Abstract

Naturalized flora of Taiwan has been increasing in the past six after the first catalogue was compiled in 2002. In order to probe into the increasing pattern behind this dramatic growth of potential invaders, we compiled and evaluated newly added naturalized species in a quest for better understanding. Furthermore, naturalized species shared with neighboring regions, such as Mainland China and Japan, were estimated as well. The results revealed that two-thirds of these newly recruited species naturalized before 2002, and only 77 actually naturalized after 2002. The proportion of naturalized flora in the native species pool increased from 8% to 12%. The compositions, origins, and life forms of these potential invaders before and after 2002 were similar with slight fluctuations presented in the ranks of the dominant families. Number of species shared with neighboring regions multiplied due to the fast growth of the naturalized flora in Taiwan; nevertheless, the number might be understated due to the inaccessibility of the latest naturalized floras from neighboring regions. The doubled flora of naturalized species in the past six years implies insufficient attention to plant invasions and lag phases of invasion. The expansion of naturalized flora in Taiwan also increased the pools of naturalized species shared with neighboring areas, including Mainland China and Japan.

中文摘要

從2002年完成了臺灣第一份歸化植物名錄後至今，臺灣的歸化植物物種數量持續的增加，為了探討急劇成長的歸化物種 (潛在入侵物種) 在這段時間的增加模式，我們匯整截至2009年底所有發表與野外記錄到歸化物種以求對整體現狀有更好的理解。此外，臺灣與鄰近區域交通貿易頻繁，物種交流機會頗多，本篇也就此鄰近三地共同歸化物種進行比對。結果顯示，過去七年之間所有新增的歸化物種中，僅有77種植物為2002年後所歸化，其餘的植物皆為2002年以前就已歸化，2002年之後才正式發表。歸化植物與原生植物物種的比例由8%上升為12%。2002年前後歸化物種的組成、起源與生活型在優勢科的排名相當類似，僅有些微變化。在過去七年期間，臺灣地區的歸化植物數量成長一倍，歸化植物數量的成長也增加了臺灣與鄰近區域，包括中國大陸和日本，共有的歸化植物數量。然而這些新增加的歸化植物多半在2002年以前就有標本採集記錄，顯示外來植物歸化狀態的更新發表速度緩慢，以管理防治的角度而言，可能造成反應不及的狀況。

Keyword: Flora, naturalized species, plant invasion, Taiwan.