This work presents the state of the art of aquatic and semi-aquatic
ecological restoration projects in The Netherlands. Starting from the
conceptual basis of restoration ecology, the successes and failures of
hundreds of restoration projects are described. Numerous successful
projects are mentioned. In general ecological restoration endeavours
greatly benefit from the progressive experience achieved in the course
of the years. Failures mainly occur through insufficient application of
physical, chemical or ecological principles. Spontaneous colonization by
plants and animals, following habitat reconstruction, is preferred.
However, sometimes the re-introduction of keystone species (e.g.
eelgrass, salmon, beaver) is necessary in case the potential habitats
are isolated or fragmented, or if a seed bank is lacking, thus not
allowing viable populations to develop. Re-introducing traditional
management techniques (e.g. mowing without fertilization, low intensity
grazing) is important to rehabilitate the semi-natural and cultural
landscapes that are so characteristic for The Netherlands.