From points to patterns: effects of small-scale diversification of arable land use on bird habitat use

Context The persistent decline of farmland bird populations across European agricultural landscapes has been linked to agricultural intensification and landscape homogenisation, making cropping system diversification an important conservation strategy. However, assessing the combined effects of multiple diversification measures at the field scale remains challenging because conventional experimental designs with independent replicates are often infeasible. Objectives This study aimed to introduce Spatial Point Pattern Analysis (SPPA) to analyse data from a high-factorial experimental design without real replicates to evaluate the effects of diversified, small-scale patch cropping on bird habitat use in arable landscapes in north-east Germany. Additionally, the influence of field structure and agricultural management intensity on spatial patterns of bird occurrence is analysed. Methods Using three years (2021–2023) of georeferenced bird observations, we compared diversified patch-cropping fields with adjacent sole-cropped large-sized reference fields and related bird occurrence to field structure and management intensity by applying SPPA. Results SPPA identified higher bird occurrence and habitat use frequency in patch-cropping fields than in reference fields. Bird observations were more strongly clustered in diversified fields, while lower pesticide use and higher weed cover were positively associated with bird occurrence. Crop type showed no clear effect. Conclusions This study showcases SPPA as a promising tool for agroecological field research under on-farm conditions, capable of detecting spatial habitat use structures in non-replicated, real-world landscapes. In particular, the findings illustrate how SPPA can identify spatial associations between diversified cropping systems, management practices and farmland bird occurrence in European arable landscapes.