| Summary: | 博士 === 國立中興大學 === 水土保持學系 === 92 === The scope involved in evaluating ecological effect is very extensive; therefore, how to choose appropriate evaluation tools is a very important issue. This study is to discuss some evaluation indices that are popular and trustworthy. Through the investigation in the field, simple and meaningful indices were established in order to be the reference for evaluating watershed.
The area of Tou-bian-ken stream watershed was been the sample area for investigation. An investigation station was established at the sections that are 50 meters in length. A total of 20 investigation stations were established. Time for investigation lasted for 8 months, starting from July 1, 2003 to February 28, 2004. In the period of investigation, hydrological quality was investigated monthly. The investigation on aquatic insects and fishes was carried out every season. The Endemic Species Research Institute helped collect the sample and authenticate the species for the study. Concerning index identification, the watershed index and landscape ecological index were adopted as the comparison and analytical variables. The environment parameters were processed by aero photograph, AicView 3.X and Feagstate for AicView. According to the result of the aero photograph and practical investigation, watershed land use was divided into 7 kinds, artificial cover, woodland, aquatic land, vacant land, grassland, farmland, and golf land. To understand the influence of different dimensions and spaces, with the inquisition points, 6 kinds of scales (with 1000 m × 1000 m, 500 m × 500 m, 200 m × 200 m, 100 m ×100 m and 50m × 50m) were compared.
Through the covariance and examinations of the inquisition data, this research reaches the following conclusions:
1.The water quality of Tou-bian-ken stream is generally fit to legal standard.
2.The water quality of Tou-bian-ken stream is between excellent to good while estimating by FBI. However, the value of IBI shows a different result which reveals the water quality is between fair and very poor. The better water quality mainly lies in the upstream and the worse water quality lies in the downstream of Tou-bian-ken stream.
3.Many researches reveal land-use may affect environmental ecology, therefore the indices of landscape ecology has been selected as indicators. The research shows that the Conductivity, DO and IBI have the distinct relation with Landscape Ecology Index.
4.After the analysis of this research, it suggests that the monitor scale in physical can be made between 50m×50m and 1000m×1000m, and then the IBI scale can be made between 500m×500m.
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