臺灣藤本植物之分佈與植群型相關性之研究

Abstract

台灣原生藤本植物分佈範圍涵蓋極廣，並隨著海拔高度增加而遞減，且出現南北分化之現象。本研究係針對台灣原生藤本植物之水準分佈及垂直分佈之情形，探討藤本植物在植群間海拔梯度上之變化及南北分化之情形，並由藤本植物攀爬的型式和宿主間的特性，探討藤本植物和宿主間的關係。 本研究選擇中部橫貫公路沿線，具有海拔差異70個10×10m2樣區；另選擇具有緯度差異的福山、蓮華池、扇平30個10×10m2樣區，共計100個10×10m2樣區。除以Blaun-Blanquet學派的植群方式，進行林木調查；並進行藤本植物株數及其與宿主關係之調查。 結果顯示隨著海拔高度增加，藤本植物的種類和數量均有變化，並和植群型之分化符合。各植群型重要值（IVI值）較高的藤本植物分別為：（一）海拔3000公尺：阿里山忍冬（二）海拔2500公尺：刺果衛矛、大枝掛繡球、台灣長春藤（三）海拔2000公尺：飛龍掌血、阿里山五味子、珍珠蓮（四）海拔1500公尺：阿里山五味子、飛龍掌血、三葉五加（五）海拔1000公尺：菊花木、猿尾藤、玉葉金花（六）海拔500公尺：猿尾藤、盤龍木、酸藤。 綜合海拔分佈，科種的組成，以中海拔（1000-2000m）較高，13-15科17-18種，高海拔最低，只有一科一種；株數以低海拔最高160株／0.1公頃。種的豐富度以猿尾藤、地錦、菊花木、刺果衛矛、台灣長春藤、阿里山忍冬較高，IVI值都超過100％。種的分佈，雖有橫跨相鄰海拔的現象，但仍有特定在某一海拔豐富度較高的顯著差異。 在水準分佈方面同一海拔高度，重要值（IVI值）較高的藤本植物北部地區是長果藤、玉葉金花、大葉廣東山葡萄；中部地區是白葉瓜馥木、血藤、石月；南部地區是菊花木、酸藤、猿尾藤、血藤、長果藤、藤相思樹。 綜合緯度分佈，科種的數量都很高（17-18科19-25種）；種和株數的豐富度以蓮華池最高（25種167株／0.1公頃）；種的豐富度以大葉廣東山葡萄最高，IVI值超過100％。種的分佈在不同緯度有明顯差異，全部51種有34種只在北中南任一緯度樣區分佈，占緯度樣區藤本植物67％；有9種在相鄰緯度分佈；有6種在南北樣區分佈；只有2種同時出現在不同緯度樣區。顯見藤本植物在不同緯度，科種的豐富度差異小，種的分佈差異大，具有南北差異分化的現象。 在七種攀爬型中，海拔樣區以主莖纏繞型（tw）最高，占46.3％，不定根型次之占28.3％，依靠型（sc）則未發現，攀爬型譜類似FM型譜；緯度樣區以不定根型（ar）最高，占43.8％，主莖纏繞型（tw）次之占32.6％，依靠型（sc）最低，占0.04％，攀爬型譜類似FH型譜。 藤本植物與宿主接觸直徑，最大為43.75cm（不定根型），較小為卷鬚型（te）、葉卷繞型（ts）、側枝卷繞型（bt），平均2.3cm；而不定根型（ar）、鉤刺型（hk）的宿主直徑最大，平均39.2cm。藤本植物能否攀升，是依其所接觸直徑大小而定，不是以宿主直徑來決定。也就是植物社會中，直徑小的枝條越多則利於藤本植物攀爬。 藤本植物與宿主接觸高度，以不定根型（ar）最低0.2m，以主莖纏繞型（tw）最高6.5m，這個高度和宿主最低分枝高度無顯著相關，意即不是樹木分枝低就容易被某一型藤植物攀爬。 藤本植物與宿主間的距離無顯著差異，藤本植物不因攀爬型不同，而選擇較近距離的當宿主。緯度樣區樹木被藤本植物攀爬率達43.26％，意即1.3藤／3樹。

