石門水庫集水區植群生態之研究

Abstract

石門水庫集水區為臺灣面積最大之水庫集水區，總面積約763.4 km2，其範圍廣闊，涵蓋部份插天山自然保留區、棲蘭野生動物重要棲息環境及雪霸國家公園，植物資源豐富，海拔約在225 ~ 3,514 m，屬亞熱帶至冷溫帶之潮濕氣候。本研究目的於進行植群生態調查，並整合於研究區內不同的植群調查個案樣區資料，總計共189區。據調查分析之結果，於研究區範圍內共紀錄之維管束植物種類共計有149科476屬1,006種，其中含有蕨類植物208種、裸子植物16種及被子植物762種；此外，蕨類商數值為6.51，高於臺灣之蕨類商數值3.97，顯示本研究區較為潮濕。 將本研究區內植群以189個樣區之五項環境因子進行相關性分析，顯示海拔高度為主要影響因子；利用矩陣群團分析，將184個森林植群樣區區分為22個林型：1. 紅檜林型；2. 臺灣肖楠林型；3. 臺灣二葉松林型；4. 臺灣黃杉林型；5. 毽子櫟林型；6-1. 錐果櫟亞林型；6-2. 錐果櫟－臺灣山毛櫸亞林型；7. 卡氏櫧林型；8. 木荷林型；9.長葉木薑子林型；10. 日本楨楠林型； 11. 臺灣山香圓林型；12. 相思樹林型；13. 臺灣冷杉林型；14. 臺灣鐵杉林型；15. 森氏櫟林型；16. 臺灣扁柏林型；17. 白匏子林型；18. 臺灣五葉松林型；19. 三斗石櫟－香楠林型；20. 臺灣櫸林型；21. 臺灣胡桃林型；22. 烏皮九芎林型。將5個草本植物社會樣區區分2個草本植物社會：1. 玉山箭竹草本植物社會；2. 高山芒草本植物社會。本區植群均勻度指數多在0.7以上，顯示區內植物種類豐富，屬於演替較後期之階段，且隨海拔升高則歧異度降低之趨勢。 另外本研究區內之31種稀有植物，分布及其生育環境進行調查與評估，推測可能遭受之威脅。

Shihmen Reservoir watershed is the biggest one of Taiwan and the total area is ca. 763.4 km2. It covers part of Chatienshan Nature Reserve, Chilan Major Wildlife Habitats and Shei-Pa National Park. The watershed ranges from 225 m to 3,514 m at altitude. It is in subtropics to cold-temperate. After integrating the plot-data from different survey cases in this area, it was set altogether 189 plots. The Ptph-Q is 6.51, more than it in whole Taiwan area (3.97). It suggested that our research area is more humid. The altitude was revealed as the major factor affected the vegetation. According to the investigating result, there were 144 families, 442 genera, 954 species of vascular plants recorded in this study area. The vegetation classification was estimated by Matrix Cluster Analysis (MCA). 22 forest types and 2 herb association were sorted: 1. Chamaecyparis formosensis type; 2. Calocedrus macrolepis var. formosana type; 3. Pinus taiwanensis type; 4. Pseudotsuga wilsoniana type; 5. Cyclobalanopsis sessilifolia type; 6-1. Cyclobalanopsis longinux subtype; 6-2. Cyclobalanopsis longinux－Fagus hayatae subtype; 7. Castanopsis cuspidata var. carlesii type; 8. Schima superba type; 9. Litsea acuminata type; 10. Machilus japonica type; 11. Turpinia formosana type; 12. Acacia confusa type; 13. Abies kawakamii type; 14. Tsuga chinensis var. formosana type; 15. Cyclobalanopsis morii type; 16. Chamaecyperis obtusa var. formosana type; 17. Mallotus paniculatus type; 18. Pinus morrisonicola type; 19. Pasania hancei var. ternaticupula－Machilus zuihoensis type; 20. Zelkova serrata type; 21. Juglans cathayensis type; 22. Styrax formosana type; 1. Yushania niitakayamensis association; 2. Miscanthus transmorrisonensis association. The eveness index of most vegetation in the area was above 0.7. There were plentiful plant species. The vegetation was in the later stage in succession. And the higher altitude, the less divergence. Moreover, the study investigated the distribution of rare plants and their habit environment for evaluating the threats they might suffer.