島嶼生態空間與時間尺度課題

Ecological Spatial and Temporal Scale Issues of Islands

林世強(Shyh-Chyang Lin)

《地理學報》 66期 (2012/09) Pp. 1-19

https://doi.org/10.6161/jgs.2012.66.01

摘要

島嶼生態是研究生物地理學之理論基石，亦是實踐生物保育之重要開端，尤其孤立之島嶼經常擁有多種特有生物，是地球珍貴之生態寶庫，然而隨著科技的進步，交通的便捷，島嶼持續受到人類開發破壞與外來物種入侵，使得特有性逐漸消失，不僅對島嶼產生無可回復之生態困境，全球生態系統亦漸趨均質化，生物多樣性隨之降低。長久以來，人類對島嶼之開發或保育多以大陸型思維規劃，殊不知島嶼面積愈小，生態系統敏感度愈高，在相似的生態環境中，相同開發面積下，島嶼愈小受到影響之物種數量愈高，其生態回復力可能愈低，所需之時間愈長，這現象反映了島嶼空間與時間尺度的問題，因此在島嶼上合宜的開發規模顯然是十分重要的課題，卻是一直被島嶼母國甚至自身島民所忽視。本文主要在比較：（1）空間尺度上，在不同大小的島嶼上，影響相同物種數量的開發面積分別為何；（2）時間尺度上，相同面積與位置之空居棲地（empty habitat），在不同大小之島嶼，生態回復之速率分別為何。本研究應用生物地理學「物種－面積關係」與關聯族群（metapopulation）生物遷移理論探討空間與時間尺度問題，並加以量化分析，最後以金門與臺灣為例進行比較。結果發現，相同開發面積影響留鳥物種之數量，金門為臺灣之63.9倍，在生態回復能力上，開發或災害所在位置較其規模更為重要，而規模須在島嶼面積1/100以上方可能產生明顯生態時間尺度之差異，本研究的通則性結果應可作為評估島嶼開發規模之理論依據。開發、建設、災害對不同大小之島嶼必然產生不同程度之破壞，島嶼建設規模應有空間與時間上尺度的觀念與準則，方不致引進不當之開發量體，衝擊脆弱的島嶼生態系統。

關鍵字

空間尺度 ； 時間尺度 ； 島嶼 ； 生態 ； 空居棲地

並列摘要

Island ecosystem is the origination of development of the theory of biogeography and is the cornerstone of biological conservation. The isolated islands are the sources of endemic species and precious biological hubs. Due to giant leaps of modern technology and continuous improvement of transportation, islands have been invaded by exotic species such that the endemism of islands suffered great losses. Global ecosystem is becoming homogenized and biodiversity has been therefore decreasing. For centuries, the continental-oriented development concepts have been implanted to islands without noticing the sensibility and vulnerability of islands. Same scale of developments would affect more species on small islands than on continents. Once destroyed, it would take longer time for small islands to recover. This is all about scales of space and time. The importance of identifying the proper scales of human development on the islands is obvious but is always overlooked by the central government and even the local residents. This research is to discuss: (1) On spatial scale: what are the sizes of developed area on a small island and on a large island respectively would affect same number of species? (2) On temporal scale: what are the lengths of time required for a small island and for a large island respectively, to recover the ecosystem for same size of an empty habitat? The species-area relationship was employed to study the spatial scale issues in Kinmen and Taiwan. The dynamics of metapopulation is applied to derive the mathematical expression of temporal issue for islands. We found that at the same scale of development Kinmen will affect 63.9 times more of species than those of Taiwan. From the perspective of ecosystem recovery, the scale of development or destruction must be larger than 1 of the area of an island to show distinguishable temporal discrepancy. The formula provided by this research can be a theoretical basis for assessing the future development strategy for islands. To different sizes of islands, the same scale of development or disasters must render different degrees of destruction. The concept and paradigm of spatial and temporal scales must be considered in development on islands to avoid out-of-scale impacts on their vulnerable ecosystems.

並列關鍵字

spatial scale ； temporal scale ； island ； ecology ； empty habitat