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biodiversity as refuges for wild species driven away from intensively used agricul-
tural plots. After 50 years of this development we can find many small landscape
segments with different successional stages of seminatural vegetation in the Czech
rural landscape. Small water stream erosion valleys in the low highlands of Central
Bohemia are among typical examples of such development. Natural and semi-
natural communities originated both in the wet bottom of the valleys along the
water stream, where narrow strips of alluvial meadows were previously manu-
ally managed, and on relatively steep slopes of the valleys which were formerly
used as dry extensive pastures with some low-yielding fruit trees. Whole valleys
of small water streams strengthened their biocorridor functions in this way. For
many wild species they became a refuge and the only functional biocorridor in the
contemporary agricultural landscape.
Two concrete examples from Central Bohemia concisely illustrate the devel-
opment of the “wet” wilderness in partly abandoned valleys of small water
streams.
(a)
Jevanský potok brook
(40 km east of Prague): land use changed on 38% of the
alluvial floodplain in the period 1990-2005, chiefly because of abandonment,
afforestation and grassing on arable lands. More than 20% of the alluvial plain is
now abandoned and covered by a varied mosaic of wet meadows, reed and sedge
communities as well as alluvial willow and alder forests in initial succession
stages.
(b)
Libechovka and Pšovka brooks
(50 km north of Prague, total length of inves-
tigated valleys 25 km, area 14 km
2
): significant land-use changes completely
changed the landscape character of both valleys from an open intensively used
agricultural landscape to a closed forested landscape scenery (Table 2.2). The
land has been rewilding and forest has taken over. This development was started
by the transfer of the German population after WWII and accelerated during
the subsequent transition to socialist large-scale agriculture. The area of culti-
vated land dramatically decreased because small-sized agricultural plots on the
wet bottom of valleys were not suitable for heavy mechanisation. Completely
new wetlands developed in abandoned alluvial floodplains along both water
streams during the last 60 years. In 1997 both valleys were declared as one of
in total 12 Ramsar Sites (wetlands of international importance) in the Czech
Republic.
Table 2.2
Land-use changes in the Libechovka and Pšovka valleys 1845-2000, as a percentage
Land-use category
1845
1938
2000
Forest and shrub
48
51
70
Permanent grasslands
13
16
15
Arable lands
25
23
3
Total agricultural lands
45
40
18
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