Determination of Micro-Habitat Preference of Adenomus kelaartii (Amphibia: Bufonidae) in and around Thotaha Stream, Yagirala Forest Reserve, Sri Lanka

Abstract

Habitat preference of Adenomus kelaartii which is an endemic species of Sri Lanka was
studied at Thotaha stream in Yagirala Forest Reserve in the low country wet zone from July
to September 2014. Nine 3×3 m2 quadrates were randomly placed in the stream habitat
including stream banks and rocky areas in the stream. Eight 3×3 m2 quadrates were randomly
placed in the stream adjacent forest habitat 30 m away from the stream. The quadrates were
considered as “occupied” if at least one A. kelaartii was found using them. Microhabitat
variables including the ambient temperature, relative humidity, substrate relative moisture,
silt/clay substrate availability, rocks covered with mosses and canopy cover were recorded in
each quadrate. Sampling was conducted once a month from 17:30 to 21:30 hrs. In order to
compare individual habitat variables between occupied and non-occupied quadrates, nonparametric
Mann-Whitney U-test (α=0.05) was used. The results revealed that the microhabitat
conditions such as ambient temperature, relative humidity, substrate relative moisture,
silt/clay substrate availability, rocks covered with mosses and canopy cover were the factors
determining micro habitat suitability for A. kelaartii. A sex based preference for refuges was
also observed in A. kelaartii. The males showed a higher preference for cervices while the
females preferred rock cervices and spaces between boulders. Juveniles preferred holes in
decaying logs and spaces in cracked tree barks.

Keywords: Micro-habitat variables, Adenomus kelaartii, Amphibian conservation