| Baiyangdian Lake is the largest and most typical fresh water lake in North China Plain, and it has important influences on ecological environment in North China. In the past decades, the ecological environment in Baiyangdian has changed a lot due to climate changes and human activity. Namely, Waterheads have decreased obviously, pollution is serious, and sediment accumulation becomes serious. The problem of ecological environment in Baiyangdian Lake is a problem of whole watershed involving natural, economical and social factors in upstream and downstream regions. The changes of environment in Baiyangdian not only relate to its conditions of natural, economical and social, but also refer to the water resources exploitation and the vegetation cover condition in upriver, and the changes of landscape pattern all over the watershed. Therefore, it is more practical important to study the ecological environment changes of Baiyangdian watershed as whole.With the application of RS technique, the difficulty of obtaining the information of ecological environment is solved. RS can provide the data in different distinguish in space, in time and in spectrum, and it can provide data sources coming from different time ,space and spectrum resolution, and it can also provide economy, shortcut and real-time data sources. It also can find out the changed region, quantified the change and tell the change trends. Contrast to other conventional measures, RS has a particular characteristic of speediness and precision. The technique of Geography Information System becomes mature and practical more and more, which has a strong ability of special analysis. By the technique of spatial analysis and dealing with ample original data, new data collection can be attained. So we can get the changed information of landscape element in many aspects such as quantity, structure and space position etc.By integrated and holistic thought of the status quo and changes of ecological environment, landscape ecology provides new theory and methods to successfully solve the ecological problems faced by human. The landscape elements arrange in space with different size and different shape is named as Landscape pattern, and it is not only the represent in heterogeneity, but also the result of all kinds of ecological processes at different scales. The landscape changes are the results and the represent of the action between all kinds of interior and exterior confliction, which is the transformation process from one state to another state of landscape. It is a study on the spatial and temporal changes in structure and quantity and the change trends to study the landscape change. Through analysis of the landscape changes in different periods of time, we can explore the cause and mechanism of landscape change, which accordingly can provide basis to make use of landscape in reason and to adjust the force and manner of human activity.Taking Baiyangdian watershed as object, with the data provided by RS and GIS, as well as the DEM altitude data, through machining and dealing with the information, combining the methods of statistical and landscape pattern, the ecological environment changes in Baiyangdian watershed have been analyzed from 1986 to 2000 from 3 aspects such as water resources, water and soil erosion, landscape pattern change, and have been analyzed the driving factors, the impact and the countermeasures.The results have been shown as follows: (l)The water resources is in shortage, the water resources decreased obviously, water area reduced in a great way , the water quality became better but still serious; (2)The water and soil erosion is more serious in 2000 than that in 1986. The area of the faint soil erosion increased, the area of the moderate, intense, severe and acute soil erosion increased.;The distribution of soil erosion was shown from different elevation zone as follows: the faint soil erosion is mainly distributed in low plain, and the light is mainly in high plain, the moderate, the intense and the severe are mainly in mid-mountain. Th... |
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