Environmental Engineering Reference
In-Depth Information
Box 22.1 The cockle controversy on the tidal fl ats of the Dutch part
of the Wadden Sea
The Wadden Sea - an estuary along the coasts of the
Netherlands, Germany and Denmark - is a wetland of
international importance from many points of view. The
tidal fl ats and the salt marshes around the sea's edges,
with extensive and soft sediment bottoms, provide a
huge amount of food for large populations of both
migratory and resident bird species. So the region has
exceptionally high biodiversity value, but this ecosys-
tem also provides multiple goods and services to
human society. Its intertidal fl ats and salt marshes, like
shallow seas of this kind in most parts of the world,
have experienced human exploitation for more than
5000 years. Initially, exploitation of shellfi sh from the
Wadden Sea consisted of small-scale fi shing and gath-
ering by hand. With the advent of motorized power
over the past century, however, and the use of large
nets and dredges, human exploitation now heavily
infl uences natural processes (Bakker & Piersma 2006).
This has resulted, since the 1980s, in an ongoing con-
fl ict between fi shermen, who were until then permitted
to freely exploit the common cockle (
Ceratostigma
edule
) and the blue mussel (
Mytilus edulis
), and various
nongovernmental organizations fi ghting for nature
conservation. The conservation lobby was supported
by university-based ecologists and colleagues from
the ABC science group (Figure 22.3) who had per-
formed research in the area for many years and had
assembled long-term data sets. In view of this confl ict
of interest, the Dutch Ministry of Agriculture, Nature
and Food Quality was confronted with a dilemma, as
it was legally designated to represent all stakeholders.
The Ministry initiated an ecological evaluation study in
the early1990s, which resulted in a fi nal report only 15
years later. Swart and van Andel (2008) analysed the
15-year long interactions among the various parties,
from which we draw the following summary.
The situation in 1980 was taken as a reference
model for the evaluation of changes since then. The
study group, called EVA (for evaluation), consisted of
supposedly 'independent' ecology researchers from a
consortium of semigovernmental institutes for applied
research, but not including the aforementioned
university-based researchers, as they were not con-
sidered independent, associated as they were with the
anti-fi shermen lobby. The latter academic group
increasingly disagreed with the interpretation of results
published by the EVA study group. As a result, in addi-
tion to conservation and commercial interests, ecology
itself became part of the controversy. For example, the
EVA study group focused its research efforts on
changes in biodiversity, as measured in particular by
the decline of bird populations, which conceivably
could result from natural cycles and fl uctuations. Other
researchers, outside this group, perceived what they
considered to be irreversible disturbances of the eco-
system, as refl ected, they argued, in changes in the
composition of soilborne fauna after dredging.
The fi nal, still informal, reports of the ministerial
study group became available in 2003. One of the hot
topics was that a popular version of the fi nal report,
meant to be read and cited by the public media,
implied that the steep decline of populations of bird
species might have been due to environmental
changes, rather than to the exploitation of their food
by fi shermen. At that time the ecological research
centre of the University of Groningen, drawn by the
scientifi c interest of the problem, organized a sympo-
sium and invited representatives of each group to a
public discussion of their results. Next, it transpired
that the ministerial study group had an internal con-
straint in their contract, which meant that they were
not allowed to speak in public about their preliminary
reports as long as an Audit Committee of three
renowned and independent scientists had not agreed
on the scientifi c quality of their reports, including the
interpretation and evaluation of the results. The Steer-
ing Committee, composed of all the stakeholders,
insisted on this point. As a result, even though the
results from the evaluation study had already been
made public, as preliminary reports, the members of
the EVA group could not participate in the public dis-
cussion. There was no choice but to postpone the
symposium until a few months later. By then, all the
scientists participating in the symposium agreed on
the conclusion that the shellfi sh exploitation was the
cause of the damage of the soil ecosystem of the
Dutch Wadden Sea. However, it remained unclear
whether the damage was irreversible, depending on
the time required for recovery and on the criteria for a
reference system.
Lessons learned from this project, as well as from
the follow-up, are given in the main text.
