Restoring ecological networks
across transport corridors in Bulgaria


Mitigation of habitat fragmentation

For each identified bottleneck location we explored what measures will be needed to solve the problems of barrier effect and road-kill for wildlife. To do so each bottleneck location was visited and the best set of measures was determined. Choices for measures were primarily based on the preferences of the indicator species for different types of measures (see matrix), the characteristics of the road/railroad and traffic, the presence of existing crossing structures, such as bridges or culverts, and the configuration of wildlife habitat around the identified problem section. This approach can be best described as a “quick-scan”, hence the mitigations suggested here should be seen as not more than a first proposal for a more detailed de-fragmentation program. We recommend that for each individual location further inventories take place to detail the specific mitigation measures necessary to reduce road impacts for all the species concerned on a prioritized basis.

In total 544 mitigation measures were identified as necessary to restore habitat connectivity and reduce wildlife mortality at all bottleneck locations. This number exceeds the number of bottleneck locations, as at 30% of all bottleneck locations more than one measure is needed to solve the problems. A significant number (331) of these proposed mitigation measures involve adapting existing structures, such as road tunnels, viaducts or bridges, to allow for better use of these structures by wildlife. In addition the construction of 213 wildlife passages is needed, which will be exclusively for the use by wildlife. An overview of the recommended measures for each bottleneck location is provided in Annex 2.

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