Biosystems Diversity Cenopopulation of Epipactis helleborine (Orchidaceae) in forest ecosystems that have been anthropogenically transformed to various degrees

of Epipactis (Orchidaceae) in ecosystems that have been anthropogenically transformed to various Because of developed symbiotic connections of the root system of trees, mycorrhiza-forming fungi and the orchid family Orchidaceae in forest ecosystems of the northeast Polissia Region – cultivated Pinus sylvestris , which are now 100–120 years old, recovery of cenopopulations of Epipactis helleborine has been observed in locations of mixed and broad-leaved forests. In natural plant cover of mature pines of the region, indigenous vegetation is gradually recovering – there occur young Quercus robur , Tilia cordata , Acer platanoides of various ages, crown density of understory formed by Coryllus avellana has reached 0.6, above-ground organic leaf foliage that is able to sustain moisture and increase fertility of soil accumulates, creating sufficient conditions of shading for seedlings and juvenile individuals of forest orchids. Special studies revealed a relationship between density of E. helleborine specimens and crown density of the tree stand, shrub strata, structure of soil cover, expressed in cenoses under various degrees of recreational pressure. Density of individuals of forest orchids in the studied populations ranges 10.0 to 0.1 ind./10 m 2 . Dynamics were seen in groupings of Betuleto-Pineta corylosa , Querceta (roboris) corylo- sa , Querceto-Pineta corylosa , Acereto (platanoidis) –Tilieto (cordatae) – Quercetum (roboris) aegopodiosum in the territory of the nature-reserve fund and structurally similar anthropogenically pressurized cenoses. We determined that all examined cenopopulations in old indi- genous zonal cenoses in the territory of the nature reserve fund are normal, they may be considered relatively stable, ontogenetic spectra are incomplete, mostly with right-sided age spectrum – maximum numbers of virgin and generative individuals of various stages. Low density of individuals and incomplete spectra of cenopopulations in light oak forests are natural, and now the largest share of generative and virgin individuals is concentrated in this area. Impact of recreation, unavoidable due to proximity to a road, is a negative factor directly decreasing their density. Ontogenetic spectra of all cenopopulations are incomplete – no seedlings were found in the natural conditions due to underground type of germination. Much more interesting data may be obtained by monitoring studies of age and morphometric dynamic changes during several years. were singular young plants of various size, namely Acer platanoides , Tilia cordata . The understorey’s density is 0.5–0.6, 6 m high; dominating species in richer edaphic conditions is Corylus avellana , and single plants of Frangula alnus , Euonymus verrucosa , Sorbus aucuparia , Rubus idaeus occur. Herbaceous stand is uniform (60–70%). In floristically rich groups of old areas of Querceta (roboris) corylosa , apart from E. heleborine , there were Neottia nidus-avis , Primula veris , Digitalis grandiflora . In the region, there are the Verhnioesmansky, Velyky Bir, Bir Masyv, Dibrova, Voronizka Dacha, Pirotchynska Dacha, Bilohryve, Tipka, Dilianka Lisu reserves. In the area of 200 х 6 m, there were recorded 180 individuals. The population is normal, incomplete, age spectrum is right-sided, single-modal, with peak at middle-generative individuals (50.6%). It is a mature population, transitional to aging.


Introduction
In Northeast Ukraine, the cultivated substitute of forest zonal cenosisforming plants caused irreversible successions in the structure of typical indigenous cenoses -most species of the herb-shrub stratum, which are bioindicators, according to Braun-Blanquet (1964), diagnostic species of the largest class of forest vegetation Querco-Fagetea Br.-Bl. et Vlieger in Vlieger 1937em. Klika 1939, represented by summer-green meso-and mesoxerophyte forests in mineral soils in the zone of moderate climate of geobotanical regions of Eastern Europe (Onyshschenko, 2009(Onyshschenko, , 2017, specifically -the commonest species of forest orchids of Epipactis genus -Epipactis helleborine, became rare . The concept of complex study of rare species at the level of populations, based on the fact that any species lives in the wild as a separate local population (Zlobin, 2009), includes analysis of life forms, peculiarities of morphogenesis of individuals taking into account morphometric data, ontogenetic and vital structures of populations, reproductive specifics of plants, characteristics of ecotope and its correspondence to ecological needs of examined rare species. The status "rare species" and categorization of "rare species" (Stoyko, 2020) were used as basic criteria for choosing the object of monitoring studies. Epipactis helleborine is a polymorphic Palearctic Eurasian nemoral species with broad ecologic-cenotic amplitude. It has been introduced in North America and Canada, where it is considered a weed species (Light & MacConaill, 2006).
