2009 Fiscal Year Final Research Report

Effects of climate changes on the water relations of endemic vegetation in the Ogasawara Islands.

Research Project

Project/Area Number	20700670
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Single-year Grants
Research Field	Geography
Research Institution	Yokohama National University
Principal Investigator	YOSHIDA Keiichiro Yokohama National University, 教育人間科学部, 准教授 (60377083)
Project Period (FY)	2008 – 2009
Keywords	小笠原諸島 / 夏季乾燥期 / 蒸散量 / 水文気候条件 / 水利用様式 / 生長期間
Research Abstract	To evaluate the effects of long-term climate changes on endemic vegetation in the Ogasawara Islands, we examined the relationships between seasonal drought and the physiological properties of endemic tree species, such as water relations and growth period. The seasonal variations of sap flow and conductance showed that the transpiration rates of endemic tree species were depressed in severe drought conditions and that the endemic tree species changed their water relations to resist the seasonal drought. Moreover, the leaf water potential of endemic species was rapidly decreased with the depletion of soil water in seasonal drought periods, and the growth period was shortened compare to that in the wetter area. These results suggested that the recent drying trend would change the water relations and growth of endemic tree species, and, therefore, that the long-term climate change could be risk factors affecting the endemic vegetation of the Ogasawara Islands.

(6 results)