Cahnov – Soutok National Nature Reserve

Cahnov – Soutok NNR lies on the alluvial plain of the Dyje and Morava rivers 8 kilometres south of the municipality of Lanžhot in the southern tip of the Jihomoravský kraj – South Moravian Region. The NNR was declared in 1949 on a territory of 13.46 ha at an average elevation of 150 metres. The main subject of the protection is the alluvial forest biotope. This alluvial forest is a typical example of primeval-like floodplain forest in south Moravia. A small floodplain meadow is also part of the reserve and has valuable wetland plants and animals.

The geological basement is of sediments of the Vienna basin, overlain by fluvial sands and gravels and with a covering of sandy alluvial loams. The oxbow lakes are filled with organic sediments (sapropel). The soil covering is of typical and gleyic Fluvisol.

The great majority of the forest growths are of hardwood alluvial forest of lowland rivers (Fraxinus pannonicae-Ulmetum) with a tree layer containing pendunculate oak (Quercus robur), narrow-leaved ash (Fraxinus angustifolia Vahl), hornbeam (Carpinus betulus), small-leaved lime (Tilia cordata), field maple (Acer campestre) and wild pear (Pyrus pyraster). Typical species in the undergrowth are wood false-brome (Brachypodium sylvaticum), tufted hair-grass (Deschampsia cespitosa), wood sedge (Carex sylvatica) and in places the rare sedge Carex strigosa. The most abundant spring flowers are of the yellow anemone (Anemone ranunculoides). Where hornbeams dominate the tree layer we can find snowdrops (Galanthus nivalis) and in some places wood speedwell (Veronica montana) in the undergrowth. Along the banks of the water channels the trees are mostly white willow (Salix alba) and species including the reed-grass Phalaris arundinacea, yellow iris (Iris pseudacorus), gypsywort (Lycopus europaeus) and hedge bindweed (Calystegia sepium) in the undergrowth. The common duckweed (Lemna minor) is abundant in the water. The meadow communities here are of the continental inundated meadows - Cnidion venosi association. The predominant species here are the foxtail Alopecurus pratensis, the meadow-grass Poa palustris and the sedge Carex preacox. Other significant species which are found here include cnidium (Cnidium dubium), spear-leaved skullcap (Scutellaria hastifolia), meadow violet (Viola pumila), the bittercress Cardamine parviflora and the rockcress Arabis nemorensis. In the wettest parts of the meadow we can find communities with the dominant sedge Carex gracilis. Several species of decay fungus have been recorded on the NNR territory, including Hypoxylon fraxinophilum, Hypoxylon macrocarpum and Hypoxylon moravicum.

Several bat species live in hollows in the old trees and nesting bird species include the stock dove (Columba oenas), grey woodpecker (Picus canus), collared flycatcher (Ficedula albicollis) and short-toed treecreeper (Certhia brachydactyla). The spotted crake (Porzana porzana) nests on the meadow in the reserve. The insect fauna which is bound to the old trees is also of note. An abundant population of great capricorn beetle (Cerambyx cerdo) lives here, as do the ground beetle Calosoma sycophanta and the rare jewel beetle Eurythyrea quercus and large colonies of the ant - Liometopum microcephalum. Many moor frogs (Rana arvalis) live in the pools on the meadow. The rare ground beetle Carabus clathratus can be found on the banks of the pools.

After forest grazing was stopped in the late 19th century the forest growths in the current reserve were left more or less to natural processes. After 1970 the reserve was a part of a large game preserve used for intensive breeding of red deer and fallow deer. The high deer populations led to the current absence of the youngest age groups in the forest growths. At the same time the oldest oaks in the canopy level are dying off and being replaced by Ash. During the early 1990s the deer populations were greatly reduced. In 2004 a fence was built around part of the NNR territory at the expense of the Ministry of Environment and this prevents the deer from entering and grazing these valuable forest growths.

The locality used to be affected by regular flooding, which ceased after the Dyje and Morava rivers were regulated during the 1970s and 1980s, resulting in a dramatic fall in the subsurface water table here. Artificial flooding of the territory has been carried out regularly since the early 1990s with the aim of reducing the negative effects of this falling water table. The meadow in the NNR requires regular cutting.