Road Ecology Center

Concern is growing over the fragmentation of habitats by roads and other transportation infrastructure. A number of measures to avoid, minimize, mitigate, or compensate for the detrimental effects of such fragmentation have been suggested. These are geared to specific scales, from culverts at the scale of a single road to plans for re-connecting habitats across entire countries or continents. They include the removal of roads, building of overpasses and underpasses at roads and railways to increase permeability for animals, restoration or creation of wildlife corridors and networks of wildlife corridors across transportation infrastructure, and the design of less fragmenting road network patterns, e.g., the bundling of traffic lines. However, it is still unknown which measures are the most effective in terms of restoring ecological processes. The investigation of their effectiveness, therefore, is an important and most urgent task because the most effective measures should be applied predominantly in order to use resources most efficiently. How can the effectiveness of such measures be evaluated (criteria and methods)? For example, possible criteria for the effectiveness of crossing structures are the reduction of road-kill frequencies, increased passage frequencies, presence of species on both sides of the road, genetic exchange across the road, recovery of lowered reproductive rates and skewed sex ratios, re-colonization success, recovery of skewed foraging intensities among foraging areas on either side of the road, and recovery of skewed predation rates. More generally, the measures should enhance landscape connectivity and restore ecological processes among habitat patches and across landscapes. During the last three years, considerable progress on measuring the effectiveness of such measures has been made in both Europe and North America. This session brought together the “Father of Road Ecology” Richard Forman with researchers from Europe (Austria, The Netherlands, etc.) and North America working at different scales and in different locations. They presented current methods and results on the success of various mitigation measures to foster cross-scale comparison and synthesis on this topic. The presentation included empirical studies, synthetic overviews, modeling studies, and conceptual studies.