12.4 Outlook
285
the organisms in the Wadden Sea is essential for the resilience of their populations to disturbances (see Chap. 9).
• Diversity of habitats: many benthic organisms in the Wadden Sea need multiple settlement sites before they reach a favourable habitat (Beukema 1993;
Reise 1985; Gunther 1991). If one of these habitats is missing, e.g. the mudflat
as settlement sites of young Arenicola marina, the entire population of this species in the Wadden Sea is affected. For the successful settlement and an undisturbed dispersal, a coherent and natural variety of habitats is required. These
conditions could be provided best by the protection of entire tidal basins in the
Wadden Sea (Reise 1993a, Reise et al. 1998).
The results from ELA W A T showed that many species and other parameters in the
Wadden Sea could react with resilience to brief, small-scale disturbances which
are part of the natural dynamic of this ecosystem (Chap. 9). Important mechanisms
for this behaviour are e.g. the mobility of many species, a functional diversity of
the micro-organisms and a phenotypic plasticity of some species. Disturbances
caused by human activities can modify boundary conditions and thus prohibit
resilient reactions. Wolff (pers. comm.) argues that either the continuous human
impact on the Wadden Sea or the slow speed of recovery processes prevent a return of this ecosystem to the conservation phase sensu Holling (1986) (see
Chap. 9). Compared with an original Wadden Sea, many habitats and species have
been lost over the past decades. For the most recent case, the decline of mudflats,
a compensation by other muddy habitats (fringes of tidal channels, biodeposit
layers in mussel beds) is not possible, because of different biotic and abiotic conditions (Flemming & Delafontaine 1994, Krbncke 1996). The loss of sedimentation areas following coastal engineering has been postulated by Flemming & Nyandwi (J 994) and Reise (1998). To counteract this development, a partial opening
of summer polders should be discussed with all stakeholders on the coast of Lower
Saxony.
It is not necessary for a protection of processes to give more weight to certain
processes than to others. Thus, we do not need to nominate a "hitlist" of "relevant"
processes based on the results of ELA W A T. For the coastal zone management of
the Wadden Sea, we recommend to give priority to the processes and components
mentioned above to ensure an ecosystem where natural processes can proceed in
an undisturbed way, as stated in the Esbjerg Declaration 1991. Altogether, the
protection of processes could be much better realized if entire tidal basins fall
under one protection category, instead of the present patchwork of protection
zones.
12.4
Outlook
ELA W AT was expected to contribute ideas to the management of the Wadden Sea
and our results could support the need for a natural development and protection of
processes. But as a basic research project, ELA W AT cannot advise on human use
or strategies to achieve sustainable development in this ecosystem. Most of the
Wadden Sea in Germany is both National Park and biosphere reserve, posing a
285
the organisms in the Wadden Sea is essential for the resilience of their populations to disturbances (see Chap. 9).
• Diversity of habitats: many benthic organisms in the Wadden Sea need multiple settlement sites before they reach a favourable habitat (Beukema 1993;
Reise 1985; Gunther 1991). If one of these habitats is missing, e.g. the mudflat
as settlement sites of young Arenicola marina, the entire population of this species in the Wadden Sea is affected. For the successful settlement and an undisturbed dispersal, a coherent and natural variety of habitats is required. These
conditions could be provided best by the protection of entire tidal basins in the
Wadden Sea (Reise 1993a, Reise et al. 1998).
The results from ELA W A T showed that many species and other parameters in the
Wadden Sea could react with resilience to brief, small-scale disturbances which
are part of the natural dynamic of this ecosystem (Chap. 9). Important mechanisms
for this behaviour are e.g. the mobility of many species, a functional diversity of
the micro-organisms and a phenotypic plasticity of some species. Disturbances
caused by human activities can modify boundary conditions and thus prohibit
resilient reactions. Wolff (pers. comm.) argues that either the continuous human
impact on the Wadden Sea or the slow speed of recovery processes prevent a return of this ecosystem to the conservation phase sensu Holling (1986) (see
Chap. 9). Compared with an original Wadden Sea, many habitats and species have
been lost over the past decades. For the most recent case, the decline of mudflats,
a compensation by other muddy habitats (fringes of tidal channels, biodeposit
layers in mussel beds) is not possible, because of different biotic and abiotic conditions (Flemming & Delafontaine 1994, Krbncke 1996). The loss of sedimentation areas following coastal engineering has been postulated by Flemming & Nyandwi (J 994) and Reise (1998). To counteract this development, a partial opening
of summer polders should be discussed with all stakeholders on the coast of Lower
Saxony.
It is not necessary for a protection of processes to give more weight to certain
processes than to others. Thus, we do not need to nominate a "hitlist" of "relevant"
processes based on the results of ELA W A T. For the coastal zone management of
the Wadden Sea, we recommend to give priority to the processes and components
mentioned above to ensure an ecosystem where natural processes can proceed in
an undisturbed way, as stated in the Esbjerg Declaration 1991. Altogether, the
protection of processes could be much better realized if entire tidal basins fall
under one protection category, instead of the present patchwork of protection
zones.
12.4
Outlook
ELA W AT was expected to contribute ideas to the management of the Wadden Sea
and our results could support the need for a natural development and protection of
processes. But as a basic research project, ELA W AT cannot advise on human use
or strategies to achieve sustainable development in this ecosystem. Most of the
Wadden Sea in Germany is both National Park and biosphere reserve, posing a