Tunisian man-made wetlands as alternative habitats for waterbirds and their role for conservation

摘要

The distribution of wintering waterbirds within some Tunisian artificial wetlands (AW) was studied during the 20042007 stable wintering periods. The survey has regarded 88 wetlands including 27 large dams, 25 hill dams and 36 hill lakes. We identified 42,840 individuals representing seven orders, eleven families, 37 species and six functional groups: dabbling ducks, grazing waterfowl, fish-eaters, deep-water foragers, shoreline foragers and waders. The population structure analysis showed an absolute dominance of the deep-water foragers with approximately 82% of observed waterbirds. The total abundance survey showed a fluctuation of population sizes and richness, from thousands to few individuals and from 1 to 25 species, respectively. Analysis results showed that the species distribution is governed by several ecological factors and there was a significant correlation between species abundance and richness and some habitat variables such as area, depth, age, plant cover and hunting disturbance. Investigated AW revealed a significant carrying capacity and refuge serving for the conservation of numerous wintering and endangered waterbird species of high nature conservation value, the White-headed Duck Oxyura leucocephala that has been observed with relatively high numbers representing more than 40% of the assessed TunisianAlgerian population.