Filip Jarzombkowski, Ewa Gutowska, Katarzyna Kotowska, Lesław Wołejko For the purpose of this overview, the area of Poland comprising the Lublin-Lviv Upland and Polesie was assumed to constitute a boundary of southeastern Poland.
These are old-glacial terrains where sedge moss fens are associated with the avail-ability of mineral-rich groundwaters, the outlets of which occur in specific geo-morphological situations (Kondracki 2011, Solon et al. 2018).
In terms of administrative division of the country, this area encompasses the Lubelskie Voivodeship and a part of Podkarpackie Voivodeship. Data accumulat-ed in the database include 35 patches of habitat 7230 covering a total area of 2,800 ha. Several of the most important regions with respect to conservation of biodi-versity of alkaline fens in southeastern Poland can be distinguished, in particular they can be found in the Hrubieszów Basin and Polesie. Moreover, individual sites have been preserved south of the aforementioned area.
Alkaline fens of the Hrubieszów Basin
The Hrubieszów Basin is a fragment of the Volhyn Upland neighboring the Lublin Upland (Kondracki 2011, Solon et al. 2018). It is located in the Vistula river catchment area in the Sieniocha and Siniocha river valleys (the latter is the Hucz-wa river tributary) emptying to the Bug river. The hydrographic grid of this area is composed of the regulated river and extended artificial drainage system and also a complex of fish ponds. The basin was formed in a belt of soft Upper Cretaceous layers in the eastern extension of the Zamojki valley. It is a plain of loess deposi-tion, almost flat with small relative heights. Its surface is covered by alternating loess, marls, alluvial soils and sands.
The basin is transversely crossed by the Bug River and its tributary the Hucz-wa river, which divide the area into two parts differing in relief. Terrain situat-ed south of its river channel gently rises while southern area rises more steeply towards the Horodło Ridge. This terrain is characterized by the presence of flat
drainless depressions and a lack of young erosional incisions. Basic landforms in-clude Pleistocene and Holocene terrace plains created in the course of alternating cycles of river erosion and accumulation
Alkaline fens existing in this area are remnants of vast fen complexes which formed in the Sieniocha and Siniocha river valleys and once covered vast areas whereas, at present, due to severe hydrological transformations connected with the development of agriculture and peat extraction, they are limited to relative-ly small patches concentrated in headwater courses of rivers. In the areas where agricultural use has been abandoned, rush, forest and willow scrub communities developed as a result of secondary succession. Sedge moss fens were preserved at better hydrated locations and in former peat hollows.
At present, the fens of this region are strongly fragmented and their vegetation constitutes a mosaic of intertwined sedge-moss, meadow and rush communities.
The atypical physiognomy of fens in this area is also a consequence of specific management methods, i.e., the burning of dead organic matter accumulated due to extensive use of land less suitable for agricultural use. Spring fires limited devel-opment of shrub species, led to renewal of grasses which can be used as feed only at a young stage (with prevailing Molinia caerulea), but only slightly increased habitat fertility. After burning of vegetation, low-sedge loose sward developed in humid places, and patches of bare soil were colonized by specific fen species, such as Pinguicula vulgaris.
The fen vegetation is not uniform and develops into transition forms between communities of the Caricion davallianae alliance concentrating mostly in peat hollows, Schoenetum ferruginei, and meadows of the Molinietalia order (including Molinia meadows of the Molinion caeruleae alliance with dominance of Molinia caerulea and presence of Succisa pratensis and Sanguisorba officinalis), and phy-tocenoses of the alliance with Carex panicea and C. lepidocarpa of the Caricetum paniceo-lepidocarpae with a great share of Molinia meadows. Hollows produced by peat extraction are occupied by communities of the Caricion davallianae alli-ance with different proportions of sedges: Carex panicea, C. davalliana, C.lasio-carpa, and the rarer C. lepidoC.lasio-carpa, C. hostiana with participation of broad-leaved cottongrass and common cottongrass Eriophorum latifolium and Eriophorum angustifolium and Schoenus ferrugineus, Salix rosmarinifolia and meadow species of the Molinietalia order. The moss layer is loose, built of Campylium stellatum, Bryum pseudotriquetrum, Plagiomnium elatum, Pseudocalliergon lycopodioides, Limprichtia revolvens, Limprichtia cossonii, Calliergon giganteum, Calliergonella cuspidata and Scorpidium scorpioides
Among all the fen patches in this area, the most distinctive is the cupola fen Śniatycze. Due to the installation of drainage facilities, the cupola is split with a channel which divides the sedge-moss fen into two parts. Schoenetum ferruginei community dominates with many relations with Molinia meadows, however in
the midst of them at the cupola top there is a patch with Cladium mariscus. It is a locality for Swertia perennis, Schoenus ferrugineus, Sch. nigricans, Tofieldia calyculata, Carex davaliana, Pinguicula vulgaris ssp. bicolor, Gentianella amarella, Epipactis palustris and Gymnadenia conopsea ssp. densiflora. Chara sp. and Pedic-ularis sceptrum-carolinum occur in old post-excavation peat pits. Moreover, the Coenonympa oedippus has been identified in this area.
