Variability of Population and Individual Characters of Gymnadenia conopsea (L.) R. Br. (Orchidaceae, Liliopsida) under Anthropogenic Load Conditions in Meadow Ecosystems of Central Caucasus

Abstract

We studied the variability and phytocenotic plasticity of the morphological characters of individuals, and the numbers, density, ontogenetic structure and vitality of 11 coenopopulations of Gymnadenia conopsea (L.) R. Br. within the Kabardino-Balkar Republic in 2015–2019. The variability and plasticity of plants features provide their adaptation to various growing conditions and improve the morphological heterogeneity of coenopopulations. The dynamics of abundance, density, age structure and vitality of coenopopulations in the changing conditions of the environment provides information about life strategies of the species. Age conditions, the variability and plasticity of plants were studied on the basis of morphological parameters of the aboveground organs without digging the plants. The studies were conducted in meadow plant communities under various conditions of anthropogenic load (recreation and grazing). The species is characterized by medium-high phytocenotic plasticity of morphological characters (Ip = 38–68%) and high variability of morphological characters (CVх¯ср = 17.10– 33.63%) under changeable growth conditions. Intensification of growth processes in the individuals with the maximum increase of the coenopopulation vitality (IVC = 0.98– 1.16) was observed in the composition of undisturbed highly wet meadows; the portion of generative individuals increased in their ontogenetic spectra (48.6–56.5%). Under the anthropogenic load intensification, the vitality of coenopopulations (IVC = 0.82– 0.95) and the density of individuals decreased; the portion of virginal individuals increased in their ontogenetic spectra (rubbly meadows) or coenopopulations were clearly aging. The rate of the seed reproduction of coenopopulations, where the density of individuals accounted for 16 ind./m2 , was high on rubbly substrata with low total projective cover (60%). Our studies have identified the mixed type of life strategy for Gymnadenia conopsea with stress-tolerant and ruderal components. The ruderal-stress-tolerant life strategy allows the species to grow for a long time in conditions of high interspecific competition and anthropogenic load, spreading quickly to unoccupied territories.