3.9. Bugmann

Keynote Presentations from the 1st ALTER-Net Summer School, Peyresq 27 August - 8 September 2006

Abstract

Mountain ecosystems provide a multitude of goods and services to humanity, such as the storage, purification and controlled release of freshwater, the protection of human infrastructure from landslides and other gravitative natural hazards, high-quality agricultural and forest products, biodiversity, and the biological storage of carbon. Today, more than half of humanity depends on freshwater resources that are provided by mountains, and about a quarter of the human population is living in mountain regions.

One particular aspect of mountain regions is the strong linkage between "upstream" and "downstream" systems. This feature renders mountain landscapes particularly vulnerable to global change, leads to strong linkages between various ecosystem goods and services, and imposes particular trade-offs on service provision.

In the first part of the presentation, I will illustrate the quantitative and qualitative role of mountains in providing ecosystem goods and services that are of global importance based on a few examples.

In the second part of the presentation, the likely direct effects of climatic change and management as well as the indirect effects via changes in the windthrow and wildfire regimes will be assessed for a number of case study landscapes in the Swiss Alps sing the landscape model LANDCLIM.

LANDCLIM was developed to portray vegetation succession as influenced by local-scale processes (plant demography and competition) as well as landscape-scale processes (plant dispersal and the spread of disturbances), taking into account the interactions between climate, the disturbance regime and vegetation development.

This analysis suggests that future landscape dynamics in the Swiss Alps will be influenced strongly by the direct effects of climate on plants, but also by changes in the wildfire regime, whereas the management regime and windthrow events will be of a lesser importance. While an enhanced disturbance regime would be positive for vascular plant diversity at lower elevations, it would have negative impacts on carbon storage at the landscape scale, and it would also interfere with the protective function of many mountain forests. The implications of these findings will be discussed for various sectors.

Recommended background literature on this presentation:

• Schumacher S, Bugmann H, Mladenoff DJ (2004) Improving the formulation of tree growth and succession in a spatially explicit landscape model. Ecol. Modelling 180: 175-194. doi:10.1016/j.ecolmodel.2003.12.055.
• Bugmann H, Zierl B, Schumacher S (2005) Projecting the impacts of climate change on mountain forests and landscapes. In: Huber UM, Bugmann HKM, Reasoner MA (eds.) Global Change and Mountain Regions: An overview of current knowledge. Advances in Global Change Research, Springer-Verlag, 433-444. http://www.springer.com/
• Schumacher S, Reineking B, Sibold J, Bugmann H (2006) Modeling the impact of climate and vegetation on fire regimes in mountain landscapes. Landscape Ecology 21: 539-554. doi:10.1007/s10980-005-2165-7.
• Schumacher S, Bugmann H (2006) The relative importance of climatic effects, wildfires and management for future forest landscape dynamics in the Swiss Alps. Global Change Biology 12: 1435-1451. doi:10.1111/j.1365-2486.2006.01188.x.