Distribution and population status of rare plant species in the Marmarosh Mountains ( Ukrainian Carpathians )

The article presents the results of multiple surveys of habitats of rare plant species in the Marmarosh Mts, Ukrainian Carpathians, and depicts their exact location and population parameters. Along with the analysis of earlier literature and herbarium data, this enabled to reveal some spatio-temporal patterns in their distribution, namely habitat characteristics and trends in population dynamics, which allowed to determine their conservation status. Numerous facts of decline and extinction, as well as examples of positive dynamics in populations of the studied species were described. Cold-dependent species (Cerastium cerastoides, Primula minima, Veronica bellidioides) proved to be vulnerable to climate change particularly at the lower limit of their distribution. Another factor of impact is decrease of grazing, which triggers vegetation succession and consequent replacement of some low-competitive rare plants (Genista tinctoria subsp. oligosperma, Koeleria macrantha subsp. transsilvanica) with shrubs or tussock graminoids. However, another group of rare species (Heracleum sphondylium subsp. transsilvanicum, Gentiana punctata, Jovibarba globifera subsp. preissiana, Veronica fruticans) benefits from the decrease of anthropogenic impact.


Introduction
The Marmarosh (or Maramureş -in Romanian transcription) Mountains are situated on the Ukrainian-Romanian border and belong to the Inner Carpathians.They have a very diverse geological structure with prevailing crystalline bedrock and rather frequent limestone outcrops.This significantly differs from the vast outer part of the Ukrainian Carpathians dominated by mostly uniform acidic sandstone flysch (Kondracki, 1989).The Marmarosh Mts are the steepest in the Ukrainian Carpathians (Kruhlov, 2008), therefore rock outcrops are quite common here.That mountain range is the second highest (after the Chornohora) massif in the Ukrainian Carpathians with two summits of Mt.Pip Ivan exceeding 1900 m a.s.l.This territory makes an isolated alpine "environmental island".In the Marmarosh Mts some rare and endemic plants are confined to the eastern edge of their ranges and do not occur elsewhere in the Ukrainian Carpathians.All the above reasons make these mountains unique in terms of their biodiversity and landscape value, therefore their considerable part was included into the Carpathian Biosphere Reserve.The flora and vegetation of the Marmarosh Mts have been studied since the late 19 th century.The most precise old chorological data concerning distribution of rare species were published by H. Zapałowicz (1889), I. Klášterský (1929Klášterský ( -1931)), V. Krist (1935), and M. Deyl (1940).Floristic studies during the Soviet period, i.e. in the 1950-1980s, were rather incomplete because of the limited access to that frontier territory, which remained one of the most understudied regions of the Ukrainian Carpathians.Though the "Flora of the Ukrainian SSR" (Flora RSS Ucr., 1950-1965), as well as V.I.Chopyk's (1976) and K.A. Malynovski's (1980) monographs contain much information on the flora of the Marmarosh Mts, most publications from the last decades lack the exact data on the localities of rare species and the status of their populations in the region.
The aim of this study is to fill that gap, i.e. to specify their distribution in the Marmarosh Mts and compare contemporary data with those contained in literature and herbaria in order to reveal possible dynamic patterns.Special attention was paid to population parameters of the rare species, their viability and conservation status.We indicated the exact location of their habitats to set a baseline for future monitoring.Ukr. Bot. J., 2017, 74(2) In small populations their total census was estimated (Elzinga et al., 2009).
Exact site locations were determined in WGS-84 system with Garmin eTrex GPS navigator with the accuracy of measurements within 10 metres.
Content of calcium and magnesium in soil was measured complexometrically and pH(H 2 O) value electrometrically (Arinushkina, 1970).

Results and Discussion
The habitats of rare species are mostly confined to sites with special ecological conditions, geological structure or landforms, which can be considered as "hot spots" of their occurrence (Ziman et al., 2009).For instance, in the Ukrainian Carpathians those are usually alpine, rocky, marshy or calcareous localities (Kobiv, 2010).
Although the presented data on the rare species are not fully comprehensive, they are supposed to depict properly their distribution and population status in the target region.

