Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) features an ancestral hawthorn-infesting race and a derived apple race differing in life-history timing and response to host fruit odor. However, previous research has focused largely on northeastern North America. To investigate life-history timing in poorly studied southeastern North American populations with very diverse hosts, we performed common garden experiments on emergence time on six southern R. pomonella populations and four other R. pomonella species-group populations. Findings were: (1) the diverse adult emergence times of southern populations resulted largely from genetic differences; (2) some southern populations had bimodal emergence curves; (3) correlations of allozyme markers and emergence times were uncommon in southern populations; and (4) mean emergence times from common garden rearings and dates of field collection of the populations were strongly correlated. [ABSTRACT FROM AUTHOR]

The mysid crustacean Hemimysis anomala (‘bloody-red shrimp’) is one of the most recent participants in the invasion of European inland waters by Ponto-Caspian species. Recently the species also became established in England and the Laurentian Great Lakes of North America. Using information from mitochondrial cytochrome oxidase I (COI) gene sequences, we traced the invasion pathways of H. anomala; the inferences were enabled by the observed phylogeographical subdivision among the source area populations in the estuaries of the Ponto-Caspian basin. The data distinguish two routes to northern and western Europe used by distinct lineages. One route has been to and through the Baltic Sea and further to the Rhine delta, probably from a population intentionally introduced to a Lithuanian water reservoir from the lower Dnieper River (NW Black Sea area) in 1960. The other lineage is derived from the Danube delta and has spread across the continent up the Danube River and further through the Main–Danube canal down to the Rhine River delta. Only the Danube lineage was found in England and in North America. The two lineages appear to have met secondarily and are now found intermixed at several sites in NW Europe, including the Rhine and waters linked with the man-made Mittellandkanal that interconnects the Rhine and Baltic drainage systems. [ABSTRACT FROM AUTHOR]

Aim The magnitude of predicted range shifts during climate change is likely to be different for species living in mountainous environments compared with those living in flatland environments. The southern edges of ranges in mountain species may not shift northwards during warming as populations instead migrate up available elevational gradients; overall latitudinal range appears therefore to expand. In contrast, flatland species should shift range centroids northwards but not expand or contract their latitudinal range extent. These hypotheses were tested utilizing Late Pleistocene and modern occurrence data. Location North America. Methods The location and elevation of modern and Late Pleistocene species occurrences were collected from data bases for 26 species living in mountain or flatland environments. Regressions of elevation change over latitude, and southern and northern range edges were calculated for each species for modern and fossil data sets. A combination of regressions andanovas were used to test whether flatland species shift range edges and latitudinal extents more than mountain species do. Results Flatland species had significantly larger northward shifts at southern range edges than did mountain-dwelling species from the Late Pleistocene to the present. There was also a significant negative correlation between the amount of change in the latitude of the southern edge of the range and the amount of elevational shifting from the Late Pleistocene to the present. Although significant, only c. 25% of the variance could be explained by this relationship. In addition, there was a weak indication that overall range expansion was less in flatland-dwelling than in mountain-dwelling species. Main conclusions The approach used here was to examine past species’ range responses to warming that occurred after the last ice ages as a means to better predict potential future responses to continued warming. The results confirm predictions of differential southern edge and overall range shifts for species occupying mountain and flatland regions in North America. The findings may be broadly applicable in other regions, thus allowing better modelling of future range and distribution related responses. [ABSTRACT FROM AUTHOR]

Species occurrence databases and climate databases were used to examine differences in patterns of species experienced climate across latitude for wide-ranging rodents in the central-eastern and western North America. The accumulated data were used to address three questions: (1) Do rodent species in the central and eastern region of North America select habitat at range edges to remain closer to climate conditions at the range core? (2) Is there a trend toward species having greater experienced climate variation consistent with smaller effects of orbitally controlled climate oscillations in the south vs. north? (3) How do species experienced temperature, precipitation, and elevation means and variation in this region compare to rodent species in the adjacent but more heterogeneous western North America? Results showed that central-eastern North American species occur in as wide a range of environmental conditions as available throughout their ranges. These patterns are different from previous findings for rodents in the adjacent western USA and highlight major differences in current structure of species experienced environmental means and variation over latitude for species in spatially heterogeneous, mountainous areas vs. those that occupy flatter lands. The differences are likely important for determining differential response to climate changes. [ABSTRACT FROM AUTHOR]

