Návrh na manažment biotopov vybraných taxónov z rodu Ophrys L. (Orchidaceae) na Devínskej Kobyle (Bratislava)

Abstract

Many valuable and threatened taxons of the family Orchidaceae, including the representatives of genus Ophrys, are disappearing from semi-natural grasslands because of the advancing secondary succession. Conservation and restoration of calcareous grasslands rich in species at the Devínska Kobyla Mt. requires appropriate interventions after the traditional forms of management will be finished. Bromus erectus is the dominant species at the Devínska Kobyla Mt., hence it is necessary to choose adequate intervention aim of which would be the reduced dominance of this species. Restoration of extensive sheep grazing in this calcareous grassland is not realistic. This is the reason why it is proposed to mow every year or at least every two years (and remove the mown mass) the growths where the taxons of genus Ophrys occur. The best moment for mowing is after maturation of the Orchid Genus Ophrys seeds. With regard to the phenologic cycles of the species concerned, the following mowing terms are proposed: end of June for the locality with occurrence of Early Spider Orchid (Ophrys sphegodes), July for localities with occurrence of Late Spider Orchid (O. holosericea) and Fly Orchid (O. insectifera). The locality with Bee Orchid (Ophrys apifera) does not require mowing due to shallow soil (Lithosol) and vegetation that is close to Poo badensis-Festucetum pallentis association. If mowing cannot be used on the particular dates, it is proposed to mow the growths with the dominating species Bromus erectus in October. The study presents the example how the number of flowering Early Spider Orchid (Ophrys sphegodes) individuals increased after the locality was mown by the employees of the State Nature Conservation in autumn 2004. Their number more than quadrupled in 2005.