The Formation Processes And Environmental Degradations Of Lagoonal Wetlands Along Shandong Peninsula: A Case Study Of Chaoyanggang Lagoon

Lagoon is one of the most important types of coastal wetlands, which is separated from open sea by sand spits, sandbars or barriers. It is also an important type of ecosystem with great values in terms of natural resource, tourism, environment and scientific research. Because of their smaller area and shallower water, lagoonal wetlands along Chinese coast are more sensitive and fragile to external environment loads than those large barrier bar-lagoon wetlands (such as those in North America), and they are favorite places for studying wetland formation, evolution and degradation.There are up to 60 lagoonal wetlands along Shandong Peninsula, they can be classificated into four types according to hydrologic characteristics: seawater lagoon, brackish lagoon, freshwater lagoon and drying lagoon. The total length of the lagoonal coastline in Shandong Peninsula is 580.4km, up to 28.7% of the coastline from Hutouya to Lanshantou. Lagoonal wetland possess very abundant resources and instinct ecosystems, which are under the threat of degradation by natural forces, such as global changes, and human's inappropriate development activities. The degradation and loss of lagoonal wetlands have resulted in eco-environment problem and become an obstacle to regional economic progress. The study on lagoonal wetland's formation, evolution, causes of wetland environmental degradation and their effect on eco-environment are very significant for lagoonal wetland resources protection.Located at the northeastern Shandong Peninsula, Chaoyanggang lagoon is one of those suffering from human forcing, and seriously experiencing degradation and loss of wetlands along Shandong Peninsula coast. A multi-principle field investigation was conducted in 2002, the collected data and historical information were used to study theecological environment of Chaoyanggang lagoon. Comprehensive core sample analyses were carried out back to the laboratory, including grain size analysis with Mastersizer2000 Laser grain size analyzer, spore-pollen and microfossils analysis of 27 samples, 14C dating of 2 samples. This information was used to study the sedimentary environment, formation and evolution of the lagoon. With principles of Landscape Ecology, the landscape pattern changes in the latest several decades were studied, as well as the human's activities impact on landscape changes. The origin of this lagoonal wetland degradation was studied, and the level of the wetland degradation and loss was assessed. Based on the degradation and loss of the wetland, eco-environmental effects were analyzed and countermeasures were suggested for wetland protection and regional sustainable development.Chaoyanggang, surrounded by low hills, is a closed shallow water lagoon, connected to the open sea only through a narrow inlet. It is about 1300 hm2 in area and an average water depth less than 1 .0m. The center of the lagoon is wide shallow tidal flat, comprised by fine sands, and mud component increase outward, and the edge is salt marsh, mainly dominated with phragmites. Limited by hydrology, salinity and soil character, the wetland habitat structure is very simple, and only few vegetation communities can be found. Self-adjusting capability of this lagoon is weak and the ecosystem is very instable, vulnerable to outer disturbances.Most lagoonal wetlands along Shandong Peninsula were formed since 6000-4000 aB.R. According to core information, at 5000~4000a B.P., this area was warm and humid, sporopollen assemblages were dominated by Quercus -Pinus- Artemisia-Polypodiaceae - Gramineae, freshwater Ostracoda was also found in the core, indicating a brackish lagoon-marsh coastal sedimentary environment. Between 4000 and 1500 aB.R, the sporopollen assemblages were dominated by Quercus - Pinus - Artemisia -Chenopodiaceae - Gramineae - Hystrichosphera, Hystrichosphera, Mullusca, such as Ruditapes philippinarum, Macoma incongrua, Batillaria cumingi and Batillariamultiformis were found too, indicating a sedimentary environment submerged by tidal water frequently, and the clima...