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Summary |
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Full report (pdf) (Viewing the pdf files requires Arcrobat
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Dutch translation
of the QSR 99
A Dutch translation of the
Report is available at InterWad.
A printed copy of the Dutch
version is available
at the RIKZ Haren. |
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German translation
of QSR 99 Chapter 6
A German
translation of Chapter 6 "Assessment and Recommendations"
has been prepared by the Germand Federal Ministry of Environment,
Nature Conservation and Nuclear Safety and can be downloaded
as pdf file (230 KB). |
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Order printed copy (10
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SUMMARY Wadden Sea QSR 1999
In December 1999 a
new Wadden Sea Quality Status Report left the printer. The main
conclusions, related to the implementation of the common trilateral
Targets, are given.
INTRODUCTION
The last Wadden Sea Quality
Status Report of the 1990s was finalized shortly before the end
of the decade. After the "Development Report" of 1991
and the "1993 Quality Status Report" it is the third
time that an integrated assessment report of the Wadden Sea has
been published.
Some 60 persons have contributed to the QSR, many on a voluntary
basis. The analysis of the chemical data was, like for the previous
two reports, done by the Dutch Institute for Coastal and Marine
Management (RIKZ). The work was coordinated by the Quality Status
Report Group, a subgroup of the Trilateral Monitoring and Assessment
Group (TMAG).
With its 260 pages the book
is more comprehensive than its predecessors. It contains chapters
on protection and management, human use, climate, marine chemistry
and biology.
For the first time dunes, beaches, estuaries and the offshore
zone are addressed. This is because, at the Leeuwarden Conference
in 1994, these habitats had become part of the trilateral cooperation.
The chapter on Marine Chemistry covers the period 1985-1996,
which is a sufficiently long period to allow for statistical
analyses of trends. Also in Chapter 5, Biology, several long
time series are assessed, amongst others for chlorophyll and
macrozoobenthos. Also, in this chapter, for the first time data
from the Demersal Young Fish Survey (DYFS) are presented.
The overall assessment part
of the QSR has been structured according to the common Targets
as adopted at the Leeuwarden Conference and evaluates progress
in the implementation of the Targets. Also, methodological considerations
about how Targets can be evaluated are included.
The conclusions and recommendations
of the QSR will be discussed in the course of this year and the
results of this dicussion will be submitted to the Wadden Sea
Senior Officials in the framework of the preparation of the 9th
Governmental Wadden Sea Conference (Denmark, November 2001).
Some of the main conclusions are given below.
QUALITY OF WATER, SEDIMENT AND BIOTA
NUTRIENTS AND EUTROPHICATION
The Target of "A Wadden Sea which can be regarded as a eutrophication
non-problem area" relates to the agreements within the Ospar
framework about dividing the Ospar area into non-eutrophication
problem areas, potential eutrophication problem areas and eutrophication
problem areas. For the Wadden Sea, criteria to differentiate
between these three categories have been elaborated in a trilateral
project, the results of which will become available this spring
(see also Van Beusekom, this issue) could not yet be used for
the evaluation of the Target.
Phosphate levels in water have decreased significantly in most
parts of the Wadden Sea whereas this is not the case for nitrate.
Also chlorophyll levels showed no decrease. As reasons for the
remaining high primary production several factors are mentioned
namely increased input of organic matter from the adjacent North
Sea, delivery of phosphorus from the sediment and the fact that
nitrogen is the main limiting factor for primary production.
The N to P ratio has increased in some areas, most notably in
the western Wadden Sea. The duration of Phaeocystis blooms in
the Marsdiep has, however, not decreased. The blooming intensity
of Phaeocystis at Norderney, expressed as number of colonies
per liter, decreased in the period 1993-1996, coinciding with
decreasing dissolved N and P concentrations. The proliferation
of potentially toxic algal species has not increased in the first
half of the 1990s.
A long-term evaluation of macrozoobenthos data from five locations
in the Wadden Sea made clear that macrozoobenthos is, to a certain
extent, regulated by winter severity and that, with the exception
of Balgzand, no clear cause-effect relationships exists with
primary productivity or eutrophic state. The observed increase
since 1988 in macrozoobenthos biomass in the coastal zone off
Norderney was related to mild meteorological conditions in winter.
NATURAL MICROPOLLUTANTS
For natural micropollutants the Target "natural background
concentrations" has been agreed upon.
Concentrations of most heavy metals in sediment are approaching
background levels. An exception is mercury which still is three
to ten times higher than background. All sediment metal concentrations
are below ecotoxicological assessment criteria (EAC) ranges as
developed by Ospar. Also metal concentrations in blue mussel
have decreased but are still, with the exception of zinc, above
background levels.
Polycylic Aromatic Hydrocarbons (PAHs) concentrations in sediment
are within the range of background levels and below EAC
XENOBIOTIC SUBSTANCES
The Target for xenobiotic or man-made substances is that levels
should be such as resulting from zero discharge. Data for PCBs,
HCB, HCH and TBT have been evaluated. Concentrations of PCBs
in sediment and HCB and HCH in bird eggs show a steady decrease.
