Mountain regions are globally important areas for biodiversity but are subject to multiple human-induced threats, including climate change, which has been more severe at higher elevations. We reviewed evidence for impacts of climate change on Holarctic mountain bird populations in terms of physiology, phenology, trophic interactions, demography and observed and projected distribution shifts, including effects of other factors that interact with climate change. We developed an objective classification of high-elevation, mountain specialist and generalist species, based on the proportion of their breeding range occurring in mountain regions. Our review found evidence of responses of mountain bird populations to climate (extreme weather events, temperature, rainfall and snow) and environmental (i.e. land use) change, but we know little about either the underlying mechanisms or the synergistic effects of climate and land use. Long-term studies assessing reproductive success or survival of mountain birds in relation to climate change were rare. Few studies have considered shifts in elevational distribution over time and a meta-analysis did not find a consistent direction in elevation change. A meta-analysis carried out on future projections of distribution shifts suggested that birds whose breeding distributions are largely restricted to mountains are likely to be more negatively impacted than other species. Adaptation responses to climate change rely mostly on managing and extending current protected areas for both

Aim: Human-induced climate change requires conservation strategies incorporating its potential effects on species and communities. Key components of population persistence can be attributed to resistance (the capacity to remain unaffected) or resilience (capacity to absorb and recover) to climate change. In situ climatic refugia can act as resistant distribution units, and ex situ climatic refugia and the corridors to reach them may enhance resilience. We develop a novel approach selecting conservation priorities, resistant units and resilient areas according to structural connectivity and future distribution, to identify strategies that maximize the chances of species persistence in a changing climate. Location: Italian Alps.Methods: Conservation priorities were defined across species according to the regional conservation status and the level of threat from climate change, and across sites according to their suitability for target species and their related potential for population persistence (in situ climatic refugia, i.e., resistant units) or redistribution (ex situ climatic refugia and main corridors according to current and future connectivity, i.e., resilient units).Results: Models suggested a marked loss of suitable area for all species by 2050 (ranging from ~50% for pygmy owl and water pipit, to 84% for snowfinch in the worst scenario), and a general loss of connectivity, which was particularly marked for pygmy owl and snowfinch. The approach applied to Alpine birds of different habitats led to a spatially explicit definition of conservation priorities. Main conclusions:The spatial definition of conservation priorities according to species (regional importance and level of threat), resistance and resilience refines the definition of management/conservation priorities (including protected area definition), complementing the existing approaches to address climate change-induced threats in planning conservation and ecological networks. K E Y W O R D SAlps, birds, distribution, ecological connectivity, global warming, spatial planning

The majority of predictions about the impacts of climate change on wildlife have relied either on the study of species' physiological tolerance or on broad-scale distribution models. In comparison, little attention has been paid to species' mechanistic responses to fine-grained, climate-induced modifications of habitat suitability. However, such studies would be pivotal to the understanding of species' ecological requirements, and hence their adaptive potential to environmental change which can act as a basis for designing management strategies. We investigated foraging microhabitat selection in a climate-change endangered, high-elevation bird species, the white-winged snowfinch Montifringilla nivalis, during the breeding season in the European Alps. Our microhabitat selection model considered various topographical and ground cover variables, as well as sward height, comparing environmental characteristics within a 5-m radius at foraging and random locations, the latter serving as controls. Foraging habitat selection of M. nivalis was positively affected by grassland cover but negatively by sward height. The response to snow cover was quadratic, with an optimum around 40%; the birds also avoided anthropized (urban areas, roads) sites. We estimated past (1976) and future (2066) climate-driven changes in foraging microhabitat suitability, assuming a progressively earlier date of snowmelt due to increasing temperatures over this entire time span. We then modelled the potential impact of snow-melt (and related sward height) on habitat suitability under two scenarios: maintaining the current situation (i.e. some seasonal grazing) and implementing targeted management (e.g.grazing) in an attempt to mitigate impacts of earlier snowmelt. Predicted foraging habitat suitability (estimated as the fraction of suitable plots) significantly declined over time, with a 23% reduction in the number of suitable plots between 1976 and 2016, and a further 32% loss by 2066. However, model outputs demonstrated that maintaining sward height below 6 cm on breeding grounds (e.g. by grazing) would significantly decrease the predicted loss of suitable foraging habitat. Our study shows that detailed information about patterns of resource exploitation not only allows the identification of mechanistic, functional responses of species to environmental change, but also enables an evaluation of habitat options that can buffer against the detrimental effects of global warming.