26G1
Lowland mesophilic oak-hornbeam forests
Relationships with habitat classifications. EUNIS: G1.A1C31 Moesian mesophillous oak-hornbeam forests; PAL. CLASS.: 41.2C3 Moesian mesophillous oak-hornbeam forests; HD 92/43: 91G0 *Pannonic woods with Quercus petraea and Carpinus betulus;Bondev (1991): 54 Ordinary hornbeam (Carpineta betuli) forests partly with Oriental hornbeam (Carpinus orientalis), 55 Mixed ordinary hornbeam (Carpinus betulus), maple (Acer campestre) etc. forests, 56 Hornbeam-Balkan durmast (Querceto-Carpineta betuli) forests (below 600 m alt.), 57 Mixed ordinary hornbeam (Carpinus betulus) and Cerris oak (Quercus cerris) forests partly with Balkan durmast (Q. dalechampii), maple (Acer campestre), etc.
Conservation status. BDA, BC, HD.
Category. Nearly Threatened [NT – A1, 2 B1 C1 D1 E1 F1 G1 H1 I L3].
General characteristics. The habitat encompasses the mesophilic and xeromesophilic forests dominated by Carpinus betulus and/or Quercus dalechampii. They have the features of the intrazonal vegetation in the belt of the xerothermic oak forests in the areas of more strongly expressed continental climate, mainly in North Bulgaria. They occur in shadowy places, humid places in relief depressions, sprawling ravines and the slope foothills. They very often make stripes 30–50 m wide along the rivers, dry valleys and canyons. They are strongly fragmented and occur at low altitudes (150–600 m alt.). The soils are fresh to humid, mostly deep and relatively rich Luvisols, Colluvisols and more rarely Chromic Cambisols and Rendzic Leptosols. In the composition of the mesophilic oak and hornbeam forests participate both typical mesophytes from the alliance Carpinion, and more xerophilic, South European, sub-Mediterranean and Pontic-Pannonian elements from the neighbouring coenoses. They belong to the alliance Quercion confertae. Acer campestre, Carpinus orientalis, Fraxinus oxycarpa, Quercus cerris, Q. frainetto, Q. robur, Sorbus torminalis, Tilia cordata, Ulmus minor participate as sub-ediphicators or as single trees. In some coenoses a secondary layer develops with Carpinus betulus, Tilia cordata, T. tomentosa, Crataegus monogyna, Euonymus verrucosus, Viburnum lantana etc. The herbaceous layer has a mosaic structure and relatively low projective cover. Buglossoides purpurocaerulea, Dactylis glomerata, Dentaria bulbifera, Euphorbia amygdaloides, Festuca heterophylla, Galium odoratum, Glechoma hirsuta, Knautia drymeia, Mercurialis perennis, Symphytum tuberosum, Vinca minor occur most often. The ephemeroids Anemone ranunculoides, Corydalis spp., Ficaria verna (= Ranunculus ficaria), Galanthus elwesii, Isopyrum thalictroides etc. develop in spring. Due to the fact that the mesophilic oak and hornbeam forests occur closely to urban places and are easily accessible they are subjected to overexploitation. Some of them have been destroyed and the ones that have survived have undergone great changes and are mainly of secondary origin (from tree shoots). In many places the degradation processes are caused by the wide participation of Carpinus orientalis.
The lowland mesophilic oak and hornbeam forests belong to the class Quercetea pubescentis, order Quercetalia pubescenti-petreae, alliance Quercion confertae. The local peculiarities, and the specific history and dynamics presuppose a greater syntaxonomic diversity at association level.
Characteristic taxa.
- Vascular plants: Acer campestre, A. tataricum, Anemone ranunculoides, Astragalus glycyphylloides, Carex muricata, C. pilosa, C. sylvatica, Carpinus betulus, C. orientalis, Convallaria majalis, Corydalis spp., Crataegus monogyna, Dentaria bulbifera, Doronicum orientale, Euonymus verrucosus, Euphorbia amygdaloides, Festuca heterophylla, Ficaria verna, Fraxinus oxycarpa, Galanthus elwesii, Galium pseudaristatum, Glechoma hirsuta, Hedera helix, Helleborus odorus, Isopyrum thalictroides, Knautia drymeia, Lathyrus laxiflorus, L. vernus, Melica uniflora, Orchis purpurea, Polygonatum latifolium, Quercus cerris, Q. dalechampii, Q. frainetto, Q. robur, Ruscus aculeatus, R. hypoglossum, Smyrnium perfoliatum, Sorbus domestica, S. torminalis, Symphytum tuberosum, Tamus communis, Tilia cordata, T. tomentosa, Ulmus minor, Veronica chamaedrys, Viburnum lantana, Vinca minor, Viola alba, V. mirabilis.
- Fungi: Macromycetes – Abortiporus biennis, Boletus fechtneri, B. luridus, Creolophus cirrhatus, Gymnopus peronatus, Hymenoscyphus calyculus, Lactarius circellatus, Leccinum carpini, Marasmiellus ramealis, Marasmius epiphyllus, Peniophora lycii, Polyporus tuberaster, Setreum gausapatum;Micromycetes – Apioplagiostoma carpinicolum, Gnomoniella carpinea, Plagiostoma arnstadtiense, Taphrina carpini (on Carpinus betulus), Rhytisma acerinum, Sawadaea bicornis (on Acer campestre), Peronospora corydalis (on Corydalis spp.), Ustilago vaillantii (on Scilla bifolia).
Distribution in Bulgaria. Southern parts of the Danubian Plain, Ludogorie region, Forebalkan and Kraiste region.
Conservation importance. The lowland mesophilic oak-hornbeam forests in Bulgaria cover about 70 000 ha. Some rare and protected species like Paeonia mascula, Galanthus elwesii and the fungus species of conservation importance Creolophus cirrhatus occur.
Threats. The main threat is due to anthropogenic activities related mainly to unregulated logging, fires, grazing, use for leaf forage, infrastructure development.
Conservation measures taken. The habitat is included in Annex № 1 of BDA and is of conservation priority. Part of the lowland mesophilic oak-hornbeam forests are within protected areas: Shumensko Plato, Russenski Lom, Vrachanski Balkan Nature Parks, Beli Lom Strict Nature Reserve, Ostritsa Managed Nature Reserve, etc. and sites of the European Ecological Network NATURA 2000.
Conservation measures needed. Study of the syntaxonomic diversity, mapping, and monitoring of the best preserved and most vulnerable localities. Increase of the habitat areas that are within protected areas; improved forest protection.
References.Horvat et al. 1974; Marinov et al. 1995; Penev et al. 1969; Radkov & Minkov 1963; Stojanov 1941; Stoyanov et al. 1955;.
Author: Marius Dimitrov
