The local population stage structures of the primrose Androsace albana and the Caucasian forget-me-not Eritrichium caucasicum were observed at permanent sites in the alpine belt of the North-West Caucasus annually for 14 years (200 9-2022), accumulating data of the "identified individuals" type according to known ontogenetic scales. The data allow us to calibrate the corresponding matrix models of population dynamics, from which we can obtain various quantitative characteristics of the monitoring object, in particular, estimate the measure of viability. A well-known approach to predicting the viability of a local population is to estimate its stochastic growth rate (lambda(S)) under a certain scenario of random changes in environmental conditions from those observed during the monitoring period. However, only artificial randomness models involved in lambda(S) calculations are proposed in the literature. Our more realistic randomness model (RRM) is associated with variations in the weather and microclimatic conditions of the habitat. It is reconstructed from a sufficiently long (60 years) time series of the weather indicator, which has turned out to be species-specific in the model perennials. The use of RRM in lambda(S) calculations by the Monte Carlo method provides the more reliable and accurate estimates of stochastic population growth rates than those using the well-known technique with an artificial randomness model. The obtained lambda(S) estimates are compared between the two species, as well as between those for each of the species obtained from the monitoring data of different durations. The comparison allows us to draw the conclusion given in the paper title.

Eritrichium caucasicum is an alpine short-lived perennial species endemic to the Caucasus. The stage structure of a local population has been observed on permanent plots in the alpine belt of the Northwestern Caucasus annually for 13 years (2009–2021), accumulating data of the “identified individuals from unknown parents” type. The latter circumstance has predetermined what is called reproductive uncertainty in the terminology of matrix models for discrete-structured population dynamics and means that the annual recruitment rates inherent in the groups of generative plants and final-flowering generative plants cannot be calibrated in a unique way. As a result, instead of the annual values of the asymptotic growth rate, the model gives only certain ranges of their values that vary from year to year, corresponding to the data. This introduces both technical difficulties and uncertainty in the viability forecast based on the asymptotic growth rates. A well-known alternative approach is to estimate the stochastic growth rate λS, but only artificial modes of randomness involved in the calculation of λS have been proposed in the literature. Our realistic model of randomness is related to variations in weather and microclimatic conditions of the habitat. It is reconstructed from a fairly long (60 years) time series of the weather indicator. Using this realistic model in Monte Carlo calculations of λS, we have obtained a more reliable and accurate estimate of the stochastic growth rate.

Restoration of aboveground biomass after its defoliation by phytophages may depend on biotic relationships and resource availability. A 3-year full-factorial experiment was conducted on the influence of three defoliation regimes (control, 1 and 2 cuttings at soil level per season), soil enrichment with N and P and the removal of neighboring plants (reduced competition) on the number of shoots and above-ground biomass of 3 species of productive Geranium-Hedysarum meadows in Teberda National Park (Geranium gymnocaulon, Hedysarum caucasicum, Festuca brunnescens). It has been shown that defoliation sharply reduces the formation of generative shoots. In most cases, defoliation significantly reduced the number and above-ground biomass of plants after 3 years of experiment. The final yield of the nitrogen-fixing legume plant (Hedysarum caucasicum), as well as grass Festuca brunnescens, did not depend on the availability of soil resources. The number of generative shoots of Geranium gymnocaulon was slightly higher when NP was added to the soil, and the total number was slightly higher when neighboring plants were removed. In general, both the enrichment of the soil with mineral nutrition elements and the removal of neighboring plants did not have a significant effect on the restoration of above-ground biomass of a productive alpine meadow, in contrast to that for low-productive alpine heaths. The restoration of aboveground biomass in plants of the productive meadow was lower than in alpine lichen heath, which may be due to the limited growing season in the first case.

