Study on Landscape Change in Nanjenshan Ecological Reserve Area
| Autor: | Chen Cheng-Hua, 陳正華 |
|---|---|
| Rok vydání: | 2001 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 89 Nanjenshan Ecological Reserve Area (NERA) is one of the five sites for long-term ecological research (LTER) in Taiwan. The objectives of the LTER program are to monitor the phenomena and processes of ecosystems in a longer time scale, and to understand the dynamic of the ecosystem. The purpose of this study is to explore natural and human impact on landscape ecosystem in landscape change process. Land use maps of three representative years (1976, 1989, and 1997), with a scale of 1:5000 derived from interpreting aerial photographs, were used as research materials. Using the Geographic Information System (GIS), 21 land use categories were digitalized. Landscape structure and dynamics analyses were quantified by a series of indices including Shannon''s diversity, maximum diversity, evenness index, and mean patch fractal dimension index. T-value as a rule was used to test the difference of landscape in different periods and disturbances. The result of the study shows that landscape change of NERA is quite significant. Diversity and evenness indices are decreasing. Two opposing forces that have shaped NERA landscape change are natural disturbance (northeastern monsoon) and human disturbances (deforestation, road and edge effects). The disturbance of northeastern monsoon can increase landscape diversity and fractal dimension indices, but it can decrease transition ratio of landscape element. In disturbed area with northeastern monsoon, transition ratio of dense-shrub is 4.60%. The major change of man-made forest landscape, which occupies 31.46% of woodland, is crown closure to be promoted. The interaction of road can increase transition ratio of landscape element. Transition ratio between different periods is 54.06%, and leads to decrease landscape stability. After NERA has been established and human disturbances are mitigated, landscape change in the edge area is lessened and core area is broadened, namely the edge effects reduce. The steadiest landscape of whole NERA is core area, there are the lowest disturbance and edge effect, and the change in landscape between periods is almost insignificant. However, in the interaction of landscape structure, human and natural disturbances do increase landscape diversity, evenness and fractal dimension indices, and heighten landscape complexity. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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