面對退化地之抉擇：被動的自生演替恢復vs.主動的人為生態復育

An optimal approach to degraded land: passively natural recovery by spontaneous succession vs. actively ecological restoration by human intervention

為解決日益嚴重的生態系退化問題，復育生態學在近20年來蓬勃發展。為改善退化之土地，我們面臨抉擇應採取被動消極地放任植群自生演替，或主動積極地以人為力量介入進行生態復育？本文闡述及圖示生態系退化與恢復的歷程、說明影響植物更新之因素、分析決定退化地之恢復對策（自生演替vs. 人工復育）時應考量的因素，建議人工生態復育措施必須是基於科學基礎，再小心謹慎地實施，當退化地之退化程度低、面積小、周邊植群近而完整、復原彈性佳，則不須人工復育，即能藉由自生演替在短期內回復植群，亦即可放任自然恢復（由老天爺／土地公種樹）的適用情況；然而當退化地之退化程度高、面積大、周邊植群遠而破碎、復原彈性差，則自生演替將十分緩慢或停滯，甚至發生持續性退化（如退化地土壤持續被沖蝕），則有必要採行積極的人工生態復育。實務上，自生演替與人工復育是可相輔相成的，因為探究自生演替原理有助於瞭解人工復育應依循之生態法則，而適宜的人工復育措施則有助於自生演替之結構與功能的加速恢復，通常整合應用自生演替原理與人工復育措施才是退化地恢復之最有效的途徑；有些退化地僅需人力最小介入的復育方式，例如分析環境特性後增加鄉土樹種種子來源即能更快地回復豐富的森林；但若未充分瞭解環境與植物特性即貿然種植不當樹種，經常是浪費資源且成效不佳，形同推舟於陸，勞而無功。 For remedying the gradually serious ecosystem degradation, restoration ecology had been developed energetically over the last two decades. The decision must be made, passively spontaneous succession vs. actively ecological restoration, to recover the degraded land. This paper interpreted and illustrated the processes of ecological degradation and recovery, the factors affecting plant regeneration, and the major considerations for adopting appropriate strategy to repair the degraded lands. We suggested that ecological restoration must be based on the scientific knowledge, and then be manipulated carefully. When the degraded site is small area, with slight degradation and higher resilience, and surrounded by natural vegetation, the passively spontaneous succession is sufficient without human intervention. When the degraded site is extensive, with heavy degradation and lower resilience, and absence of remnant vegetation, the actively ecological restoration is necessary. We suggested that put natural succession theory in artificial restoration practice, they complement and supplement each other. Consequently, a mixed passiveactive repair manipulation should be the most effective approach. For some degraded sites the minimum intervention approach is a considerable option. For example, adding indigenous seeds appropriate to local environment could facilitate the recovery of rich forest. When one rushed plants the incongruous trees without careful investigation and planning would often be doomed to failure and be in vain.