Studies on the composition and structure of living organisms communities in terms of their functional traits became very popular the last decades. The functional approach is widespread, but is still rarely applied for solving two associated questions: (1) how species from a given community differ from random samples in their mean values of functional traits (with the same number of species) of local flora; (2) how much mean values of functional traits in community species differ from community weighted means (by species abundance), or, in other words, how much higher or lower are these values in dominants compared with those of other species. The aim of this study was to answer these questions using the example of alpine communities of the northwestern Caucasus. We studied leaf functional traits in four types of alpine communities, which cover maximum area in the alpine belt of the northwestern Caucasus: alpine lichen heaths (ALH), Festuca varia grasslands (FVG), Geranium–Hedysarum meadows (GHM) and alpine snowbeds (SB). Water saturated leaves of ALH plants had a significantly lower mass and specific leaf area (SLA) but a higher dry matter content compared with the samples of species from “random” communities. The dominants of this community had smaller leaves with a higher dry matter content and a lower SLA. Leaves of FVG plants had a lower area and wet mass, but a higher dry mass, while dominants had a higher leaf dry mass and dry matter content, but a lower leaf area and SLA. For the plants from more productive GHM, larger leaves and higher dry matter content are typical compared with “random” species samples. Only three size traits (leaf area, wet mass, and dry mass) were significantly higher in the dominants of GHM in comparison with other species of this community. Plants of alpine snowbeds, which grow under late snowmelt time and short growth season, had smaller leaves with high dry matter content and SLA. The dominants of these communities, in contrast, have larger leaves compared with other species of SB. The results we obtained confirm the delimiting role of stress tolerance for establishment of communities in habitats with low snow cover and for dominance there (ALH and FVG), the significant role in competitive strategy of more large-leaved species in more productive GHM and comparatively high role of ruderality in formation of SB.

Fires play an important role in structure and function of terrestrial ecosystems, but their long-term impact on the composition and structure of plant communities in humid high mountain regions remains almost not studied. At the most dry alpine grasslands, dominated by a dense-tussock grass Festuca varia, with substantial accumulation of non-decomposed litter, the 23-years long experiment with regular (every two years) litter burning was established. The composition of plant community changed significantly. The mortmass (mass of litter), aboveground vascular plant biomass and relative abundance of dominants decreased substantially. In aboveground biomass the proportion of grasses decreased and that of forbs increased. The shoot numbers of Anthemis cretica, Campanula collina, Deschampsia flexuosa, Festuca ovina, Nardus stricta, and Veronica gentianoides increased after burning. Two-fold increase of alpha-diversity of vascular plants was observed on plots with burning treatment, it was twice as high as initial value, and was significantly higher than the values in the control plots. Long-term burning did not substantially change mean P, Ca and Mg content in the biomass of the most of studied species, only K content decreased in some species, while Mg content increased in Festuca varia and Nardus stricta. The increase of P and Mg content in the mortmass was observed. During long-term burning, weak soil acidification and the decrease of Ca content, as well as strong decrease of nitrogen content and the intensity of nitrogen transformation processes were observed. Generally, the observed patterns were similar to those in other studied herb communities, however, the decrease of K content during the regular burning was not reported earlier.

The investigation of belowground plant production and its determining factors is critical for better understanding carbon turnover in the biosphere. The measurement of fine root production is a methodical and difficult task. To reveal factors determining fine root production in mountain ecosystems, we introduced a new modification of ingrowth method with the use of filter balls (tea strainers). We studied root production in 16 communities from upper forest to subnival belts in the range of 2184–3069 m a.s.l. in the Teberda Reserve, Northwestern Caucasus, Russia. The filter balls were filled with sifted soil (without roots or stones) and buried in the soil 7–8 cm deep. The mass of root ingrowth was measured after two months of incubation under natural conditions. Mixed-effect models were applied to test the relationships between root mass, elevation, soil moisture, organic matter content, and pH. The highest root production was observed in an alpine snowbed (247 mg per filter ball in 60 days), the lowest was in forest and subnival communities (3–20 mg per filter ball in 60 days). The communities with woody dominants had lower production than herb communities. It increased with soil moisture, which was the most important factor. In herb communities the production of roots tended to decrease with the elevation. Soil organic matter as a separate factor had a positive relationship with root production in herb communities. There were no links between root ingrowth and soil pH. The method introduced presently both allows for the comparison of plant communities by their root production and reveals factors determining it.

