Spontaneous colonization of restored dry grasslands by target species: restoration proceeds beyond sowing regional seed mixtures

Abstract Dry grasslands are endangered habitats across Europe, and their restoration requires increasing attention, including their re‐creation on arable land. We studied spontaneous colonization by eleven target species on thirty‐five dry grassland sites restored with regional seed mixtures 1–13 years ago in the eastern part of the Czech Republic, a region where species‐rich dry grasslands often occur in the vicinity of the restored grasslands. Occurrence of the target species (not sown in the restored grasslands) was quantified inside and outside each restored grassland up to distances of 100 and 500 m, and the distance to the nearest population outside was assessed. Data were processed using univariate (Spearman rank‐correlation coefficient, generalized linear models) and multivariate (redundancy analysis) statistics. The establishment of all target species was closely related to their occurrence in the surroundings. Occurrence of species at a distance of up to 500 m, minimum distance to the nearest population and time since start of restoration significantly influenced the occurrence of all the species in the restored grasslands, while distance up to 100 m influenced all except two species. The most successful were wind‐dispersed C irsium canum and I nula salicina and, the least successful was the myrmecochorous E uphorbia virgata . Seeding regional seed mixtures may be considered an appropriate first step in the restoration of species‐rich grasslands on arable land. Following diversification of the vegetation in restored grassland, spontaneous establishment of additional species may occur if the species occur in the vicinity. Results are discussed in the context of grassland restoration and agri‐environmental objectives.