mitigation of the effects of road construction on sites of high ecological interest

This report describes a study which examined measures provided for the mitigation of adverse ecological effects of road construction on designated sites and protected species, and determined the extent of their success. In particular, the design and management of such measures was examined. Fourteen sites were selected as case studies. These were either designated sites (Sites of Special Scientific Interest (SSSIs), National Nature Reserves (NNRs) both of which are the UK's most important sites for nature conservation), or the habitats of protected species. This report describes each of the case study sites in terms of its ecological interest, the extent of the impact of road construction on the site, the mitigation measures taken, and assesses the success of these mitigation measures. At eleven of the sites assessment of the mitigation was by field surveys conducted during 1996 or 1997, by Scott Wilson Resource Consultants, under contract to TRL. At the remaining three sites assessment of the mitigation methods relied on documented evidence. Of the fourteen schemes studied, possibly only three could be regarded as successful. Of the remainder, most could be considered partially successful, or their success is uncertain at the present time, and three could be regarded as failures. The main reasons for failure was inadequate management of the implementation of the scheme, or inadequate post-implementation management. (A)