Vulnerability of birds to climate change in California's Sierra Nevada

Abstract

ABSTRACT. In a rapidly changing climate, effective bird conservation requires not only reliable information about the current vulnerability of species of conservation concern, but also credible projections of their future vulnerability. Such projections may enable managers to preempt or reduce emerging climate-related threats through appropriate habitat management. We used NatureServe's Climate Change Vulnerability Index (CCVI) to predict vulnerability to climate change of 168 bird species that breed in the Sierra Nevada mountains of California, USA. The CCVI assesses species-specific exposure and sensitivity to climate change within a defined geographic area, through the integration of (a) species' range maps, (b) information about species' natural history traits and ecological relationships, (c) historic and current climate data, and (d) spatially explicit climate change projections. We conducted the assessment under two different downscaled climate models with divergent projections about future precipitation through the middle of the 21st century. Assessments differed relatively little under the two climate models. Of five CCVI vulnerability ranking categories, only one species, White-tailed Ptarmigan (Lagopus leucura), received the most vulnerable rank, Extremely Vulnerable. No species received the second-highest vulnerability ranking, Highly Vulnerable. Sixteen species scored as Moderately Vulnerable using one or both climate models: Common Merganser ( . Species associated with alpine/subalpine habitats and aquatic habitats received significantly more vulnerable rankings than birds associated with other habitats. In contrast, species of foothill, sagebrush, and chaparral habitats ranked as less vulnerable than other species, and our results suggest these species may respond to climate change in the region with population increases or range expansions. Vulnérabilité des oiseaux aux changements climatiques dans la Sierra Nevada en CalifornieRÉSUMÉ. Dans le contexte d'un climat qui change rapidement, la conservation efficace des oiseaux passe non seulement par un besoin d'information fiable sur la vulnérabilité actuelle des espèces préoccupantes, mais également par des projections crédibles de leur vulnérabilité future. Les projections de ce type peuvent permettre aux gestionnaires d'écarter ou d'amoindrir les menaces qui se profilent en raison du climat grâce à une gestion appropriée de l'habitat. Nous avons utilisé l'indice de vulnérabilité aux changements climatiques (CCVI pour Climate Change Vulnerability Index) de NatureServe afin de prévoir la vulnérabilité aux changements climatiques de 168 espèces d'oiseaux qui nichent dans la Sierra Nevada en Californie, aux États-Unis. Le CCVI détermine le degré d'exposition et de sensibilité aux changements climatiques spécifiques aux espèces dans une région géographique donnée par l'intégration des éléments suivants : a) la répartition de l'espèce; b) les caractéristiques de l'histoire naturelle et les relations écologiques de l'espèce; c) les données climatiques h...

Phenology and productivity in a montane bird assemblage: Trends and responses to elevation and climate variation

“…The extent that such variability affects birds at moderately lower elevations in the montane zone is poorly known. Understanding how montane bird populations in the Sierra Nevada respond to annual climate variation could help explain observed population trends or changes in distributions of birds (Tingley et al, 2012;Tingley, Monahan, Beissinger, & Moritz, 2009), as well as enable better predictions of future population changes in the region (Siegel et al, 2014;Stralberg et al, 2009).…”

Heterogeneity in avian richness-environment relationships along the Pacific Crest Trail

“…Models forecasting the effects of climate warming on species occurrences and richness generally assume that species will respond similarly to climate across their range (Sekercioglu et al 2008, Stralberg et al 2009, Siegel et al 2014. Although not all regions in our study area are sampled along the exact same extent in environmental space, regionspecific interactions contrasted with at least one other region where environmental gradients did overlap (Figs.…”

“…Temperature is projected to increase by 2 to 5°C across the state (Snyder et al 2002) and although there is less agreement among climate models on the direction of precipitation change (IPCC 2007), there is more agreement that the proportion of precipitation that falls as rain will increase, while snowfall will decrease. These climatic changes may have a profound effect on birds and their habitats (Siegel et al 2014), by altering plant productivity, vegetation structure, and plant species composition, including a projected loss of 50 to 90% of subalpine and alpine habitats by the year 2099 (Hayhoe et al 2004). Some climaticinduced habitat changes are already occurring on California's mountains (Thorne et al 2008, Dolanc et al 2013.…”

Great Gray Owls Nesting in Atypical, Low-Elevation Habitat in the Sierra Nevada, California

“…Alternately, if Great Gray Owls were indeed present in the area long before their recent discovery, that would seem to bolster the possibility that there could be substantial numbers of Great Gray Owls elsewhere in the lower-montane zone that have not yet been detected. Those owls, at the lower margin of the species' elevation range, may be highly vulnerable to climate change; indeed the Great Gray Owl has been identified as one of 17 bird species in the Sierra Nevada with at least moderate vulnerability to climate change (Siegel et al 2014). Understanding the species' distribution, ecology, and conservation needs at the lower extreme of its elevation range in California should be considered a high priority, as this may be the first segment of the population to be at serious risk due to climate change.…”