New Vision of the Role of Land Reclamation Systems in Nature Protection and Water Management - Wetlands and Water Framework Directive: Protection, Management and Climate Change - page 94

oak-elm-ash riparian forests;

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coniferous and bog forests;

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transitional moors and quaking bogs.

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These habitats are rather not endangered by reclamation, however, the protection
of the

first three habitats is associated with fl flood control problems described in

Sects. 6.3 and 6.6 .

6.5 Possibilities of Improving Natural Habitat Through
Land Reclamations

Proper water management in habitats transformed by human activity is of great
importance for environmental protection. Maintaining ground water levels at a
depth optimum for meadow sward facilitates the protection of soil organic matter.
This may be achieved by regulated out

ow of water from reclamation ditches with
the help of water lifting facilities (weirs or permanent sills).
Preservation of riparian rush vegetation, trees and shrubs may contribute to
maintaining a mosaic character of the landscape, important for its biodiversity. In
reclamation ditches this vegetation is usually removed since it interferes with
mechanical conservation works. A lack of this type of vegetation means nonexis-
tence of buffer zones being a

fl

filter for dissolved nutrients runoff from surrounding
croplands, disappearance of bird sanctuaries for waterfowl and singing birds and

finally the overheating of water and its decreased aeration. Radical mowing of
bottom plants and de-silting is unfavourable from the nature protection viewpoint.
Apart from the disappearance of aquatic and wetland plants and of benthic fauna, a
stream devoid of vegetation loses its water puri

cation properties.
Of fundamental importance for biodiversity is to provide an unobstructed fl ow in

streams. Water lifting facilities desired in regulated or arti cial streams pose a risk

for the role streams play as ecological corridors. The equipment of larger dams with
effective fish ladders and proper shaping of permanent sills is important in this

aspect.
The question is, whether the abandonment — overgrowing by plants and siltation

— of reclamation ditches is favourable from the nature protection viewpoint?

Obviously yes, providing it is not associated with the abandonment of adjacent
grasslands and when ditches are not equipped with water lifting facilities. More-
over, a lack of such facilities results in accelerated water out

fl ow and increased

fl flood risk.

It is worth mentioning of the importance of properly performed reclamation for
the mitigation of climate changes. According to approximate calculations, the
intensity of CO 2 release from meadows on peatlands dried in uncontrolled way is
by 22 % larger than from irrigated meadows. Maintaining ground water levels at
depths given in Table 6.1 would decrease CO 2 emission to the atmosphere by ca.
17,000 tons a day in in the scale of Poland (Czaplak and Dembek 2000 ).