Demutational changes in the population structure and species composition of the Festucetum supinae plant community in the alpine belt of the Ukrainian Carpathians

Abstract

The article discusses the results of population analysis and changes in the species diversity of herbaceous perennials from the Festucetum supinae plant group, which occur during vegetation demutations in the Alpine belt of the Chernogorsky Range (Ukrainian Carpathians). Until 1975, this grouping was under grazing conditions. From the time when this territory became part of the Carpathian Nature Park, it was withdrawn from economic circulation. The author sums up the results of long-term (1974–2021) population studies and draws conclusions about general trends, prospects for restoring the primary species composition and optimizing the population structure of the herbal components of Festucetum supinae. Data are presented on the characteristic changes in the species composition of this community and the patterns of structural transformations of populations of herbaceous perennial plants (number of individuals, ontogenetic and vitality structure). It has been established that the main changes in the species composition of Festucetum supinae occur quickly and are completed already in the first 4–7 years after conservation. On the other hand, further optimization of their population structure requires a long time and has not yet been completed even now. It is concluded that sheep grazing promotes invasions of diaspores from other phytocenoses and activates the vegetative reproduction of herbaceous perennials by mechanical particulation. Periodic counts of the species composition in this phytocenosis showed that formally (quantitatively) it almost did not change (19 species in pastures, against 20 species of herbaceous plants in protected areas). But the demutation caused its significant qualitative renewal (for more than 50% of the species composition of Festucetum supinae). Interestingly, none of the new species is adventitious for this area. On the contrary, these are native species inherent in the primary composition of alpine meadows in the Carpathians. That is, unlike some plant groups studied by the author in the subalpine belt, the demutation of the pasqual (pasture) group Festuceta supinae caused unambiguously positive changes. We are talking not only about the transformation of the population structure of herbal components, but also about the formation of new populations by typical alpine plants from neighboring groups. Thus, there is a gradual restoration of the primary species composition of the Festuceta supinae plant community. This is facilitated by the low invasiveness of this group, which hinders the introduction of alien species into it. At the same time, almost all herbaceous perennials have undergone fundamental changes in the ontogenetic, vitamin structure and number of individuals. If, according to the ontogenetic type, unstable invasive or invasive-regressive populations prevail in pasture areas, now they have been replaced by stable populations of the normal type. Similar changes occurred in their vitality composition. Now, in the community of Festucetum supinae, instead of depressive, vitally incomplete populations, vitality-full-membered populations of equilibrium or prosperous types already predominate. These results are indisputable evidence of the positive impact of demutation processes on the restoration of the natural species diversity of degraded plant groups in the alpine belt of the Carpathians. Based on the results of the research, it was concluded that, unlike the subalpine meadow groups, changes in the species composition and population structure of the grass components of the groups in the Alpine belt occur without successional changes in the dominant, which the Festuca supina Schur population has always remained. In all cases, it remained stable in terms of its ontogenetic or vitality structure and in terms of the stability of the flow of generational replacement. The author concludes that although the moderate grazing of agricultural animals does not formally change the species diversity of the Festucetum supinae plant community, it contributes to the destabilization and regression of the structure of most of its components. Further development of such trends creates a real threat of complete extinction of populations of a number of native species in Festucetum supinae. According to the results of observations (1974–2021), during demutation in this phytocenosis, an increase in the size (vitality) of individuals and the total projective cover (60% to 80%) was noted. It is also interesting that all these changes took place not only without the expected successional change of the dominant, but even without weakening its population positions. The author concludes that during demutations, the general recovery process is determined by the typical types of alpine flora inherent in alpine meadow communities in the Carpathians.