Materials and Methods
The results presented below were obtained during field surveys carried out in 2002, 2006, 2010, and 2016 in the Marmarosh Mts, Ukrainian Carpathians.The studied area stretches about 15 km along the Ukrainian-Romanian border (Figure).
Thorough analysis of the previous publications and herbarium data on rare species had been performed before surveying their known localities in situ.
The map of the target area with locations of the surveyed habitats of rare species is provided in the Figure where their numeration corresponds to Tables 1-3.
The species were considered as rare following K.A. Malynovski et al. (2002) compendium.
Studied localities of rare species in the Marmarosh Mts. 1, 2 ... 30 -locality numbers A small population of an East-South-Carpathian endemic, Heracleum sphondylium L. subsp.transsilvanicum (Schur) Brummitt (= H. palmatum Baumg.), is situated in a steep hollow near the summit of Mt.Nenieska.Its core zone is confined to the tallforb community, which covers about 30 m² (locality 1).Density of flowering undividuals of H. sphondylium subsp.transsilvanicum is 1.8 specimens per 1 m².This aclonal species is capable only of seed reproduction.
All the mentioned species are restricted to the subalpine zone within 1700-1800 m a.s.l.In terms of occurrence of the rare plants (for instance, Achillea oxyloba subsp.schurii, Allium montanum, Aster alpinus, Astragalus australis subsp.krajinae, Draba siliquosa, Erigeron alpinus, Leontopodium alpinum, Primula halleri), the rocks of Mt.Nenieska have most resemblance to saxicolous sites from the Svydovets Mts that apparently can be explained by similar geological structure.
The next cluster of rare species' localities is the highest part of the Marmarosh Mts, i.e.Mt.Pip Ivan with adjacent Mt.Gropa, Mt.Shcherban (aka Zherban), and Mt.Polonynka built mostly of crystalline bedrock -gneisses, metamorphic schists and amphibolites.Considerable area is covered with alpine vegetation there.Snowbed habitats that harbor highly specialized prostrate cold-adapted species are most characteristic of the alpine environment.One of such chionophilous species is Salix herbacea L. We found its two small populations (localities 10, 12) confined to snowbeds on the highest elevations at the ridge on Mt.Pip Ivan on poorly insolated N and NW aspects.Due to clonal growth S. herbacea forms dense mats, while its patches cover small areas of 15 and 4 m².
Another chionophilous species is Cerastium cerastoides (L.) Britton, which inhabits bottoms of large snowbeds in the glacial cirques of Mt.Pip Ivan.It occurs mostly on gravel sites with poor floristic composition and low abundance of other herbaceous plants (locality 8).Cerastium cerastoides can form mats up to 100-150 cm² with 15-20 flowering shoots.However, flowering is not common and most individuals are vegetative and stunted.The species is rare now and we found only two its small populations restricted to 1745-1820 m a.s.l.altitudinal range.It is remarkable that according to M. Deyl (1940) it was much more abundant in the late 1930s being recorded in 19 localities within 1600-1910m a.s.l. Moreover, earlier H. Zapałowicz (1889) had reported on its still lower locality at 1580 m a.s.l.Apparently, decline of C. cerastoides is caused Therefore, our results are presented with regard to such hotspots.
Mt. Nenieska.This site is remarkable for its ca.500 m long steep rocky north-eastern slope with calciterich sandstone bedrock.It is a habitat of many rare saxicolous species, most of which are calciphilous (Table 1).One of them, Leontopodium alpinum (L.) Cass., we discovered in two localities (#3, 4), where only about a dozen of its flowering individuals occur.Local rangers confirm that the population number has decreased significantly during the last decades, because the plants have been illegally dug up by souvenir hunters.That has undermined the population viability and only some solitary individuals have survived in the most inaccessible rocky loci.Therefore, the species is critically endangered.
The rocks of Mt.Nenieska harbor an East-Carpathian endemic Astragalus australis (L.) Lam.subsp.krajinae (Domin) Domin, which is restricted to steep slopes (localities 2, 3) where the density of its flowering individuals is about 0.3 specimens per m².The population is maintained by seed recruitment.
