I ()
2 ELA WAT: Goals and Conceptual Framework
of emergent properties at the level of the ecosystem is doubted by a number of
authors (Sommer 1996; Wiegleb & Broring 1996), and the interpretation of
"emergent property" also varies among authors (Muller et al. 1997). This debate
became apparent during an international workshop organized by ELA W A T on
conceptual aspects of ecosystems (Dittmann et al. 1996). For ELA W AT, the
workshop discussions enabled to extend the scope beyond the single stability
property addressed by the project title. Thus, ELA W A T turned into a more general
search for possible emergent properties of the system investigated.
A distinction must be drawn between "collective" and "emergent" properties
(Wiegleb & Broring 1996). Collective properties are the sum of properties of a
system, e.g. the total biomass in a definite area equaling the sum of the biomass of
all the organisms in that area. However, the spatial and temporal distributions or
variations in biomass cannot be calculated as a sum over all organisms, as population dynamics, interactions between populations and the impact of disturbances
come in for this. Emergent properties are best described by the famous sentence
"the whole is more than the sum of its parts". This may be the case for many ecosystems, e.g. forests, coral reefs or savannahs, but is it also true for the Wadden
Sea? Is this ecosystem a system at all - or is it a more or less loose collection of
subsystems (e.g. populations)?
This question is by no means limited to academic relevance, as answering it
would have far-reaching methodological consequences: if there were no emergent
properties at the level of the entire system, it would be sufficient to investigate
subsystems independently, e.g. the decline of mussel beds in the East Frisian
Wadden Sea since the 1980s (Zens et al. 1997). However, if there are emergent
properties, then the decline of mussel beds cannot be considered detached from the
entire system.
Aim of the synthesis
The task for the ELA W AT synthesis was to combine the results of specific system
components derived from the sub-projects and thus to deduce possible stability
properties of the Wadden Sea (Chap. 9). To do so, the results of the various investigations of all the disciplines involved had to be summarized and evaluated.
Thus the synthesis achieves an overview of the study area and the processes affecting temporal and spatial patterns as well as the regeneration after disturbances
(Chaps. 3, 5, 6, 7 and 8). Statistical methods to assess change and, in turn, stability
properties are described in Chap. 4. The evaluation of stability properties is given
in Chap. 9. Finally, ELAWAT also critically analysed the approach used
(Chap. 10) and developed recommendations for future research and the realization
of interdisciplinary projects in the Wadden Sea (Chap. II). Further recommendations address approaches for the conservation of the Wadden Sea (Chap. 12).
2 ELA WAT: Goals and Conceptual Framework
of emergent properties at the level of the ecosystem is doubted by a number of
authors (Sommer 1996; Wiegleb & Broring 1996), and the interpretation of
"emergent property" also varies among authors (Muller et al. 1997). This debate
became apparent during an international workshop organized by ELA W A T on
conceptual aspects of ecosystems (Dittmann et al. 1996). For ELA W AT, the
workshop discussions enabled to extend the scope beyond the single stability
property addressed by the project title. Thus, ELA W A T turned into a more general
search for possible emergent properties of the system investigated.
A distinction must be drawn between "collective" and "emergent" properties
(Wiegleb & Broring 1996). Collective properties are the sum of properties of a
system, e.g. the total biomass in a definite area equaling the sum of the biomass of
all the organisms in that area. However, the spatial and temporal distributions or
variations in biomass cannot be calculated as a sum over all organisms, as population dynamics, interactions between populations and the impact of disturbances
come in for this. Emergent properties are best described by the famous sentence
"the whole is more than the sum of its parts". This may be the case for many ecosystems, e.g. forests, coral reefs or savannahs, but is it also true for the Wadden
Sea? Is this ecosystem a system at all - or is it a more or less loose collection of
subsystems (e.g. populations)?
This question is by no means limited to academic relevance, as answering it
would have far-reaching methodological consequences: if there were no emergent
properties at the level of the entire system, it would be sufficient to investigate
subsystems independently, e.g. the decline of mussel beds in the East Frisian
Wadden Sea since the 1980s (Zens et al. 1997). However, if there are emergent
properties, then the decline of mussel beds cannot be considered detached from the
entire system.
Aim of the synthesis
The task for the ELA W AT synthesis was to combine the results of specific system
components derived from the sub-projects and thus to deduce possible stability
properties of the Wadden Sea (Chap. 9). To do so, the results of the various investigations of all the disciplines involved had to be summarized and evaluated.
Thus the synthesis achieves an overview of the study area and the processes affecting temporal and spatial patterns as well as the regeneration after disturbances
(Chaps. 3, 5, 6, 7 and 8). Statistical methods to assess change and, in turn, stability
properties are described in Chap. 4. The evaluation of stability properties is given
in Chap. 9. Finally, ELAWAT also critically analysed the approach used
(Chap. 10) and developed recommendations for future research and the realization
of interdisciplinary projects in the Wadden Sea (Chap. II). Further recommendations address approaches for the conservation of the Wadden Sea (Chap. 12).