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Global and national commitments to slow biodiversity loss by expanding protected area networks also provide opportunities to evaluate conservation priorities in the face of climate change. Using recently developed indicators of climatic macrorefugia, environmental diversity, and corridors, we conducted a systematic, climate‐informed prioritization of conservation values across North America. We explicitly considered complementarity of multiple conservation objectives, capturing key niche‐based temperature and moisture thresholds for 324 tree species and 268 songbird species. Conservation rankings were influenced most strongly by climate corridors and species‐specific refugia layers. Although areas of high conservation value under climate change were partially aligned with existing protected areas, ∼80% of areas within the top quintile of biome‐level conservation values lack formal protection. Results from this study and application of our approach elsewhere can help improve the long‐term value of conservation investments at multiple spatial scales.

With a shrinking supply of wilderness and growing recognition that top predators can have a profound influence on ecosystems, the persistence of large carnivores in human-dominated landscapes has emerged as one of the greatest conservation challenges of our time. Carnivores fascinate society, yet these animals pose threats to people living near them, resulting in high rates of carnivore death near human settlements. We used 41 y of demographic data for more than 2,500 brown bears—one of the world’s most widely distributed and conflict-prone carnivores—to understand the behavioral and demographic mechanisms promoting carnivore coexistence in human-dominated landscapes. Bear mortality was high and unsustainable near people, but a human-induced shift to nocturnality facilitated lower risks of bear mortality and rates of conflict with people. Despite these behavioral shifts, projected population growth rates for bears in human-dominated areas revealed a source-sink dynamic. Despite some female bears successfully reproducing in the sink areas, bear persistence was reliant on a supply of immigrants from areas with minimal human influence (i.e., wilderness). Such mechanisms of coexistence reveal a striking paradox: Connectivity to wilderness areas supplies bears that likely will die from people, but these bears are essential to avert local extirpation. These insights suggest carnivores contribute to human–carnivore coexistence through behavioral and demographic mechanisms, and that connected wilderness is critical to sustain coexistence landscapes.

1. Habitat choice is an evolutionary product of animals experiencing increased fitness when preferentially occupying high-quality habitat. However, an ecological trap (ET) can occur when an animal is presented with novel conditions and the animal's assessment of habitat quality is poorly matched to its resulting fitness. 2. We tested for an ET for grizzly (brown) bears using demographic and movement data collected in an area with rich food resources and concentrated human settlement. 3. We derived measures of habitat attractiveness from occurrence models of bear food resources and estimated demographic parameters using DNA mark-recapture information collected over 8 years (2006-2013). We then paired this information with grizzly bear mortality records to investigate kill and movement rates. 4. Our results demonstrate that a valley high in both berry resources and human density was more attractive than surrounding areas, and bears occupying this region faced 17% lower apparent survival. Despite lower fitness, we detected a net flow of bears into the ET, which contributed to a study-wide population decline. 5. This work highlights the presence and pervasiveness of an ET for an apex omnivore that lacks the evolutionary cues, under human-induced rapid ecological change, to assess tradeoffs between food resources and human-caused mortality, which results in maladaptive habitat selection.

The challenge of understanding how composite disturbances affect ecosystems is a central theme of modern ecology. For instance, anthropogenic footprints and wildfire are increasing globally, but how they combine remains poorly understood. Here, we assessed how a disturbance legacy of about 10-m-wide cutlines, cleared for seismic assessments of fossil fuels, affects wildfire dynamics and species assemblages in boreal peatland forests. One year after the Fort McMurray Horse River wildfire of 2016 (Alberta, Canada), we assessed differences in plant and butterfly assemblages across forests and cutlines, from unburned and severely burned peatlands. We hypothesized that, by reducing fire severity, cutlines could support plants and butterflies in the presence of a severe wildfire (the “refuge hypothesis”). Proportion of burned duff was five times higher in burned forests compared to burned cutlines (53% vs. 11%). We found 107 plant and 46 butterfly taxa, with species richness being, respectively, about 1.4 and 1.7 times higher in lines than in forests, independently from wildfire. Models for single species demonstrated different responses to disturbance, including no responses (25% of species), dominant effects of fire or lines (50%), additive effects (10%), and interactive effects (15%). Cutline refuges occurred for 20% of plant and 70% of butterfly species. Multiple lines of evidence suggest that anthropogenic refuges from fire occur in these peatland forests, yet different patterns of responses confirm the complex effects occurring with composite disturbances. Given that cutlines dissect thousands of square kilometers of boreal forests in North America, further studies should investigate their implications on recovery trajectories of these forests’ succession after wildfire.

