A. Marine habitat

Communities of annual halophytes in coastal salt marshes at the Black Sea

Relationships with habitat classifications. EUNIS: A2.5515 Black Sea annual Salicornia, Suaeda and Salsola salt marshes, A2.552 Mediterranean coastal halo-nitrophilous pioneer communities; PAL. CLASS.: 15.115 Continental glasswort swards; 15.12 Mediterranean halo-nitrophilous pioneer communities; HD 92/43: 1310 Salicornia and other annuals colonising mud and sand; Bondev (1991): 146 Halophytous grass communities with a prevalence of Puccinellieta convolutae, Limonieta gmelinii, Aeluropeta littoralis, Salicornieta europaeae, etc., partly of secondary origin.

Conservation status. BDA, BC, HD.

Category. Endangered [EN – A1, 2 C3 D2 E2 G2 H2 I J L1].

General characteristics. Communities of mainly annual species of Chenopodiaceae (mostly from the genus Salicornia)or grasses that occupy periodically flooded muddy and sandy places in the periphery of the hyperhaline and more rarely brackish marshes along the Black Sea coast – Atanasovsko, Pomoriisko, Beloslavsko lakes and Shablenska Tuzla locality. These communities belong mainly to the class Thero-Salicornietea (typical halophytic communities). Halo-nytrophilic perennial and more rarely annual coenoses often occur in close proximity. More typical for Bulgaria is the first group (dominated mainly by Artemisia santonicum). The distribution of the second group is very fragmented and some of them have disappeared. Due to some significant differences the two subtypes have been treated separately below.

1. Pioneer halophytic communities. This habitat covers the drying, over-wet beds of the hypersaline marshes along the Black Sea coast and in the salt farms. They are 20–40 cm deep, salinity is usually 50–60 ‰, the bottom is clay-muddy, slightly sandy in some places. Large colonies of the blue-green algae Lyngbya spp., Microcoleus chotonoplastes, Phormidium spp., Rhzioclonium spp., Spirulina spp. cover the beds of these water bodies. After drying up, these algae remain as thick, cracked crust on the bottoms of the marshes. Mostly the halophytic coenoses develop by the end of the summer when the salt farms are dried up in order to obtain the salt. Mosaic coenoses of different size of Salicornia europaea agg.(Salicornia prostrata and S. europaea species complex) develop on the dry bottom. Co-dominants (that rarely form independent coenoses) are Aster tripolium, Bassia hirsuta, Limonium vulgare, Salsola soda, Suaeda altissima,and S. maritima.Some grasses, such as Aeluropus littoralis, Puccinellia convoluta,and P. limosa also participate and in some places they dominate the conenoses. Aeluropus littoralis forms almost uniform coenoses in more elevated and more rarely flooded places.

2. Pioneer and perennial halo-nitrophilic communities. Annual and perennial halo-nitrophilic plants appear on the periphery of the typical pioneer halophytic coenoses, on more elevated places like the dikes of the salt farms. They develop on drier, richer and often nitrogen-polluted soils. The communities of Petrosimonia brachiata are very typical,and form concentric circles on the periphery of the water bodies. They belong to the group of halo-nitrophilic terrophytes. In Bulgaria, species belonging to this group are also Frankenia pulverulenta (Pomoriisko lake and near Sozopol), Salsola soda (in many places), Cressa cretica (only near Primorsko). These coenoses are very rare and probably some of them are extinct (Frankenia pulverulenta and Cressa cretica). More frequent are the perennial halo-nitrophilic coenoses of Artemisia santonicum. They occupy the more elevated parts of the water bodies, including the artificial dikes of large stone pieces. Atriplex tatarica, Elymus elongatus, Lactuca saligna, Limonium gmelinii, L. vulgare, Melilotus officinalis,and Polygonum pulchellum also participate in these coenoses.

Characteristic taxa.

Distribution in Bulgaria. Black Sea coast, around hyper-saline and brackish lakes – Atanasovsko and Pomoriisko lakes, Mandrensko lake (Poda Protected Site), Varna, and Beloslav (Povelyanovo living quarter of Devnya and Yatata locality) lakes, Balchishk Tuzla locality, Shablenska Tuzla locality and at the estuary of Ropotamo River.

Conservation importance. Many rare and protected plants in Bulgaria participate in this habitat: Cressa cretica,Frankenia pulverulenta,Halimione pedunculata,H.portulacoides,Petrosimonia brachiata.

Threats. Intensive development of marine tourism; changes in the water circulation of the salt marshes with which this habitat is connected. These changes reflect in the salinity (it decreases) of the marshes, thus having impact on the quality of the habitat.

Conservation measures taken. The habitat is included in Annex №1 of the national Biodiversity Act. Some localities are within protected areas – Atanasovsko ezero Managed Nature Reserve, Poda, Pomoriisko Ezero and Shablensko Ezero Protected Sites and in sites of the European Ecological Network NATURA 2000 in Bulgaria.

Conservation measures needed. Termination of the destruction of the coastal and marine habitats; decrease of the tourist pressure; maintenance of a favourable water regime in the salt farms. Reintroduction of the extinct or very rare halophytes such as Cressa cretica, Frankenia pulverulenta, Halimione portulacoides.

References. Ganchev et al. 1971; Tzonev et al. 2008.

Authors: Rossen Tzonev, Chavdar Gussev

Communities of annual halophytes in coastal salt marshes at the Black Sea (distribution map)