Vitality structure of three populations of Spiranthes spiralis (Orchidaceae) from Ivano-Frankivs’k and Lviv regions

Abstract

This paper presents the results of investigation of local populations of Spiranthes spiralis from Yaremche town and vicinity of villages Dora and Shoomyna including two new loci. Effective number and population density were analyzed; population vitality analysis was conducted. S. spiralis in considered localities usually forms small in area and effective number populations. They often consist of separated loci, adapting to favourable habitats. Studied populations of S. spiralis have both balanced and depressing vitality structure that vary in time, apparently in responce to weather conditions in certain seasons. Most generative individuals of S. spiralis, irrespective of the vitality structure of population, continue their onthogenesis. This indicates favourable conditions for and stable state of populations. In considered habitats S. spiralis grows at pastures and mowed meadows that determines dependance of species’ presence on anthropogenic influence. The major threats for populations from Yaremche and Dora are development of cites or ploughing up. For population from vicinities of Shoomyna, the major threat is a decrease of herding with subsequent transformation of coenosis.

Keywords

• population
• vitality
• Spiranthes spiralis
• Red Book of Ukraine
• Subcarpathian