Brooke L. Bateman

Nature-based solutions (NbS) can mitigate the climate crisis and provide co-benefits to biodiversity and human well-being. We identified opportunities for NbS in the US by mapping both critical habitat for birds under a changing climate and carbon stocks and sinks. We then investigated the alignment of these locations with areas important for human well-being and land-dependencies. Finally, we identified High Priority NbS areas that align with irrecoverable carbon to focus conservation efforts on places with significant long-term carbon storage potential. Although ~ 30% of US lands have some protection, < 3% of protected US lands align with priorities for birds, carbon, and human well-being. Of the 312 million acres of priority areas for birds, carbon, and human well-being identified, 71% lack legal protection or formal conservation plans (14% of US lands). Targeting such areas for NbS conservation and restoration would help achieve equitable climate benefits by guiding conservation investments to marginalized communities, while also ensuring maintenance of lands that are critical for biodiversity tracking a changing climate. At least 80% of all birds, carbon, and human well-being priorities co-occur with local communities who have cultural and socioeconomic ties to the land, making it imperative to work with these communities to achieve successful conservation outcomes.

Global agreements to reduce the extinction risk of migratory species depend critically on intersecting migratory connectivity—the linking of individuals between regions in different seasons—and spatial patterns of environmental change. Here we integrate movement data from >329,000 migratory birds of 112 species to develop a parameter representing exposure to global change: multispecies migratory connectivity. We then combine exposure with projected climate and land-cover changes as a measure of hazard and species conservation assessment scores as a metric of vulnerability to estimate the relative risk of migratory bird population declines across the Western Hemisphere. Multispecies migratory connectivity (exposure) is the strongest driver of risk relative to hazard and vulnerability, indicating the importance of synthesizing connectivity across species to comprehensively assess risk. Connections between breeding regions in Canada and non-breeding regions in South America are at the greatest risk, which underscores the particular susceptibility of long-distance migrants. Over half (54%) of the connections categorized as very high risk include breeding regions in the eastern United States. This three-part framework serves as an ecological risk assessment designed specifically for migratory species, providing both decision support for global biodiversity conservation and opportunities for intergovernmental collaboration to sustain migratory bird populations year-round.

As a field, ecology has historically misunderstood or overlooked female organisms, or assumed that they are ‘similar enough’ to males. The typical unit of study for ecology research stops at the species level, but that can be too coarse and can obscure important intraspecific differences. Projecting the results of studies based on only half of the population (i.e. males) onto females can be misleading, if not dangerous, as female birds differ from males in key aspects of their biology. Birds are widespread and can be sexed more often than most other taxa; yet although it uses them as model organisms, current ornithological research is disproportionately based on male birds. We review some fields pertinent to ecology and conservation and highlight biases and key research gaps. We find that, counter to ‘traditional’ assumptions, reproductive roles are balanced between sexes across many, but not all, species. In addition, female birds sing, tend to be more dispersive than males, have lower survival, often use different habitats – which has implications for conservation – and may be affected by climate change differently. We call for ornithologists to study sexes separately because the lack of attention to these differences has real‐world conservation implications. Potential solutions include training observers to recognize female traits, using more field methods that increase the detection of female birds (e.g. catching birds during the migration season, using DNA to determine sex), broadening geographical regions of study and recruiting a diverse group of scientists to help equalize the field of ornithological research.

Area-based conservation targets, such as ‘30−30’, if strategically applied, can increase resiliency to climate change and provide co-benefits to people and biodiversity. However, protected areas historically were not designated within the context of global change, and human communities at highest risk are often overlooked in conservation planning. To inform 30−30 conservation planning in the United States (i.e., America the Beautiful; ATB), we evaluated where US conservation opportunities exist by identifying habitats that can simultaneously benefit climate change mitigation and bird populations, as well as who lives in these areas and how conservation actions could both improve human well-being or potentially be at odds with local communities. To inform the equitable implementation of area-based conservation targets, we integrated maps of critical habitat for birds now and under a changing climate with carbon stocks and sinks and developed a prioritization framework to investigate the spatial alignment of these locations with areas identified as important for both human well-being and land-dependent human communities. Although nearly 30% of US lands have some level of protection, only 6% of US lands (143 million acres) are managed for biodiversity and align with Bird and Carbon (BC) priorities, and what counts as conservation actions towards the 30% goal and what successful conservation outcomes that benefit biodiversity, climate change mitigation, and human communities look like.