It is a unique natural site on a European scale with regard to the dating of organic deposits (Dobrowolski et al. 2016). The well-preserved sequences of de-posits from the last 10 000 years allow for a relatively precise reconstruction of past conditions, and the obtained results are comparable with reference locations for Poland and Europe.
Alkaline fens in the Hrubieszów Basin are protected as Special Areas of Con-servation: Dolina Sieniochy PLH060025 and Dolina Górnej Siniochy PLH060086.
Besides, the establishment of a nature reserve comprising the cupola spring fen Śniatycze was postulated (Stanicka 2010) (see Chapter 8).
Photo 91: The Śniatycze cupola fen split by a channel. The best preserved vegetation occurs to the right of the channel (at the cupola top) with great fen sedge Cladium
mariscus. The photo also shows the channel impact on vegetation changes and the range of its strong impact (photo by R. Stańko).
Alkaline fens in the surroundings of the city of Chełm
This area contains 8 alkaline fens in the vicinity of the city of Chełm in the Lublin Upland, within the mesoregions: Chełm Hills and Dubienka Depression (Kondracki 2011, Solon et al. 2018).
The most important sites in this area include the large-surface area com-plexes: Sobowice mire (known also as Zawadówka), situated west of Chełm (Pawlikowski 2011c), and a group of fens known as Chełmskie Torfowiska Węglanowe located north-west of Chełm (Buczek & Buczek 1993, Buczek 2005, Pawlikowski 2011a) and encompassing fens in the nature reserves: Brzeźno, Roskosz and Bagno Serebryskie.
These fens were formed as a result of accumulation of organic and mineral matter in karst dolines, called “werteby”, eroded in calcareous rocks. They include both ecosystems of terrestrialized lakes in which the deep peat bed is sometimes underlain by gyttja deposits, and soligenous fens supplied by groundwaters. The central part of the Sobowice mire is occupied by a vast spring cupola which was a focus of detailed paleoecological studies (Dobrowolski 2000, Dobrowolski et al.
2005). In the light of these studies, development of this spring fen began ca. 9900 years ago.
These sites are unique natural habitats on a national scale. In terms of surface area, they are dominated by calcareous fens (7210) with vast areas harboring beds of Cladietum marisci and Caricetum buxbaumi. Elements of alkaline fens of hab-itat 7230, the area of which was estimated at ca. 570 ha (ca. 35% of the total fen area) are most often concentrated in marginal fen parts and in transition zones to meadow communities. The third important structural element of the Chełm mires, Molinia meadows (6410), is of special importance because they cover, among others, drier, carbonate hills (called “grądziki”) within fens with shallow chalk deposits distinguished by a host of floristic rarities. All three types of veg-etation contain plant species characteristic of the Caricion davallianae alliance, which sometimes is a source of serious difficulties with sharp distinguishing of habitat patches belonging to different types.
Typical vegetation of the alkaline fens is composed of associations of Carice-tum davallianae and SchoeneCarice-tum ferruginei. CariceCarice-tum davallianae is a low-sedge tuft-forming rush occurring in small patches (from several square meters to seve-ral ares) in mosaic with other sedge rushes and Molinia meadows. The largest patches of this community are located in the southwestern part of Roskosz mire and in islands scattered in the central part of the Brzeźno mire. Schoenetum fer-ruginei occurs over relatively larger areas in the Bagno Serebryskie.
