Abundance and microhabitat association of Barbourula busuangensis (Anura: Bombinatoridae) in Busuanga Island, Philippines

Abstract

Barbourula busuangensis, commonly known as the Philippine Flat-Headed Frog, is a near-threatened species endemic to Palawan, Philippines. Despite its distinct ecological niche and unique characteristics, including a flat head and body to support its fully aquatic lifestyle, limited studies have been conducted to understand its habitat requirements and population status. We conducted visual encounter surveys and hand captures along 30–100 m belt transects in two Barangays, Cheey and New Busuanga. A total of 270 individuals were recorded and microhabitat variables were compared between the two sites. However, the abundance of B. busuangensis was significantly higher in Cheey compared to New Busuanga. We found significant differences in six key microhabitat variables (relative humidity, temperature, stream/river depth and width, rocks percentage, water flow and turbidity) between the two locations, suggesting diverse environmental conditions impacting frog populations. Additionally, 14% of the captured frogs (23 individuals) exhibited morphological deformities, though the cause remains undetermined. Our findings underscore the urgent need for further research and targeted conservation efforts to ensure the survival of this species. This study provides essential data on the distribution and habitat preferences of B. busuangensis, informing conservation strategies to mitigate population declines and address environmental challenges affecting this unique amphibian.