- 期刊
- OpenAccess
臺灣半乾旱區域與潛在疏林植群之探討
Examination of Semi-arid Regions and Potential Savanna Vegetation in Taiwan
摘要
氣候對植群之類型與分布具有決定性的影響，但臺灣之半乾旱區域的範圍及其潛在自然植群仍有待探討。本研究以地理資訊系統計算各種可表示乾旱狀態的生態氣候指標並展示其圖層，結果表明臺灣半乾旱區域在氣溫最高、冬半年降水最少之西南部低地，及氣溫較高、年降水量最少之西部近海一帶，其中，西部近海一帶曾被認為具有疏林植群。本研究將疏林定義為分布於熱帶及亞熱帶之氣候形塑的極相植群，氣候分析結果表明臺灣半乾旱區域之缺水逆境並不嚴重，再配合現生殘存植群之觀察，發現臺灣有形相為疏林的現生局部性植群，但其潛在自然植群應為參雜有乾旱落葉之闊葉樹種的森林，並不存在較大面積之潛在的氣候型極相疏林。
並列摘要
Climate is the main determinant of natural vegetation types and their distributions. Yet, the range and potential vegetation of semi-arid regions in Taiwan have not been extensively explored. In this paper, various ecoclimatic indices related to drought and their spatial layers were calculated and mapped using a geographical information system. The results illustrate that semi-arid regions in Taiwan include: (1) southwestern lowland with the highest temperature as well as the lowest winter half-year precipitation; and (2) an area on the west coast with a higher annual temperature as well as the lowest annual precipitation. Some researchers believe that the latter area possesses savanna vegetation. Savannas are closely associated with seasonal drought, and they may be defined by climatic climax vegetation in tropical and subtropical areas. Based on the ecoclimatic analyses as well as the surviving vegetation in Taiwan, we inferred that the potential natural vegetations of these 2 semi-arid regions were not savanna but forest with some drought-deciduous trees. In conclusion, the physiognomic type of grassland dotted with trees may occur in small areas at present, but Taiwan lacks climate-shaped savanna climax vegetation.