應用地理資訊系統監測森林地景變遷之研究

Application of GIS in Monitoring Landscape Change

鄭祈全(Chi-Chuan Cheng) ； 許立達(Li-Ta Hsu) ； 賴玉菁(Yu-Ching Lai)

《台灣林業科學》 16卷1期 (2001/03) Pp. 1-9

https://doi.org/10.7075/TJFS.200103.0001

摘要

本研究以林試所六龜生態系經營區為試區，目的在應用地理資訊系統，結合地景結構指數及logit機率模式，探討天然及人為因素對地景結構的影響，以及地景變遷之影響因子。研究方法係應用數位航測技術製作1988及1996年之各地景類型分布圖，並應用地理資訊系統計算不同時期之地景結構指數，再以logit機率模式探討不同地點發生地景變遷之機率。地景結構指數分析結果顯示天然區隔與人為改變對森林地景結構具有明顯之影響。河川區隔會形成一些形狀較不規則的小區塊。在人為改變方面，闢建道路會使得完整的大區塊被切割為許多小區塊，而使區塊平均面積大幅變小；人工造林會增加許多異於天然林的區塊，但由於造林地一般較為規則，因此反而使區塊的平均形狀指數減小。logit機率模式分析結果顯示影響地景變遷的主要因子包括地形與邊緣效應。一般而言，低海拔、靠近天然林的人工林，較容易成為天然林。高海拔、坡度較陡及靠近道路的地方則較容易發生裸露、崩塌。遠離道路、坡度較緩及靠近天然林的裸露崩塌地則愈容易恢復為天然林。

關鍵字

地景變遷 ； 地理資訊系統 ； 監測 ； 地景指數 ； logit模式

並列摘要

This study selected the Liukuei ecosystem management area of the Taiwan Forestry Research Institute as the study area. Geographic information systems (GIS), together with landscape indices and probabilistic logit models, were used to analyze the effects of natural segregation and man-made modifications on the landscape, and also to examine the influential factors of landscape changes. Landscape maps of 1988 and 1996 were derived from aerial photographs using digital photogrammetry. GIS was used to calculate the indices of the landscape structure at different stages. Logit models were then used to examine the probabilities of landscape changes at different locations.
The results of landscape analysis indicated that both natural segregation and man-made modifications had significant effects on the landscape structure. Landscape segregated by streams formed several irregularly shaped patches. As to man-made modifications, road building divided large patches into many smaller ones, therefore reducing the average size of patches. Forestation created many heterogeneous patches on the landscape, but because plantations were more regularly shaped, the mean shape index decreased. The results of logit models showed that the major factors affecting landscape changes were topographic effects and edge effects. In general, plantations located at lower elevations and near natural forests were more likely to become natural forests. Bare lands, on the other hand, were more likely to occur at high elevations, on steep slopes, and near roads. Bare lands away from roads, on gentler slopes, and near natural forests were more easily reclaimed by natural forests.

並列關鍵字

landscape changes ； GIS ； monitoring ； landscape indices ； logit models