Use of fractral dimension and landscape index to discuss river habitant

• Main Authors: Jian-Yuan Juang, 莊健源
• Other Authors: Ray-Shyan ,Wu
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/98625989570642605284

碩士 === 國立中央大學 === 土木工程研究所 === 93 === ABSTRACT The distribution of river habitant is important to the river ecological system, and the discharge is considered to be one of the most important indices to influence that. In this study, flow velocity and water depth are selected to classify river habitant pattern. Moreover, the fractal theory and landscape ecological indices, which are calculated by FRAGSTATS, are used to investigate the properties of distributions. The Wu-Chi river is selected as the study site, and the simulated discharges are focused on 2 CMS to 400 CMS. Comparative results demonstrated that the fractal dimension is discrepancy among small patches. However, the fractal dimension achieves to a constant (1.5-1.6) as increasing areas. In this case, the values of Total (Class) Area, Mean Patch Size, Total Edge, and Patch Size Standard Deviation all are directly proportion to the river flow, and the Mean Patch Fractal Dimension is between 1.02 and 1.18, and Area-Weighted Mean Patch Fractal Dimension is between 1.10-1.24. The study found that the area of riffle is the maximum as the discharge is about 6 CMS (Q95). Moreover, the area of glide in the case of 6 CMS is also reaching the 80% of maximum total area of glide in all cases. In the average area of habitant, run is the biggest ,and pool is the smallest. In shape index, pool is the most closed to a square, but glide revealed discrepancy in a square. Pool and glide have the high values of area weighted mean patch fractal dimension which shows that the edge is more complex. The highest value of Shannon Diversity Index is 0.77 at 14CMS.