Another rare saxicolous species, Aster alpinus L., is abundant in the same localities.Its clones with numerous flowering shoots may cover up to 200 cm².
The rocks are inhabited by a highly viable population of Primula halleri J.F. Gmel.The average density of its flowering individuals is 0.05 specimens per m².The only way for recruitment of this short-lived species is seed reproduction.
Much more abundant are Hieracium villosum Jacq.which forms dense clones on rocky shelves and Botrychium lunaria (L.) Sw. mostly confined to loci of almost barren gravel.Rhodiola rosea L. that occupies both types of these habitats is also rather frequent but subjected to severe damage due to illegal extirpation of its rhizomes for medicinal purposes.
Other species occurring in a single locality (number in brackets) -Adenostyles alliariae (1): 2; Alchemilla sp. ( 5 past data (Klášterský, 1931;Deyl, 1940) shows that the species was much more abundant there in the 1930s, and the lowermost limit of its distribution has shifted about 100 m upwards in the altitudinal terms since then.This proves that currently V. bellidioides is at the brink of extinction in Ukraine.Such dynamics is in line with the decline of the species in the Sudetes (Szczęśniak et al., 2011) at comparatively low elevations, as well as upward shifts of its altitudinal limits in the Alps (Pauli et al., 2007;Frei et al., 2010), which apparently have resulted from climate change.
Another cold-adapted species, Luzula spicata L., has also demonstrated vulnerability to climate change and consequent decline in the Alps (Pauli et al., 2007;Frei et al., 2010).It was reported from the very top of Mt.Pip Ivan at the end of the 19 th century by H. Zapałowicz ( 1889), but we failed to find it in the Marmarosh Mts.Most probably, L. spicata, which was documented in several highest massifs of the Ukrainian Carpathians in the late 19 th -early 20 th century, has become completely extinct in the region by now, because it has not been confirmed anywhere in Ukraine since World War II.
We also did not manage to reconfirm the occurrence of another chionophylous species, Saxifraga carpatica Sternb., which is documented by an old herbarium specimen from Mt. Pip Ivan (LWS 46140).
According to the European compendia on ecological indicator values (Ellenberg et al., 1992;Zarzycki et al., 2002), the above mentioned species, which show declining trends in their distribution in the Marmarosh Mts (Cerastium cerastoides, Luzula spicata, Primula minima, Saxifraga carpatica, Veronica bellidioides), belong to the most cold-adapted plants in the Carpathian flora.Their Marmarosh habitats are restricted to the lowermost limits of their ecological ranges and the ongoing climate change has an adverse impact on them.
We managed to find the locality of an arctic-alpine saxicolous species Potentilla crantzii (Crantz) Beck ex Fritsch (locality 14) on a steep rocky slope at the NW summit of Mt.Pip Ivan, which was reported by M. Deyl (1940) but has not been reconfirmed ever since.The area of the site is only about 10 m².The species produces compact clones with numerous subprostrate flowering shoots.
An East-South-Carpathian endemic Anthemis cretica L. subsp.pyrethriformis (Schur) Govaerts (= A. carpatica Waldst.& Kit.ex Willd.subsp.pyrethriformis (Schur) Prodan) is restricted to the high-mountain zone of Mts Gropa, Pip Ivan and Shcherban.This is mainly by shrinkage of its snowbed habitats due to decreasing thickness and duration of snowpack that has been described in the Carpathians recently (Micu, 2009).Interestingly, M. Deyl (1940) admitted that some largest snowbeds on Mt.Pip Ivan even persisted throughout some growth seasons in the 1930s, though that has never happened in the last decades.
The aforementioned chionophylous species are adapted to long-lasting snow cover, short growth period and are confined to snowbed communities that belong to the class Salicetea herbaceae Br.-Bl.1948.They are low-competitive and most viable on moss-dominated or barren patches with initial soil.As a result of warminginduced succession they are being gradually replaced by more competitive sward-forming cold-tolerant graminoids, for instance Poa granitica Br.-Bl.subsp.disparilis (Nyár.)Nyár.(= P. deylii Chrtek & V. Jirásek).The latter taxon, which is endemic to the Eastern and Southern Carpathians, is rather common in the alpine zone of Mt.Pip Ivan.
