## 2 Materials and Methods
### Study Sites  
The first site is located in the northwest portion of Orbroich, including portions of Krefeld, a city of roughly 225,000 people on the western side of the Rhine River. The area within the Orbroich site is a mixture of developed areas along with arable land, grassland, open water, and forested areas. The second site covers Wahnbachtal approximately 25 km southeast of Cologne. Compared to the Orbroich site, the study site in Wahnbachtal contains a less densely populated, undulating landscape with small towns and includes more woods and natural grassland. The characterization of grassland change at the Wahnbachtal site was of particular interest as agricultural land use was dominated by grasslands (17% of agricultural area and 47% of agricultural parcels, Table S1). The spatial extent of both study sites is defined by a 10 km radius which is centered on an individual insect trap location from [5], encompassing approximately 315 km\({}^{2}\) (Figure 2).  
A spatial delineation of land cover parcels was performed via visual identification and classification based on high-resolution aerial imagery. Orbroich data were digitized from 64 aerial imagery tiles (10 cm resolution) from 2012/2013 obtained from Bezirksregierung Koln ([[https://www.bezreg-koeln.nrw.de/](https://www.bezreg-koeln.nrw.de/)]([https://www.bezreg-koeln.nrw.de/](https://www.bezreg-koeln.nrw.de/)), accessed on 10 June 2020), with a focus on non-developed land area (i.e., densely developed areas were not the focus of parcel digitization). A total of 17,711 parcels comprising 18,944 ha were identified as 1 of 31 land classifications using three levels of categorization (Table S1). This study area utilized four agricultural grassland classes of meadow, meadow-orchard, silage, and other grassland as well as the neglected grassland (in total comprising 15.8% of the total parcel area (4234 parcels)). Other natural land cover classes (2130 parcels) comprised 1.4% of the total parcel area. Arable agriculture was the dominant land cover comprising 74.5% of the parcel area (Table S1).  
Figure 2: Orbroich and Wahnbachtal study areas and starting land cover polygons.  
Wahnbachtal parcels were digitized in May 2020 from high-resolution basemap imagery within ESRI's ArcGIS Online platform. Parcel digitization for Wahnbachtal was focused on grassland only (Figure S2). This resulted in 3256 parcels comprising 7548 ha with an average parcel size of 2.3 ha (Table S2).  
Grassland polygons were subsequently reviewed to remove parcels that were too small or narrow for appropriate characterization based on a 30 m resolution of the satellite imagery. This selection process only included polygons with a minimum size of 0.4 ha and an area-to-perimeter ratio >10 (which eliminated the long narrow and oddly shaped polygons). The remaining polygons were buffered inward by 30 m to reduce the potential for mixed pixels to be included in the analysis and rasterized in alignment with the satellite imagery (Figure S3). After this pre-processing of the input parcels, a final set of grassland polygons remained composed of 818 polygons for Orbroich and 1367 polygons for Wahnbachtal.