Abstract

In this study, we attempted to understand changes in the vascular plants of Isl. Pengchiayu, an islet in waters north of the main island of Taiwan. In addition to visiting the islet 3 times to survey the flora, documents regarding floral studies of Isl. Pengchiayu since 1906 and specimens of this islet deposited in 2 local herbaria, TAI and TAIF, were all referenced. Records of species on this islet were divided into 2 periods: the past (1904~1933) and recent (1992~2005) across about 100 years. All the vascular plants known to have existed during this period are listed. Results show that there were 144 species, including infraspecies, inhabiting the islet in the past period. Among them, 53 species have not been found recently. On the other hand, 39 species which apparently did not occur in the past have recently been recorded. In total, 130 species are known to exist on the islets recently. Possible reasons for the changes are also proposed.

中文摘要

為了解彭佳嶼上的維管束植物種類的變化情形，作者三度前往彭佳嶼採集植物，並 整合自1906 年以來的名錄、相關文章等，同時查閱存放在臺灣大學植物標本館 (TAI) 與 臺灣林業試驗所標本館 (TAIF) 內的標本。島上植物種類之記錄被區分為昔日 (1904~1933) 與今時 (1992~2005) 兩部分，時間幅度長約百年。比對並列表該小島在這 段時期曾存在的植物種類，結果確認昔日存在的144 種中，有53 種消失，但另新增39 種，目前島上存有130 種。文中對這些種類變化提出可能的原因。

Keyword: Taiwan, Isl. Pengchiayu, Flora, Island biogeography.