Identifying drivers of the treeline ecotone in the Alps – a remote sensing and GIS approach
Project Number: CH-6355
The treeline ecotone in the European Alps is the transition zone above the subalpine forest and beneath the alpine zone. As the growing season in the alpine region is limited due to the decreasing temperature with altitude, it determines the establishment of trees (Cudlín et al. 2017). Various authors (Holtmeier and Broll 2005, Gehrig-Fasel et al. 2007, Case and Buckley 2015) state, that changes in the transition zone are induced by topography and climatic variables at micro and macro scale. The topographic features determine the distribution of snow and the exposure of plants to wind and sun.
Through an analysis in GIS, I aim to capture differences in altitude of the upper tree limit in the Alps based on temperature and the actual limit derived from remote sensing data. Those differences will be analyzed regarding topographic and climatic variables. Especially snow cover and depth is a parameter, which is highly dependent of topography and wind, and delimits the establishment of trees. The study areas are three Nationalparks in the Alps, which are involved in the project of ECOPOTENTIAL. The Gran Paradiso Nationalpark in Italy, the Swiss Nationalpark in Switzerland and the Northern Limestone Nationalpark in Austria, are three different protected areas considering, temperature, precipitation and topography
The commonly accepted determining factor for the upper limit of trees in the Alps, is the altitude above sea level and the coupled decrease of temperature, which will be tested in the first step of this study: Is temperature actually the main limiting factor for the establishment of trees in the treeline ecotone?
Topographic features determine the distribution of snow and the exposure of plants to wind and sun. In depressions, snow cover can persist until the summer and ridges can pass without any cover over the whole season. Therefore, the mosaic of plant communities displays the different patches of snow cover duration. Considering changes in climate, does snow prevent an upward-shift of the treeline?
The altitude of the treeline ecotone will be derived in two ways, firstly after the temperature isotherms, as defined by Körner (2012), and secondly from a remote sensing product. In quantifying the differences of altitude of the two products, I will also include parameters like slope, aspect, wind and precipitation. If data is available an analysis of the trend of snow cover duration and the resulting effect on the treeline ecotone will be included.
Menzinger B. 2018. Identifiying drivers of the treeline ecotone in the Alps - a remote sensing and GIS approach. Masterarbeit, Universität Graz.
Last update: 5/24/19
Source of data: ProClim- Research InfoSystem (1993-2020)
Update the data of project: CH-6355