Countries have set targets for conserving natural areas to mitigate biodiversity loss, such as the protection of 30% of lands by 2030, commonly referred to as “30 by 30”. Yet strategic conservation planning to align those targets with climate‐change refugia is lacking. We investigated the feasibility of achieving 30 by 30 in North America by assessing the proportions of state/provincial/territorial land projected to provide refugia for terrestrial biodiversity and the proportions of those refugia that are currently protected. We also conducted a reserve selection prioritization to identify priority areas that complement the current protected area network and capture refugia for seven taxonomic groups. In North America, <15% of refugia are protected, but ample opportunity exists to expand protection if warming is limited to 2°C. Beyond 2°C, however, the majority of refugia will occur only at high latitudes and elevations. Incorporation of refugia into 30 by 30 efforts will facilitate species persistence under climate change.

Climate‐informed spatial planning is urgently needed to guide initiatives aimed at both conserving biodiversity as a whole (e.g. protection of 30% of lands and waters by 2030) and recovering North American avifauna in particular. Various methods for prioritizing conservation areas exist, yet alternative methods may direct managers to different lands for protection, and thus varying recommendations for meeting area‐based targets. Here, we used bird species distribution models and landcover projections to systematically evaluate two widely used methods for prioritizing areas most likely to facilitate the persistence of multiple species under climate change: 1) in situ macrorefugia, identified as areas of high predicted species retention; and 2) complementarity‐based optimizations, identified using the Zonation conservation planning software. For 17 biogeographical groups in the continental United States, we compared priority areas for bird conservation derived from these two alternatives with respect to their spatial distributions and consensus (i.e. overlap), expected conservation outcomes (e.g. species and functional diversity), predicted climate change exposure, habitat characteristics, landscape configurations and degree of formal protection. Spatial distributions of priority areas differed by biogeographical group and method, with 40.5% consensus on average across groups. Consensus was extensive within mountainous and coastal regions, and limited at high latitudes (e.g. Alaska) and in flat, interior regions (e.g. grasslands). As expected, complementarity‐based optimizations more efficiently represented species than retention‐based in situ macrorefugia, especially for forest groups, and had greater overall biodiversity value and better habitat condition. Conversely, in situ macrorefugia encompassed higher elevations and larger contiguous patches and were expected to experience less winter‐season warming. Formal protection averaged < 50% across biogeographical groups, regardless of prioritization method. Our findings illustrate the value of complementarity‐based optimizations for bird conservation under climate change. More broadly, comparing approaches for prioritizing areas for long‐term species persistence can reveal critical trade‐offs in recommendations for climate‐informed protected area planning.

The National Wildlife Refuge System (NWRS) provides one of the United States’ greatest protected area networks for wildlife conservation. As climate changes beyond historical ranges of variability, refuge managers are confronted with assessing the utility of refuges, including how to best manage refuges both individually and as a system to help species cope with rapid change. Using published species distribution models, we projected species-specific changes in environmental suitability for 590 native North American bird species under a 2°C future warming scenario (~2050s under RCP8.5) at 525 refuges. For each species, we classified projected changes in suitability (i.e., improving, stable, or worsening suitability) and whether they crossed a model-derived persistence threshold at a refuge (i.e., potential colonization or potential extirpation). Overall, we found that a quarter of species (23% in summer, 26% in winter) could be different (i.e., turnover) across the refuge system despite protections. Summer and winter communities are not equally affected, so managers should consider different strategies for the different seasons. We forecast a slight net species loss in summer, from a mean of 109.0 ± 0.8 to 102.0 ± 0.7 species per refuge. In winter, we forecast a net gain in species, from a mean of 97.1 ± 2.2 to 118.5 ± 1.8 species per refuge. This includes an average of 12 species per refuge that may overwinter rather than migrate south. Refuges at northern latitudes will see relatively more turnover in species, while southern and coastal refuges will see fewer changes. Despite these species changes, dominant habitat association groups (e.g., waterbirds, forest birds) will generally stay the same across most of the NWRS. Some species may be lost from the entire NWRS and can benefit in the near term from targeted management. Regions of high extirpation and colonization (i.e., at northern latitudes) can be prioritized for strategic additions of new refuges.

