| The research of multi-spatial-temporal scales ecological process is the basic way which could recognize and deeply understand the ecological changes in some particular areas. Plateau lake-marsh research has long been the weak parts in the field of wetland researches. And if the analysis method of multi-spatial-temporal scales would be used in the recognition of landscape pattern change process of plateau lake-marsh, the ecosystem changing mechanism could be understanded in a multi-dimension way. Napa Wetland (Ramsar Wetlands) has the typical feature of plateau lake-marsh. So, to carry out the study of multi-spatial-temporal landscape pattern change process and to comprehend its driving mechanism would be a proper way to understand the ecological succession process of this kind of wetland.This researche proceed by using the Geographic Information System (GIS), through 4 spatial-temporal scales. Such as: (1) multi-year, small watershed spatial-temporal scale; (2) multi-year, wetland zone spatial-temporal scale; (3) seasonal, wetland zone spatial-temporal scale; (4) one time point in summer, patch and plant community spatial-temporal scale. And the main conclution are as follow:1.Napa wetland catchment has 593km2, and its main landscape type is forest. The wetland landscapes are only 6% of the whole catchment. The landscapes of the watershed have little change quantitatively from 1994 to 2006, but turely there is mutual transformation among some types. This phenomenon had shown the maintenance of an ecological balance through some destruction and protection.2.The annual precipitation decreased from 1994 to 2006. The descent also has little impact on the whole watersed, but impacts on Napa wetland significantly. (1) All wetland landscape types are fragmentary; (2) Wetland landscape changed into non-wetland landscape substantially; (3) The total wetland in the catchment lost (transform) 16.8%, mainly in Napa wetland area; (4) Transformations also appeard among the wetland landscape types for the hydrological changes in Napa wetland area. Wetland ecosystems in this area degrade severely. Specific disturbance of human activities on Napa wetland areas are the significant impact to the wetland ecosystem. Such as: the construction of reservoir in the upstream of the rivers, which inflow into the wetland; canalization of these rivers; dredging the caves which are the drain of the water from wetland to Yangzi river; upgrading the"Surrounding the wetland"road by using concrete and so on.Climate change and human activities collaboratively prompt the degradation of the wetland.3.Analyzing the seasonal landscape change of Napa wetland area by using remote sensing data in December 2008 and May 2009 (the dry season and wet season), a huge differentiation is found from the two seasonal landscapes. The wetland landscape shrinks sharply and a lot of wetland landscape change into non-wetland. This is determined by the seasonal significant variation of precipitation in the catchment.Various types of landscape change into destroyed land landscape, mainly because the unordered stocking by the villagers under the condition of seasonal climate differentiation. The destroyed land landscape has already been 15.74% of Napa wetland area, and spread over the whole area.The climat differentiation during spring and summer, and human activities in the area are the direct driving force of hydrology and landscape pattern change in Napa wetland area.4.Based on the investigation of soil and vegetation of Napa wetland area in June-August 2009, the plant community structure and species are described. Initially reveal the self-recovering model of plant community in destroyed patch. And the study also show that moderate controlling of high human interferences and environmental factors of wetland water is the indispensable way to promote the self-restoration of the degradation patches in Napa wetland.
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