Implications for conservation: In every hayfield habitat where Isophya costata is present, mosaic mowing is recommended, with at least 1 ha of uncut patches of good natural condition without invasive plant species (e.g. Solidago gigantea, Asclepias syriaca). Our findings underline the importance of continuity of land use in hayfields without short-timed divergences from the traditional mowing regime. In addition, to protect the individuals during the treatment, we suggest using bar mowers in Isophya costata habitats and cutting with high stubble (min. 10–15 cm). In arid years with a warm spring, abandonment of mowing over the year is highly recommended (climate change adapted land use).