Population Status and Habitat Suitability of the Endangered Zanzibar Reed Frog, Hyperolius puncticulatus, in Masingini Forest Reserve, Zanzibar

Abstract

Visual encounter surveys along 1 km transects with systematic 50 × 50 m plots, supplemented by pitfall traps with 100 m drift fences, were conducted targeting the endangered Zanzibar reed frog (Hyperolius puncticulatus), an amphibian endemic to Unguja Island, Zanzibar. Only one adult individual was found, indicating a critically small population and urgent conservation needs, as this species lacks sufficient ecological data to guide protection efforts. The species was found in a moist forest-edge microhabitat characterized by dense leaf litter, fallen branches, and proximity to breeding pools. Water quality at all four sampled breeding sites was pristine, with low nutrient levels and slight alkalinity, conditions highly supportive for amphibian reproduction. Habitat suitability modelling using a Random Forest classifier (AUC = 0.94) predicted that 63.3% (≈358 ha) of the reserve is highly suitable, primarily in central and southwestern areas with north and east facing slopes and high topographic wetness. These findings highlight the need for strict habitat protection, boundary enforcement, targeted restoration, and long-term population monitoring to prevent local extinction of this threatened amphibian.