Hydro-ecological relations in the Delta Waters

favna often is the wrrmg policy, whatever rare the species may be.
It is more important to get a good idea af the (abiotic) processes in
aad the ecologioal potenzidries of the atea. 0x1 the basLs of this
knowledge we must formulate a management plan with a goal for ecosystem
development a~ the long run. The long-term goal must be used to
evaluate what short-term measurements can be taken. For instmce, with
the Long-term goal to st5uslate woodland and shrub develbpment it will
be difficult to accept short-term mowiq to canserve breeding habitats
for rare shore birds. Mren the lerrg-term goal is the development of
grassland ewsysfems a mowing regime during some gears may be quite
acceptable, particularly when endangered species are involved. Even in
rhe last case, however, it is possible that the breeding habitat gets
more and more unattractive.
The author is ~uch indebted to J, van Baalen, C.
Bisseling,
A.R.L. Huiskes, D.J. de JMg and espeeiallx W.@. Beeftink for valuable
tornenta on earlier dr&ts of the manuscript.
J. Visser (Bi>kewaterstaat, Directorate Flevoland) and G.J. Slab
fk'atiofuil
Forest Service in the Netherlands) kindly provided some data.
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