Kanitzia 18. - NYME Természettudományi Kar - Nyugat ...

warming up-drying up processes, inducing subdesert-like microclimate and local steppe
conditions of the very dry slopes and landslides developed on sandy and marly substrates
of southern expositions.
The vegetation physiognomy present an open-loosed structure, the general cover
having cca 65-85%, realized preponderant by the two characteristic species (K. ceratoides,
A. cristatum). The coenotic composition of the plant community is well defined by the diagnostic
species group: Artemisia campestris agg., A. pontica, Brassica elongata, Stipa lessingiana,
Artemisia austriaca, Astragalus monspessulanus, Cephalaria uralensis
(Artemisio-Kochion s.l., Festucion rupicolae). The species composition contains a diversity
of xerothermic elements, from which some present good constancy values (III-V): Elymus
hispidus, Astragalus austriacus, Phlomis tuberosa, Jurinea mollis, Festuca rupicola (Festucetalia
valesiacae), Salvia nemorosa, Euphorbia cyparissias, Poa angustifolia, Koeleria
cristata (Festuco-Brometea). Other species considered as xerothermic generalists participate
in the vegetation structures with a medium frequency values (Vinca herbacea, Nepeta nuda,
Linum austriacum, Scabiosa ochroleuca, Medicago falcata, Asparagus officinalis etc.).
The stands of Agropyron cristatum-Krascheninnikovia ceratoides present a relatively
well balanced vegetation unite, because their coenotic structure are permanently supplemented
with various xerothermic species from the neighboured steppic and dry
grasslands (Stipetum pulcherrimae, Stipetum lessingianae, Stipetum capillatae, Bothriochloetum
ischaemi, Carici humilis-Festucetum rupicolae) (Vultureni, Groapa, Poiana).
Even if the species immigration is a long process, it can be remarked for all relevés analysed
the absence of some genuine steppe elements like: Crambe tataria, Salvia nutans, S. transsylvanica,
Echium maculatum, Ajuga laxmannii, Astragalus excapus subsp. transsylvanicus
etc. Instead of these, actually the weeds and weed-like species can be spreading more:
Calamagrostis epigeios, Melilotus officinalis, Daucus carota, Elymus repens, Ballota nigra,
Artemisia vulgaris, Carduus acanthoides etc.The coenotic relations with the fringe communities
and the semi-dry grassalnds is indicated by the presence of Dorycnium
herbaceum, Brachypodium pinnatum, Galium glaucum etc. The dendrogram of the cluster
analysis of the sampled plots (Fig. 5.) shows that the relevés are separated in a specific
group, are in coenological relationships with the next two groups of the Potentillo arenaiae-Stipetum
capillatae and the Bothriochoetum ischaemi communities plots. The distance
between the relevés (1-10) signed also their separation and fragmentation in relation
with the specific field and ecological conditions. The ordination diagramm (Fig. 6.) obtained
by the principal component analysis expressed this fragmentation also.
The stands dominated by K. ceratoides in Transylvania after the actual coenological
structure, species composition and peculiar habitat characteristics constitute a distinct
plant community with transitional characteristics between the Artemisio-Kochion s. l. and
Festucion rupicolae alliances. We described them as a new plant community named
Agropyro cristati-Krascheninnikovietum ceratoidis ass. nova (Table 1, typus relevé 7). The
new association has coenotic and ecologic relationships with the Artemisietum ponticocampestris
SOÓ 1947 (Transylvanian Basin) and with the Agropyro cristati-Kochietum
prostratae ZÓLYOMI 1958 (Pannonian Basin). The new xerothermic plant community is
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