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Dutch title: Verspreiding en dynamiek van dieren in een estuariene omgeving
Reference no: OND1290751
Period: January 2001 till December 2005
Thesaurus terms: Distribution; Macrobenthos; Population dynamics
Geographical term: ANE, Netherlands, Westerschelde [Marine Regions]
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- Koninklijk Nederlands Instituut voor Onderzoek der Zee; NIOZ Yerseke, more, secretariat
This project addresses the questions related to the dynamics of macrobenthic animal populations in the estuarine landscape. In the first phase, it will focus on the description and modelling of spatial distribution of macrobenthic populations at different scales, and on how to relate these to the physical characteristics of the landscape. In a later phase, detailed studies related to dispersion, recruitment and its consequences for population dynamics will be tackled. OBJECTIVES:
· To describe and statistically model the spatial distribution of macrobenthic animal species in an estuarine landscape.
· To scale up from local process knowledge to the estuarine scale.
· To compare predictive models across different estuaries.
· To understand the processes, which could affect spatial heterogeneity of assemblages.
· To use the information gained in descriptive studies as a basis for deterministic modelling of benthic-pelagic exchange in estuarine models.
Spatial distribution models for macrobenthos have been established at the scale of the estuary for Westerschelde, Oosterschelde and a New Zealand estuary. For the latter comparison, a description in terms of functional groups has been made. Failure of extrapolation from one estuary to another have been analysed, but it has proven difficult to find system-wide characteristics needed in the models to make them applicable across systems. Analysis of the variance structure of Westerschelde macrobenthos has shown the importance of small-scale patchiness, and has suggested new approaches, including experimental ones, to tackle the problem.
Small-scale distributions will be analysed statistically to disentangle the relative importance of spatial autocorrelation and trend related to fluctuations in the external environment. Spatial scales in these studies will range from 10 cm to 50 m. Experimental studies in the field will investigate the importance of local hydrodynamics for settlement and recruitment success of bivalves. Experiments will be conducted to reveal the importance of (patchy) algal wreck settlement as a factor contributing to the overall structure and composition of the macrobenthic assemblage. Manipulative experiments will be done to understand the role of algal wrack in determining heterogeneous distribution of animals at small spatial scale. Dead seaweeds can patchily distribute on intertidal flats. They can contribute to change the distribution and the fate of nutrients in the sediment and, as a consequence, they can affect species composition of macrofaunal assemblages, where they lay, compared to bare patches.