CARL - Connectivity Analysis of Riverine Landscapes

Mar 29, 2011
Within WP5 (barriers and corridors) of the Econnect Project a specific goal is the Connectivity Analysis of Riverine Landscapes (CARL) throughout the Alps. Recent activities were concentrated on the Alpine wide definition of riverine landscapes and the analysis of existing fragmentation.

On a higher resolution level, the spatial analysis of Alpine riverine landscapes focuses on detailed analysis within two pilot regions, in particular the National Park Hohe Tauern and the Northern Limestone Alps.
A potential riverine landscape was defined as the river and the surrounding areas by calculating a buffer zone of 100 meters along the river course. As mountain slopes delimit the river valleys, the defined flood plain was laterally restricted to the line where the gradient of the slope was above 35 degree. For example the resulting potential riverine landscape in the whole pilot region Northern Limestone Alps covered 23% of the area.
Within these riverine landscapes different fragmentation-causing elements like land use, settlements or specific obstacles were identified and put into the spatial analysis of fragmentation. As an indicator of fragmentation the "effective mesh-size" was calculated, which is based on the probability of two points chosen randomly in an area will be connected to each other. The more barriers in the landscape, the lower the probability that the two points will be connected, and the lower the effective mesh size. In order to compare the river landscapes among each other, the "effective mesh-size" was averaged for each smaller catchment.
The current state of potential barriers and obstacles in the Alpine riverine landscapes are overlayed with the potential and effective habitats of key species. These analyses are still ongoing but we already see very interesting preliminary results.