DAY AND NIGHT ACTIVITIES OF THE GREEN WATER DRAGON (Physignathus cocincinus Cuvier, 1829) IN THE MOUNTAIN REGION OF THUA THIEN HUE PROVINCE

Abstract

We observed a total of 89 individuals during the day and 211 individuals at night in order to investigate day and night activities of the Green Water Dragon (Physignathus cocincinus Cuvier, 1829), a threatened reptile species listed in the Vietnam Red Data Book (2007) which is ranked as Vulnerable in Thua Thien Hue province, Vietnam. Most of the recorded individuals were found on trees (71,9 % of the total recorded individuals in the daytime and 96,7 % at night). The Green Water Dragon is more abundant and active between ten and thirteen o’clock (65,2 %). At night, this species starts appearing on the perches of streams, taking a rest; the number of individuals found from twenty to twenty-two o’clock occupies the highest rate (60.2 %). Individuals of the Green Water Dragon were regularly found in three types of microhabitats: hardwood, leaves, and vines and shrubs. The air temperature and humidity were found to affect the choice of the microhabitat of the Green Water Dragon (p ≤ 0.005). We also found the spatial partitioning in different age groups of the Green Water Dragon: adults usually lived at higher position (over 3 m above the water surface), juveniles usually were found at the lowest position (under 0.5 m), and subadults were usually seen at the middle position (about 1.01–2.0 m).