04G1
Riverside woodlands of Alder (Alnus spp.) and Common ash (Fraxinus excelsior)
Relationships with habitat classifications. EUNIS: G1.2116 Dacio-Moesian ash-alder woods; PAL. CLASS.: 44.316 Dacio-Moesian ash-alder woods; HD 92/43: 91E0 *Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae).
Conservation status. BDA, HD, BC.
Category. Vulnerable [VU – A1, 2 B1 C1 D2 E2 F1 G1 H1 J L2].
General characteristics. Mixed riverside gallery communities with common alder (Alnus glutinosa) as the main edificator. In some places edificators and co-edificators are the grey alder (Alnus incana), Oriental plantane (Platanus orientalis) and common ash (Fraxinus excelsior). Different willow species, most often the fragile willow (Salix fragilis) and white willow (S. alba) also occur. This type of gallery forests occurs more often in the low mountain belt and more rarely in the mid-mountain belt. They develop on humid to sporadically flooded soils that are well aerated and well drained (Fluvisols). The herbaceous cover most often includes Aegopodium podagraria, Carex remota, C. sylvatica, Circaea lutetiana, Cirsium appendiculatum, Equisetum spp., Filipendula ulmaria, Galium aparine, Impatiens noli-tangere, Lycopus europaeus, Lythrum salicaria, Myosotis scorpioides, Ranunculus repens, Rumex sanguineus, Scirpus sylvaticus, Stellaria media, S. nemorum, Urtica dioica, etc.The mixed riverside gallery communities with common alder as the main ediphicator differ from the forests dominated by this species in the lowlands and the lower parts of the valleys of large rivers. The participation of lianas and thermophilic species is restricted in these forests. The floods are rare and short due to the steepness of the areas and the fact that the river valleys are narrower. In the upper parts of the mountains the galleries dominated by the common alder are replaced by galleries of forests dominated by the grey alder with participation of higher numbers of boreal species. Mountain forests of the common alder that are relatively distant from rivers and streams develop very rarely in Rhodopi Mts (near Dospat town). Most often they occupy the skirts of slopes with wet, diluvial soils (Colluviosols). The projective cover of the tree layer is approx. 80–90%. Apart from the common alder, Juglans regia also participates. Therefore, one can presume that these forests are of secondary origin and are influenced by anthropogenic activities. The shrub species represented in these forests is Crataegus monogyna. The total projective cover of the herbaceous synusium is approx. 90%. It is dominated by Galium aparine, Parietaria erecta (= Parietaria officinalis) and Urtica dioica. Brachypodium sylvaticum, Cardamine impatiens, Geranium robertianum, Geum urbanum, Mycelis muralis, Oxalis acetosella, Rumex sanguineus, Stachys sylvatica, etc. also occur. Syntaxonomically the riverside ash-alder woodlands belong to class Populetea albae, order Fraxinetalia and alliance Alnion incanae.
Characteristic taxa.
- Vascular plants: Aegopodium podagraria, Alnus glutinosa, Brachypodium sylvaticum, Calamagrostis pseudophragmites, Carex remota, C. sylvatica, Chrysosplenium alternifolium, Circaea lutetiana, Cirsium appendiculatum, Equisetum spp., Filipendula ulmaria, Galium aparine, Impatiens noli-tangere, Lycopus europaeus, Lythrum salicaria, Mentha longifolia, Myosotis scorpioides, Nasturtium officinale, Poa sylvicola, Ranunculus repens, Rumex sanguineus, Scirpus sylvaticus, Stachys palustris, Stellaria media, S. nemorum, Urtica dioica, etc.
- Fungi: Macromycetes – Calicina alniella, Ciboria amentacea, Cytidia salicina, Exidia glandulosa, Gyrodon lividus, Hymenoscyphus calyculus, Inonotus hispidus, I. radiatus, Laccaria tortilis, Lachnum virgineum, Mitrophora semilibera, Naucoria alnetorum, N. escharoides, N. striatula, Paxillus filamentosus, Pezizella minutula, Phellinus igniarius, Pyrenopeziza revincta, Scutellinia scutellata, Tremella mesenterica; Micromycetes – Ascochyta syringae (on Fraxinus excelsior), Gnomonia comari (on Filipendula ulmaria), Gnomonia ditopa, Gnomoniella tubiformis, Phyllactinia guttata, Plagiostoma alneum, Septoria alni (on Alnus glutinosa), Hypoxylon fuscum, H. multiforme, Melampsora caprearum, M. epitea (on Salix caprea), M. salicis-albae (on Salix alba), Peronospora conglomerata (on Geranium sylvaticum).
Distribution in Bulgaria. The riverside ash-alder woodlands have fragmented distribution along rivers in the foothills and low mountain areas in most of the Bulgarian mountains from approx. 300 to 1000 m alt.
Conservation importance. Some species of conservation significance occur in these rare phytocoenoses: Lathrea rhodopaea, Osmunda regalis, etc.and a fungus of conservation value, Gyrodon lividus.
Threats. Unregulated and wrongly conducted logging, corrections and clearing of river beds, infrastructure constructions and building of micro-water electric power stations.
Conservation measures taken. The habitat is included in Annex № 1 of the national Biodiversity Act and is of conservation priority. Parts of this habitat are within protected areas: Rila National Park, Vitosha Nature Park, etc. and in sites of the European Ecological Network NATURA 2000 in Bulgaria.
Conservation measures needed. Phytocoenological studies of the habitat and expansion of the borders of the protected areas in which they occur; elaboration of forest-typological scheme for more efficient and nature friendly management; mapping and monitoring of the habitat; termination of restoration felling; improved forest protection; restoration of the habitat in places not covered by forests or in places favourable for forest development; elaboration and implementation of information campaigns revealing the significance of the habitat.
References. Dimitrov 2005.
Authors: Marius Dimitrov, Alexandar Tashev