Species that are frequently introduced to an exotic range have a high potential of becoming invasive. Besides propagule pressure, however, no other generally strong determinant of invasion success is known. Although evidence has accumulated that human affiliates (domesticates, pets, human commensals) also have high invasion success, existing studies do not distinguish whether this success can be completely explained by or is partly independent of propagule pressure. Here, we analyze both factors independently, propagule pressure and human affiliation. We also consider a third factor directly related to humans, hunting, and 17 traits on each species' population size and extent, diet, body size, and life history. Our dataset includes all 2362 freshwater fish, mammals, and birds native to Europe or North America. In contrast to most previous studies, we look at the complete invasion process consisting of (1) introduction, (2) establishment, and (3) spread. In this way, we not only consider which of the introduced species became invasive but also which species were introduced. Of the 20 factors tested, propagule pressure and human affiliation were the two strongest determinants of invasion success across all taxa and steps. This was true for multivariate analyses that account for intercorrelations among variables as well as univariate analyses, suggesting that human affiliation influenced invasion success independently of propagule pressure. Some factors affected the different steps of the invasion process antagonistically. For example, game species were much more likely to be introduced to an exotic continent than nonhunted species but tended to be less likely to establish themselves and spread. Such antagonistic effects show the importance of considering the complete invasion process. [ABSTRACT FROM AUTHOR]

Aim To assess which climatic variables control the distribution of western hemlock ( Tsuga heterophylla), how climatic controls vary over latitude and between disjunct coastal and interior sub-distributions, and whether non-climatic factors, such as dispersal limitation and interspecific competition, affect range limits in areas of low climatic control. Location North-western North America. Methods We compared four bioclimatic variables [actual evapotranspiration (AET), water deficit (DEF), mean temperature of the coldest month (MTCO), and growing degree-days (GDD5)] with the distribution of T. heterophylla at a 2-km grid cell resolution. The distribution is based on a zonal ecosystem classification where T. heterophylla is the dominant late-successional species. For each bioclimatic variable and at each degree of latitude, we calculated the threshold that best defines the T. heterophylla distribution and assessed the extent to which T. heterophylla was segregated to one end of the bioclimatic gradient. We also fitted two forms of multivariate bioclimatic models to predict the T. heterophylla distribution: a simple threshold model and a complex Gaussian mixture model. Each model was trained separately on the coastal and interior distributions, and predicted areas outside of the T. heterophylla distribution (overprediction) were evaluated with respect to known outlier populations. Results Actual evapotranspiration was the most accurate predictor across the T. heterophylla distribution; other variables were important only in certain areas. There was strong latitudinal variation in the thresholds of all variables except AET, and the interior distribution had wider bioclimatic thresholds than the coastal distribution. The coastal distribution was predicted accurately by both bioclimatic models; areas of overprediction rarely occurred > 10 km from the observed distribution and generally matched small outlier populations. In contrast, the interior distribution was poorly predicted by both models; areas of overprediction occurred up to 140 km from the observed distribution and did not match outlier populations. The greatest overprediction occurred in Idaho and Montana in areas supporting species that typically co-exist with T. heterophylla. Main conclusions The high predictive capacity of AET is consistent with this species’ physiological requirements for a mild and humid climate. Spatial variation of MTCO, GDD5 and DEF thresholds probably reflects both the correlation of these variables with AET and ecotypic variation. The level of overprediction in portions of the interior suggests that T. heterophylla has not completely expanded into its potential habitat. Tsuga heterophylla became common in the interior 2000–3500 years ago, compared with > 9000 years ago in the coastal region. The limited time for dispersal, coupled with frequent fires at the margins of the distribution and competition with disturbance-adapted species, may have retarded range expansion in the interior. This study demonstrates that bioclimatic modelling can help identify various climatic and non-climatic controls on species distributions. [ABSTRACT FROM AUTHOR]

A controversial question in biogeography and ecology involves the extent to which vicariance and dispersal interact to determine the structure of continental biotic assemblages. Accumulating evidence of distributional changes during the past 40000 years (Late Quaternary) hassuggested to ecologists that changes in geographic ranges during thePleistocene were of sufficient magnitude to erode prior associationsbetween earth and biotic evolution in continental biotas. This paperfirst argues that this question can only be addressed by examining the magnitude of Late Quaternary range-shifting at the spatial scale established within the framework of historical biogeography (e.g., areas of endemism) rather than that of ecology (e.g., local community assemblages); and second reassesses patterns of range-shifting in the FAUNMAP data base recording Late Quaternary distributions of North American mammals. At the scale of geomorphological provinces, North American rodents have exhibited highly stable distributions during this time frame, suggesting that previous inferences drawn from analyses ofstability at a local community scale are not relevant to questions of congruence between earth and biotic history at regional or continental scales. A comprehensive understanding of processes underlying theassembly of continental biotas still requires incorporation of biogeographic patterns developed well before episodes of Late Quaternary climatic turbulence. [ABSTRACT FROM AUTHOR]

Aphyllon castilloi Franc.‐Gut., Cházaro & Espejo (Orobanchaceae), a new species discovered in central Veracruz, Mexico is herein described, illustrated and compared with other Aphyllon species recorded from Mexico. The new species inhabits tropical semideciduous forest, a novel ecosystem for Aphyllon species native to North America, in contrast to most collections from Mexico, which are from warm sandy deserts. In addition, it parasitizes Simsia foetida (Asteraceae: Heliantheae). As far as known, the distribution of the new species is very restricted. [ABSTRACT FROM AUTHOR]