Using an online survey to assess the spatial distribution of wild boar (Sus scrofa L.) crop damage and factors influencing this distribution and severity in Limburg province, Belgium

Abstract

Wild boar (Sus scrofa L.) reappeared in Flanders (northern Belgium) in 2006 after almost half a century of absence. Interactions between wild boar and human activities are frequent due to extensive fragmentation of the landscape in Flanders. Complaints about agricultural damage are increasing but the actual extent of crop damage remains unknown. The goal of this study was to assess the current risk and the spatial distribution of crop damage, as well as factors influencing damage distribution in the province of Limburg (eastern Flanders). An online survey was sent to farmers by email. Moreover, as we expected potential respondent bias towards farmers that already experienced damage, we also conducted a follow-up non-respondent check by telephone. Our study showed that the current crop damage probability on a farm lies between 42% (likely an overestimation due to respondent bias in the online survey) and 22% (an underestimation based on the non-respondent check). There is considerable geographical variation in the proportion of farms that report boar damage; probability for crop damage due to wild boar is relatively high for farmers in Limburg but shows a geographically heterogeneous spread. Factors explaining the crop damage probability differed strongly between the online survey and the non-respondent check and no consistent results could be found. Our results show that using the online survey, it was possible to get an initial insight in the geographical distribution of crop damage. However, as we found differences between the results of the online survey and the non-respondent check, taking management decisions based solely on online survey results without conducting a non-respondent check could lead to misguided actions.