The Invisibility of Plant Communities-A Case Study of Northern Coastal Range of Taiwan

• Main Authors: Che-Hao Tu, 涂哲豪
• Other Authors: Yue-Joe Hsia
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/74212392764414709516

碩士 === 國立東華大學 === 自然資源與環境學系 === 99 === Ecologists have been trying to understand which factors influence the invisibility of indigenous plant communities since biological invasion has become one of the major threats to biodiversity globally. Although ecologists have proposed several hypotheses, however field results have not always matched their predictions. Field plot survey data of three habitat types (roadside green, abandoned cropland, secondary forest) along the highway 11 and 193 at Hualien County were used to test hypotheses of fluctuating resource availability, stress-gradient, and propagule pressure. Result suggested that factors of unused resource, competition and facilitation effects, alien-plant propagule significantly influence the invisibility of plant communities but contradictions of prediction from single hypothesis also suggested that integration of different hypotheses are needed. Hypothesis of fluctuating resources is unsuitable in the community which has weak interaction among plants. As in the community that the interaction among plants is strong then stress-gradient hypothesis does not hold. On the other hand, propagule pressure hypothesis ignores the effects of biotic factors and abiotic factors that influence the success of propagule of plant. Domain or limitation of specific hypothesis has to be clearly recognized before application of these hypotheses. A preliminary framework on application of these hypotheses is proposed. Firstly, whether resources availability is high or low is used to differentiate two environmental limitation categories. In the rich resources category, hypotheses of fluctuating resources availability and propagule pressure would apply if the interaction among plants is weak. If the interaction were strong then stress-gradient and propagule pressure could be held. In the poor resources category, both stress-gradient and propagule pressure should be considered if facilitation could enhance resource availability. On the other hand, as facilitation has little effect on resource availability, fluctuating resources might be the dominated hypothesis.