Zoological Studies

Comparison of Stream Frog Assemblages at Three Elevations in an Evergreen Forest, North-Central Thailand

Ratchata Phochayavanich, Harold K. Voris, Wichase Khonsue, Somying Thunhikorn, and Kumthorn Thirakhupt (2010) A study of stream-dwelling frog assemblages was conducted at 800, 950, and 1250 m in elevation on the Nam San Noi stream, Phuluang Wildlife Sanctuary, north-central Thailand.  Three transects, each 100 m long which ran along the stream, were designated at each elevation.  Visual encounter surveys were conducted within each transect at night from June 2006 to May 2007.  The Shannon-Wiener index of species diversity indicated that the diversity was highest at the lowest elevation and lowest at the highest elevation, while Morishita’s similarity index indicated that species compositions at 800 and 950 m were very similar to each other, but both of them differed from that at the highest elevation (1250 m).  Over all 3 elevations, 4 of the most common species (with abundances exceeding 1%) were least abundant at the highest elevation, while 2 species, Limnonectes kuhlii and Odorrana aureola, were most abundant at the highest elevation.  The abundance of Lim. gyldenstolpei fluctuated among the 3 elevations.  These results indicated that the frog compositions significantly differed between 2 elevation groups, that is between (a) the group consisting of 800 and 950 m and (b) that at 1250 m, and also that frog diversity tended to be highest at the lowest elevation.