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Volume 5 Pages 1 - 83 (March 1990)
Citation: Walter, J. (1990) Restoration
plan for the otter habitat in the Netherlands. IUCN Otter Spec. Group Bull. 5: 41
- 44
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Restoration plan for the otter habitat in the
Netherlands
Just Walter
Ministerie van Landbouw, Naturbeheer en
Visserij, Bezuidenhoutseweg 73, Postbus 20401, 2500 EK 's-Gravenhage
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Abstract: This paper reviews the provisions of the
new otter recovery plan for the Netherlands, launched in July 1989.
Threats to otters are reviewed, and mitigation measures specified, along
with maximum levels of pollutants. Improvement in water quality is
the first aim of the scheme. A principal role is given the the
Stichting Otterstation Nederland.
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In July 1989 the Minister of Agriculture. Nature management and Fisheries of
the Netherlands launched a recovery-plan for the otter in this country. This
plan "De otter in perspectief. een perspectief voor do otter: herstelplan
leefgebleden otter" (The otter in perspective, a perspective for the otter:
restoration plan otterhabitats) gives an analysis of the causes of the decline
(and extinction) of the otter in this country and contains an action plan for
the measures that are to be taken to achieve the survival of otters in the
future. The threats described are the deterioration of water quality (pollution
with PCBs. eutrophication etc.) and water quantity (lowering of the water
level), fragmentation by urbanization, motorways etc. disappearance of bank
vegetation and reedbeds, disturbance by water-based recreational activities,
drowning in fyke-nets and road casualties. The report gives a scheme of how to
cope with all these problems, like
- promotion of the preparation and implementation of regional schemes,
including measures such as constructing and maintaining reed beds,
adaptation of mowing regimes, taking zoning measures with respect to
recreation, reducing the height at. intervals of about 300m where
sheetpiling is too high etc
- promotion of source oriented control of environmental pollution
- promotion of the reduction of the use of toxic antifouling layers
- prevention of the filling-in of valuable waters in the context of land
development projects
- taking compensatory measures in the event of inevitable damage to an otter
habitat
- purchase of habitats which are important for the otter
- promotion of the construction of tunnels under roads
- promotion of the use of stop-grids in eel traps
The restoration plan has a summary in English of 6 pages, from which the
above mentioned measures are an abstract. Worth mentioning is the
formulation of a number of target criteria with respect to the quality of the
bank zone, the lack of disturbance and the quality of the water. These criteria
have been formulated for the sake of the implementation of this plan and to
facilitate the evaluation of the otter habitat policy. They are not definitive,
but based on the best professional judgement at present.
BANK STRUCTURE AND VEGETATION
- Banks higher than 30cm and with a steepness of > 60% are not to exceed
300m in length. However, if there are no alternatives, a number of
arrangements are to be made to facilitate the otters climbing into and out
of the water (e.g. lowering or shifting sheetpiling). The minimum
required length of these provisions shall be 5m, and they are to occur at
regular intervals of about 300m (500m max).
- The banks of the various lakes, ditches, canals and other waterways are to
be covered with ground cover bank vegetation for at least 60% of the total
length.
- This bank vegetation shall be at least 1m in breadth and 3m in length and
is to be within 50cm of the average land/water division. To qualify as
ground cover vegetation, the vegetation (reed. trees and shrubs, scrub)
shall be at least 50cm high
- The intervals between the ground cover vegetation is not to exceed 500m.
DISTURBANCE
- Core areas shall have one reserve per 20 sq km of at least 1 ha. which can
serve as an exclusive seclusion area and is suitable for breeding and
rearing cubs.
- Core areas shall have at least four otter refuges per 20 sq.km.; areas of
at least ΒΌ ha width can afford the otter optimum cover
WATER QUALITY
- The highest possible quality as defined under the national long term
indicative Plan (IMP) for Water 1985-1989 (IMP Water 1985-1989,appendix 2,3)
shall be aimed for with regard to the water quality of lakes and pools,
canals, ditches, bog holes and other watery areas. To the parameters used in
this IMP (such as oxygen, pH, chloride, phosphate) a norm should be added
concerning PCBs, as the latter play a crucial role in the survival and
reproduction of the otter.
- Fatty tissues of otters are not to contain more than ca. 10mg PCB per kg
fat.
- The concentration of PCB in potential otter food (eel and various other
fish) should be on average lower than 0.025 mg PCB per kg. food.
- The allowable concentration of PCB in sediment is fixed at a maximum of
0.001 mg PCB per kg sediment on average.
- The concentration of PCB in water is not to exceed 0.025 x 10-6
mg PCB per litre of water.
In the meantime the implementation has been started. In Friesland. one of the
core-areas, the government has financed a (+/- #500,000) restoration project.
Other projects will follow. In the future a re-introduction project will be set
up. depending on an improvement of water quality. This Improvement is the first
aim. An otter centre for research, breeding and education will be set up. A
central role in this field has been given to the Stichting Otterstation
Nederland (Dutch Otter Foundation).
The publication is well illustrated. It is to be hoped that the Dutch
government will succeed in the implementation of this integrated plan.
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