Spatial preferences for invasion management: a choice experiment on controlling Ludwigia grandiflora in a French regional park

If individuals have spatially differentiated preferences for sites or areas impacted by an invasive alien species, effective management must take this heterogeneity into account and target sites or areas accordingly. In this paper, we estimate spatially differentiated preferences for the management of primrose willow (Ludwigia grandiflora), an invasive weed spreading in a French regional park. We use an original spatially explicit discrete choice experiment to evaluate individuals' willingness to pay (WTP) to control the invasion in different areas of the regional park. Our results indicate that WTP for management highly depends on the area considered, with areas where it is three times higher than others. We analyze the main factors explaining the heterogeneity of preferences and show that the closer respondents live to the park, the more they visit and/or practice activities in it, the higher their WTP and spatial preferences. Park residents and regular users have high WTP and unambiguous preferences for targeting control to specific areas. Non-residents and occasional users have much lower WTP and more homogeneous spatial preferences. These results suggest that implementing management strategies that spatially target invasion control according to public preferences is likely to produce significant utility gains. These gains are all the more important as the preferences taken into account are those of the stakeholders directly concerned by the invasion, the residents and regular park users. Ignoring these spatial preferences will lead to sub-optimal invasion management.