The objective of the study was performing complex comparative studies of cenopopulations of E. helleborine to determine life strategies of the species at population and organism levels, which manifest in the conditions of dynamics of anthropological pressure on protected and adjacent territories in different types of successive broad-leaved forests in east Ukrainian Polissia. On lands that have been earlier occupied by indigenous forest ecosystems -mixed and broad-leaved forests, Pinus sylvestris trees are now 10-120 years old. Because of the developed symbiotic relationships between root systems of trees, mycorrhiza-forming fungi, species of herbaceous cover with obligate mycorrhiza, including the species we studied, the indigenous flora is recovering. Important components of the biocenosis are not only zonal dominants of tree stands of nemoral forests, understory, but also young Quercus robur, Tilia cordata, Acer platanoides, terrestrial fertile leaf foliage that is able to accumulate and restrain moisture, thereby increasing soil fertility. This creates sufficient conditions for shading seedlings and juvenile specimens of nemoral forest flora. We consider the discovered localities of Epipactis helleborine in Shostka geobotanical district separate cenopopulations, therefore we recognize their clear confinement to the surrounding conditions (Rabotnov, 1950;Zlobin, 2009).
The territory of the conducted studies is in the farthest northeast Polissia of Ukraine. It is a terrace lowland in the valley of the Desna River and the moraine-sandur plain -Yampil Plateau, segmented by river valleys of left-bank tributaries of the Desna-Svyha, Bychyha, Ivotka (tributaries -Kremlia, Ivot, Svisa, Studenok), Svirzha, Vita, Shostka (left tributary of the Ponurka), Osota, Esman (left tributaries of the rivers Hlystianka and Ret).
Forest in the region accounts for 28% of the area (Chornous, 2006), mean value for the Ukrainian Polissia being 29% (Andrienko et al., 2006). Indigenous tree stands of oak-pine and oak forests account for small areas in mostly nature-protected territories. In general, the region's protected complexes of forest vegetation account for 192 km 2 . In some forestries (Prudyshchianske, Olynske, Dubovytske, Zemliankivske, Sloutske, etc.), over 300 year old oaks have preserved, indicating the former greatness of the region's forests. The network of objects of the nature-reserve fund in this territory is represented by 6 categories out of 11 existing in Ukraine. The percentage of protected area is 5.8. A total of 19 objects are located in the overall area of 9,480 ha, with only one forestry having State Protection status. Eight reserves are recognized as locally significant, as well as eight protected tracts. Climatic changes, aridization, against the background of global warming, gradual destruction of natural wetland, forest, meadow types of vegetation, disruption of hydrological regime of landscapes, increase in alien plants in the vegetative cover are some factors in the endless list of anthropogenic transformations. Not only are anthropogenic changes occurring in a particular nature region, but across the whole of Ukraine, and around the globe in general.

Materials and methods
According to the results of reconnaissance studies in forest tracts of the Shostka geobotanical district (Table 1) during 2003-2021, we found a large amount of newly discovered E. helleborine, which may suggest expansion of the species' range. The area we studied belongs to the European broad-leaved geobotanical region of the Eastern European (Sarmatian) province of coniferous-broad-leaved and broad-leaved forests of the Polisia coniferous-broad-leaved and Middle Russian subprovinces of leaved forests of Pryseimsky district of linden-oak, maple-linden-oak and oak forests, meadows and eutrophic wetlands (Didukh & Shelyah-Sosonko, 2003) within Ukraine. According to physical-geographic zoning, it is a zone of mixed forests of Eastern-European physical-geographic province (Marinich et al., 1968).
As model object, we chose E. helleborine. Sample plots were established in forest blocks with the most numerous populations of the species. In sample plots, on both sides of 146 to 400 m long transects along the glade and from the node in the direction deep into the forest, we established 1 х 1 m squares. In each square, on the spot, we identified and counted plants of various age groups. High frequency of the species' occurrence in plots of geobotanical descriptions allowed us to obtain reliable selection. Studying and describing ontogenesis in field conditions is practically impossible due to peculiarities of biology (presence of protocorm and mycorrhizae, which have been in forest litter for 9 years). Vegetative reproduction was observed in less than in 5% of individuals, took place by division and dying of old regions of root systems during formation of two and more above-ground shoots, leading to particulation. By type of reproductive strategy, it belongs to species with stable dominance of seed reproduction.
