A guide for planners and managers - IUCN

Box I-1. Ecosystem Conservation: Lake lchkeul in Tunisia
PART I
The Roles of Protected Areas
Lake lchkeul in Tunisia is an example of a protected area where ecosystem processes
are maintained. Lake lchkeul was declared a National Park by the Tunisian government
and also nominated as a World Heritage Site, a Wetland of International Importance
(under the so-called Ramsar Convention) and a Biosphere Reserve (under the United
Nations Man and the Biosphere Reserve Programme). In the early 1980s it was the only
area in the world with three international categories. This reflected the richness of its
biota, its ecological diversity, its regional importance, and the value of the processes that
sustain it.
Lake lchkeul is considered to have the most important wetlands (marshlands) in
the Mediterranean region. Hundreds of thousands of migratory birds rely on its marshes
as a seasonal habitat, making this a crucial site in the international conservation of these
species, which are of high economic value at both the north and the south extremes of
their migrations.
The water balance of Lake lchkeul is determined by the alternation of summer
evaporation (lowering the water level and causing an influx of salt water) and winter
inundation (raising the water level and causing dilution of the lake). In winter, 250 to
400 million cu. m of freshwater flow into the lake from five main sources. The flooded
marshes of the lake then give shelter to migratory birds flying over the Mediterranean
to spend the winter in North Africa. Toward the end of spring, as the water drops below
sea level, seawater flows into the lake. Between 10 and 30 million m 3 of saltwater flow
into lchkeul annually through the Tinja Canal to compensate for summer evaporation,
and the lake’s salinity increases tenfold. The ecosystem depends on these annual cycles.
The marshes, birds, and fishes are all adapted to these processes in the site’s complex
hydrology.
Source: Baccar, 1982.
External impacts on coastal ecosystems are widespread: industrial and agricultural
pollution, siltation from eroded uplands; filling to provide sites for industry, housing,
recreation, airports, and farmland; dredging to create, deepen, and improve harbors;
quarrying; and the excessive cutting of mangroves for fuel. As the commercially
valuable fisheries for fish, crustaceans, and molluscs become more fully exploited,
the effects of habitat destruction and pollution will become more evident, particularly
on those species depending on coastal wetlands and shallows or on wetlands for
nutrients or for spawning grounds and nurture areas (Figure I-9). Correction of these
problems can be addressed by integrated systems, such as Coastal Zone Management
(CZM), which are mainly intended to control shore based impacts.
A system of protected areas that includes examples of representative, unique,
and critical habitats, as well as species-rich habitats, along with the processes that
link them into the complex marine-coastal ecosystem, provides the maximum
guarantee of biodiversity conservation and the continuity of native stock available to
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