Fens of the Chełm surroundings are a key refuge of valuable flora on a nation-al scnation-ale. Alknation-aline fen and meadow communities of this area harbor three species mentioned in the Habitats Directive, namely Ligularia sibirica, Liparis loeselii and Ostericum palustre. Rare species characteristic of the Caricion davallianae alliance include, among others, Swertia perennis, Carex buxbaumii, Epipactis palustris, Tofieldia calyculata, Pinguicula vulgaris ssp. bicolor, Pedicularis sceptrum-carolinum and Dactylorhiza incarnata (ssp. ochroleuca). Moss layer contains: Ctenidium mol-luscum, Tomentypnum nitens, Bryum neodamense and Bryum pseudotriquetrum, Scorpidium scorpioides, Campylium stellatum, Limprichtia cossonii and Fissidens adianthoides. Other rarities often occurring at the borderline of fens and grass-lands and meadows include: Ophrys insectifera, Betula humilis, Dianthus suberbus, Gentiana pneumonanthe, Gentianella uliginosa, Senecio macrophyllus, Gladiolus imbricatus, Iris sibirica, Veratrum lobelianum, Cirsium canum, Aconitum variega-tum, Trollius europaeus and Phyteuma orbiculare (Kucharczyk 1996, Pawlikowski 2011a).
The survival of the alkaline fens of the Chełm neighborhood is shrouded in uncertainty in spite of different forms of legal protection. In all of the fens drain-age facilities were installed as early as before WWI. At present, the abandoning of grassland use of some of their parts also poses a threat. However, the greatest risk is created by the proximity of the urban and industrial center in Chełm which is related with large-scale disturbances of water conditions, namely water intake for the city is situated within the Sobowice mire, and a cone of depression connected with limestone extraction for a cement plant poses a threat to local water relations.
These problems were addressed at an international level and became the basis for the resolution of the International Mire Conservation Group (IMCG) addressed to the Polish Government in 2010 postulating that the Chełm fens should be taken under efficient – not only formal – protection. The existing forms of protection comprise nature reserves: Brzeźno, Roskosz, Bagno Serebryskie and Torfowisko Sobowice, Special Area of Conservation Torfowiska Chełmskie PLH060023, Spe-cial Protected Area Chełmskie Torfowiska Węglanowe PLB060002, Chełm Land-scape Park and Chełmno Protected LandLand-scape Area.
Alkaline fens of the Lublin Polesie
Polesie extends throughout a substantial area from the Bug River to the Dnie-pr River, but only a small part of this subDnie-province is located in Poland (Kondracki 2011, Solon et al. 2018). The Polish part is situated on the edge of pre-Cambrian East European Platform (Żelichowski 1974), and also along a borderline between plant-climatic zones. This area is dominated by denudation and alluvial plains with local occurrence of carbonate rocks, which favored the development of al-kaline fens. This subprovince includes the mesoregion Łęczna-Włodawa Plain where several valuable fens are located. The largest and the most important of them – Bubnów mire (ca. 931 ha) and Staw mire (ca. 276 ha) – are situated in the Polesie National Park. As in the case of the Chełm fens, these fens are located in complicated wetland complexes covered by a wide spectrum of aquatic, rush, fen and meadow phytocenoses. The surface area of the alkaline fens within these sites estimated at ca. 600 ha.
Sedge-moss vegetation is represented mostly by the Caricetum davallianae and Schoenetum ferruginei associations. In these complexes there are also (often prevail) fen sedge beds and Caricetum buxbaumii communities. The majority of the fens are of sedge rush character with a large contribution of species of the Scheuchzerio-Caricetea fuscae class, and also meadow and rush species: Carex lasi-ocarpa, C. caespitosa, C. appropinquata, C. elata and C. disticha (Sugier et al. 2010, Sugier & Różycki 2010).
A vast complex of Krowie Bagno mire is located north of the border of the Polesie National Park. It is a very spacious, well-documented in terms of natural values, drained calcerous fen (Kozub 2011). At present, Krowie Bagno is not in-cluded into the list of important alkaline fens in Poland, however a comparative analysis of its vegetation structure described in the paper by Sugier et al. (2010) shows its similarity to flora of Bubnów mire.
As in the case of the Chełm fens, the greatest threat to Polesie fens is likewise posed by large-scale industrial endeavors both already realized and planned. It is particularly relevant to hard coal mining and associated disturbances in the hy-drological conditions. These projects are contested by the international scientific community which was expressed by the next resolution of the International Mire Conservation Group (IMCG) of 2018 regarding plans of construction of a coal mine in the neighborhood of Torfowisko Bubnów.
The Polesie sedge-moss fens are currently protected as Natura 2000 sites Osto-ja Poleska PLH060013 and Krowie Bagno PLH060011, and in the Polesie National Park.