| "Other land" categories are: 100 % coverage of non-native species (Amopha fruticosa) 44 %, canals 6 %, weekend cottage 11 %, minor roads, common land 31 % and embankment 8 %.
Three big rivers (Danube, Tisza, Maros) played a key role in the formation of the present landscape of this area. From the rivers silting up the one-time Lake Pannon, approximately 2.5-3 million years ago the ancient Danube appeared in the area, and running through the present Danube-Tisza Mid-Region, at first it flowed into the Tisza valley at Szolnok, later at Csongrád. The ancient Tisza and its tributaries arrived from the direction of the Körös basin at that time. The ancient Danube left the Danube-Tisza Mid-Region and took up its north to south direction of flow. The huge ridges of alluvial Danube sediments (which are of sandy origin in this reach) became independent of the river and were gradually covered partly by wind-blown loessy sediments and partly by 'drifting sand'. These wind-blown sediments (moving sand and loess) are characteristic near the surface up to the present day. About 18-20 thousand years ago the ancient Tisza took up its present direction of flow as well. It was then that the bends of Tisza developed (which can still be traced on the surface) mainly as a result of 4-6 times bigger water output 12-16 thousand years ago. This surface continued to change due to the floods and unique lower and higher (flood-safe) inundation area levels developed along the River Tisza. River control and surface drainage from the middle of the nineteenth century radically changed the water conditions of the region. The comprehensive control of the River Tisza began in 1846 and started at Csongrád in 1856. The biggest bends were cut through (the 11 cuts shortened the river by 58 km) and the river was forced between dykes. As a result, half of the county was saved from recurrent floods.
On the vegetation map, the so-called 'gallery forests and swamps' vegetation covers an extensive area in the site. According to a map from the eighteenth century, this area was mainly a large swamp with little forest vegetation indeed. Gallery forests were typical of earlier times. River control in the nineteenth century divided this wide inundation area into two parts: the active flood plain inside the dyke, and the protected (inactive) flood plain. The major part of the protected flood plain is now cultivated but fragments of the natural vegetation can be found in the active flood plain.
The river bed is lined by (Polygono hydropipero-Salicetum triandrae) community. The extremely resistant willow species: (Salix alba, S.triandra, S. purpurea, S. viminalis) tolerate flooding, drought and icy floods and grow bush-sized on the deposit laid down by the river. In the northern part of the Boszorkány island in Szeged we can observe the 'birth' and the 'death' of willow groves. Sailing on the River Tisza, we can see that this community along the banks of the river is almost unbroken. Forests in the bank zone consisting of autochthonous willow and poplar groves (soft-wood groves, Salicetum albae-fragilis) are of great environmental value. Three tree species can be found in soft-wood gallery forests: White willow (Salix alba), White poplar (Populus alba) and Black poplar (Populus nigra). During natural renewal, one of these trees has bigger patches and becomes dominant in the tree canopy. Unfortunately the number of those stands are very low where we can admire huge, old White or Black poplars-it is more often that we meet a lonely tree in planted forests. The shrub layer of soft-wood galleries along the Tisza have only allochthonous species. The Box elder (Acer negundo) and the American ash (Fraxinus pennsylvanica) spread by foresters find their optimal conditions in the flood plain, their seedlings may become dominant in the herb layer, they are common in the shrub layer and sometimes form the lower tree layer. The herb layer of poplar communities in the flood plain resembles that of (Polygono hydropipero-Salicetum triandrae) communities. The following boggy species are common: (Carex gracilis), Yellow iris (Iris pseudachorus), Gipsywart (Lycopus europaeus), Yellow loosestrife (Lysimachia vulgaris), Bittersweet (Solanum dulcamara) and Comfrey (Symphytum officinale).
Dykes are lined by so-called 'navvy forests'. In this zone we find the ditches and navvy pits of which the dykes were built. These ditches have boggy vegetation, their flora is of great value. The most characteristic tree species is the White willow (Salix alba) of which the lower branches and twigs are regularly pollarded, so their trunks are bare and the trees have a big 'head' and are locally called 'headed willows'. The wickers of these willows were used to reinforce the dykes. One reason to preserve these willow communities is that old willows become hollow thus providing a habitat for hole-nesting birds, the other is their cultural significance - their scenic value is significant. Their herb and shrub layers are similar to that of soft-wood galleries. The beautiful Leucanthemelle serotina and the Summer snowflake (Leucojum aestivum), both protected, are common in the fringe of the forests of the River Tisza. As the most important role of these forests is to preserve dykes, their management involves longer shifts of cutting, so there is more chance to create near-natural communities than in case of hybrid poplar forests treated with shorter shifts of cutting. If the flood plain is narrow, the gallery woods at the banks and the 'navvy forests' may overlap but the middle part of the flood plain is usually occupied by hybrid poplar plantations whose territorial proportion is the highest in Csongrád county's flood plains. Plantations, consisting of allochthonous species planted in checkrow, managed with intense short period cutting after a thorough preparation of the soil, cannot be considered real forests. A high proportion of invasive and weed species are typical here. Forests with significant numbers of allochthonous species but the same structure as autochthonous forests can be of great natural value as their avian fauna is rich, with heron colonies, and other protected and strictly protected birds also nesting. Natural renewal of soft-wood galleries is common, still, the largest part of the flood plain forests are planted and their structure and species composition are far from natural. Natural forests of the higher inundation area are oak-ash-elm (Fraxino pannonicae-Ulmetum) groves. Genuine, natural hardwood groves do not occur along the River Tisza in Csongrád county but some planted Pedunculate oak communities of different age are to be found in the flood plain and the protected (inactive) flood plain too. Their herb layer is poor in the active flood plain, and due to the floods, species of natural hardwood forests cannot survive here. Grasslands in the site are usually hayfields with Meadow foxtail (Alopecurus pratensis), Phalaroides arundinacea and Reed sweet-grass (Glyceria maxima) stands. Those along the flood plain form transitions with bog communities creating a mosaic pattern. Their extension is very small. In order to maintain flood plain hayfields, management is needed (without management, the area is invaded by Amorpha fruticosa, an invasive acacia species, or later soft-wood groves may evolve during a longer period of time) but then we lose grassland species, biocoenoses and scenic values. The planted grass of dykes also has natural significance because it can provide a habitat adequate for wild plant and animal species and can become near-natural. The most important protected species of the Tisza flood plain are: Leucanthemelle serotina, the Summer snowflake (Leucojum aestivum) and the Meadow clematis (Clematis integrifolia) which are most common between the forest and the dyke. The last natural habitat along the River Tisza to be presented, the bog, was the most characteristic habitat in the end of the eighteenth century. This is the typical habitat of boggy bottom-lands, shallower ditches beside the dyke and silt-up backwaters. Their extension is not significant and they are strongly fragmented. Zones dominated by Schoenoplectus lacustris, Branched bur-reed (Sparganium erectum),the Flowering rush (Butomus umbellatus), sedges (Carex spp.), (Phalaroides arundinacea), Purple loosestrife (Lythrum virgatum, L. salicaria), Common reed (Phragmites australis) and Bulrush (Typha latifolia, T. angustifolia) form zonation complexes depending on water depth. If there are shallow, open water surfaces in the bog, they offer particularly valuable feeding places for birds, however, their amphibian fauna is rich also. Fortunately this habitat is able to regenerate quite easily. It quickly develops in ditches (even in artificial ones) with adequate depth and water supply. |