The numerical estimation of ecological strategies (according to the classification of J. Grime) can contribute to plant dominance iunder certain environmental conditions. Alpine plants are traditionally considered as stress-tolerators (S) that are adapted to low temperatures and poor soils. We assessed the hypothesis that the C strategy is more expressed in relatively productive alpine meadows, whereas the R strategy is more important in communities with a short growing season and a heavy snow cover. The structure of the aboveground biomass (ratio between the species) and the parameters of leaves of all species of vascular plants were studied in four communities (alpine lichen heath, ALH; Festuca varia grassland, FVG; Geranium – Hedysarum meadow, GHM, and snowbed community, SBC). Based on these values, the contribution of the C, S, R components to the overall strategy of each species (according to S. Peirce et al.) and the weighted mean values ​​of the contribution of strategies for each community were calculated. The a priori hypothesis was confirmed, while the dominant species showed an increase in the role of stress tolerance on ALH and FVG and competitiveness on GHMs, which indicates the adaptability of these strategies in the studied communities. The contribution of C and S is in good agreement with the role of competition in the formation of various communities: it is maximal for GHMs, in which the C strategy is expressed, and minimal for FVGs, in which stress tolerance is most pronounced.

Revealing the relative role of abiotic and biotic factors determining the present structure of plant communities is an actual task. One of the approaches to this problem is linked with plant functional traits variability: abiotic factors usually cause trait convergence, while biotic ones cause its divergence. With the example of experiments on long-term (18 years) reciprocal transplantations of sod plots in four alpine plant communities in the north-western Caucasus, we studied the concordance of intraspecific changes of leaf traits (leaf mass and area, water content, thickness, specific leaf area) with community weighted means of the corresponding traits in acceptor communities. In most cases (65 of 78, or 83%, p < 0.001), the significant changes of the studied traits were concordant to those of community weighted means, but few exceptions were observed for every trait. Thus, our data suggest the more important role of abiotic factors in alpine plant communities, but in more productive meadows the cases of divergence were observed, confirming the role of biotic factors, such as competition.

The regrowth of the aboveground biomass of certain plant species after complete or partial defoliation in highlands can depend on competition with neighboring plants, as well as on the level of availability of soil resources, primarily mineral nutrients (especially N and P). A 3-year full-factorial experiment on the effect of three defoliation regimes (control and single and double mowing at the soil level per season), enrichment of soil with N and P, and removal of neighboring plants (competition reduction) on the shoot number and aboveground biomass of three plant species (Anemone speciosa,Festuca ovina, andOxytropis kubanensis) in alpine heaths was carried out (in total, 12 variants in 10 replications). It is shown that the removal of competing vegetation in low-productive communities of alpine heaths does not contribute to the biomass recovery after defoliation, unlike the addition of NP fertilizers. The regrow of a nitrogen-fixing legume did not depend on the availability of soil resources.

The parameters of functional diversity are studied on the example of plant height for four alpine communities (alpine lichen heaths, Festuca varia grasslands Hedysarum-Geranium meadows, and alpine snowbed communities) in Teberda Reserve of the northwestern Caucasus. The work tests the hypothesis that, when plants that use different volumes of air, a low volume of the environment is used more evenly than a high volume. It was assumed that the divergence in plant height is more pronounced in meadow communities, where the competitive relationship is stronger and the level of production is higher. For the four main types of phytocenoses (alpine heaths, Festuca varia grasslands Hedysarum-Geranium meadows, alpine snowbeds), data were obtained on the average height of the plant species forming them, the biomass of individual species, and the weighted average plant height in the communities. The indices of functional richness, evenness, and divergence were calculated based on these data. It is shown that taking into account the abundance of species in the community significantly affects the values of average height and indices of functional diversity. Contrary the a priori hypothesis, it was found that the value of evenness is significantly lower at a low air volume occupied by the community (alpine snowbeds) than for a high volume ( Festuca varia grasslands). The functional divergence in alpine snowbed communities with low productivity is higher than that in the more productive meadow phytocenoses, e.g. Festuca varia grasslands. The aboveground production positively correlated with functional richness in the aggregate analysis of all data, but this correlation is not detected within communities. Functional evenness is not related to community production. An unimodal relationship between the index of functional-divergence and aboveground biomass was shown only for the Festuca varia grasslands (the maximal divergence is observed on plots with average biomass).

