Road kills of roe deer (Capreolus capreolus) in the Netherlands

Collisions between wildlife animals and motor vehicles are a worldwide problem and influence drivers’ safety and animal welfare. In the Netherlands, the roe deer (Capreolus capreolus) is one the main wildlife animals frequently ending up as road kill, as a result of about 10.000 collisions involving this species per year. Natuurmonumenten (NM), a Dutch nature conservation and wildlife protection organisation, administers multiple natural areas bordering roads where collisions between roe deer and vehicles occur. Therefore, NM called for an examination of measures to mitigate roe deer vehicle collisions (DVC) in the Netherlands. In addition NM called for the creation of an action plan to advise administrators of NM on how to reduce DVCs in the natural area under their administration. This information need was translated into the following research question: “How can roe deer vehicle collisions in the Netherlands be reduced?”. The main research question was translated into two partial research questions: “Where, how frequently and why do collisions with roe deer happen in the Netherlands?” and “Which mitigation measure(s) are effective in reducing DVCs?”. To answer the partial research questions a review of Dutch and international literature was done and interviews with experts on this subject were performed. Concerning the causes of DVCs, it turned out that the DVCs are related to a combination of the natural behaviour of the roe deer, such as the territorial behaviour of dominant bucks during spring, and the influence of humans, such as disturbance by recreational activities in nature. Possible mitigation measures where then reviewed on the criteria of their effectiveness, risks, management option and costs. Readily available information was used to evaluate the measures, with the heaviest weight attributed to the criteria of effectiveness and risks. From the evaluation it was found that a small subset of mitigation measures, such as the wildlife signalling system and a reduction in maximum driving speed to 50 km/h were considered as most effective in theory. However, as the ‘real’ effectiveness of the mitigation measures is influenced by the characteristics of the DVC location, such as maximum driving speed and the presence of residential areas, an action plan was created to identify the most appropriate mitigation measure for the DVC location. The action plan was established for NM natural area administrators and consists of a questionnaire and a flowchart. Through the questionnaire the necessary information on DVC s can be collected. Afterwards, this information can be applied to use the flowchart. The flowchart connects the characteristics of a DVC area, such as maximum driving speed, to a mitigation measure that, according to the author, would be the most suitable for the particular location. The action plan was then tested for three case areas in the Netherlands, on the basis of which the action plan was slightly adjusted and it could be concluded that the action plan gives the most suitable option for the tested DVC case areas. In conclusion, it was found that multiple potential mitigation measures to reduce DVCs in the Netherlands are available. In addition, there are mitigation measures, such as the virtual fence, light warning system and general education, that seem promising, but data on the effectiveness of these measures was inconclusive at the moment of writing this report and this would thus need more research. It is recommended that to reduce DVCs, it is most appropriate to combine multiple mitigation measures as this is expected to reduce habituation by driver and/or roe deer and give the best results. The action plan is a practical tool to identify the most suitable mitigation measure for the particular DVC location and it is recommended to be widely applied. Furthermore, it is important to encourage innovative strategies to reduce DVCs. And finally, cooperation and exchange of knowledge with neighbouring countries are advised. In doing so, more information on the effectiveness of the different mitigation measures is collected which could improve the scientific grounds for the advice that is given to all administrators of natural areas on how to reduce DVCs in the area under their administration