Primula minima L. is also a cold-adapted lowstatured species, which forms patches of 25-40 rosettes per 100 cm².It occurs at saxicolous alpine habitats up to the highest elevations, while the lowest locality that we found on Mt.Shcherban is on 1750 m a.s.l.Interestingly, M. Deyl (1940) reported the species locality situated 100 m lower, while H. Zapałowicz (1889) -as low as on 1580 m a.s.l.
A frequent component of many alpine communities is Sedum alpestre Vill.It is noteworthy that in one of the glacial cirques of Mt.Pip Ivan (locality 13) this species dominates in the snowbed community and forms dense mats that cover up to 0.25 m², which is uncommon for other regions of the Carpathians.
It is remarkable that in population replenishment of all the aforementioned alpine cold-tolerant species vegetative reproduction markedly prevails over seed recruitment.That provides for their better persistence in harsh climatic conditions.
One of the rarest and most endangered species, Veronica bellidioides L., occurs on the ridge at the NW summit of Mt.Pip Ivan, which is its only locality still remaining in the Ukrainian Carpathians (Kobiv, 2009).The area of its saxicolous habitat is merely about 15 m² (locality 15).Monitoring of the population showed that the number of flowering individuals has decreased in 14 years from 25 to only 3 specimens by 2016, which is critical, because seed recruitment is crucial for further survival of the species.Moreover, the density of its seedlings has decreased dramatically.Analysis of the mostly on the Romanian side.The species forms lax clones with about 1.5 flowering stems per 100 cm².
Gentiana punctata L., a Central European alpine species, is very common in the Marmarosh Mts.Due to clonal growth it may form clumps up to 3 m² with 8-10 flowering shoots per 1 m².
As follows from the above data, the massif of Mt.Pip Ivan with the adjacent territory is a remarkable hotspot, where localities of many rare alpine species are concentrated on a comparatively small area (Figure).
Another unique area comprises Mt.Petros and Mt.Berlebashka (aka Latundur).A series of alpine calcareous species occur here (Table 2), because limestone bedrock lies at a considerable altitude, which is unusual for the Ukrainian Carpathians.One of them is Genista tinctoria L. subsp.oligosperma (Andrae) Jáv., an East-South-Carpathian endemic, which does not occur anywhere else in the Ukrainian Carpathians.It is a mat-forming dwarf shrub, 10-15 cm high.The mats cover up to 300 cm² and contain 20-40 flowering shoots.It is restricted to only two small localities (#22, 28) in the subalpine zone.The area of each of them is ca.150-200 m².However, as follows from M. Deyl's (1940) monograph, the taxon inhabited a larger range of localities in the 1930s, which leads to an assumption that it has declined significantly by now.
The same habitats harbor Jovibarba globifera (L.)J. Parnell subsp.preissiana (Domin) Holub, a West-East-Carpathian subendemic.Besides one locality on Mt.Berlebashka, its largest metapopulation inhabits the rocks on Mt.Petros and consists of several scattered subpopulations.They are replenished mainly by stolon growth.Numbers of rosettes of J. globifera subsp.preissiana ranges within 5-35 specimens in each subpopulation, while the percentage of flowering ramets may reach up to 22%.
