摘 要
關鍵詞：外來植物、棲地類型、入侵種、墾丁國家公園、物種豐度
一、緣起
墾丁國家公園區域內，有豐富的自然生態，例如台灣僅存的低海拔原始森林－南仁山生態保護區、高位珊瑚礁自然保留區、龍坑生態保護區，以及極為稀有的香蕉灣熱帶原生海岸林等處，這些地方都是原生物種多樣性極為豐富的地方，需要我們投入極大的關注，使其不受人類或外來物種(alien species)的危害。但近年來隨著全球經濟一體化、貿易的大幅增長以及旅遊業的迅速發展，外來物種打破地理上的隔閡，有很高的機會到達自然分布範圍之外的區域，到達新的生態系。外來生物的入侵已成為國際間共同重視的問題，除了對當地經濟帶來損失外，更嚴重的是對生態環境的衝擊，造成物種瀕危甚至滅絕，造成生態系組成、結構及功能的重大改變。
二、方法及過程
本研究之目標為瞭解外來植物在墾丁國家公園陸域範圍出現之種類及其分布範圍，並分析不同棲地類型所出現之外來植物種類與頻度，建立基本資料供進行族群管理之參考依據。研究過程將調查範圍分成12個地理區域，並將棲地環境區分為15個類型，記錄各區域出現之外來植物及其地理座標位置。
三、重要發現
經實地踏勘範圍內12個區域902個觀察點，總共記錄到138種外來植物，分屬 47科115屬，其中種數最多的前三個科分別為菊科(Compositae)19種、豆科(Fabaceae)15種及禾本科(Poaceae) 12種。此12個區域中以出火-滿州，以及南仁山生態保護區等兩區域有較多的外來植物種數，分別為80及62種。在15種棲地類型中，以「道路邊」有最多的外來植物種數，達109種，其次為「廢耕地」62種，「森林步道」61種。在所調查到的138種外來植物中，出現頻度最高者為大花咸豐草，達所有調查樣點的74%，尤其在廢耕地、墓地、荒廢地、果園、竹林等5種棲地類型之出現頻度均在90%以上，分布範圍及豐量均高。此外，藉由設置124個面積各為0.5 m2的定量樣區，發現南仁山森林步道低光遮陰處原生種比例及覆蓋率會高於外來種，高光空曠地則相反，顯示遮陰環境不利外來陽性植物入侵。南仁湖濱水區的外來種李氏禾也有被原生種水生黍取代的趨勢。本區所調查到的小花蔓澤蘭、馬櫻丹、香澤蘭、刺軸含羞木、銀合歡及南美蟛蜞菊等6種，為世界自然保育聯盟2000年公佈之「世界百大入侵種」名單所列之入侵植物，其中刺軸含羞木、香澤蘭及南美蟛蜞菊數量及分布並不多，但今後仍須注意其擴散狀況。公園綠地等8種棲地類型的外來種比例至少佔有50%以上，原生種植物被排斥的情況明顯；反觀森林步道不論是空曠或林下遮陰環境的外來種尚不及25%，由此可證明空曠高光的環境有利外來種的建立，且會明顯抑制原生種植物的生存。
四、主要建議事項
外來入侵生物的風險評估、檢疫及防治工作是全球各國均極為重視的課題，身負本土動植物保育任務的國家公園管理單位對此問題重視。本計畫已踏勘墾丁國家公園各生態保護區，自然公園及主要道路，紀錄各地出現之外來歸化植物種類與位置，並設置124處量化樣區，對本區出現之外來入侵或歸化植物的組成及族群密度有初步結果，但今後人需有長期例行監測工作，了解不同年度不同地點新入侵或某物種族群量突然增加之動態變化狀況，在變成過度擴張之前即能有效控制，使墾丁國家公園本土生物能不受外來生物的嚴重威脅。
計畫類別：[植物生態]
英文摘要：Abstract
Keywords: alien species, habitat type, invasive species, Kenting National Park, species richness
Introduction
Kenting National Park has abundant nature ecological systems within its range. There exist a primitive lowland forest (i.e. Nanjenshan ecological preserve), an uplifted coral reef natural preserve, Longkung ecological preserve, and a rare tropical coastal forest (i.e. Siangjiao Bay). All these places have rich biological diversity that deserves our special attention to prevent the ecological systems from being endangered by alien species and/or human. However, as the pace of globalization in world economy and the development of international trading and traveling speeds up, alien species have high chances to penetrate the geographical barriers and spread out of the range of their natural distribution to a new ecosystem. Therefore, problems associate with invasive alien species have become common issues among the international communities. Besides bringing losses to local economy, the most serious problem of invasive alien species is the impacts to local ecosystems, such as endangering indigenous species and even causing their extinction, as well as changing the composition, structure, and function of the original ecosystems.
Methods
We investigated the species and distribution range of alien plants in Kenting National Park, and recorded how many species and calculated their frequency in various habitat types. A data base was established accordingly as a reference for management. The whole investigation area was classified into 12 geographical regions and 15 habitat types. We recorded the species and geographic coordinates of each alien species in every category.
Results
We found 138 alien plant species, belonging to 47 families and 115 genuses, at 902 inventory locations in the 12 geographical regions. The most abundant species included 19 species of Compositae, 15 species of Fabaceae, and 12 species of Poaceae. Among the 12 geographical regions, Chuhou-Manjhou and Nanjenshan ecological preserve had the highest number of alien species, 80 and 62 species respectively. Among the 15 habitat types, “roadside” had the most abundant species (109 species), followed by 62 species in “cultivation abandoned land,” and 61 species in “forest trail.” Among the 138 alien species, Bidens pilosa had the highest frequency, appearing in 74% of our inventory locations. Especially, in “cultivation abandoned land,” “cemetery,” “waste land,” “orchard,” and “bamboo plantation,” its frequency was higher than 90%. In addition, observed by our 124 quantitatuve sampling plots (0.5 m2 each), there were more indigenous species either in the amount or the coverage than alien species at low-light shaded trials while contrary at high-light wide open field. This result indicated that shaded environment was not suitable for alien shade-intolerant species. The alien species, Leersia hexandra, growing at wetland of Nanjen lake was gradually replaced by an native species, Panicum paludosum.In our investigation, Leucaena leucocephala, Lantana Camara, Mikania micrantha, Mimosa pigra, Sphagneticola trilobata, and Chromolaena odorata were listed in the “100 of the world’s worst invasive alien species” published by IUCN in 2000. Although the amount and distribution of Mimosa pigra, Sphagneticola trilobata, and Chromolaena odorata were still limited, we would monitor continuously their spreading.
辦理單位：國立屏東科技大學
計畫屬性：本處委託辦理
執行年度：98B07
計畫主持人：郭耀綸
中文關鍵字：外來植物、棲地類型、入侵種、墾丁國家公園、物種豐度
英文關鍵字：alien species, habitat type, invasive species, Kenting National Park, species richness