1. Climate and land-use change are expected to substantially alter future plant species distributions leading to higher extinction rates. However, little is known about how plant species ranges, richness and phylogenetic diversity of continents will be affected by these dynamics. 2. We address this gap here by examining the patterns of species' distributions and phylogenetic relationships for 7465 seed plant taxa in North America. An ensemble of species distribution models was used to estimate the potential suitable habitat of species under different sets of climate, land-use and dispersal constraint scenarios. We then evaluated the vulnerability and extinction risk of individual species to changes in climate and land use, and examined whether rare, endangered and evolutionarily distinct species were disproportionally threatened by climate and land-use change. 3. We show that ~2000 species may lose > 80% of their suitable habitats under the A1b emission scenario for the 2080s, while ~100 species may experience > 80% range expansions (a 20 : 1 ratio of loss to gain). When considering > 50% range retraction and expansion, the ratio of loss to gain was 13 : 1. A greater loss of species diversity is expected at low latitudes, while larger gains are expected at high latitudes. Evolutionarily distinct species are predicted to have significantly higher extinction risks than extant species. This suggests a disproportionate future loss of phylogenetic diversity for the North American flora. 4. Synthesis and applications. Our study provides continental-scale evidence of plant species extinction risk caused by future climate and land-use change, and highlights the importance of integrating phylogenetic measures into conservation risk assessments. This work provides insight into the status, trends and threats for a large share of North America's plant species by identifying risks and prioritizing conservation in a rapidly changing world.

Canopy height is a key factor that affects carbon storage, vegetation productivity and biodiversity in forests, as well as an indicator of key processes such as biomass allocation. However, global variation in forest canopy height and its determinants are poorly known. We used global data on Light Detection and Ranging‐derived maximum forest canopy height (Hₘₐₓ) to test hypotheses relating Hₘₐₓ to current climate (water availability, ambient energy and water–energy dynamics), regional evolutionary and biogeographic history, historical climate change, and human disturbance. We derived Hₘₐₓ for 32 304 forested 55‐km grid cells using 1‐km global canopy height data (maximum height of 1‐km cells within a 55‐km grid). Variation in Hₘₐₓ was related to latitude and biomes, along with environmental and historical variables. Both spatial and non‐spatial linear models were used to assess the relative importance of the different hypothesized factors. Hₘₐₓ was inversely related to latitude (i.e. tall canopies at the equator), but with high geographical variability. Actual evapotranspiration and annual precipitation were the factors most correlated to Hₘₐₓ globally, thus supporting the water–energy dynamics hypothesis. However, water limitation emerged as a key factor in tropical and temperate biomes within specific geographic regions, while energy limitation was a more important factor in boreal regions where temperature is more limiting to trees than water. Hₘₐₓ exhibited strong variation among biogeographic regions, supporting the role of regional evolutionary and biogeographic history in structuring broad‐scale patterns in canopy height. Furthermore, there were divergent relationships between climate and Hₘₐₓ between the Southern and Northern Hemispheres, consistent with historical evolutionary contingencies modulating these relationships. Historical climate change was also related to Hₘₐₓ, albeit not as strongly, with shorter canopy heights where late‐Quaternary climate has been less stable. In contrast, human disturbance was only weakly related to Hₘₐₓ at the scale (55 km) examined here. Synthesis. This study confirms that forest canopy height is strongly controlled by current climate, but also provides evidence for an important supplementary role for regional–historical factors. This highlights the importance of considering evolutionary and biogeographic history for achieving a comprehensive understanding of forest ecosystem properties.

Climate refugia can serve as remnant habitat for cold‐adapted species and delay forest transitions. The world's largest freshwater lake by surface area, Lake Superior, serves as a model system for understanding cooling‐mediated refugia effects, as its cool summer water temperatures have maintained disjunct populations of arctic–alpine plants on its shoreline since deglaciation. It is known to affect local inland climates by providing a summer cooling effect; however, the inland temperature gradient and spatial patterns of cooling have not been well quantified. Here, we describe the extent, degree, and patterns of temperature buffering and examine drivers of buffering and disjunct plant occurrence for Lake Superior's north shore over a 3‐year period at distances of 10, 100 m, 1, 10, and 100 km inland. We analyzed temperature data by year, month, summer maximum (July), and growing degree days (GDD0) for each site. Average summertime cooling at shore sites (10 m) was ~5°C cooler than reference sites (100 km inland), with a maximum difference of −19.2°C. The magnitude of cooling varied geographically, with sites further west and southeast showing little to no cooling effect, while the exposed north‐central shore showed the highest degree of buffering (5.8°C cooler) and had a shorter growing season than reference sites. Finally, north‐central shorelines had fewer days above 16°C, a threshold above which disjunct plants are unlikely to grow. These sites also showed the highest proportion of disjunct arctic–alpine species, reflecting the highest buffering from inland sites. On north‐central shores, sites up to 10 km inland had less than 10 days per year warmer than 20°C, a threshold identified for boreal forest transition. An understanding of the extent of lake‐mediated cooling on adjacent forests can better inform the risk to disjunct species, inland forests, and vegetation transition models on Lake Superior's north shore. Large lakes can provide a climate refugia effect on their shorelines and adjacent inland forests, providing potential buffering from regional vegetation transitions. Here, we describe the extent, degree, and patterns of temperature buffering for Lake Superior's north shore, with implications for cold‐adapted plants on the shoreline and adjacent inland regions.

