The Use of Stochastic Models as a Management Tool in a Shallow Temperate Estuary of South Europe (Mondego, Portugal). Chapter 5.
Data
2011
Autores
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Robert S. Pirog (Ed)
Resumo
A long-term monitoring program has been carried out since the early 1990's in the
Mondego estuary, on Portugal's west coast, which is presently under heavy human
pressure. Likewise other coastal systems worldwide, the Mondego estuary has been
exhibiting clear evidence of eutrophication as a result of nutrient loading from several
industries and agricultural run-off, mainly from rice fields. In this shallow warmtemperate
estuary, a significant macroalgal proliferation was observed, which represented
a clear sign of nutrient enrichment. As a consequence of the eutrophication process, the
seagrass meadows (mainly Zostera noltii) almost disappeared, reducing in extent from 15
ha in the early 1980's to 0.02 ha in the mid-1990's. The increase ofmacroalgal biomass
and shift of other primary producers resulting from eutrophication had profound effects on estuarine trophic chain. In 1998, some mitigation measures were implemented aiming
the recover of the Zostera noltii meadows. The hydraulic regime was improved and
nutrient loadings from upstream agricultural areas were minimised due to better
management and appropriate sluice handling.
Management of coastal and estuarine systems has an increasing need for tools
capable to relate environmental variables and system parameters with external factors
that affect those systems. In this scope, the need for rapid, standardized and cost-saving
assessment methodologies is crucial. This study examined the applicability of stochastic
models in predicting the interactions between conceptually isolated key-components,
such as primary producers ( macroalgae and seagrass ), some relevant benthic
macroinvertebrates, wading birds and changes in local physicochemical conditions.
Overall, the simulation results are encouraging since they seem to demonstrate the
models reliability in capturing the trophic dynamics of the studied estuary, by predicting
the behavioural pattern for the most part of the components selected under very complex
and variable environmental scenarios, with a focus on the Zostera noltii meadows
recovery after the implementation of important management measures.
The ultimate objective is to encourage the discussion about the development and use
of stochastic models from which management strategies can be designed to restore
coastal ecosystems ftmctions and biological communities that have been damaged by
anthropogenic disturbances.
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Stochastic Models , Management Tool , Estuary , South Europe , Mondego , Portugal
Citação
Silva-Santos P. et al, 2011