15G1
Moesian mixed thermophilic oak forests
Relationships with habitat classifications. EUNIS: G1.768 Moesio-Danubian thermophilous oak forests; PAL. CLASS.: 41.768 Moesio-Danubian thermophilous oak forests; HD 92/43: 91M0 Pannonian-Balkanic Turkey oak-sessile oak forests; Bondev (1991): 91 Mixed cerris oak (Quercus cerris) and Quercus frainetto forests, 93 Mixed cerris oak (Quercus cerris), Quercus frainetto and Oriental hornbeam (Carpinus orientalis) forests of secondary origin, 100 Querceta frainetti forests, 103 Mixed Quercus frainetto and Flowering ash (Fraxinus ornus) forests in areas with continental or transitional-continental climate.
Conservation status. BDA, BC, HD.
Category. Endangered [EN – A1, 2 C2 D1 E2 F2 G2 H2 I L3].
General characteristics. This habitat type is represented by xerothermic to meso-xerothermic oak forests in the hilly plains, foothills and low mountains of the Forebalkan, southern and western parts of the Danubian plain, southern parts of Ludogorie region, West Bulgaria (Sofia, Kyustendil, Pernik regions) up to about 800 (1000) m alt. These forests most often are mixed, but in most places Quercus frainetto is the dominating species or it makes mixed communities with Quercus cerris, and in places with higher altitudes – with Quercus dalechampii. The soils are diverse, mostly different subtypes of Luvisols, Phaeozems and more rarely – Chernozems or shallow Leptosols – rendzic and rankers (mainly in West Bulgaria). The soils are relatively rich and deep, dry (particularly in summers), rarely moderately wet with more pronounced drought in the summer. The bedrock is both silicate and limestone. The mixed thermophilic oak forests occur on slopes with different exposure and on the ridges of the hills. With the advancement of the erosion and the impoverishment of the soil in the driest places as well, these coenoses are replaced by communities dominated by Quercus pubescens and Carpinus orientalis. The canopy of the Moesian mixed thermophilic oak forests is 0,7-0,8 and have good light. The tree layer reaches 8–12 m height on average. Most of the phytocoenoses originate from shoots and are a result of several subsequent cuttings. There are several reasons why Quercus cerris dominates in some places, but one of them is that Quercus frainetto was selectively cut for its more precious wood. In other places, where the conditions have deteriorated as a result of grazing and logging, secondary increase of Quercus cerris is observed due to its higher plasticity and tolerance. Quercus frainetto is adapted to the milder climate of the Forebalkan in comparison with the more continental parts of the Danubian plain where it is absent or reduced. Other species that occur frequently in these forests are Acer campestre, Fraxinus ornus, Quercus dalechampii, Q. pubescens, Q. virgiliana, Sorbus domestica, S. torminalis, Tilia tomentosa.In the shrub layer Crataegus monogyna (can be dominant with its height of 3–4 m) but also Acer tataricum, Cornus mas, Euonymus verrucosus, E. europaeus, Rosa canina occur. Paliurus spina-christi and Prunus spinosa occur in the most deteriorated, open places. Species typical for the xerothermic oak forests occur in the herbaceous layer such as Brachypodium sylvaticum, Buglossoides purpurocaerulea, Bupleurum praealtum, Campanula persicifolia, Carex muricata, Crocus flavus, Dactylis glomerata, Festuca heterophylla, Fragaria vesca, Galium pseudaristatum, Geum urbanum, Helleborus odorus, Iris variegata, Laser trilobum, Lathyrus niger, Lychnis coronaria, Melica uniflora, Peucedanum alsaticum, Physospermum cornubiensis, Poa nemoralis, Potentilla micrantha, Tanacetum corymbosum, Teucrium chamaedrys, Veronica chamaedrys, Viola hirta, V. odorata, and Viscaria vulgaris.As the altitude increases the air and soil humidity also increases. For instance in the Forebalkan, in the composition of the xerothermic oak forests appear some mesophytic forest species, herbs and shrubs such as Aremonia agrimonoides, Carex montana, Carpinus betulus, Cerasus avium (= Prunus avium), Luzula forsteri, L. sylvatica, Neottia nidus-avis, Stellaria holostea, and Veronica officinalis. Juniperus communis can enter the oak forests in some places, in the foothills of the mountains.
Moesian mixed thermophilic oak forests are a part of the relatively small complex of oak forests from the hilly plains of Southest Europe that belong to the alliance Quercion frainetto. If they are considered as a part of a polymorphic association (senso lato) Quercetum frainetto-cerris, represented by various synvicariants in different parts of the Balkan Peninsula, then the Moesian oak forests are a part of the large association Quercetum frainetto-cerris moesiacum. It is distributed in North and West Bulgaria and East Serbia. Moesian mixed thermophilic oak forests of Quercus frainetto and Quercus cerris have been subjected to strong anthropogenic impact for several centuries: various logging practices, grazing, fires, etc. In many places they are destroyed and replaced by derivative tree, shrub and herbaceous coenoses, for example, Agrostis capillaris, Bothriochloa ischaemum (= Dichanthium ischaemum), Carpinus orientalis, Chrysopogon gryllus, Juniperus communis, and Pteridium aquilinum. They make complexes with the open coenoses of Quercus pubescence on more shallow and eroded soils.
Characteristic taxa.