Nutrient balance is a strong determinant of animal fitness and demography. It is therefore important to understand how the compositions of available foods relate to required balance of nutrients and habitat suitability for animals in the wild. These relationships are, however, complex, particularly for omnivores that often need to compose balanced diets by combining their intake from diverse nutritionally complementary foods. Here we apply geometric models to understand how the nutritional compositions of foods available to an omnivorous member of the order Carnivora, the grizzly bear (Ursus arctos L.), relate to optimal macronutrient intake, and assess the seasonal nutritional constraints on the study population in west-central Alberta, Canada. The models examined the proportion of macronutrients that bears could consume by mixing their diet from food available in each season, and assessed the extent to which bears could consume the ratio of protein to non-protein energy previously demonstrated using captive bears to optimize mass gain. We found that non-selective feeding on ungulate carcasses provided a non-optimal macronutrient balance with surplus protein relative to fat and carbohydrate, reflecting adaptation to an omnivorous lifestyle, and that optimization through feeding selectively on different tissues of ungulate carcasses is unlikely. Bears were, however, able to dilute protein intake to an optimal ratio by mixing their otherwise high-protein diet with carbohydrate-rich fruit. Some individual food items were close to optimally balanced in protein to non-protein energy (e.g. Hedysarum alpinum roots), which may help explain their dietary prevalence. Ants may be consumed particularly as a source of lipids. Overall, our analysis showed that most food available to bears in the study area were high in protein relative to lipid or carbohydrate, suggesting the lack of non-protein energy limits the fitness (e.g. body size and reproduction) and population density of grizzly bears in this ecosystem.

Optimal foraging theory (OFT) and the energy maximization hypothesis (EMH) have long been essential when examining wildlife habitat selection. At high latitudes and altitudes, animals in winter face greater limitations in availability and accessibility of forage. Here we explore the foraging behavior of wood bison (Bison bison athabascae) during winter within the Ronald Lake bison herd in northeastern Alberta, Canada, and examine the trade‐offs they face due to limitations in forage abundance and availability (snow conditions), as well as the need to minimize predation risk. We used Global Positioning System (GPS) location data collected from 70 female wood bison to identify winter foraging sites and craters selected by bison to access forage beneath the snow. Within wetlands used by bison we selected 190 pairs of used (foraged) and random (available) sites to test eight a priori hypotheses explaining how bison traded‐off between forage availability, accessibility, and minimizing predation risk. We found with matched‐paired logistic regression that Carex atherodes was 1.21‐times more likely to be selected per unit increase in ground cover, compared to 1.17‐times per unit ground cover for C. aquatilis and C. utriculata. However, all Carex species showed an increase in selection when cover was > 50% cover within individual craters. While the importance of Carex was clear, forage site selection was still inversely related to snow depth. There is also a neutralizing combined effect of snow depth and Carex species ground cover which suggests that bison maximized their energy return by avoiding areas with deep snow (> 30 cm) that demanded intensive cratering, even when highly selected forage was accessible beneath. Avoidance of forage areas with deep snow demonstrates that wood bison employed a foraging strategy that considers both forage availability and environmental conditions, with snow depth being a limiting factor. We highlight the relationship between optimal foraging based on food availability and the trade‐offs within an energy restrictive winter season, furthering the understanding of how large herbivores forage strategically to maximize energy intake in northern environments. We studied the winter foraging ecology of wood bison in northeastern Alberta. Finding that wood bison select for sedge species, but, increased snow depths lead to decreased selection despite the presence of highly selected forage species beneath. This study highlights bison strategies to maximize energy in northern winters.

Studying an organism's foraging behavior, especially for predator species, provides insight into their ecology, habitat needs, and interspecific relationships. American black bears (Ursus americanus) are generalist omnivores, with a diet primarily composed of vegetation and are known predators of a number of ungulate species, particularly their neonates. In this study, we analyzed the spring diet of black bears occupying the neonatal range of a small, threatened wood bison (Bison bison athabascae) herd in the Ronald Lake area of northeast Alberta to determine the predation risk of neonate bison. To estimate black bear consumption rates of bison, we used scat analysis and DNA metabarcoding to describe the spring diet of bears occupying the Ronald Lake wood bison herd's (RLBH) neonatal range. If black bears occupying the RLBH's neonatal range are consuming bison, either through predation or scavenging, then we would expect bison DNA to be present in black bear scats. We predicted that the increased availability of neonate bison in the spring would provide bears with greater predation and scavenging opportunities. Conversely, if black bear predation risk is low within the RLBH's neonatal range, then we would predict that herbaceous plants would dominate black bear diet early in the spring and berries later in the spring and summer. The spring diet of black bears was dominated by herbaceous and fruiting plants. Bison DNA, without visual evidence of animal remains, was found in only 1 of 79 scat samples (1.3%). Our results suggest that consumption rates of bison are low and that predation risk to neonate wood bison, during the RLBH's occupancy of their neonatal range, from black bears is likely minimal despite the two species' overlap in space and time. In this study, we used scat analysis and DNA metabarcoding to analyze the spring diet of black bears in the neonatal range of a small, threatened wood bison herd in northeast Alberta to assess predation risk of neonate bison. Our results suggest that consumption rates of bison are low and that predation risk to neonate wood bison, during the RLBH's occupancy of their neonatal range, from black bears is likely minimal.