The range of ecological CSR strategies for subalpine tall-herb communities of the northwestern Caucasus (Teberda state natural biosphere reserve) has been studied by the measurement of leaves’ functional traits. These communities are developed in swales, river valleys, and runoff depressions of the subalpine belt and represent a typical element of the Caucasian flora. The dominating species are represented by tall forbs, such as Rumex alpinus, Senecio platyphylloides, Cephalaria gigantea, Ligusticum alatum, etc. To evaluate ecological strategies of plants, three functional traits, including leaf area and the weights of wet and dry leaves, have been measured. Based on these measurements, the strategy parameters have been calculated for 42 vascular plant species. The majority of plants of the subalpine tall-grass community manifest traits typical for the competitive (C) and competitive-ruderal (CR) strategies. According to the calculation algorithm, 11 species (Angelica purpurascens, A. tatianae, Cirsium chlorocomos, Heracleum asperum, H. leskovii, H. sosnowskyi, etc.) are referred to the C-strategy. The CR strategy is observed for Aconitum nasutum, Cirsium simplex, Geranium sylvaticum, Hesperis voronovii, Rumex alpestris, and some other species. Two species (Achillea millefolium and Dactylis glomerata) are characterized by the competitive and stress-tolerant (CS) strategy. The stress-tolerant (S) strategy is observed for three species (Veronica filiformis, Lilium monadelphum, and Millium effusum). Finally, the mixed CSR strategy is typical for two species (Trifolium pratense and Astrantia maxima). The majority (93%) of the species studied is characterized by clear competitive traits; the contribution of this strategy type positively correlates with the average vegetative height of a species. In addition, many of the studied species (26% on average) are also characterized by some R-strategy traits. In our opinion, this fact results from a long-term grazing history of alpine plant communities in this region. The obtained results contradict the common opinion about the domination of stress-tolerant species in highlands. This contradiction may be explained by the fact that the studied subalpine meadows are located in the most favorable habitats providing competitive advantages for rapidly-growing tall-herb species. The study confirms the hypothesis that the dominated species of the subalpine tall-grass community of the northwest Caucasus are characterized by significantly (up to 95%) manifested traits of C strategy.

We aimed to research the spectrum of the CSR strategies for subalpine tallgrass communities of the Northwest Caucasus (Teberda state natural biosphere reserve). The community is typical of the subalpine zone in the altitude range of 1850 to 2600 m (mean 2300 m). It occupies the lower portions of slopes, valley bottoms and depressions on slopes with significant winter snowpack accumulation. Stable water supply from the upper part of slopes is an important factor increasing its productivity. A few tall and highly productive species have established at such sites, since grazing was stopped. The community dominants are Rumex alpinus, Senecio platyphylloides, Cephalaria gigantea, Ligusticum alatum and other. Accomplish this we measured key functional traits of the leaves: leaf area, wet leaf mass, dry leaf mass. On the basis of these traits we calculated CSR-strategies for the 42 species of the tallgrass communities. We defined six types of CSR-strategies and confirmed that most of explored species has strongly pronounced traits of the competitive (C) and competitive-ruderal (CR) strategies. For the 11 species C-strategy was identified (for example, Angelica purpurascens, A. tatianae, Cirsium chlorocomos, Heracleum asperum, H. leskovii, H. sosnowskyi ). The degree of C-selection has positive correlation with mean height of the species. CR-strategy was shown for the Aconitum nasutum, Cirsium simplex, Geranium sylvaticum, Hesperis voronovii, Rumex alpestris and other. Two species ( Achillea millefolium, Dactylis glomerata ) have competitive-stress-tolerant strategy (CS). Stress- tolerant (S) strategy has been identified for the three species Veronica filiformis, Lilium monadelphum, Millium effusum . Two species have CSR-strategy ( Trifolium pratense, Astrantia maxima ). Also, 70% species have the ruderal strategy features (on average, 26%). We assume it is result of the anthropogenic influence for many centuries. Our results contradict the popular point of view that highland species have stress-tolerant strategy. This can be explained by the ecological conditions in the lower portions of slopes, valley bottoms and depressions on slopes. In this conditions competitive species are most adaptive. Our hypotheses was supported; constant Caucasus species of the subalpine grass communities have significantly racteristics of competitive strategies (up to 95%) (except V. filiformis ).