TBT, however, is a reason for concern. Levels in sediment of
up to 1000 times EAC have been recorded.
THE TIDAL AREA
Two categories of Targets
apply to the Tidal Area, namely Targets for the geomorphology
and Targets for the Biology. It is concluded that, as a result
of human interference, most notably fixed coastal constructions,
but also fisheries, dredging sand extraction and gas extraction,
the ability of the system to compensate for sea level rise may
have decreased. Also, the settling conditions for fine-grained
sediment may have become worse.The Target of an increased area
and a more natural development of natural mussel beds, eelgrass
meadows and Sabellaria reefs has not been reached. The decline
in number and size of mature beds of the blue mussel and seagrass
meadows has continued in this decade.
The decrease of these structure-building communities may also
influence hydrology and sedimentology in the Tidal Area. Because
our present understanding of the hydrological and geomorphological
processes and their interactions, together with the role of mussel
beds and seagrass meadows, is still insufficient, there is an
urgent need for further research on the interactions between
sediment composition, disturbances and subsequent biotic developments.
SALT MARSHES
The Targets for salt marshes
are to increase the area of natural salt marshes and improve
the natural vegetation structure of artificial salt marshes.
Much has been achieved in the past ten years with regard to improving
the natural situation in salt marshes by the reduction, or phasing
out, of grazing and artificial drainage. The outbanking of summer
polders has, so far, only been applied in the Dutch Wadden Sea.
This practice not only increases the salt marsh area, but could
also be favorable for creating new fresh-salt transitions and
for maintaining the sediment balance of the Tidal Area.
A precise comparison of the situation regarding the natural situation
of salt marshes in the different parts of the Wadden Sea is presently
not possible because of a lack of actual data and of common criteria.
The last trilateral survey of salt marshes was carried out in
1986. It is therefore recommended to initiate a new survey on
the basis of harmonized criteria.
The erosion of salt marshes
does not yet seem to have increased as a result of sea level
rise, bottom subsidence and higher wave energy.
BEACHES AND DUNES
For beaches and dunes it
is the Target to increase the natural dynamic situation and the
presence of a complete natural vegetation succession. The status
of the dunes in the Wadden Sea Area has been, and still is, determined
by conservative measures of coastal protection which preserve
directly (planting of marram grass) or indirectly (building of
sand dikes, groynes etc.) the zoning patterns. As a result, there
is a relatively high percentage of intermediate stages and an
underrepresentation of primary and oldest stages.
There are considerable differences in the percentage of primary
dune area between the different barrier islands but, generally,
it may be concluded that there is a good potential for the implementation
of the Targets.
ESTUARIES
With regard to estuaries
it has been agreed that valuable parts will be protected and
that the river banks will be restored in their natural states,
as far as this is possible.
Only five estuaries have remained in the Wadden Sea area (Ems,
Weser, Elbe, Godel, Varde Å). As a consequence, natural
transitions of fresh and salt water hardly exist in the Wadden
Sea Area.
The Varde Å and Godel are estuaries which have retained
their natural character.
The Ems, Weser and Elbe and
their tributaries have been modified considerably by diking and
deepening. The anthropogenic impact on these estuaries is still
increasing as a result of the current deepening of the Elbe and
Weser and the construction of a barrage in the Ems.
It is concluded that these estuaries are moving farther away
from the Targets.
THE OFFSHORE ZONE
For the Offshore Zone the
Target is to increase the natural morphology. It is concluded
that both from physical and biological perspectives, the Offshore
Zone and Tidal Area are closely connected.
It therefore is recommended that the management and protection
of these two habitats be closely tuned. The evaluation of impacts
in the Offshore Zone should also take into consideration effects
in the Tidal Area and vice versa.
BIRDS
For birds favorable conditions
with regard to food availability, breeding, moulting and roosting
have been set as Targets. It is concluded that the populations
of many bird species in the Wadden Sea have increased in the
last decades and few have declined. The main factors for the
increase of breeding birds are an improved protection during
the breeding season, a substantial reduction in egg collection
and reduced levels of pollutants.
Kentish plover and little
tern populations have decreased which is due to a lack of sufficient
undisturbed breeding habitats at beaches and in primary dune
areas. It is, amongst others, recommended to increase the proportion
of beach habitats available for birds and to reserve the most
preferred habitats, such as primary dunes, beach barriers, sand
spits and shell banks, for birds.
MAMMALS
For the marine mammals common
seal, grey seal and harbour porpoise the Target is to have viable
stocks and a natural reproduction capacity.
The population size of the common seal is much higher than before
the epidemic in 1988 and the population may be regarded as viable.
The grey seal population in the Wadden Sea is relatively small.
The observed growth is also due to immigration from outside the
area. There is insufficient knowledge to judge whether the population
is viable. Also about the harbour porpoise too little is known
about the population dynamics to be able to evaluate the target. |
