CHARACTERIZATION OF TEMPERATURE ENVIRONMENT ON MIKURA-JIMA ISLAND, JAPAN CONSIDERING VEGETATION RECOVERY

Abstract

Vegetation recovery following landslides caused by typhoons has been monitored on Mikurajima Island, Japan. Despite having a temperature profile of a warm temperate zone, Mikura-jima has many plant species representative of a cool temperature zone. Temperature environment is an essential parameter for determining the development of vegetation and flora, but little data are available for the island. In the present study, we measured atmospheric temperature by thermographs at seven different elevations (130, 300, 400, 500, 600, 700 and 800 m) over a period of 5 years (from 2013 to 2017), and we determined the warm index, cool index and rate of decline with elevation. The lapse rate along elevation gradient was 0.98 ˚C per 100 m for elevations 500 m and below, and 0.66 ˚C per 100 m for elevations 500 m and above. Warm index (W.I.) was estimated to fall below 85 at elevations over about 800 m, which allows the existence of a cool temperature zone. The re-examination of temperature environment in the present study will facilitate planning of goals and evaluation or estimation of vegetational succession on Mikura-jima Island.