| Studying the health of watershed ecosystem is of great significance for the awareness on the watershed ecosystem health, the integrated development and watershed management and the sustainable development. Jinchuanhe River Basin, which has an important ecosystem value, now faces the ecological security and regional coordinated development issues. The ecosystem health dynamic synthesis appraisal may for further promulgate the wetland ecosystem healthy mechanism, expounded the health protects and restores mechanism. It can provide new foundation data and scientific basis based on wetland management and protection for the management goal. It can guarantee sustainable development of the Jinchuanhe River Basin ecosystem.Taking the Jinchuanhe River Basin as the study object, basing on ecosystem health theory and combining the ecosystem structure and function, this paper designs ecosystem health estimate index system of Jinchuanhe River Basin, established the watershed ecosystems information database by the support of RS and G1S technology, discusses the influence of human activities by taking the natural conditions limiting factors-health instructions factors-human activities affect factors evaluation model as the conceptual frame and evaluates its health status. The main work and conclusions are as follows:1 This paper designed the ecosystem health estimate index system of Jinchuanhe River Basin based on the natural conditions limiting factors-health instructions factors-human activities affect factors evaluation model. The results showed that the assessment index system, weight system, assessment model and index level standards put forward by this paper were practical and realistic, and they were also reasonable and scientific. The reasons were: (1) On the foundation of the works of pre-human, combined with the facts of the forest ecosystem in the Jinchuanhe River Basin, consulted the related research results in and out of country, the intact assessment index system of ecosystem health was put forward from the point of views of environmental background, forest ecosystem and social economic; (2)On the foundation of extensive consultation to lots of specialists, combined with the theory of analytic hierarchy process, through endowing with weight value on each indicator of each level, there reasonable weight system was put forward; (3) the scientific assessment model and assessment index level standards of ecosystem health were established.2 Base on RS&GIS technology, ecosystem information data of Jinchuanhe River Basin are obtained, ecosystem information database of this area are established. The raster database includes DEM, NPP, vegetation index, et al. The vector database includes the boundary of study area, centers of villages and towns, rural residential area, landuse, soil erosion, et al. Attribute database includes landscape pattern indexes, population, GDP data, et al. The calculation of NPP is based on the source code and algorithm related to the study of ground surface parameters remote sensing inversion method in the doctoral dissertation of Tang Shihao, and using VC++6.0 as the platform, a data interpolation of different factors and a utility for calculating NPP are developed.3 Using ecosystem information database, this paper evaluated the situation of ecosystem health of Jinchuan River Basin in 2006, analyzed the spatial pattern and typical township for the basin-wide ecosystem health. The results of the analysis are as follows: (1)the threshold of Jinchuan River Basin ecosystem health is distributed between 1.48 and 7.98. The region that is relatively good accounted for 7.0%, 23.3% relatively general, 31.3% relatively poor, 38.4% very poor, and no relatively excellent region. In addition to score of 2.75 and 2.96 that appears higher frequency, other values are more evenly distributed. The average score is 4.42, and the overall situation is worse. (2)From the runoff area of the upper reaches to the dissipation area of the middle reaches and then to the runoff lost area of the lower reaches, scores are basically a ladder descending. In the mountain runoff of the upper reaches, the conditions are good for natural resources which include mainly woodland, high grass cover, low population density, less human interference. The system has greater flexibility and the situation of the ecosystem health is relatively good. Restricted by natural resources, the oasis of the dissipation area of the middle reaches includes mainly dry land with a higher population density. The oasis marginal land degrades obviously by human activities. The current system is still stable, playing the basic ecological functions of oasis, and can maintain a sustainable development. Desert area which mainly includes bare land, Gobi, sand and artificial oasis is also water loss area. Bare lands, deserts, sand areas are greatly restricted by the conditions of natural resources. The structure of land use is single, the flexibility of the system is very low, and the situation of the ecosystem health is very poor. Artificial oasis was obviously interfered by human activities, the system's structure is irrational with an appearance of ecological exception and poor ecosystem health. (3) As the typical representative of mountain, mountain - oasis, oasis, oasis - desert, desert area, this paper made a comparative analysis among township of Huangcheng, Xinchengzi, Hongshanyao, Dongzhai, Hongshagang and found their ecosystem health are gradually deteriorated. Shuangwan on the artificial oasis of desert area was badly interfered by human activities, although it had higher productivity, but the flexibility of the system is small, almost with the resumption of the poor state of ecosystem health.4 This study proves: it is feasible that assessment of ecosystem health is carried out by RS and GIS based on the scientific indicators system and the reasonable method of synthesizing those indicators. The result of assessment can sufficiently offer spatial characteristic of watershed ecosystem health.
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