Climate change is known to affect key life‐history traits, such as body mass, reproduction, and survival in many species. Animal populations inhabiting mountain habitats are adapted to extreme seasonal environmental conditions but are also expected to be especially vulnerable to climate change. Studies on mountain ungulates typically focus on populations or sections of populations living above the tree line, whereas populations inhabiting forested habitats are largely understudied. Here, we investigate whether forested areas can mitigate the impact of climatic change on life‐history traits by evaluating the interactive effects of temperature and habitat characteristics on body mass variation in the Alpine chamois Rupicapra rupicapra rupicapra. We examined data of 20,573 yearling chamois collected from 1993 to 2019 in 28 mountain ranges in the Austrian Eastern Alps, characterized by different proportion of forest cover. Our results show that the temporal decline of chamois body mass is less pronounced in areas with greater proportion of forest cover. For chamois living in forest habitats only, no significant temporal change in body mass was detected. Variation in body mass was affected by the interaction between density and snow cover, as well as by the interaction between spring temperatures and forest cover, supporting the role of forests as thermal buffer against the effects of increasing temperatures on life‐history traits in a mountain ungulate. In turn, this study suggests a buffering effect of forests against climate change impacts. Assessments of the consequences of climate change on the life‐history traits and population dynamics of mountain‐dwelling species should thus consider the plasticity of the species with respect to the use and availability of different habitat types.

Knowledge of population trends is of key importance for sustainable management of wildlife and finding reliable and cost–effective monitoring methods is therefore of great interest. In two populations of Alpine chamois Rupicapra rupicapra, we collected data on mortality from 12 424 individuals hunted or found dead and population size data based on ground counts over a period of 28 years. Our study had three aims: 1) we investigated if changes in population size obtained with a simple deterministic population reconstruction (DPR) approach using hunting and natural mortality covary with population size estimates obtained from ground count data. 2) We investigated if the performance of DPR is affected by the removal of natural mortality data. 3) We assessed how many years of mortality data are needed to obtain consistent population trends using DPR. Our results suggested that 1) population abundance from mortality data using DPR significantly and positively correlated with population abundance obtained with ground counts. 2) DPR without natural mortality data performed similarly as compared to DPR using full data (hunting and natural mortality). 3) Consistent estimates of population trends can be obtained with ≥10 years of mortality data, however, this time span was influenced by the mean age at death, which in turn was affected by the local hunting regime. Our results suggest that DPR and ground counts perform similarly for the estimation of temporal trends in Alpine chamois abundance. The consistence of ground counts and DPR supports the use of these methods as reliable tools for tracking abundance of chamois populations over time. However, the reliability of abundance estimates using DPR may vary between populations and the influence of different hunting regimes must be considered for the correct interpretation of results.

Uptake and use of energy are of key importance for animals living in temperate environments that undergo strong seasonal changes in forage quality and quantity. In ungulates, energy intake strongly affects body mass gain, an important component of individual fitness. Energy allocation among life‐history traits can be affected by internal and external factors. Here, we investigate large‐scale variation in body growth patterns of Alpine chamois Rupicapra rupicapra rupicapra , in relation to sex, age, temperature, and habitat variations across 31 (sub)populations in the Central European Alps. Taking advantage of an exceptionally large dataset ( n = 178,175) of chamois hunted over 27 consecutive years between 1993 and 2019 in mountain ranges with different proportions of forest cover, we found that (i) patterns of body mass growth differ between mountain ranges, with lower body mass but faster mass growth with increasing proportion of forest cover and that (ii) the effect of spring and summer temperatures on changes in body growth patterns are larger in mountain ranges with lower forest cover compared to mountain ranges with higher forest cover. Our results show that patterns of body mass growth within a species are more plastic than expected and depend on environmental and climatic conditions. The recent decline in body mass observed in Alpine chamois populations may have greater impacts on populations living above the treeline than in forests, which may buffer against the effects of increasing temperatures on life‐history traits.