Numbers of plant species were recorded in speciesrich meadows in the Bílé Karpaty Mts., SE Czech Republic, with the aim to evaluate the sampling error made by well-trained observers. Five observers recorded vascular plants in seven plots ranging from 9.8 cm 2 to 4 m 2 independently and were not time-limited. In larger plots a discrepancy of 10-20% was found between individual estimates, in smaller plots discrepancy increased to 33%, on average. The gain in observed species richness by combining records of individual observers (in comparison with the mean numbers estimated by single observers) decreased from the smallest plot (27-82% for two to five observers) to the largest one (13-25%). However, after misidentified and suspicious records were eliminated, the gain was much lower and became scale-independent; two observers added 12% species, on average, and the increase by combining species lists made by three or more observers was negligible (3% more on average). It is concluded that most discrepancies between individual observers were caused by misidentification of rare seedlings and young plants. We suggest that in species-rich meadows plants should be recorded by at least three observers together and that they should consult all problematic plant specimens together in the field, to minimize errors.

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Questions: Although the role of landscape context, often interpreted as the available species pool, is generally assumed to be important for the restoration of disturbed sites, not many studies evaluating this role quantitatively in restored dry grasslands have been carried out. There is especially a lack of large-scale, multi-site studies. We asked how many unsown target species established spontaneously in restored dry grasslands and how spontaneous establishment depended on their occurrence in the surrounding landscape.Location: White Carpathian Mts., eastern Czech Republic (48°50 0 -49°05 0 N,Methods: We studied spontaneous colonization by unsown target species in dry grasslands on ex-arable land at 82 sites, sown with a regional seed mixture, commercial clover-grass seed mixtures or left to spontaneous succession. In total, 246 phytosociological relev es in 5-m 9 5-m plots were recorded. Restoration started 1-31 yr ago. Nearby semi-natural grasslands were included as reference sites (94 phytosociological relev es). A total of 108 target species were defined and their presence evaluated in the surroundings of the restored grasslands, i.e., in grid cells (3.1 km 9 2.8 km) in which the restored sites were situated. Data were processed using multivariate analyses (DCA, CCA) and GLM.Results: The number of target species at the restored sites significantly increased with time elapsed since restoration started and the number of target species occurring in the surroundings. The sites, although restored in different ways, converged in their species composition towards ancient grasslands. The maximum relative colonization of a restored grassland by target species from the surroundings was 23.4%, and the restored grasslands contained max. Fifty-seven percent of the average number of dry grassland target species present in the ancient grasslands.Conclusions: Sowing seed mixtures should be seen as not more than a first phase in the restoration of species-rich grasslands. In a next phase of restoration, we can reasonably rely on gradual spontaneous colonization by target species if they occur in the surroundings, even at sites sown with commercial seed mixtures or restoring spontaneously. However, full restoration probably takes decades or more.

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Large-scale (circa 500 ha) restoration of species-rich dry grasslands was conducted using a high-diversity regional seed mixture in the White Carpathians Protected Landscape Area and Biosphere Reserve, Czech Republic, Central Europe. After sowing, the restored grasslands were regularly mown. Vegetation was analyzed at sites restored 1-12 years ago and compared with that of ancient, extremely species-rich grasslands nearby. Nearly all (98%) sown target species successfully established and nearly half of unsown target species established spontaneously, partly dependent on distance to the ancient grasslands. Early mowing in the first half of June appeared to support species diversity and broad-leaved forbs at the expense of competitive grasses. Using a regional seed mixture appeared to be an effective way of restoring dry grasslands and is especially recommended in the proximity of still existing ancient grasslands where spontaneous establishment of unsown target species may reinforce the success of restoration more easily.