雪山山脈臺灣冷杉林 （Abies kawakamii(Hayayta) Ito） 地被植群多樣性

Understory vegetation diversity at Abies kawakamii (Hayata) Ito forest in Mt. Shei

臺灣冷杉（Abies kawakamii （Hayata） Ito）是臺灣特有之冰河孑遺針葉樹種，為森林界限樹種組成之一。本研究針對雪山山脈臺灣冷杉林地被植物組成多樣性、地被植物與環境因子相關分析和物種多樣性探討，以期瞭解臺灣亞高山生態系臺灣冷杉林型地被環境對於臺灣冷杉之相關性。本研究設置39個樣區（10 m ×25 m），調查計得維管束植物50科、99屬、145種（含種以下分類群）植物，其中為臺灣特有種62種，特有種比例約42.8%。分析生活型譜以半地中植物77種最多，依序是挺空植物、地表植物、地中植物、一年生植物。依據群團分析及降趨對應分析結果，臺灣冷杉林下地被植群型可分為5型：1. 臺灣冷杉－－臺灣鬼督郵型；2. 臺灣鬼督郵－－玉山耳蕨型；3. 玉山當歸－－臺灣繡線菊型；4. 玉山箭竹－－臺灣鬼督郵型；5. 玉山箭竹－－玉山杜鵑型。加入環境因子及多樣性指數進行典型對應分析結果，雪山山脈臺灣冷杉林型地被植物多樣性指數與全天光空域呈負相關，顯示臺灣冷杉林下地被植物組成與樣區受到地形遮蔽後光照範圍所影響。此外，由於林下玉山箭竹具有緻密的地下莖及密度極高的莖稈，是影響臺灣冷杉林下地被物種多樣性及臺灣冷杉天然更新的重要因素。 Abies kawakamii (Hayata) Ito (Taiwan fir) is an endemic of glacial relic species. It is one of the species which composed the forest line. They are usually gregarious pure forest type at the subalpine ecology in Taiwan, and then became the important one of subalpine vegetation. The object of this study is to investigate the understory vegetation of Taiwan fir forest and classify, discussing the correlation with the environmental factors at the subalpine in Taiwan. Totally we set up 39 plots (10 m × 25 m), in the floristic surveys of vascular plant, 145 species (including under taxa species) belonging to 99 genera in 50 families. We found 62 species are endemic in Taiwan (endemic ratio is 42.8%). According the plant life form spectrum, there are 77 understory species classified into hemicryptophytes. Analyses the results of cluster and detrended correspondence analysis (DCA), the understory vegetation can be classified into 5 types: (1)Abies kawakamii-Ainsliaea latifolia type; (2)Ainsliaea latifolia-Polystichum morii type; (3)Angelica morrisonicola-Spiraea formosana type; (4)Yushania niitakayamensis-Ainsliaea latifolia type; (5)Yushania niitakayamensis-Rhododendron pseudochrysanthum type. Adding the environmental factors and diversity indexes to do CCA analysis, the diversity indexes are negative correlation with whole light sky (WLS). It means the species composition of understory vegetation in Abies forest would effected by solar radiation based on the topography shelter. Furthermore, because of the dense rhizomeand extremely high stem of Yushania niitakayamensis is an important role to affect the understory diversity and regeneration of Abies kawakwmii.