Basic Concepts and Management Issues of Rivers - River Dynamics and Integrated River Management - page 26

development of hydric soils—soils that are saturated, flooded, or ponded long enough during the growing
season to develop anaerobic conditions in the upper part (National Academy of Sciences, 1995).
Fig. 1.20 Wetlands defined in Ramsar Wetland Convention
Wetland functions include fish and wildlife habitat, water storage, sediment trapping, flood damage
reduction, water quality improvement/pollution control, and ground water recharge. Wetlands have long
been recognized as highly productive habitats for threatened and endangered fish and wildlife species.
Wetlands provide habitat for 60 to 70 percent of the animal species federally listed in the U.S. as threatened
or endangered (Lohoefner, 1997).
Mangroves —Mangroves are a diverse group of plants, which have been able to exploit a habitat of
inter tidal zones. There are 55 species of mangroves in 10 families. The largest mangrove forests are in
Bangladesh and Nile Delta. China has mangrove forests in Guangxi and Hainan Provinces and the Pearl
River delta. The last few decades have seen a rapid growth of interest in the mangrove ecosystems. This
is due, on the one hand, to the perception that mangrove ecosystems are valuable resources, and, on the
other hand, due to vested economic interests. Mangroves are remarkable tropical plants that grow with
their roots partly or wholly submerged in seawater. They make tidal forests in the tropical and subtropical
zones, and these rainforests, referred to as "mangal," straddle the abrupt interphase between sea and land.
They are economically important because they are a source of timber. The bark of mangroves are materials
for production of red dye, therefore, they are named red tree in Chinese. Mangroves also protect
shorelines from wave damage and provide a nursery for many commercial fish. To the scientist they offer
an interesting opportunity to study organisms that adapt to both marine and terrestrial environments