A counting unit was considered a partial individual with a single-axis separate individual shoot of E. helleborine, regardless of whether it was a genet or ramet. The counting unit (specimen) is a complex individual with long existing geophilic areas of shoots as residuals of the root system. Short-rooted species and borders of individuals in natural conditions were impossible to determine, since we used only undamaging methods of morphometry in the territory of the nature-reserve fund where rare species included in the Red Book of Ukraine grow . Forest litter was not dug in order to avoid damaging the populations and no plants were dug out of it. Specifics of the biology were analyzed according to a number of studies (Varlygina & Vakhromeeva, 1998;Efimov, 2004;Vakhromeeva et al., 2014). Epipactis helleborine is a herbaceous polycarpic plant with perennial sympodially overgrowing monocyclic vegetativegenerative skeletal long-shoot axes. It is geophyte or axillary-rooted hemicryptophyte, the roots live for over 3 years, hypogenically-short-rooted with short stem parts of stem-root tuberoids, short internodes of monopodially overgrowing shoots, with no specialized accumulating organs. Axillary roots are located on typical roots. Shoots have no thickenings. Summer-green plant with 30-100 cm long above-ground shoot and 3-5 months life span of leaves.
Three groups of leaves were seen in E. helleborine (Serebrjakov, 1952): 1) lower formations: type I -scale-like leaves of roots; type II -transitional leaf (cataphyll) in the restoration zone; type III -sheath leaf with underdeveloped leaf lamina; 2) middle formations: type I -transitional sheath leaf with insufficiently developed leaf lamina with rounded apex; type II -well developed sheath leaves with sharpened apexes; type III -small sessile leaves, transitional to bracts; 3) upper formations -bracts of inflorescences.
Since the life cycle of E. helleborine lasts for 30-35 years, it is very hard for one scientist to study its ontogenesis. Measuring and distinguishing ontogenetic conditions were carried out according to the concept of discrete description of ontogenesis (Light & MacConnaill, 1994).
Seeds (sm) -productivity -3-4th in fruit, one individual can form around 26 th seeds. Actual seed productivity of adult generative individuals was not determined. Research shows that after entering the soil, it remains latent for 9-12 months, and only 5% germinate after fungal infection, and therefore reproductive success is low. The determining limiting factor of seed germination, and therefore tolerance of populations, is formation of mycorrhiza with the same fungi as the dominant species of trees. Intensity of mycorrhiza formation to a high degree depends on fertility and moistening of the substrate (Perebora, 2011).
Seedling (p) lives underground. It comprises protocorm and mycorrhizome. Protocorm is initial stage of post-seed development of sporophyte of orchids before bud formation. The mycorrhizome is the initial shoot with scale-like leaf. We found no seedlings.
Juveniles (j) -plants starting from year 9, since appearance of first leaf on first above-ground shoot, after transition to autotrophic nutrition. The shoot has 1-2 types I and II middle formation leaves. Leaf length is 5-6 cm, width is 1.0-1.5 cm. Internodes are short. Immature (im) plants bear 3-4 type II leaves of middle formation, 6-8 cm long and up to 3 cm wide, with shortened internodes.
Primarily virgin (v), or adult vegetative plants have 4-5 type II leaves of middle formation, 7-11 cm long and 2-4 cm wide. Internodes are shortened, and there is false whorl at the apex.
Annually blossoming for many years E. helleborine transits into second latent condition for 2-7 years or only vegetates for several years, because inflorescences of species of Epipactis and Cephalanthera genera are developing inside buds for 13-14 months. Plants have external morphological features: dried apex with clearly expressed external features of dying; axis of inflorescence is well-developed, has no generative organs, there is 1rarely 2 -type III sessile leaves of middle formation on the axis.
Secondary virgin (vv) -we determined that the average height of such individuals is 30 cm. Plants have a large transitional type I leaf of middle formation, 5 and more type II leaves of middle formation, 7-11 cm long, 2-4 cm wide. Internodes are elongated. False whorl is absent. Number of leaves is always 1-2, type III middle formation.
As marker diagnostic features of generative conditions (g1, g2, g3), we used: length of shoot, number of stem leaves (middle formation), number of veins in leaf lamina, extent of manifestation of internodes (long, short), length of the first internode of inflorescence, number of flowers in it.
