Abstract

The state of, and changes to, altitudinal and polar treeline ecosystems and their services in selected mountain regions in Europe were analyzed using the drivers-pressures-state-impacts-responses (DPSIR) framework. The analysis was based on 45 responses of experts from 19 countries to 2 semi-structured questionnaires on treeline ecosystem services (ESs), stakeholders and the DPSIR factors, and 11 case study descriptions of best management practices. The experts recognized climate and land-use changes as the main drivers, resulting in various pressures that contrasted among the regions. The impacts of the pressures were mainly considered as negative (e.g. loss of biodiversity, root rot diseases, moth and bark beetle outbreaks, wild fires, decrease of (sub)alpine grasslands, browsing), but also as positive (e.g. increase in forested area). The influence of climate warming, altered precipitation regimes, a longer growing season, annual variation in winter climate and increased ground-level ozone concentrations were considered less critical for recent treeline dynamics than land abandonment, increased tourism and livestock pressure. Current policy responses to emerging pressures and stakeholder demands were considered insufficient and incoherent. Mitigation, adaptation and restoration actions were rare and with no evident long-term impact. We conclude that (1) locally-specific human−environment interactions have greater influence on treeline dynamics than global warming; (2) ecological and social sustainability of the treeline areas can be enhanced by simultaneously promoting traditional land use and regulating tourism development; (3) ES users should look for new opportunities arising from environmental change rather than trying to sustain current levels of ESs indefinitely; and (4) to safeguard the unique ecological and social values of treeline areas, more coherent and proactive policies are needed.