Population and biological features of <i>Beckmannia syzigachne </i>(Steud.) fern cenopopulation under conditions of Viluy zone (Central Yakutia)
Five coenopopulations (CP) of Beckmannia syzigachne were studied under natural conditionis that differ in moisture and salinity gradients, species composition and the level of anthropogenic impact. Variability of morphological parameters of vegetative organs is high and medium, while that of the reproductive organs is medium and low. The number and structure of correlative ties between the morphological parameters are determined by cenopopulations’ state: under unfavourable conditions statistically significant correlations are numerous and show various levels of strength, while under favourable conditions they decrease in number and strength or absent. The studied coenopopulations appeared to have a protective ontogenetic strategy, corresponding to the R (explerent) type. Such a strategy allows the species to occupy new territories and various synanthropic habitats. Three types of ontogenetic tactics were revealed with regard to variation of the ecological-coenotic gradient: divergent, convergent and stabilization tactics. Given the similar age composition, CPs differed from each other by vitality composition along different sections of the ecological-coenotic cline. The vitality types of the studied CPs varied from prosperous one to the depressive. The analysis of the age spectrum showed that, all the studied CPs are normal, incomplete and basically left-sided. They feature the presence of rather large proportion of plants of pregenerative period, represented mainly by immature and virgin plants, and a small proportion generative and subsenile individuals.