Young generative (g1) -first 10 years of blossoming -plant in the 20th year of its life. Leaves: 1 type I large transitional leaf of middle formation, 4-5 -type II, 1 -type III. In inflorescence, the number of flowers is low, the first internode is short.
Average-generative (g2) -second decade of blossoming. Plants have large type I transitional leaf of middle formation, 6-8 type ІІ and 1-2 type ІІІ leaves. First internode is very short. Inflorescences are loose raceme, long, with lots of flowers.
Old generative (g3) -third decade of blossoming. Type I leaf of middle formation -1 small, 3 -4 type ІІ and 1 type ІІІ leaves. The first internode of inflorescence is short, with low number of flowers.
Senile (s) plants are old vegetative plants with 6-7 leaves, with no generative shoot, fruit-bearing stops. In the wild, ontogenetic condition is seen rarely, because many plants die right after they blossom for the last time.
To determine the degree of the development of generative individuals using methods of non-destructive morphometric technique, we took into account 7 features: H veg -overall length (height) of vegetative shoot, (cm); H gen -general length (height) of generative shoot (cm); N fil -number of developed shoot leaves (quantity); L fil -leaf length (cm); L s -leaf width (cm); n -number of veins, L in -length (height) of inflorescence (cm); N fl -number of flowers in inflorescence (quantity). Categories of the populations were determined according to the generally adopted methods (Uranov, 1975(Uranov, , 1977Smirnova et al., 1976;Zlobin, 2009). The conditions were evaluated according to types of age spectra, their completeness, number, density per unit of examined area. We analyzed the conditions of the populations depending on age of the tree stands. The populations were described according to different extents of recreational pressure in the territories of the nature reserve fund -in nature reserves, in conditionally primary (100 years) forest ecosystems under moderate recreational pressure, under strong recreational pressure, late-succession (100-120 years).

Results
According to the results of morphometry, we obtained materials for distinguishing g1, g2, g3 conditions of generative age period of ontogenesis. Additional diagnostic features for identification: quantity, sizes of leaves of middle and upper formations, length of internodes, presence/ absence of false whorls of leaves, number of involucra of inflorescence, distance between the nodes of involucra (Tables 3, 4). The results of morphometry are given in Tables 4, 5. Leaves of lower formation are not described, as we had not dug the soil and forest litter.    Note: "-" absence of the indicated morphological features in leaves of apex formation (involucrum) and internodes.

Table 5
Ontogenetic spectra of cenopopulations of in succession forests in the territory of Shostka geobotanical district represented by nemoral species, the number of species on average per one geobotanical description (400 m 2 ) equaled 29-30, projective cover was 40-85%, dominant plants were Stellaria holostea (20-30%), subdominants were Carex pilosa, Pulmonaria obscura, Glechoma hirsutа, Lathyrus vernus, Trientalis europaea. This cenosis is included in the first and second editions of The Green Book of Ukraine: Syntaxon 11. The group of associations of oak-pine forests with hazel Querceto-Pineta corylosa is a typical old indigenous forests of the Polisia, where E. heleborine, Neottia nidus-avis, Primula veris, Lilium martagon grow in floristically-rich sites. In the studied region, rare cenoses of such type have been described and are protected in Bohdanivsky and Voronizky Reserves (Ass. Querco-Pinetum Cl. Querco-Fagetea). Total number of this population is almost impossible to determine, because it potentially may be over 1,000 specimens per general area of compartment or block. Therefore, we should consider the average density. At the distance of 10 m from the node, average density was the highest -3.3 ind./10 m 2 . In 100 х 10 m area along the transect, we observed more than 227 plants of E. helleborine. The population was young. Age spectrum was normal, incomplete, left-sided monomodal with virgin specimens accounting for the maximum number of individuals in the share (48.1%). The generalized data of completeness of ontogenetic ranges in different types of successive cenoses are presented in Table 6.