The native vines in Taiwan spread out over a vast area, reduction in abundance along with increase in altitudinal gradient, and present differentiation between northern and southern parts. According to climbers distributed vertically and horizontally, the diversities of vines over an altitudinal gradient in vegetation zones and the situation of differentiation between northern and southern parts were surveyed in this study. In the sight of the different types of climbing mode that the vines attached to their host trees, the relationships between vines and host trees were studied. The present study, 70 sample plots of 10×10 m2 having variations in elevation were established along the East-West Cross-Island Highway. In addition to these above, 30 sample plots of 10×10 m2 which had variations in latitude were selected in Fu-Shan, Lien-Hua-Chih and San-Pin; a total of 100 sample plots of 10×10 m2 were recorded. Aside from making investigations of woodland by using the method of Blaun-Blanquet school, I made studies of vine abundance and the correlation between vines and host trees. The results revealed that there were alterations in vine variety and abundance as increase in altitudinal gradient. The results were also in accord with the differentiation of vegetation types. Vines with higher important value index (IVI) in different vegetation types respectively were as follows: (1) at altitudes of 3000 m: exemplified by Lonicera acuminata; (2) at altitudes of 2500 m: exemplified by Euonymus echinatus; (3) at altitudes of 2000 m: exemplified by Toddalia asiatica, Schizandra arisanensis, and Ficus sarmentosa var. noipponica; (4) at altitudes of 1500 m: exemplified by Schizandra arisanensis, Toddalia asiatica and Acanthopanax trifoliatus; (5) at altitudes of 1000 m: exemplified by Bauhinia championii, Hiptage benghalensis and Mussaenda parviflora; (6) at altitudes of 500 m: exemplified by Hiptage benghalensis, Malaisia scandens and Ecdysanthera rosea. Synthesizing the distributions of vines along altitudinal gradient, the component of species and families was highest at middle elevation of about 1000?2000 m containing 17?18 vine species representing 13?15 families and lowest at high elevation containing only one vine species representing one family. Vine abundance was largest at low elevation in this study. There were averages of 160 vines in each 0.1 ha plot. Species richness of vines was found to be higher in Hiptage benghalensis, Parthenocissus heterophylla, Bauhinia championii, Euonymus echinatus, Hedera rhombea var. formosana and Lonicera acuminata with important value indices (IVI) more than 100%. There were significant variations about that the vines appeared to be particularly abundant at a special altitude although the distributions of vine species across the adjacent elevation. In the aspect of distributing horizontally at the same altitudinal gradient, the vines with higher important value index in the northern part were Trichosporum acuminatum, Mussaenda parviflora and Ampelopsis cantoniensis var. leecoides, in the central part were Fissistigma glaucescens, Mucuna macrocarpa and Stauntonia hexaphylla forma rotundata, and in the southern part were Bauhinia championii, Ecdysanthera rosea, Hiptage benghalensis, Mucuna macrocarpa, Trichosporum acuminatum and Acacia intsia. Synthesizing the distributions along latitudes, the quantity of vine species and families were all large. 19?25 species belonging to 17?18 families were recorded. The abundance of vine species and number was highest in Lien-Hua-Chih having average of 167 vines representing 25 species in each 0.1 ha plot. Species richness of vines had been shown to be highest in Ampelopsis cantoniensis var. leecoides with important value index (IVI) more than 100%. There were significant differences in the distributions of vine species at different latitudes. Thirty-four species of a total of 51 vine species distributed only in one of the sample plot at a specific latitude of northern, central or southern parts, respectively. The distribution of 34 vine species occupied 67% of the sample plots along latitudes. There were 9 vine species distributed across the adjacent latitudes, 6 vine species were common in both northern and southern sample plots, and only 2 vine species were found to be in different sample plots at different latitudes simultaneously. Obviously, the difference in abundance of vine species and families was small and the dissimilar in distributions of vine species was large at different latitudes. The phenomena presented differentiation between northern and southern parts. There were 7 types of climbing mode in this study. In sample plots along altitudinal gradient, the highest proportion of climbing mode was the type of twiners (tw) possessing 46.3%, the second one was the type of adventitious root climbers (ar) among 28.3%, and the type of scramblers (sc) was not found. The types of climbing mode were similar to FM model. In sample plots along latitudes, the highest proportion of climbing mode was the type of adventitious root climbers (ar) possessing 43.8%, the second one was the type of twiners (tw) among 32.6%, and the lowest one was the type of scramblers (sc) occupying 0.04%. The types of climbing mode were about the same as FH model spectra. The largest vine diameter coming into contact with host trees was 43.75 cm belonging to the type of adventitious root climbers (ar). The observed smaller average diameter of the types of tendrils (te), touch-sensitive leaves (ts) and branch twiners was 2.3 cm. While the largest diameter of host trees that was in touch with vines was 39.2 cm and the climbing mode of vines belonged to the types of adventitious root climbers (ar) and hook climbers (hk). Whether vines climb up or not is determined by the diameters coming into contact with host trees but not by the stem diameters of host trees, that is, in plant community, the more presence of small-diameter branches, significantly more climbers enter their host trees. The lowest height of vines in touch with host trees was 0.2 m belonging to the type of adventitious root climbers (ar) and the highest one was 6.5 m by the type of twiners (tw). There was no striking correlation between the height in touch with host trees and the lowest branches of host trees. The meaning was the same as that the vine climb did not correspond to the lowest branches of host trees. The distance between different vines and host trees had not significant differences. Climbing plants did not select the nearest support as host because of different types of climbing mode. Forty-three point twenty-six per cent of trees supported vines in sample plots along latitudes and the mean number vines per three trees were 1.3.