A guide for planners and managers - IUCN

PART II
Protected Areas for Lagoons and Estuaries
is a shift from an algae- based photosynthetic production to a detritus-based production
according to season (Nordlie and Kelso, 1975). Yet in Malaysia phytoplankton
productivity never contributes much to the estuary relative to the huge inputs from
mangroves.
Without too much trouble the various compartments of the food chain can be
identified. Knowledge of the following elements will be useful:
– Photosynthetic, (a) producers (phytoplankton, rooted submerged aquatic plants,
and attached algae), (b) consumers, (c) detritivores
– The detrital food chain, (a) sources (mangroves, salt marshes, and other wetland
and terrestrial sources), (b) transport to and through the estuary, and (c) the
resulting food chain or web
– Overlaps between the two food chains
– Seasonal and diurnal patterns (noting that photosynthesis stops at night)
– Correlations with major physical and chemical features
2.9 Design Principles
It is worth repeating that the estuary hydrological regime and water quality
characteristics determine the basin’s ecosystem and hence its biodiversity and value
for fisheries and wildlife. Salinity gradients determine the distribution of plants,
animals, and whole communities in estuaries, so activities outside estuaries that
alter the water balance must be carefully managed. Consequently, maintaining water
cycles and water quality are an important part of estuary management. As an estuary’s
watershed (or catchment) may cover many hundreds of square kilometers, the
effective design and management of its protected areas can be a difficult task and one
the MPA manager cannot accomplish alone.
Not all estuaries/lagoons and wetlands habitats within them are equally valuable
for all activities. Establishing protected areas in these environments should follow
surveys classifying particular habitats according to different values and appropriate
uses. An MPA or several MPAs for the basin can then be chosen that are most suited
to management objectives, with priority to those that suit both economic objectives
and resource conservation objectives.
Management should extend over the largest area practicable (Figure II-24). This
may be done through multiple use management, protecting the most critical areas
strictly, and confining different uses to specific zones. Large estuaries should be
managed as multiple use areas, optimally through combined CZM and MPA designation
(Clark, 1998).
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