Cenopopulation 2 of E. helleborine. Late-successional forest. It is an area of birch-pine forest with hazel Betuleto-Pineta corylosa (Carici pilosae -Quercetum roboris (Mercurialo-Quercetum, Aceri campestris -Tilietum cordatae)) aged 90-110 years, which comprises Pinus sylvestris, where leaved species are undergoing recovery. Tree stand 5J5D, 8J2D: Pinus sylvestris of 30-32 m height, with 38-42 cm diameter. Betula pendula was 24-26 m high, 22 cm in diameter, and crown density equaled 0.7-0.8. The understorey (0.6-0.8) was composed of Corylus avellana. The floristic "kernel" of herbaceous-shrub stratum was represented by Аegopodium podagraria, Carex pilosa. This cenosis is included in the first and second editions of Green Book of Ukraine: Syntaxon 11. Group of associations of oak-pine forests with hazel -Querceto-Pineta corylosa -typical old indigenous forests in Polissia. In the region, cenoses are protected in the territory of Dibrova and Kniazhytsky Landscape Reserves of local significance and Pidivotsko-Chuhuivska Dacha and Dialianka Lisu Botanical Reserves. In the area of 250 х 4 m, the number exceeded 250 individuals with maximum density of 10.0 ind./10 m 2 . The plants grow separately, more rarely in groups of 3-4 individuals in each. Incomplete (no seedlings and senile plants), normal, is characterized by rightsided age spectrum peaking at middle-generative. Share of temporary non-blossoming generative individuals, which after g2 g3 period transit into virgin ontogenetic condition, accounts for 5%.
Cenopopulation 4 of E. helleborine. Conditionally ancient forest, area of sun-lit floristically rich group of associations of Quercetum convallariosum, Q. pteridiosum, Populeto-Quercetum franguloso graminosum. Areas are characterized by high floristic diversity, absence of expressed dominants in the lower strata, on average 69 species of higher vascular species per one geobotanical description, or 50-55 species per 100 m 2 .
Cenopopulation 6 of E. helleborine. Successional forest. A highway has been paved across the forest. The described plot is on a roadside and is generally spread across the oak-pine forest (Populeto-Querceto-Pineta corylosa/Carici pilosae-Quercetum) with scattered Populus tremula, Betula pendula, Picea abies. The understorey is composed of Corylus avellana, with 0.6 density. Terrestrial cover is almost without mosses, the structure of the cenosis has been disturbed by presence of synanthrophic species. Young plants are Acer platanoides, Tilia cordata. Among natural nemoral species, there are Aegopodium podagraria, Stellaria holostea, Asarum europaeum. This population is the smallest by spread area (400 m 2 ), number (17 individuals) and density (0.1 ind./10 m 2 ). The ontogenetic spectrum is incomplete -we saw no rejuvenation -there are no juvenile and immature plants, indicating instability, right-sided, -we only found virgin and generative individuals, which dominated.
Around 100 years ago, before intensive forestry was introduced in the northeast Ukraine, most forested areas of the region were broad-leaved associations of As.  (1960) 1961(Panchenko & Onishchenko, 2005Panchenko, 2018). We saw such examples in a number of objects of the nature-reserve fund (Prudyshchansky Regional Landscape Park, Verhnioesmansky, Velyky Bir, Dibrova Reserves, etc.) at the locations of primary cenoses, which at the age of 60, at the stage of restorative successions, have formed As.  Onyshchenko 2005 prov.). At such plots, the dominant species in the tree stand is Pinus sylvestris, and cenotypic positions of Quercus robur are being gradually recovered, and under the crown of Corylus avellana, young individuals of species of shaded broadleaved forests grow with Acer platanoides, Tilia cordata. The "kernel" of the herbaceous-shrub stratum is formed by nemoral species: Carex pilosa, Aegopodium podagraria, Stellaria holostea, Pulmonaria sp., etc.
An example of research on the status of the population of E. helleborine in constant sample plots in plantations of the Novhorod-Siverske Polissia is the study by Panchenko (2010). There are data about differently-oriented fluctuations in density of E. helleborine in conditionally primary light oak forest of as. Mercurialo-Quercetum (0.2 ind./10 m 2 ) and derivative groups in pine forests with hazel, small-leaved and small-leavedpine forests. Density of populations in light oak forests of associations of Lathyro-Quercetum ranges 6.1 ind./10 m 2 (Sytnovshchyna Tract of Kamianske Forestry) to 18.4 ind./10 m 2 in the territory of the Ichnia National Nature Park.
We saw that the level of development of generative specimens correlates with density of crowns of the tree stands, shrub stratum, structure of terrestrial cover, soil fertility, presence of leaf foliage, and young plants of Acer platanoides occurred in all the releves. Satisfactory condition of studied populations in maple-linden spruce cenoses was observed. E. helleborine tolerates increased anthropogenic pressure in indigenous cenoses of broad-leaved forest ecosystems.
