台灣西南部泥岩分布區裸地成因之探討

Factors Affecting Bare Land Formation at The Mudstone-distributed Area in Southwestern Taiwan

林昭遠(Chao-Yuan Lin) ； 王美欣(Mei-Hsin Wang)

《中華水土保持學報》 30卷1期 (1999/03) Pp. 13-23

https://doi.org/10.29417/JCSWC.199903_30(1).0002

摘要

台灣西南部泥岩的裸露面積正逐年擴展增加，裸露泥岩地區之植生復育工作已刻不容緩。本研究係以深坑子溪與二仁溪主流匯流處以東之集水區爲主要研究對象，篩選泥岩地區植生復育之影響因子，運用遙感探測與地理資訊系統技術，建立各因子屬性資料庫，再應用多變量統計分析，探討泥岩地區裸露之主因。由逐步迴歸分析結果顯示，所篩選之地形與土壤因子對集水區之植生現況皆有顯著影響。判別分析結果顯示，裸露地與果園作物區可由地形與土壤因子正確判識，而林地則無法由地形與土壤因子判別，若只討論坡度大於30％的坡地，則裸露地的判別率可提高至67.8％。由地形及土壤因子所判釋之裸露地與植被現況比較，可用來估算研究區植生復育因難等級；若將研究區之裸露地依地形與土壤特性予以分類，可歸納成：A.較高海拔－徒坡－東南向－淺層土壤－坋質壤土；B.較低海拔－緩坡－南向－淺層土壤－坋土；C.中海拔－陡坡－南向－淺層土壤－坋土等三類，其中以B類裸露地所佔面積最大（78％），可知本研究區裸露地之成因主要是人爲墾耕及土壤結構不良所致。

關鍵字

泥岩 ； 多變量分析 ； 植生復育 ； 地理資訊系統

並列摘要

There is an urgent need to restore the bare lands at the mudstone areas of Taiwan. The purpose of this study is to examine the affecting factors for vegetation in the mudstone-distributed watershed, which has the outlet located at the joint of San-ken-chi River and Erlan River. Discriminant analysis shows forest land in the watershed can not be directly recognized accurately from the topographic and soil factors, which affect the delineation of bare and tillage lands. The interpretation rate for the bare land in the watershed can be increased to 67.8% by limiting the study area to portions with slope greater than 30%. Comparing the actual vegetation status with the vegetation map derived from discriminant analysis, the difficult areas for revegetation can be estimated. According to the topography and soil analysis, the bare lands in the study area can be classified as: Group A with the higher elevations, extremely steep slopes, southeast aspect, extremely shallow soil depth, and loamy silty soil texture; Group B with lower elevations, gentle slopes, south aspect, shallow soil depth, and silty soil texture; Group C with medium elevations, steep slopes, southwest aspect, shallow soil depth, and silty soil texture. Because group B comprises 78% of the total bare lands in the watershed, cultivation, fine soil texture, and shallow soil depth are the major factors that contributed to the bare lands in this watershed.

並列關鍵字

mudstone ； multivariate analysis ； revegetation ； Geographic Information Systems (GIS)