Snow-bed alpine communities of the Lesser Caucasus occupy significant areas and form under specific environmental conditions: long-term snow cover and a short growing period (about 2 months). We have assumed that the main components of floristically poor plant communities under these conditions are characterized by a well-developed mycorrhiza. The intensity of mycorrhizal infection was studied on the Aragats Massif (3300 m) according to the approach by I.A. Selivanov, and the percentage of root length colonization was calculated for ten plant species. Well-developed arbuscular mycorrhizas were revealed in all cases, even for representatives of families that usually do not form mycorrhiza (Carex oreophilla (Cyperaceae) and Minuartia aizoides (Caryophyllaceae). The intensity of mycorrhizal infection of Gagea pusilla (58 ± 6%) and Ranunculus dissectus (44 ± 4%) was determined for the first time. Thus, snow bed alpine communitiesare characterized by well-developed arbuscular mycorrhiza of plants, despite pronounced ruderal features.

Alpine snowbeds in the Lesser Caucasus are rather considerable in area and develop under quite specific environmental conditions such as prolong snow cover and short vegetation period (about 2 months). We assumed that under these conditions main components of floristically poor plant communities would have well developed mycorrhiza. On the Aragats Massif (3300 m), the intensity of mycorrhizal infection is studied by I.A. Selivanov method and the percentage of root length colonization is measured for 10 plant species. In all cases, well developed arbuscular mycorrhiza is detected, even in representatives of families usually not infected by mycorrhiza (Carex oreophilla - Cyperaceae, Minuartia aizoides Caryophyllaceae). The intensity of mycorrhizal infection in Gagea pusilla (58 +/- 6%) and Ranunculus dissectus (44 +/- 4%) is determined for the first time. It is concluded that plants in Alpine snowbeds possess well developed arbuscular mycorrhiza despite pronounced ruderal traits.

Reciprocal transplantations of turf pieces have been conducted in alpine plant communities of the northwestern Caucasus. The changes in floristic richness and successional rates have been registered for 25 years. The study objects were plant communities located in a toposequence from ridges to deep depressions along the gradients of an increase in the snow cover thickness and a decrease in the growth season: alpine lichen heaths (ALHs), Festuca varia grasslands (FVGs), Geranium–Hedysarum meadows (GHMs), and snow bed communities (SBCs). The results of the study confirm the hypothesis about the approach of the floristic richness of transplanted pieces to that of the background acceptor community. It is shown that variability reduces during succession if turf pieces from different communities are transplanted into a common community. In particular, this is obvious in the case of SBCs, where the floristic richness of turf pieces transplanted from ALHs and GHMs has been noticeably reduced. The results also show that the more different are the donor and acceptor communities, the higher is the rate of their changing. However, the assumption of a higher succession rate in more productive communities has not been confirmed. On the contrary, the communities with initially low productivity changed more rapidly than those with high productivity. It is found that turf pieces transplanted to upper plots of the toposequence have a higher rate of alteration in comparison with those transplanted to lower plots, which may be related to the longer growth season, which indicates a more prolonged period of high functional activity, and, hence, more time for the effects of competition, seed transfer, etc. In general, the rate of succession decreases as the time since the moment of transplantation increases, especially in communities with low productivity.

The results of the experimental research of alpic plants regeneration on the high mountain station of the MSU “Malaya Khatipara” (Teberdinsky reserve) are analyzed in the article. For the plants stability assessment the was used the method of mechanical cutting tye vegetating and generating parts periodically.