Appendix A1: Connectivity calculation Polygons of coverage of CG in and around Hampshire were used to produce a 100×100 m raster, with the value of each cell corresponding to the % cover of CG within it. Connectivity to CG was calculated to the same resolution, with the connectivity of each cell being a function of the distances to and % coverage of all other cells in the landscape. Assuming a negative exponential dispersal kernel (Hanski 1994), connectivity of each cell was calculated such that C i (1) where is the % coverage of CG habitat in cell and is the Euclidian distance (km) between A j dij the centres of cells and For the purposes of this study, the multiplier of = 2 was selected to i j. α represent a mean distance of 1km. We extracted the connectivity to CG of each trap location from the raster using the package (Bivand & Lewin-Koh 2014). R maptools Mark-release-recapture (MRR) studies on common farmland moth species have found mean distances covered between first capture and first recapture to be up to 0.65 km (Merckx et al. 2009, 2010). However, the maximum distance between any two of the capture sites in both of these studies was only 1.44 km, therefore lifetime dispersal of the species studied is likely to be greater (Schneider 2003). A larger-scale MRR of Slade (2013) on forest fragments around et al. Wytham Woods, UK, had a maximum pairwise trap distance of 4.13km. In this study there were some highly mobile species which had modelled mean distances moved within one week that were greater than 1km, but these were woodland specialists that were rarely caught in our study. Macro-moth species in Slade (2013) were more generally expected to have a net et al. displacement of between 250 and 500m per week; given the scale of their study, we believe that 1km is a reasonable approximation of what the mean lifetime displacement might be for individuals in our study, hence we use a mean distance of 1km in our dispersal kernel.
Appendix A1: Connectivity calculation Polygons of coverage of CG in and around Hampshire were used to produce a 100×100 m raster, with the value of each cell corresponding to the % cover of CG within it. Connectivity to CG was calculated to the same resolution, with the connectivity of each cell being a function of the distances to and % coverage of all other cells in the landscape. Assuming a negative exponential dispersal kernel (Hanski 1994), connectivity C of each cell i was calculated such that (1) where A is the % coverage of CG habitat in cell j and dij is the Euclidian distance (km) between the centres of cells i and j. For the purposes of this study, the multiplier of α = 2 was selected to represent a mean distance of 1km. We extracted the connectivity to CG of each trap location from the raster using the R package maptools (Bivand & Lewin-Koh 2014). Mark-release-recapture (MRR) studies on common farmland moth species have found mean distances covered between first capture and first recapture to be up to 0.65 km (Merckx et al. 2009, 2010). However, the maximum distance between any two of the capture sites in both of these studies was only 1.44 km, therefore lifetime dispersal of the species studied is likely to be greater (Schneider 2003). A larger-scale MRR of Slade et al. (2013) on forest fragments around Wytham Woods, UK, had a maximum pairwise trap distance of 4.13km. In this study there were some highly mobile species which had modelled mean distances moved within one week that were greater than 1km, but these were woodland specialists that were rarely caught in our study. Macro-moth species in Slade et al. (2013) were more generally expected to have a net displacement of between 250 and 500m per week; given the scale of their study, we believe that 1km is a reasonable approximation of what the mean lifetime displacement might be for individuals in our study, hence we use a mean distance of 1km in our dispersal kernel.
1-s2.0-S000632071730174X-mmc1.docx