Mountain regions provide diverse goods and services to human society. At the same time, mountain ecosystems are sensitive to rapid global development. Over the past 2 decades the number of papers mentioning “ecosystem services” (ESS) has risen exponentially. While the concept holds great potential to improve the societal relevance of conservation efforts, it is at risk of dying of misuse and reduction to a buzzword. The definitions of the term often compete and the utility of the concept is under debate. The present article reviews the literature on mountain ESS to investigate whether the term was understood correctly by the community, and addresses the question whether ESS is a suitable concept to protect mountain regions. We link land use and other physical properties of terrestrial ecosystems with their capacity to provide ESS with a view to mapping the global supply of ESS and we contrast it with population density data as a proxy for the demand for ESS. The spatially explicit assessment shows that we can distinguish between mountain areas where demand and supply are well balanced from mountain areas where demand and supply are unbalanced. For these different types of mountain regions we suggest different approaches to package the concept of ESS into spatial decision-making.

The concept of “commons” is complex; it may relate to property regimes, rules of use and access, recognition of collective importance, or a mixture of these. This paper explores the arguments—developed by a growing epistemic community—to promote mountains as global common goods within the third category. This process may be viewed as starting with the UN Conference on Environment and Development (UNCED) in 1992, and continuing, in particular, through the International Year of Mountains 2002. It has been supported and advanced by focused publications, the establishment of global networks, and advances in technology. Specific arguments state that mountains are important because they provide ecosystem services that are vulnerable to climate change, are home to a significant part of humanity, including many who are disadvantaged, and are centers of cultural, religious, and ethnic diversity. Nevertheless, this proposal has been contested within the scientific community, and the implications for mountain people remain to be discussed.

From both social and environmental perspectives, water is the main connection between highland and lowland processes in mountain watersheds: Water flows downhill while human impacts flow uphill. For example, in the Oregon Cascades mountain range, geology, vegetation, and climate influence the hydrologic connections within watersheds. Geology determines which watersheds are surface runoff-dominated and which are groundwater-dominated. In this Mediterranean climate with dry summers, surface runoff watersheds will consistently experience near-zero late summer discharge, so declining snowpacks will have little effect on low flows. This contrasts with groundwater-dominated watersheds, where a shift from snow to rain or a decline in precipitation will reduce recharge, thereby reducing late summer groundwater contributions to streamflow. Earlier snowmelt causes forests to transpire earlier, resulting in decreased springtime streamflow. Reduced snowpacks lead to soil moisture stress, making forests more vulnerable to extensive wildfires and affecting the lifespan and composition of forests. Monitoring and quantifying these complex linkages and feedbacks require appropriate measurement networks. Sampling strategies often use watershed typology to identify where measurements should be focused. Such an approach should include not only established watershed classification parameters such as topology and geology but also interannual climate variability and land cover. As concerns of water scarcity and vulnerability move to the forefront, our watershed classifications should be extended to include ecosystem and social–ecological parameters. An integrated and agent-based modeling scheme called Envision has been developed to simulate alternative future landscapes at the watershed scale. Using fully coupled models of hydrology, ecosystems, and socioeconomics, decision-makers can simulate the effects of policy decisions in conjunction with other climate forcing, land use change, and economic disturbances. To understand the combined impacts of climate change and humans on water in mountain watersheds, researchers must develop integrated monitoring and modeling systems that explicitly include connections across eco-hydrologic and social-ecological systems.

The conference on Global Change and the World's Mountains held in Perth, Scotland, in 2010 offered a unique opportunity to analyze the state and progress of mountain research and its contribution to sustainable mountain development, as well as to reflect on required reorientations of research agendas. In this paper we provide the results of a three-step assessment of the research presented by 450 researchers from around the world. First, we determined the state of the art of mountain research and categorized it based on the analytical structure of the Global Land Project (GLP 2005). Second, we identified emerging themes for future research. Finally, we assessed the contribution of mountain research to sustainable development along the lines of the Grand Challenges in Global Sustainability Research (International Council for Science 2010). Analysis revealed that despite the growing recognition of the importance of more integrative research (inter- and transdisciplinary), the research community gathered in Perth still focuses on environmental drivers of change and on interactions within ecological systems. Only a small percentage of current research seeks to enhance understanding of social systems and of interactions between social and ecological systems. From the ecological systems perspective, a greater effort is needed to disentangle and assess different drivers of change and to investigate impacts on the rendering of ecosystem services. From the social systems perspective, significant shortcomings remain in understanding the characteristics, trends, and impacts of human movements to, within, and out of mountain areas as a form of global change. Likewise, sociocultural drivers affecting collective behavior as well as incentive systems devised by policy and decision makers are little understood and require more in-depth investigation. Both the complexity of coupled social–ecological systems and incomplete data sets hinder integrated systems research. Increased understanding of linkages and feedbacks between social and ecological systems will help to identify nonlinearities and thresholds (tipping points) in both system types. This presupposes effective collaboration between ecological and social sciences. Reflections on the Grand Challenges in Sustainability Research put forth by the International Council for Science (2010) reveal the need to intensify research on effective responses and innovations. This will help to achieve sustainable development in mountain regions while maintaining the core competence of mountain research in forecasting and observation.

Based on our work in mountain communities in Mexico (and in other parts of Latin America), we suggest the need for a “dialogue of knowledge systems” or dialogo de saberes, a concept used in Latin America that is akin to the concept of transdisciplinarity used by some European scholars. If these societies are to liberate themselves from the globalized straitjackets imposed by international economic integration with its imperatives of “free” trade and markets, then communities have to expand beyond the improvement of individual capabilities and the exercise of individual freedoms. Although individual improvement and self-betterment continue to be significant objectives for direct intervention, we focus on the primacy of collective determinations of the worth of their activities and the focus on collective entitlements by assuring the viability of community processes for individual participation. An alternative strategy for participating communities is proposed.

The history of mountain research is most fascinating. Three names for 3 centuries may give an idea of the growing knowledge about the world's mountains: Horace Bénédict de Saussure, who climbed and studied the Mont Blanc in 1787; Alexander von Humboldt, ever investigating the environment during his attempt to ascend the Chimborazo in 1802; and Carl Troll, who founded the International Geographical Union's Commission on High-altitude Geoecology in 1968. Awareness of the growing impact of human activities on the environment led to scientific and political initiatives at the global level, beginning in the 1970s. The Perth conference in 2010 has offered an opportunity to both look back on these developments and explore the future of the world's mountains in a time of rapidly growing “global change” problems and processes.

Sustainable Mountain Development (SMD) in the context of global warming, world population growth, increased water and energy consumption, persisting food insecurity and biodiversity loss, more frequent and intense natural calamities, and the depletion of vital natural resources is a key concern for humanity. It requires the attention and support of many stakeholders and shareholders, including development agencies. The Swiss Agency for Development and Cooperation has been a major promoter of SMD at the global policy and networking level. By supporting the Perth mountain conferences, it has also emphasized the role of research for SMD. With Rio 2012 fast approaching, it is important to understand past efforts to design what new support is needed for ensuring that SMD takes place effectively.