Using Artificial Community Of Phragmites Australis To Ecologically Restore The Land/Inland Water Ecotone In Subtropical Area

Land/Inland Water Ecotones(LWEs) refer to the border zones between terrestrial and aquatic ecosystems. LWEs have many functions, such as bank erosion control, improving water quality, beautifying environment, supplying special habitats, and so on. However, LWEs are vulnerable ecological area and very sensitive to environmental changes. So the restoration of LWEs remains a difficult task in the global environment industry.This study takes Xikeng Reservoir of Shenzhen city in the subtropical area as a case to explore the theory and technology of restoring damaged LWEs. A 50 meters long of experimental bank was constructed by restoration ecology theory and ecological engineering methods. During this process, we analyzed and evaluated the effects of the restoration in the experimental area, mainly from the following aspects: the growth and reproduction of introduced plant species Phragmites australis under drought stress and waterlogging stress, vegetation succession, animal visiting, and corrosion extent of the bank. Results showed that :1. The damaged LWEs could be restored by using plant box designed in this study based on restoration ecology theory and ecological engineering methods. This study will be a fine example for LWEs restoration in other areas.2. Plant community in the experimental area was under drought or waterlogging. During the experience period,even the whole growing season was absolutely under drought or waterlogging, Phragmites australis could keep reproducing and growing. It is highly tolerant and to drought or waterlogging. It is a wonderful plant for LWEs restoration. Phragmites australis could reproduce and grow normally under low-level waterlogging(submerged 0-/3) and medium level waterlogging(submerged 1/3-2/3), whereas high level waterlogging (submerged 2/3-) and drought could restrict the reproduction and growth of Phragmites australis.3. The Phragmites australis community was rehabilitated successfully and the structure of community was optimized in the experimental zone in almost three years. Till 2008, species had increased to 10, which covered 91% in area. Biodiversity increased too.4. The quality of habitat are improved in experimental area. It can provide breeding place for fish and dragonfly, etc. Density of fish, density and settling time of dragonfly appear in: experimental aera > contrast area.5. The plant community structure in the experimentalarea has been to a healthy ecosystem with higher vegetational cover. During May, 2006 to the October, 2008,the eroded soil in contrasting area was 4795 t/km2?a, Which is 0t/km3?a in the experimental area. The bank slope is safeguarded effectively after the rebuilding and restoration. Furthermore, the cost of the plant box is RMB 82.8 per square meter, which is lower than the cost of the bank by concrete and stone(RMB 120 per square meter). At the same time, the former can produce some the additional ecological functions and esthetics values.