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The restoration of grasslands is one of the primary targets of nature conservation. An easy tool to stimulate the growth of plant species currently absent from the aboveground vegetation but hidden in the “dark”, is to make use of the soil seed bank. Here, seeds of rare and endangered species may still be present. However, the potential contribution of soil seed banks to effective grasslands restoration still remains unclear, as some but not many valuable species built up a persistent seed bank. To evaluate the potential of the soil seed bank for grassland restoration, we installed an experiment in 73 differently managed grasslands in Germany, where the seed bank was activated by mechanical sward disturbance. We also determined the species richness, the density of viable seeds, and the functional composition of seed banks and monitored the regeneration of the aboveground vegetation over two seasons. Our results show that sward disturbance led to an activation of the soil seed banks, which, however, contributed only little to the revegetation after sward disturbance. In addition, the severe impoverishment of the soil seed bank indicated a restricted potential for the restoration of temperate grasslands. Nevertheless, the activation of the soil seed bank increased not only the richness of arable weeds but also slightly the richness of typical grassland species. We conclude that only in recently improved and strongly species‐impoverished grasslands, sward disturbance alone might be able to slightly increase plant species richness. To achieve a distinct increase in species richness, additional diaspore transfer is needed. [ABSTRACT FROM AUTHOR]

Despite great efforts in European nature conservation, semi-natural habitats such as calcareous grasslands are still suffering considerable declines due to abandonment. Shrub cutting and subsequent grazing or mowing are effective restoration measures to counteract the adverse effects of management cessation. Here, for the first time, we used leafhoppers (Auchenorrhyncha) as bioindicators to assess the conservation value of restored calcareous grasslands. We compared environmental conditions and leafhopper assemblages of 21 restored grasslands and 21 regularly managed sites (control) within the largest area of calcareous grasslands in the northern part of Germany. Furthermore, we applied Generalised Linear Mixed-effects Models (GLMM) to assess the effects of environmental parameters on species richness of leafhoppers within the restored grasslands. After a period of three to eight years, the restoration measures had led to species-rich leafhopper assemblages, including both habitat specialists and threatened species. However, we still found clear differences in leafhopper composition compared to the control. Within the restored grasslands, a pronounced field layer and an increased number of host plants positively affected species richness. In conclusion, the restored grasslands form open fringe-like habitat structures that clearly enhance the conservation value of calcareous grasslands by (i) harbouring numerous exclusive (indicator) species leading to a higher leafhopper diversity at the habitat level and (ii) by providing habitats for several habitat specialists which occurred only rarely on control grasslands. In order to maintain or even increase the biodiversity of calcareous grasslands, we recommend a combination of traditional grazing and small-scale shrub cutting. • First study using leafhoppers for the evaluation of calcareous grassland restoration • Restoration measures have formed open fringe-like habitat structures within calcareous grasslands. • These new habitat structures were colonized by species-rich leafhopper assemblages. • Species composition clearly differed between restored and extant calcareous grasslands. • Restored sites provided habitats for several specialised species. [ABSTRACT FROM AUTHOR]

Land-use change has been identified as the most important factor responsible for the recent loss of biodiversity. One major problem is the abandonment of management, especially in semi-natural grassland ecosystems. Numerous restoration projects were, therefore, launched to counteract this development. However, the effects of restoration are not yet fully understood. Especially the early successional stage, i.e. the composition of the vegetation in the first years after the restoration measures, has received little attention probably due to its supposedly low conservation value. As study area, we selected the largest area of calcareous grasslands at the northern edge of the German uplands. About 35 ha of formerly abandoned calcareous grasslands have been restored by cutting shrubs here in the last eight years. Within the restored sites, 50 randomly chosen vegetation surveys were made and the results were compared to 50 control plots. Our study revealed that the value of the early successional stage for biodiversity conservation was previously underestimated. Even though the target state – calcareous grassland – is far from being reached, the early successional stage enhances the conservation value of calcareous grasslands by (i) increasing diversity at the landscape scale, (ii) hosting numerous target species as well as (iii) contributing to a higher habitat quality and heterogeneity. Future restoration of calcareous grasslands should focus on sites with low nutrient content of the soil, a shallow topsoil, and a warm microclimate. At such sites, the chances are greatest that species with a high nature conservation value, i.e. characteristic species of calcareous grasslands as well as thermophilous fringe and ruderal species, will re-establish. • Large-scale restoration study within one of the largest calcareous grassland areas of central Germany • The restored sites in their early successional stage increased phytodiversity. • They were characterised by a mixture of plants from many different ecological groups. • Number of thermophilous fringe and ruderal species was highest within the restored sites. • Restored sites harboured a high number of functional plants such as pollen sources for specialised wild bees. [ABSTRACT FROM AUTHOR]