Assessing the sensitivity of alpine birds to potential future changes in habitat and climate to inform management strategies

Climate change has resulted in upward elevational shifts in the distribution of animals and plants in many areas. The potential consequences of such changes for alpine bird communities were assessed by modelling data on breeding bird distributions along altitudinal gradients in the European Alps in relation to habitat, topography and temperature. Models were used to assess species’ sensitivity to potential future environmental change by estimating distributions under a range of scenarios of habitat and climate change, thereby identifying likely future conservation priorities. Distributions of the majority of forest or shrub species remained stable or increased in response to climate change as a result of elevational shifts in suitable habitats. However, open habitat species may face a severe decrease in distribution as grasslands are colonised by forest and shrubs, because much of the area considered is not at a sufficient altitude to accommodate further elevational shifts. This may be exacerbated if vegetation development is constrained at high altitudes, leading to a habitat ‘squeeze’ caused by an asymmetric response of vegetation zones to climate change. These results suggest that grassland species may be of conservation concern in the future, and that management strategies to maintain openness should be prioritised. However, model outcomes also suggested such management may not be sufficient for a number of species if climate change results in a mismatch between the distribution of suitable climates and suitable habitats. The loss of open habitats may therefore present a serious conservation problem for mountain biodiversity in the future.