Similar metapopulation pattern and habitat requirements refer to other clonal high-mountain saxicolous calcareous species, Veronica fruticans Jacq.and Potentilla crantzii, which often occur together.Altitudinal range of Jovibarba globifera subsp.preissiana, V. fruticans, and P. crantzii on the rocks of the S and E aspects of Mt.Petros is 1530-1755 m a.s.l.(localities 18, 19, 21, 22).Monitoring carried out in selected localities showed considerable increase in the numbers of flowering individuals of J. globifera subsp.preissiana and V. fruticans (2.6-4 and 2.8 times, respectively) in 14 years.This can be caused by the obvious decrease of grazing during that period.the only area in Ukraine where it occurs.Apparently, A. cretica subsp.pyrethriformis forms a metapopulation comprised of a number of local populations scatthered within a rather narrow stripe along the Ukrainian-Romanian border.This suffruticose plant occurs on rocky and grassland habitats mostly in the alpine zone.Its highest density (up to 20 flowering individuals per m²) was noted alongside of the tourist path (locality 7) in the gaps among the heath or herbaceous vegetation, which result from moderate trampling.Such gaps provide suitable microhabitats for seed recruitment of A. cretica subsp.pyrethriformis (Kobiv, 2012).Its lowermost locality is situated at 1520 m a.s.l. at the SW foot of Mt.Shcherban, where the density of individuals has decreased by 1.8 times over the 14-year monitoring period.
Rhododendron myrtifolium Schott & Kotschy, a narrow-range high-mountain species, has a similar distribution pattern.It is very abundant in the massif of Mt.Pip Ivan and occurs up to the highest elevations (localities 10, 15).
A large metapopulation of a pan-Carpathian endemic Sempervivum carpathicum Wettst.ex Prodan subsp.carpathicum (= S. montanum L. subsp.carpathicum (Wettst.ex Prodan) Wettst.ex A. Berg.) inhabits rocky outcrops in the high-mountain zone of Mt.Pip Ivan within about 5-hectare area.The species produces mats of numerous rosettes that may cover up to 300 cm².The population is sustained primarily by vegetative reproduction provided by stolon growth.
Gentiana lutea L., a high-mountain Central European species, is widely spread in glacial cirques on NE slopes of Mt.Pip Ivan and Mt.Gropa within 1600-1900 m a.s.l.The species occurs either in the open grassland habitats or at the edge of scrub vegetation.The largest population on Mt.Pip Ivan (locality 11) covers ca. 4 hectares and includes 3.5-5.5 thousand flowering individuals.Density of flowering shoots in clusters may reach 4 specimens per m².
On the saddle between Mt.Shcherban and Mt.Polonynka (locality 16) we found Narcissus angustifolius Curtis, a species protected by the Bern Convention.Its population, which numbers ca. 100 flowering individuals occupies about 30 m².
Not far from that site, on the rocks at the W summit of Mt.Polonynka we found a small locality of Campanula carpatica Jacq., a pan-Carpathian endemic (locality 17).It occurs on an area of only about 2 m², apparently being a fragment of the large metapopulation situated  Укр. бот. журн., 2017, 74(2) Number in 2016, whereas C. carpatica is more common on the rocks in the forest zone.
On the same limestone bedrock nearby the abovementioned habitat we found a small population of Heracleum carpaticum Porcius, an East-South-Carpathian endemic (locality 24).It occupied only ca. 10 m² in 2016 and contained 6 flowering and 19 vegetative individuals.This aclonal species is replenished only due to seed reproduction.The habitat conditions are rather unusual for that alpine species, which is confined to a forest glade there at a comparatively low elevation.
A large population of Gentiana lutea stretches along steep hollows on the N and NE slopes of Mt.Petros near its summit (locality 20).The population is confined to 1660-1770 m a.s.l., occupies about 5000 m² and numbers 1.5-2.0thousand flowering individuals.
The last noteworthy "hotspot" of the rare species is the Bilyi Potik Valley, which is remarkable for numerous cliffs of marbelized limestones situated in the beech forest zone at much lower elevations in comparison with the listed above localities.Campanula carpatica is very abundant on such cliffs and smaller outcrops and forms lax mats, with up to 3 flowering shoots per 100 cm².
Cortusa matthioli L., a saxicolous chasmophite, inhabits shady rock fissures.Its largest population (locality 30) contains over 100 flowering individuals.The species number is limited by the availability of suitable microhabitats and low seed productivity (Kobiv, 1999).Some publications (Shushman, 2008) and herbarium data indicate that a very rare saxicolous species, Sempervivum marmoreum L., also occurs on the cliffs near the Bilyi Potik stream, but we failed to find it.
