Phenology of Ficus virgata in Taiwan

• Main Authors: Guan-Yi Li, 李冠誼
• Other Authors: Lien-Siang Chou
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/28517812849228964494

碩士 === 國立臺灣大學 === 生態學與演化生物學研究所 === 100 === Phenology is important basic information for understanding the mutualistic interactions between Ficus plants (Moraceae) and fig wasps (Agaonidae). The purpose of this study is to investigate the growth and reproduction pattern of Ficus virgata at northen Taiwan. Ficus virgata is one of the common fig tree species in Taiwan which is a dioecious hemiepiphytic shrub or tree. It mainly distributed in tropical area and the its northern limit is Ryukyu Islands (Japan) and the North of Taiwan Island. In this study, 14 trees at Taipei city and 11 trees at Bitou cape ( on the northeast coast) were regularly surveyed by every 1-3 week from April 2010 to March 2012. Besides establishing the first baseline data on description of phenology and fig growth patterns of this Ficus species, my analyzing focus are variation between genders and between habitats. The leaf phenology showed that F. virgate was a evergreen plant species and the life span of leaves lasted about one year. New leaves germinated before old leaves fell off , thus the total leaves maintained stable on the tree. In contrast, the fig phenology showed two main growing seasons, early spring to early summer, and late summer to autumn. In addition, the fig phenology showed obvious difference between two study sites as well as between sexes of trees, the amount of leaves and figs on female trees were higher at Taipei than at Bitou, but those on male trees were opposite. The spatial variation is consistent with the microclimate variation. Urban heat island effect should be stronger at Taipei city, while Bitou cape was relatively cold and wet due to facing beach and northeast monsoon. On the whole, the growth of F. virgata in northern Taiwan was very stable, although there is its northern limitation for distribution. The crops of two study sites showed similar patterns, the male trees carried continuous crops for all year round and the female trees only bred crops during warm and humid seasons. However, the size and weight of figs showed significantly sexual variation, female figs were bigger and heavier than those of male figs. The female figs should load more nutrients to help seed developing and attract frugivores. In addition, while the male and female plants of F. virgate generally showed high within-trees synchrony, but the evenness varied with different sexes as well as sites. The evenness was higher for female trees at Taipei, but it was higher for male trees at Bitou cape. These variation may related with adaptive strategy for different environments, and to maintain wasps population and expansion of this Ficus population. In future research, the analysis of the composition of wasps and seeds can be added to understand the growth pattern of male and female trees in different seasons. So that we can know more about the phenology of dioecious Ficus, and more helpful for the conservation for tropical plants.