North American birds require mitigation and adaptation to reduce vulnerability to climate change

Abstract

In an emerging climate crisis, effective conservation requires both adaptation and mitigation to improve the resilience of species. The currently pledged emissions reductions outlined in the Paris Agreement framework would still lead to a +3.2°C increase in global mean temperature by the end of this century. In this context, we assess the vulnerability of 604 North American bird species and identify the species and locations most at risk under climate change. We do this based on species distribution models for both the breeding and nonbreeding seasons, projected under two global warming scenarios (an optimistic mitigation scenario 1.5°C and an unmitigated 3.0°C scenario). We evaluate vulnerability under each season and scenario by assessing sensitivity and adaptive capacity based on modeled range loss and range gain, respectively, and based on species specific dispersal abilities. Our study, the first of its magnitude, finds that over two‐thirds of North American birds are moderately or highly vulnerable to climate change under a 3.0°C scenario. Of these climate‐vulnerable species, 76% would have reduced vulnerability and 38% of those would be considered nonvulnerable if warming were stabilized at 1.5°C. Thus, the current pledge in greenhouse gas reductions set by the Paris Agreement is inadequate to reduce vulnerability to North American birds. Additionally, if climate change proceeds on its current trajectory, arctic birds, waterbirds, and boreal and western forest birds will be highly vulnerable to climate change, groups that are currently not considered of high conservation concern. There is an urgent need for both (a) policies to mitigate emissions and (b) prioritization to identify where to focus adaptation actions to protect birds in a changing climate.

Migratory behavior and winter geography drive differential range shifts of eastern birds in response to recent climate change

“…Drying trends have not been uniform across the tropics, and further research exploring the effects of winter geography (e.g., Caribbean vs. Central America vs. South America) and winter habitat preferences on breeding season range shifts is needed. These results also underscore the limits of predicting the future distributions of migratory species using climate envelope models (19,20) and highlight the need for more mechanistic species distribution models.…”

“…To date, most attempts to assess climate change vulnerability in birds have used climate envelope models to project species distributions under different emissions scenarios and quantify the degree to which future distributions will overlap with current distributions (19,20). These methods, however, assume that species will track climate change in space and therefore do not account for adaption in place (21) or constraints on the ability to colonize newly created habitats (22).…”

Interrelated impacts of climate and land‐use change on a widespread waterbird

“…Similarly, common loon productivity in southern Ontario has declined markedly since the early 1980s (Bianchini et al, 2020), alongside negative trends in the number of breeding loons across much of its southern range (Evers et al, 2020). Few studies have explored simultaneous impacts of climate and land-use on adult survival in waterbirds (but see Kéry et al, 2006), yet this guild is one of the most vulnerable to climate change (Bateman et al, 2020) and already in great conservation need. We reveal that incorporating environmental changes on loon population dynamics could reverse an otherwise positive population trajectory.…”

“…Waterbird populations are considered particularly vulnerable to climate change (de Pol et al, 2010;Van Lehikoinen et al, 2013) because their key habitats, wetlands and waterbodies, are sensitive to fluctuating climate conditions (Sofaer et al, 2016). Specifically, common loons have an anticipated breeding range loss of 97% within the lower 48 states and a nearly 30% loss breeding rangewide (Bateman et al, 2020). Loons are also viewed as important ecological indicators (Evers et al, 2008) because of their prolonged exposure to local environmental stressors (longevity is up to 30 years).…”

“…watercraft use, lead fishing tackle) can pose hazards to adults and chicks (Grade et al, 2018;Mitro et al, 2008;Newbrey et al, 2005). While evidence suggests that both climate and land-use changes may shift future distributions of the common loon and related species (Bateman et al, 2020), their relative impacts on population viability have not been quantified for any loon species. By projecting estimates of loon demography under feasible climate and land-use scenarios, we evaluated possible population-level ramifications of environmental variability for this iconic inhabitant of northern lakes.…”