Basic approaches to determining stability of rare plant species populations

The results of approbation of three methods of an estimation of stability and probable development trends of populations on the example of rare plant species of National natural park „Desnyansko-Starogutsky” are presented. The study objects were three rare plant species of NNPDS listed in the third edition of the Red Data Book of Ukraine: Eрipactis helleborine (L.) Crantz (the population occurs in the phytocoenosis Querceto-Pinetum coryloso (avellanae)-caricosum (ericetorum), Listera ovatа (L.) R. Br. (in the phytocoenosis Betuleto-Pinetum coryloso (avellanae)-stellariosum (holosteae) and Platanthera chlorantha (Cust.) Rchb. (sporadically spread throughout the woodlands in National Nature Park “Desniansko-Starogutsky”, in Querceto-Pinetum coryloso (avella­nae)-caricosum (ericetorum). It is established that MVP and the analysis of populations structure methods do not give a trustworthy information about the real development trends in local populations, particularly if in disposal of researcher data only for one or for 2–3 years of observations are available. PVA is a highly effective method that enables to assess stability of plant populations on a complex of individuals features in the population and population characteristics as a biological integrity. Thus, three me­thods revealed the likelyhood of degradation of E. helleborine and L. ovata local populations and relatively higher stability of local population of P. chlorantha. The organization of long-term monitoring of local populations of rare plant species is recommended on all protected areas