National parks often serve as a cornerstone for a country’s species and ecosystem conservation efforts. However, despite the protection these sites afford, climate change is expected to drive a substantial change in their bird assemblages. We used species distribution models to predict the change in environmental suitability (i.e., how well environmental conditions explain the presence of a species) of 49 Canadian national parks during summer and winter for 434 bird species under a 2°C warming scenario, anticipated to occur in Canada around the mid-21st century. We compared these to existing species distributions in the 2010s, and classified suitability projections for each species at each park as potential extirpation, worsening, stable, improving, or potential colonisation. Across all parks, and both seasons, 70% of the projections indicate change, including a 25% turnover in summer assemblages and 30% turnover in winter assemblages. The majority of parks are projected to have increases in species richness and functional traits in winter, compared to a mix of increases and decreases in both in summer. However, some changes are expected to vary by region, such as Arctic region parks being likely to experience the most potential colonisation, while some of the Mixedwood Plains and Atlantic Maritime region parks may experience the greatest turnover and potential extirpation in summer if management actions are not taken to mitigate some of these losses. Although uncertainty exists around the precise rate and impacts of climate change, our results indicate that conservation practices that assume stationarity of environmental conditions will become untenable. We propose general guidance to help managers adapt their conservation actions to consider the potentially substantive changes in bird assemblages that are projected, including managing for persistence and change.

One of the most pressing questions in ecology and conservation centers on disentangling the relative impacts of concurrent global change drivers, climate and land‐use/land‐cover (LULC), on biodiversity. Yet studies that evaluate the effects of both drivers on species’ winter distributions remain scarce, hampering our ability to develop full‐annual‐cycle conservation strategies. Additionally, understanding how groups of species differentially respond to climate versus LULC change is vital for efforts to enhance bird community resilience to future environmental change. We analyzed long‐term changes in winter occurrence of 89 species across nine bird groups over a 90‐year period within the eastern United States using Audubon Christmas Bird Count (CBC) data. We estimated variation in occurrence probability of each group as a function of spatial and temporal variation in winter climate (minimum temperature, cumulative precipitation) and LULC (proportion of group‐specific and anthropogenic habitats within CBC circle). We reveal that spatial variation in bird occurrence probability was consistently explained by climate across all nine species groups. Conversely, LULC change explained more than twice the temporal variation (i.e., decadal changes) in bird occurrence probability than climate change on average across groups. This pattern was largely driven by habitat‐constrained species (e.g., grassland birds, waterbirds), whereas decadal changes in occurrence probabilities of habitat‐unconstrained species (e.g., forest passerines, mixed habitat birds) were equally explained by both climate and LULC changes over the last century. We conclude that climate has generally governed the winter occurrence of avifauna in space and time, while LULC change has played a pivotal role in driving distributional dynamics of species with limited and declining habitat availability. Effective land management will be critical for improving species’ resilience to climate change, especially during a season of relative resource scarcity and critical energetic trade‐offs.

Together climate and land‐use change play a crucial role in determining species distribution and abundance, but measuring the simultaneous impacts of these processes on current and future population trajectories is challenging due to time lags, interactive effects and data limitations. Most approaches that relate multiple global change drivers to population changes have been based on occurrence or count data alone. We leveraged three long‐term (1995–2019) datasets to develop a coupled integrated population model‐Bayesian population viability analysis (IPM‐BPVA) to project future survival and reproductive success for common loons Gavia immer in northern Wisconsin, USA, by explicitly linking vital rates to changes in climate and land use. The winter North Atlantic Oscillation (NAO), a broad‐scale climate index, immediately preceding the breeding season and annual changes in developed land cover within breeding areas both had strongly negative influences on adult survival. Local summer rainfall was negatively related to fecundity, though this relationship was mediated by a lagged interaction with the winter NAO, suggesting a compensatory population‐level response to climate variability. We compared population viability under 12 future scenarios of annual land‐use change, precipitation and NAO conditions. Under all scenarios, the loon population was expected to decline, yet the steepest declines were projected under positive NAO trends, as anticipated with ongoing climate change. Thus, loons breeding in the northern United States are likely to remain affected by climatic processes occurring thousands of miles away in the North Atlantic during the non‐breeding period of the annual cycle. Our results reveal that climate and land‐use changes are differentially contributing to loon population declines along the southern edge of their breeding range and will continue to do so despite natural compensatory responses. We also demonstrate that concurrent analysis of multiple data types facilitates deeper understanding of the ecological implications of anthropogenic‐induced change occurring at multiple spatial scales. Our modelling approach can be used to project demographic responses of populations to varying environmental conditions while accounting for multiple sources of uncertainty, an increasingly pressing need in the face of unprecedented global change.