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ŠUMARSKI LIST 13/2005 str. 165     <-- 165 -->        PDF

E. Klimo, J. Kulhavy: THE ROLF. OF FLOODPLAIN FORESTS IN SOUTHERN MORAVIA ... Šumarski list - SUPLEMENT (2005), 155-164
ve been changed, step by step, into intensively cultivated
agroecosystems, with high inputs of fertilizers. In
this way, the floodplain forest has assumed the character
of a corridor ecosystem, with typical high inputs of elements
transported from neighbouring ecosystems.


Our study was oriented towards the evaluation of
the present situation in N and P budget. Based on the
data given in Tab. 1, it is possible to see that nitrogen is
an important element for the existence of a floodplain
forest and so the forest can also fulfil the role of retaining
the element as a pollutant for the Morava and Dyje
Rivers the former being an important tributary of the
Danube River. Its total value accumulated in the whole
ecosystem amounts to 25 842 kg.ha"´, the highest proportion
of which being accumulated in the soil environment,
particularly in the root layer (14 846 kg.ha"´).
Nitrogen value in the forest stand biomass is also high
as compared with other forest ecosystems in a temperate
zone (1804 kg.ha"´).


Nitrogen and phosphorus accumulation in a surface
humus is relatively low the fact being the result of an
intensive decomposition of litter. Nitrogen and phosphorus
input into the soil environment occurs particularly
through the litter from all components of the ecosystem
biomass but also through the input from atmosphere
either as dry depositions or as precipitation (input by litter
fall and precipitation). N and P input in precipitation
is markedly affected. The forest forms a barrier protecting
the water ecosystems from pollution (Fig. 2).


The process of N and P input by flood waters from
the Dyje and Morava Rivers was stopped by the construction
of Nove Mlyny reservoirs in 1972. At present,
it is partly substituted by artificial flooding. Since
1972, regular natural floods and thus also inputs of
sludges into the floodplain forest do not occur. Sedimentation
of the sludges occurs only on banks of watercourses
(Fig. 3).


2.4 Nutrient removal
The floodplain forest ecosystem can uptake and
bind large amounts of particularly nitrogen and phosphorus
due to high levels of plant biomass production
and considerable soil adsorption capacity (Tab. 4).


Nutrient uptake by the forest stand was 18 kg.ha"1
year"1 P and 224 kg. ha"´ year"´ N. Maximum of both
nutrients was obtained by trees; shrubs and herbs contributed
in the process markedly less (Tab.3).


At the same time, in addition to the pollutant removal
capacity, the forest ecosystem forms a wind erosion
barrier from heavily fertilized agricultural land in the
surrounding landscape (Fig. 3).


Due to the facts, it is possible to recommend preservation
and enlargement of the ecosystems their function
in the landscape to be restored.


2.5 Economic evaluation of floodplain forests in Southern Moravia
Economic evaluation of floodplain forests is related
to their basic characteristics which are as follows.


1.
biological value, viz. plant and animal biodiversity;
2.
primary production, ie tree, shrub and herb biomass;
3.
recreational role of the region;
4.
protection of water resources (retention of elements);
5.
educational, aesthetic and scientific importance.
Alternation of forest, grassland, wetland and water
(rivers, ponds) ecosystems is typical of the floodplain
forests of southern Moravia.
There is not much experience with the economic
evaluation of the roles of forest ecosystems and our
conclusions are based mainly upon the WWF publication
"Economic Evaluation of Danube Floodplains
(1995). We quote, therefore, the introductory part of
the publication here:
In evaluating the "purification" function of the
floodplain forest through the process of N and P reten


tion in ecosystem components (trees, shrubs, herbs, humus,
soil) we can find very high accumulation particularly
of N (25.842 kg.ha"1). If we consider that 1 kg N
corresponds to ECU 14 then total amount is equal to


361.788 ECU ha"´. As for P, 10.173 kg.ha"´ is accumulated
and when 1 kg P corresponds to ECU 4 then total
amount is equal to 40.692 ECU ha"´.
In addition to actual forest stands the purification
function aimed at water resources occurs also in other
ecosystems which are the component of floodplain forests.
It refers particularly to pools, oxbows and grasslands.
Here, the function is applied of phytoplankton
and retention of nitrogen and phosphorus in grasslands
where aboveground biomass is consumed by mowing
and grazing and a rich root system accumulates considerable
amounts of elements.