- Vascular plants: Acer campestre, A. tataricum, Ajuga laxmannii, Althaea cannabina, Aremonia agrimonoides, Brachypodium sylvaticum, Buglossoides purpurocaerulea, Bupleurum praealtum, Campanula bononiensis, C. persicifolia, Carex montana, Carpinus betulus, C. orientalis, Clinopodium vulgare, Cornus mas, Crataegus monogyna, Crocus flavus, Dactylis glomerata, Echinops banaticus, Euonymus europaeus, E. verrucosus, Euphorbia amygdaloides, E. polychroma, Festuca heterophylla, Fragaria vesca, Fraxinus ornus, Galium pseudaristatum, Geum urbanum, Helleborus odorus, Hieracium racemosum, H. sabaudum gr., Iris variegata, Laser trilobum, Lathyrus latifolius, L. niger, L. vernus, Ligustrum vulgare, Luzula forsteri, L. sylvatica, Lychnis coronaria, Malus sylvestris, Melica uniflora, Neottia nidus-avis, Peucedanum alsaticum, P. cervaria, Physospermum cornubiensis, Poa nemoralis, Potentilla micrantha, Primula veris, P. vulgaris, Pyrus pyraster, Quercus cerris, Q. frainetto, Q. petraea agg. (incl. Q. dalechampii), Q. pubescens, Q. virgiliana, Scorzonera hispanica, Silene viridiflora, Sorbus domestica, Tanacetum corymbosum, Teucrium chamaedrys, Veronica chamaedrys, V. officinalis, Viola hirta, V. odorata, Viscaria vulgaris; mosses – Brachytheciastrum velutinum, Hypnum cupressiforme.
- Fungi: Macromycetes – Amanita caesarea, A. franchetii, A. phalloides, Armillaria mellea, A. tabescens, Boletus aereus, B. aestivalis, B. appendiculatus, B. fechtneri, B. queletii, B. radicans, B. regius, B. rhodopurpureus, B. satans, Clavariadelphus pistillaris, Cortinarius bulliardii, C. infractus, C. orellanus, C. rufoolivaceus, C. trivialis, Ganoderma lucidum, Geastrum melanocephalum, Grifola frondosa, Hericium erinaceum, Hygrophorus poetarum, H. russula, Inonotus dryadeus, I. nidus-pici, Lactarius acerrimus, L. flavidus, Meripilus giganteus, Omphalotus olearius, Peniophora quercina, Phellinus ferruginosus, Pleurotus dryinus, Polyporus tuberaster, Russula virescens, Tricholoma acerbum, T. ustaloides; Micromycetes – Apiognomonnia errabunda (on Quercus frainetto), Diplodia mutila (on Quercus cerris), Erysiphe euonymi (on Euonymus europaeus), Gnomonia rosae (on Potentilla micrantha), Hypospilina pustulata, Microsphaera alphitoides (on Quercus cerris, Q. frainetto), Hypoxylon mediterraneum (on Q. cerris), Urocystis floccosa (on Helleborus odorus).
- Animals: Invertebrates – Cerambyx cerdo, Lucanus cervus, Lymantria dispar; Vertebrates – Caprimulgus europaeus, Dendrocopus medius, Dryomis nitedula, Emberiza citrinella, Felis sylvestris, Fringilla coelebs, Hieraetus pennatus, Hypsugo savii, Jynx torquilla, Lacerta praticola, Myotis capaccinii, Nyctalus leisleri, N. noctula, Parus coeruleus, Pipistrellus pipistrellus, P. pygmaeus, Rana dalmatina.
Distribution in Bulgaria. North Bulgaria – Forebalkan, southern and western parts of the Danubian Plain and Ludogories region (to the South from the line connecting the towns Vidin – Lom – Byala Slatina – Pleven – Levski – Pavlikeni – Byala – Vetovo – Dobrich), East Balkan Range, mountain foothills and low mountains of West Bulgaria (Pernik, Sofia, Kyustendil districts).
Conservation importance. These forests have been subjected to very strong anthropogenic pressure – logging, grazing, fires, etc. Some rare, endangered and protected species participate in their composition such as Anemone sylvestris, Chamaecytisus kovacevii, Crocus tommasinianus, Galium bulgaricum, Hesperis sylvestris subsp. velenovskyi, Paeonia mascula, Vicia dumetorum, V. pisiformis, as well as some fungi of conservation importance – Amanita caesarea, A. franchetii, Boletus radicans, B. regius, B. rhodopurpureus, B. satans, Clavariadelphus pistillaris, Cortinarius bulliardii, C. coerulescens, Geastrum melanocephalum, Grifola frondosa, Hericium erinaceum, Hygrophorus arbustivus, H. poetarum, H. russula, Lactarius acerrimus, Tricholoma acerbum, Tuber aestivum. These forests are the source of some important medicinal plants such as Crataegus spp., Teucrium spp., Helleborus odorus, Primula spp., etc.
Threats. The major threats are the large- scale clear cuttings and illegal logging related to overexploitation of wood, mainly for heating. Other threats are the replacement of the oak forests by plantations of species not typical for the area (Black pine, Scots pine, False acacia), grazing (mainly goats), fires, general aridisation of the climate, slow reproduction and fungal deceases that attack the young shoots, natural erosion processes on the slopes, etc.
Conservation measures taken. The habitat is included in Annex №1 of the Bulgarian Biodiversity Act. Some of the localities are within protected areas: Vrachanski Balkan and Vitosha Nature Parks and in protected sites of the European Ecological Network NATURA 2000.
Conservation measures needed. Legal amendments so as to terminate the clear cuttings in the private forests; restoration measures including restoration from seeds and fighting of the fungal diseases on the shoots; proclamation of some of the representative coenoses as protected areas.
References. Kochev 1976; Radkov & Minkov 1963; Velchev 1971.
Authors: Rossen Tzonev, Petar Zhelev, Evgeni Tzavkov