According to our data, the highest parameters of sizes of generative individuals were in population 2. Increase in density of generative individuals, high share of juvenile and generative plants indicates a"wave of restoration" (Rabotnov, 1950). In average-aged successive cenoses, population 1 is invasive, recovers, is currently having left-sided incomplete ontogenetic spectrum, where young pre-generative individuals (j, im, v) prevail. It is a young population, growing in the conditions of accumulation of leaf foliage that is able to hold moisture and increase soil fertility. The study determined that all examined populations in old indigenous cenoses (2, 3, 5) in the territory of the nature-reserve fund are normal (definitive), they may be considered relatively stable, ontogenetic spectra are incomplete, mostly with right-sided age spectrum, peaking at generative individuals of various stages. The large share of juvenile and generative individuals in populations 1-3 indicates their rejuvenation.
Left-sided incomplete ontogenetic spectra peaking at virgin individuals were described by Klimenko (2011) in the conditions of forest restoration successions (As. Querceto-Pinetum coryloso (avellanae)-caricosum (ericetorum), Betuleto-Pinetum coryloso (avellanae)-stellariosum (holosteae)). The author did not determine the overall number and density per unit area. We determined that population 4 has lower number and incomplete spectra. The largest share of young generative and virgin individuals is now in the light oak forests.
Studies of influence of anthropogenic pressure indicated significant deviation from the basic spectrum and low density in population 6. There, E. helleborine experiences no heightened competition caused by other species of plants, and ecological-cenotic conditions did not reach the optimum level; we recorded an insignificant amount of foliage from broadleaved species, since the accumulation of organics is the obligate limiting factor of recovery and spread of species, shading of trees (0.9) and shrub stratum (0.7) is sufficient. In the literature, there is an opinion (Panchenko, 2010) that decrease in light, increased share of broad-leaved species, crown density of the understory with Corylus avellana has directly caused the decrease in the number of E. helleborine. However, it is precisely forest ecosystems of broad-leaved forests with existing natural understorey which are the primary natural biogeocoenoses of the studied species.
In the literature, there are data that intense impact of people (cutting, recreation, etc.) rapidly decreases numbers of plants. The first to disappear are juvenile and immature, and then adult plants, and in 4-5 years, a population can disappear completely. In particular, decrease in crown density to 0.6, caused by selective sanitary cutting of old Quercus robur trees in unprotected areas, is critical, having destructive effect on cenopopulations of forest orchids, leading to their complete disappearance from all the blocks (Yarova et al., 2020). Emergence of "windows" in crowns and rapid increase in light lead to decrease in moisture, deterioration of growing conditions and overgrowing by other species of plants. Therefore, we consider population 6 invasive-regressive -we recorded only virgin and generative individuals. We can state that populations exposed to anthropogenic impact are unstable, vulnerable.
Ontogenetic spectra of all the studied cenopopulations are incomplete -no seedlings spread by underground type of germination were found in the wild, while senile individuals were determined as those dying after the last blossoming, and therefore determining that individuals in this ontogenetic status needs more detailed studies. In particular, Smoliar & Smagliuk (2015) also notes a locality of E. helleborine with 5 individuals in the territory of the basin of the downstream Sula in a 70 year old broadleaved oak-hornbeam forest of sprout origin with crown density equaling 0.9, understorey accounting for 20%, herb stand of 75%, synusia of spring ephemeroids: Scilla bifolia, Corydalis solida, Ficaria verna, Anemone ranunculoides, Gagea lutea, G. minima. Ontogenetic status of that population was not determined.
Right-sided, complete, two-peaked ontogenetic spectra of E. helleborine with dominance of young generative individuals were observed in the territory of nature-reserve fund with no recreation pressure (Russian Forest Reserve) (Vakhromeeva et al., 2014) in old oak-ash-hornbeam cenoses without expressed understorey which are on grey forest soils. However, deterioration in the population and incompleteness of the spectra were observed in the territory of that reserve under anthropogenic impact. A number of studies provide data about recent dynamics of density of individuals of the species in cenoses under anthropogenic pressure of various extents. A number of studies (Solomakha, 2020;Tymochko & Solomakha, 2020;Solomakha et al., 2021) indicate data on dynamics of density of individuals in cenoses under various extents of anthropogenic pressure.

Conclusions
According to the results of monitoring studies of populations of E. helleborine, we observed disadvantages and perspectives of the study. To analyze generalized morphometric data, a several year long monitoring of populations is needed. Only long periods of study can reveal the dynamic of the range. Improved methods of selecting marker features of ontogenetic statuses would allow us to obtain data of dynamics of the status of populations in the conditions of Northeast Ukraine.