From remnant meadows to open-habitat mosaics: Modelling dry grassland potential for threatened species conservation across boreal landscapes

Traditional semi-natural dry meadows are biodiversity hotspots, but they now persist mainly as small remnants within dry open-habitat mosaics that also include anthropogenic analogues and naturally open habitats used by many threatened species. Conservation and restoration planning therefore require spatial information on dry grassland potential across this wider habitat mosaic. This study tested whether independently fitted models based on mapped dry meadows and threatened or near-threatened dry-meadow-associated vascular plants and insects identified similar spatial patterns of dry grassland potential. It also examined how accessibility-related predictors should be interpreted in presence-only modelling of synanthropic systems. Separate presence-background models were fitted for inland, coastal and archipelago regions of Finland. Observation biases were addressed using species-level downsampling, spatial thinning and dataset-specific background sampling. Model agreement, predictor responses and vegetation-type associations were compared to assess whether predicted dry grassland potential reflected a shared ecological signal, taxon-specific habitat use or residual sampling structure. Habitat and species models showed broad spatial coherence within regions, with strongest agreement generally between dry meadows and vascular plants. The models also revealed regional differences in dry open-habitat mosaics and in the importance of continuous human land use. Accessibility-related predictors, especially proximity to inhabited buildings, appeared to capture both sampling-related effects and a shared ecological signal linked to environmental conditions and land-use history. Comparing independent habitat- and species-based models can help distinguish ecological signal from residual sampling structure in synanthropic systems. The resulting 20-m maps provide spatial information for targeted surveys, restoration planning, connectivity analyses and conservation status assessment.