Calcicolous flora of these habitats is typical of the belt of Pieniny and Marmarosh limestone cliffs, which stretches along the border between the Inner and Outer Carpathians.
We also discovered other positive examples of some rare species dynamics, namely establishment of their new populations on limestone bedrock on the S slope of Mt.Berlebashka.Thus, in 2010 we found a few individuals of Potentilla crantzii on anthropogenic outcrops of limestone that had appeared on the sideslope of a recently constructed road (locality 27).The species was missing there in 2002, whereas its quite viable population has developed at the site by 2016.Most probably, P. crantzii has dispersed from its large «mainland» population on Mt.Petros situated ca. 2 km eastwards.
A newly established population of Acinos alpinus (L.) Moench (= A. baumgartenii (Simk.)Klokov) was first found near that site on a pasture (locality 26) in 2010.It occupied about 500 m² area then, but has expanded to ca. 2000 m² by 2016.However, the average density of flowering individuals of A. alpinus has not changed significantly remaining within 1.1-1.3specimens per m².
Quite opposite dynamics was revealed for Saxifraga adscendens L., an arctic-alpine species that occurred in the same locality in 2001, but was not found there in the later surveys.
The same refers to Koeleria macrantha (Ledeb.)Schult.subsp.transsilvanica (Schur) A. Nyár., an East-South-Carpathian endemic, which was reported from the S slope of Mt.Petros by M. Deyl (1940), but was never confirmed later.That author also indicated the altitude of the locality and published its phytosociological relevé, with a very peculiar floristic composition, which enabled to locate the site correctly (locality 22) and to make sure that K. macrantha subsp.transsilvanica has become extinct in its only known Ukrainian habitat.Its extinction could be caused by considerable decrease of grazing and consequent overgrowth of its habitat with more competitive graminoids or shrubs.
Nevertheless, Festuca saxatilis Schur, another East-South-Carpathian endemic, has persisted in the same locality, which is the only one we managed to find in the region.This saxicolous species forms dense tufts and occurs within about 25 m².That locality is also inhabited by a large population of Bellardiochloa violacea (Bellardi) Chiov.
A limestone rock in the spruce forest at the SW foothill of Mt.Petros provides a habitat for some rare calcareous species, e.g.Aconitum anthora L. (= A. jacquinii Rchb.), Campanula carpatica, Symphytum tuberosum L. (locality 23).The first of them is very rare in the region and its population numbered only 14 flowering individuals frontier regions of the Ukrainian Carpathians are: Festuca saxatilis, Jovibarba globifera subsp.preissiana, Sempervivum marmoreum, Veronica fruticans.Some of the listed species, for instance, Veronica bellidioides, are critically endangered, while Koeleria macrantha subsp.transsilvanica, has aready become extinct in the Marmarosh Mts.The localities of these taxa in the Marmarosh Mts are confined to the northeastern limit of their distribution in Central Europe and their extinction causes contraction of the species' geographical ranges and possible irreversible loss of biodiversity, because some peripheral populations have a unique gene pool (Lesica, Allendorf, 1995).As follows from the above results, many rare species of the Marmarosh Mts are narrow-range and the mentioned facts of decline or extinction are most worrying for the endemics (Genista tinctoria subsp.oligosperma, Koeleria macrantha subsp.transsilvanica).Decline of coldadapted alpine species (Cerastium cerastoides, Luzula spicata, Primula minima, Saxifraga carpatica, Veronica bellidioides) has taken place mainly at the lower limit of their ecological range and can be explained by climate change.
Another factor that affects rare species is considerable decrease of grazing in the region, which has been observed lately.Along with climate change it triggers natural succession of vegetation in the habitats of some rare species and their replacement by highly competitive tussock graminoids or shrubs.For that reason, mild grazing regime that still remains in some open habitats of saxicolous or chionophylous species, e.g. on Mts Nenieska, Pip Ivan, Petros, Berlebashka is favorable for their persistence, because it mitigates adverse changes in these localities.This refers mostly to low-statured poorly competitive species (e.g.Acinos alpinus, Cerastium cerastoides, Saxifraga adscendens, S. carpatica, Veronica bellidioides), which need gaps in vegetation for their recruitment (Virtanen et al., 1997).The mitigating effect of grazing against warminginduced decline of alpine species has been proved experimentally (Klein et al., 2004).
