Connectivity modelling with automatic determination of landscape resistance values. A new approach tested on butterflies and burnet moths

•A novel method for computing potential functional connectivity was proposed.•A new method for determining land feature resistance was proposed.•The new Raster Connectivity method makes it possible to distinguish where a management measure is meaningful, and where not.•The method is universally applicable, it was tested in South Moravia with butterflies as the selected species. Our study presents a connectivity modelling approach to addressing issues relating to the decline in biodiversity in the landscape of Southern Moravia, one of the most productive agricultural areas in the Czech Republic, markedly changed in the post-war period of collectivization. A modified Hanski-based method was applied in modelling, with the use of least-cost distance evaluation. We propose a new concept of landscape resistance determination, based on occurrence data of species rather than expert opinion. This species-specific approach enables us not only to evaluate overall raster connectivity of landscape, but also to accurately identify locations where management intervention could support the targeted species, and where it would be ineffective. The approach is demonstrated using model groups of butterflies and burnets in the cadastral area of Šardice and its surroundings. Only day-active Lepidoptera associated with semi-natural grassland (43 species) were selected for connectivity modelling. Except for remnants of dry to mesic semi-natural grassland and transitional mosaic of grassland-forest habitat, the most preferable areas for the study and the model group are those of meadows and vineyards. Among the best routes for butterflies and burnets are the grassy verges of roads and railways. Closed forest, bushes, built-up areas and sports grounds are landscape segments of high resistance. The results suggest that, for organisms associated with open habitat, the existing platform for landscape protection is insufficient and, in some cases, even counterproductive.