The Study On The Landscape Pattern Changes And Its Eco-environmental Effects On The Typical Coastal Zone Of Bohai Bay

Coastal zone is one of the most abundant and most sensitive ecosystems. Serious degradation of habitat has been brought by the human's exploitation to coastal zone. Therefore, in order to prevent the ecosystem deterioration, it is necessary to assess the degradation of the coastal zone with proper methods.Tianjin coastal zone in 1954, 1970, 1981, 1990 of Bohai bay with total area 1882.11 km~2 is selected to research as a typical coastal zone. The landscape data are acquired from the 1:50 000 geographical maps of Tianjin coastal zone. By using the theory of landscape ecology and the GIS techniques, this paper emphasizes to assess the variational patterns of high quality landscape units and to study primarily the succedent eco-environmental effects in Tianjin coastal zone. In addition, the ecosystem service value of Tianjin coastal zone is evaluated with eco-economic methods in the paper. Some conclusions from studies are drawn as follows:(1)The decrease of high quality landscapes area is the principal important phenomenon in land use of Tianjin coastal zone. The areas of the four high quality landscapes are 1385.59 km~2, 638.84 km~2, 732.37 km~2, 816.25 km~2 respectively in the four various years. In total, the area has decreased by 569.34 km~2 from 1954 to 1990. The main influencing factor is the sea enclosure and urban expanding.(2)From 1954 to 1990, the diversity index increases from 2.30 to 2.60, the dominance index decreases from 0.59 to 0.45, and the fragmentation index of high quality landscapes increases from 0.33 to 0.42. These changes mostly ascribe to urban land expanding and culture pond enlargement. As a result, these patches obstruct the nutrient material cycle and energy flow among species, which show the course of habitat degradation.(3)The negative environmental effects are brought when the landscape pattern change from high quality to low quality. And the low quality landscape such as, culture pond, resident place, building land and oil field can produce pollutant. Their emission quantity increase by 470.72 ton(COD), 7.71×10~7 ton(municipal sewage), 1.07×10~8 ton(industrial sewage) and 15.85 ton(oil). These pollutants finally deteriorate the ecosystem of the coastal zone.(4)The total service values of Tianjin coastal zone are 13.748 billion, 9.938 billion, 9.500 billion and 9.457 billion respectively in the four various years, and indicates the degradation of the coastal zone ecosystem. However, there is no obvious change between 1970 and 1990, which results to the establishment of the coast defence road, which restrains the sea enclosure and shoal exploiture. The results show that ecosystem degradation hold back the development of Tianjin coastal economics. So, in order to realize the sustainable development, we must properly protect the ecosystem and environment.