Defragmentation in the Netherlands: a success story?

In the Netherlands the problem of habitat fragmentation due to transport corridors is being addressed by a Long-Term Defragmentation Programme. Priority spots for defragmentation measures (i.e., locations where wildlife passages are most urgently required) were assessed by combining population viability modelling with local knowledge of critical road sections. Monitoring studies proved that wildlife passages are frequently used by a variety of wildlife species, but only if regularly inspected and maintained. Model simulations suggest that improperly managed passages may result in the extinction of local populations. More robust passages may considerably mitigate problems associated with poor management. In order to judge the success of the implemented defragmentation measures, their long-term effect on population viability needs to be assessed in future monitoring studies