On the other hand, another group of species has benefited from the decrease of grazing.They demonstrate their highest viability in undisturbed conditions.This Because of steep topography, wetlands are infrequent in the Marmarosh Mts.The largest peat bogs that cover 100-750 m² (localities 6, 25) are inhabited by Carex limosa L. and C. pauciflora Lightf.
In many of his relevés M. Deyl (1940) mentioned Avenula pubescens (Huds.)Dumort.subsp.laevigata (Schur) Holub, which could imply that this narrowrange montane plant is rather common in the Marmarosh Mts.Apparently, that results from misidentification, because thorough examination of the specimens, which we collected in the region (including the localities stated by that author) and their comparison with the type material (Nachychko et al., 2017) proved that they belong to A. pubescens subsp.pubescens, and the former taxon hardly occurs in Ukraine.
Soil analysis in the selected localities of rare species (Table 3) showed the highest pH values and content of calcium on the limestone cliffs in the Bilyi Potik Valley.Rocky habitats of Mt.Nenieska are also rich in calcium.By contrast, most acidic and calcium-poor soil is in the snowbed locality in the glacial cirque of Mt.Pip Ivan.Almost equal content of calcium and magnesium was noted in some localities on crystalline bedrock on Mt.Pip Ivan and Mt.Petros, whereas the former element prevails significantly in most soils all over the Ukrainian Carpathians.Apparently, presence of markedly basiphilous species in some of these localities is considerably contributed by magnesium.

Conclusion
In biogeographical terms, the Marmarosh Mountains are the area of remarkable biodiversity, where many rare plants occur.Some of them, namely Anthemis cretica subsp.pyrethriformis, Genista tinctoria subsp.oligosperma, Potentilla crantzii and Veronica bellidioides, do not occur elsewhere in Ukraine, because edges of their geographical ranges slightly protrude into the Ukrainian territory only in that area, while they are much more abundant in the Romanian Carpathians.That floristic specificity is caused mostly by the geological structure of the region, which differs from the rest of the Ukrainian Carpathians.Other rare range-edge species that in addition to the Marmarosh Mts have a very limited distribution in some other concerns primarily tall forbs (Heracleum sphondylium subsp.transsilvanicum, Gentiana punctata), but also refers to some rare saxicolous components of grassland or dwarf-shrub communities (Jovibarba globifera subsp.preissiana, Veronica fruticans).Thus, various groups of rare species have different needs for their effective conservation, which should be carefully considered in implementation of land-use measures in their habitats.Supposedly, their persistence in open saxicolous and chionophilous localities could be best provided by maintenance of mild grazing regime to prevent overgrowth of their habitats with highly competitive species.
By contrast with the above-mentioned extinction events, we have revealed a few facts of colonization of new habitats by some rare species (Acinos alpinus, Potentilla crantzii), which happened recently in anthropogenically disturbed localities.
Thus, populations of many rare species in the Marmarosh Mts undergo continuing transformations responding to changes in climatic factors and varying anthropogenic pressure or resulting from succession of vegetation in their habitats.
Almost all species mentioned in this article are listed in the Red Data Book of Ukraine (Chervona knyha…, 2009).Our survey proved that some studied taxa should be included into its next edition, namely, Koeleria macrantha subsp.transsilvanica and Luzula spicata, both as extinct (EX); however, a few historical localities of the latter species in the Chornohora still need to be thoroughly checked for its presence.
Though Potentilla crantzii is rare and confined to a very small area in Ukraine, it is not prone to decline and therefore does not require any conservation status.

Table 1 . Floristic composition in localities of rare plant species in the hotspots of Mt. Nenieska and Mt. Pip Ivan with adjacent area (
names of rare species in boldface)

Table 2 . Floristic composition in localities of rare plant species in the hotspots of Mts Petros-Berlebashka and the Bilyi Potik Valley
(names of rare species in boldface)