| 摘要: | 陽明山國家公園的植物群落主要受到人為開發的影響。根據前人報告緊臨 人為環境的野外地區,皆有外來種植物分布,非洲鳳仙花、大花咸豐草、四季海 棠等常見的外來種植物也到處可見。外來入侵種植物是否造成陽明山國家公園的 生態危害,必須加以追蹤調查,為經營管理之參考。目前已知在園區內有 110 種外來種(如:非洲鳳仙花、大花咸豐草、紫花藿香薊...等),但其中是否成為入 侵種?其入侵的程度如何?尚未有研究調查。
本研究選擇園區內 7 種外來種植物之大花咸豐草、巴西水竹葉、吊竹草、加拿 大蓬、非洲鳳仙花、洋落葵、紫花藿香薊為研究對象。每種植物群落設置 2~5 個樣區不等,各樣區散佈在園區內 4 條主要道路(陽金公路、百拉卡公路、菁山 路、萬溪產業道路)上,設置帶狀橫截樣區。每季節(3 個月)調查樣區一次,觀察 其 4 季優勢度的變化。觀察上述植物之入侵程度及其對景觀的影響,研究成果可 做為國家公園經營保育之依據參考。
調查結果顯示,所有監測的 7 種外來種植物中,僅巴西水竹葉第 2 季(冬季) 生長良好,且優勢度逐季增多,巴西水竹葉為本研究 7 種外來種植物中最危險的 入侵種;非洲鳳仙花在觀察組樣區內優勢度逐季降低,但在除草後的樣區和吊竹 草觀察樣區內卻有逐季增加的趨勢,且不畏寒冬,非洲鳳仙花可能為本區的入侵 種。觀察組內的非洲鳳仙花逐季遞減可能與樣區內的水鴨腳秋海棠產生相剋作用, 故此,水鴨腳秋海棠可以作為未來防治非洲鳳仙花的最佳選擇植栽。大花咸豐草、 吊竹草冬、春 2 季生長均不優勢,但春季以後又逐漸增加,但 2 者在其他地方為 入侵種,是否常年生長都如此,在本區是否持為入侵種需多年觀察。據觀察發現 洋落葵大多出現在人為開墾過的地方,受人類干擾較嚴重,外來種植物較易入侵。 洋落葵樣區內的外來種種類最多,且種類數量有逐季增加的趨勢,另一方面洋落 葵可能受到摘採以致有逐季遞減的趨勢,但在其地方已為入侵種,在本區是否持 為入侵種還需多年觀察。加拿大蓬逐季減少,為荒廢干擾地的先驅物種(Pioneer species),似乎無法和本地原生種競爭,應不是本區的入侵種。紫花藿香薊因遭 工人誤除草,調查資料不足,在本區是否持為入侵種也還需多年觀察。
除草組經除草後,大多數的樣區內的外來種植物的種類不減反增,由此可知, 進行人工除草同時可能也會帶進其他外來種植物的種子或莖葉,反而會助長更多 外來種入侵。
In recent years, Yangmingshan National Park was influenced by human development. Alien plants can be found in those areas which are near human activities. According to former records, there were 110 alien plant species, such as Bidens pilosa L.var radiata Sch.Bip. , Impatiens walleriana HooK. f. and Ageratum houstonianum Mill...etc. These alien plants can be seen everywhere in Yangmingshan National Park .Whether and how many of these species have the potential to become invasion species in the area will become one of the most severe problems of the national park.
Seven out of 110 alien plant species (Bidens pilosa L.var radiata Sch.Bip.,Tradescantia fluminensis Vell.FL.Flum,Conyza canadensis (L.) Cronq. var. canadensis,Tradescantia zebrina Hort. ex Bosse,Impatiens walleriana HooK. f.,Anredera cordifolia (Ten.) Steenis,Ageratum houstonianum Mill.) were selected to observe in this study. For each species 2-10 sampling plots were set along 4 main highways(Younjing road,Bailaka road,Jingshan road and Wanshi road) in Yangmingshan National Park. The survey was made every 3 months.
The results indicated that only the population of Tradescantia fluminensis Vell.FL.Flum increasing at the 2nd season (winter) and kept increasing the following seasons. Then it is suggested that Tradescantia fluminensis Vell.FL.Flum is the most dangerous alien plant among the 7 species observed. Impatiens walleriana HooK. f. was declining in the sampling plots but increasing in other plots. The species was also observed sturdy during cold winter, so it was considered to become an invasive plant in this area. On the other hand, Begonia formosana (Hayata) Masamune might have allelopathic effects to Impatiens walleriana HooK. f., according to the fact the former suppressed the later in the observed plots.
Bidens pilosa L.var radiata Sch.Bip. and Tradescantia zebrina Hort. ex Bosse had been considered as invasive species in other places but were not aggressive in the area. More survey is needed before arriving any conclusion of these two species. Anredera cordifolia (Ten.) Steenis was founded at lands disturbed by human activities. More alien species were found in the sample plots of the species than others. The species was also recognized as invasive species in other places, but it was declining by seasons in the area. Whether it is invasive species or not is still uncertain. Conyza canadensis (L.) Cronq. var. canadensis is a pioneer species and was declining by seasons in the sample plots. It is therefore less possible an invasive plant in the area. Ageratum houstonianum Mill. sampling plots were weeded by careless workers at the 4th season, so data is unavailable in this study plots. More studies are needed to understand the role of species in the area in the near future. Finally, it is worth to noticing that alien species increased in most weeding plots. |
