Vegetation data from field boundaries on outer field borders and around habitat islands on the field

Data was sampled in 2021 and 2022 on 40 fields, all managed conventionally and grown with winter cereals in the year of the survey. The fields were chosen in pairs in which each pair contained one field without any habitat islands and the other field had at least one habitat island. Only kettle holes were considered, as those are the dominant type of habitat islands in this region. The field pairs had to be nearby but separated through a real barrier like a field path, a lane, or a hedge – fields of one pair were not allowed to border on each other directly. The field pairs had a distance of at least 2.5 km from each other to avoid spatial autocorrelations.
On outer borders 4 plots were sampled on each field and additional four plots were sampled on inner borders of field with kettle holes (all around one kettle hole or equally distributed if there was more than one habitat island per field).
Plots were 2 x 4 m large and located directly at field borders: 1 x 4 m located on the crop edge (CE) and 1 x 4 m located in permanent vegetation (field margin) outside the field (FM).
All plant species were determined and their abundances were estimated using the Londo-scale (Londo, G. 1976*). For the survey, the plots were divided into 8 subplots of 1x1 m each to better estimate abundances. For analysis, plots were aggregated, using mean values.
N = 160 outer CE + 160 outer FM + 80 inner CE + 80 inner FM = 480 vegetation survey plots.

*Londo, G. “The Decimal Scale for Releves of Permanent Quadrats.” Vegetatio 33, no. 1 (1976): 61–64. http://www.jstor.org/stable/20036965.