Abstrakt
Decline in wet grasslands, which in the past resulted particularly from the intensification of agriculture, was accompanied by the loss of a lot of populations of organisms, including protected and endangered species of plants and animals associated with these habitats e.g. terrestrial orchids. The survival of populations of many species of European orchids is strongly dependent on appropriate site management, especially regular mowing or grazing.
In addition, humans can negatively affect the persistence of orchid populations in various ways, such as conversion of orchid meadows into building areas, dams, roads etc. or the intensive use of fertilizers and contamination of areas by fertilisers from nearby fields. Comparison of historical data with the present distribution of orchids can reveal a lot about the main reasons for the decline in this endangered group of plants.
Here we present an extensive study of the persistence of 192 historical orchid sites in South Bohemia, with particular reference to the 5 commonest species of orchids, Anacamptis morio, Dactylorhiza majalis, Epipactis helleborine, Epipactis palustris and Platanthera bifolia. We show that the most abundant species at the sites studied was Dactylorhiza majalis.
E. palustris, A. morio and P. bifolia are currently not present at any of the historical localities for these species. Considering more recent history, the situation regarding orchid localities in South Bohemia is not critical, but the fate of these species should be closely monitored.
The majority of this loss is due to the cessation of mowing of the sites. Thus more attention should be paid to the management of the existing sites.
During this study, some new sites were discovered.