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Continental and Pannonian loess flora and vegetation on the southern border of its distribution
Project: “Improving nature conservation relations and enchancing cooperation in biomonitoring
activities in areas along the frontier river Drava, for developing the European Ecological Network”
1
2
Dragica PURGER and János CSIKY
1
Department of Animal Ecology, Institute of Biology, Faculty of Sciences, University of Pécs, [email protected]
2
Department of Phytotaxonomy and Geobotany, Institute of Biology, Faculty of Sciences, University of Pécs, [email protected]
Areas covered by loess are parts of the forest steppe zone distributed in the Great Hungarian Plain. The last
natural climax community of this zone on loess substratum was Aceri tatarici - Quercetum roboris Zólyomi
1957. Some areas were covered by species-rich steppe grasslands such as Salvio nemorosae - Festucetum
rupicolae Zólyomi ex Soó 1964. On extremely steep loess cliff surfaces natural vegetation of open, pioneer
grassland (Agropyro cristati - Kochietum prostratae Zólyomi 1958) is formed. The majority of these lands
had been converted to agricultural fields, and only small fragments of original loess vegetation have
remained unploughed. Therefore “reconstruction” of natural vegetation on the basis of recent remnants of
flora and vegetation patches is not easy task.
The main aims of our survey were:
i) to determine species pool of loess vegetation,
ii) to explore occurring of loess specialists, as well as,
iii) to estimate major threats for loess plant species and loess vegetation.
STUDY AREA
Botanical survey was carried out on the southern (south-western), marginal part of loess ridges, on Baranya Hills (S
Hungary) and on Bansko Hill in Baranja (NE Croatia).
Photo: Dragica Purger
Photo: Dragica Purger
Pécsvárad
Photo 2: Spring aspect of steppe with flowering
Adonis vernalis near Pécsvárad.
Photo 1: Species-rich dry grassland on Baranya Hills
near town of Pécs
Pécs
Mohács
Görcsöny
Hercegszántó
Photo: Dragica Purger
Siklós
Photo 4. 5.: Loess cliff near Zmajevac - “refugium” for
loess specialists
Beli Manastir
Donji Miholjac
Valpovo
Photo: Dragica Purger
20 km
Photo: Dragica Purger
Photo 3: Taraxacum serotinum is pioneer loess
specialist, protected in Hungary
Osijek
Iris pumila
Prunus fruticosa
Rapistrum perenne
Reseda inodora
Inula germanica
Agropyron pectinatum
Inula ensifolia
Taraxacum serotinum
Amygdalus nana
Map 1: Distribution of some loess plants in the investigated area
RESULTS
In Baranya Hills and Bansko Hill 271 and 241 steppe, forest-steppe and forest species were
recorded, respectively. Comparison of species richness shows, that 215 of these species are
common, occuring in the both region.
56 plants species occur only on Baranya Hills. Most of them belong to Eurasian, Europaean and
Central-Europaean floristic elements. Some loess specialists grow on Baranya Hills, e.g.: Ajuga
laxmannii, Taraxacum serotinum, Anchusa barrelieri, but absent from Croatia.
Photo: Janos Csiky
Photo 6: “Cultural-desert” on plateau of Bansko Hill
(Croatia)
During our survey on Bansko Hill Iris pumila L. and Reseda inodora (plants with Pontic-Pannonian
distribution) are registered as new taxa for Croatian flora (in press).
For the first time were found e.g.: Erodium ciconium, Inula germanica, Rapistrum perenne, Rosa
gallica, Stipa capillata. Among 26 differential plants registered only in Bansko Hill
Submediterranean (Pontic-Mediterranean) floristic elements (e.g.: Scorzonea hispanica, Vicia
narbonensis ssp serratifolia, Orlaya grandiflora) prevailed. Data about populations of some rare or
poorly documented plants in the continental part of Croatia: Acer tataricum, Astragalus cicer,
Astragalus onobrychis, Campanula bononiensis, Chamaecytisus supinus, Euonymus verrucosus,
Festuca valesiaca, Nonea pulla, Salvia nemorosa, Thymus glabrescens were also collected.
Photo: Janos Csiky
Photo: Janos Csiky
Photo 7: Agropyron pectinatum – Critically endangered
(CR) species in Croatia
Photo 8: Reseda inodora - (CR), new species
for Croatia
Photo: David Schäffer
Photo 9: Iris pumila L. - CR species, known on single 1
locality in Croatia
CONCLUSIONS
Photo: Janos Csiky
Photo: Dragica Purger
Photo: Janos Csiky
Photo 11: Erodium ciconium – rare natural weed
Photo 10: Catabrosa aquatica (CR species) is frequent
and abundant plant on bottom of streams and canals on
Bansko Hill and flat area of Baranja.
Acknowledgement:
This work is supported by INTERREG III A, SLO-HU-CRO 2006/01/167/HU.
We are grateful to Boža Janžekoviè, Balázs Kevey, Stjepan Krèmar, Tibor Mikuska, Jenõ
Purger, Dávid Schaffer, Béla Tallósi and Jasenka Topiæ for collaboration.
Photo 12: Loess steppe patches (in Batina vicinity)
with domination of grasses: Elymus hispidus, Stipa
capillata, Chrysopogon gryllus, Cleistogenes serotina,
Bothryochloa ischaemum and Festuca rupicola.
Our recent investigations showed, that some loess plant species riches the southern (southwestern) border of theirs distribution, just in study area, e.g. : Ajuga laxmannii, Taraxacum
serotinum, Anchusa barrelieri, Iris pumila, Reseda inodora, Agropyron pectinatum and Salvia
nemorosa.
Loess vegetation in the study area consists of very few fragments of differently degraded seminatural stands of forest-steppe and steppe grasslands, which are also the most southern (southwestern) occurrence of these vegetation types.
It is known that species occurring on the very border of their distribution faces larger risk
of extinction, therefore more attention should be paid on protection of such plants!
The major threats to loess steppes and loess wall vegetation in Hungary as well as in Croatia
are continuous shrinking of its overall area and degradation of habitats (decrease of its
natural values, based on species composition and structure) caused by human activities:
construction, excavation of loess wall, deposition of garbage and household wastes, use of
fertiliser and other chemicals on arable fields, changes in grasslands use: cessation of grazing vs.
overgrazing as well as invasion of shrubs, trees and invasive alien plants, e.g.: Robinia
pseudoacacia, Ailanthus altissima, Lycium barbarum, Elaeagnus angustifolia, Asclepias
syriaca.