Study On Landscape Ecological Evolution And Ecosystem Health Assessment Of Liaohe Estuarine Wetland

Estuarine wetland ecosystem is located at intersection point between rivers and marine ecosystems. Because of current mixing of Runoff and tidal current, the estuarine has unique environment characteristic and the biological composition. That is high for the productive forces, rich in biodiversity, obvious salinity gradient, jamming intense and so on. At present, the main ecological problem of Liaohe estuarine is decreasing in wetland, environmental pollution, decreasing in the amount of sand brought from the river to the sea, decreasing in biodiversity. According to complexity of estuarine wetland ecosystems and importance of ecology service function, it is necessary to carry on ecosystem heath study of Liaohe estuarine. This study took 3S as the basic tool and studied the dynamic evolution tendency of Liaohe estuarine, analyzed the driving force of nature and human being. Based on the study above, the factors on press and ecological response element was identified, ecosystem health assessment model was set up. Using this model, the condition of Liaohe estuarine's ecological health is analyzed.The main content as follows:(1) dynamics analysis of Liaohe estuarine wetland landscapeThis study established the distant estuarine wetland landscape classification system, chosen unsupervised-supervised classification approach. The maps of Liaohe estuarine wetland landscape type of 1999 and 2004 were drawn using RS and GIS. The change of the wetland landscape area is analyzed. The landscape transfer matrix from 1999 to the year of 2004 was calculated. The study also analyzed the change of area of Suaeda heteroptera salina wetland. The result indicated that there is a tendency that the natural wetland is changing into artificial wetland. Especially Cultivation land expanded from 3532.68 hectare in the year of 1999 to 5267.61 hectare in the year of 2004. The area of Suaeda heteroptera salina decreased a lot due to the change of salinity, water and sediment dynamic conditions and spatial migration.(2) Analysis of Landscape Evolution driving force of Liaohe estuarineThe direct driving force of degradation of natural wetland ecosystems is water environmental factors. The natural driving force is lack of water caused weather and hydrological conditions. The artificial driving force is agricultural development, decrease of land caused by aquaculture, and pollution caused by petroleum.(3) Third, Ecosystem health asessment of Liaohe estuarine wetlandAccording to the characteristics of estuarine wetland and PSR model, the index system of ecosystem health assessment of Liaohe estuarine are established by the pressure, the environmental states of ecosystem and biological response. The catastrophic progression method is introduced into the ecosystem health assessment of the wetland ecosystem in the study. The method uses catastrophe fuzzy subordinate function which is generated by catastrophe theory combining with fuzzy mathematics and normalizing formula to calculate the scores of ecosystem health. The catastrophic progression method is used to analyze and assess the health states of Liaohe estuarine wetland ecosystem in 1996 and 2000. The result shows that, the health value of Liaohe estuarine wetland ecosystem is 0.9791 in 1996 and 0.9618 in 2000, in other words, it from heath turned to sub-heath, and the main influence factors are water resource shortage and the increasing oil pollution. It suggests that to strengthen the management of oil production, make good use of water resources of the Liaohe estuarine wetland, maintain the ecological water requirements of the wetland and promote the heath development of the ecosystem health of Liaohe estuarine wetland.