Eggs and Tadpoles Survival Probability of Javan Tree Frog Rhacophorus margaritifer Schlegel 1837 in Mount Gede-Pangrango National Park, West Java

Abstract

Javan tree frog (Rhacophorus margaritifer) is an endemic species found in Java Island. The presence of javan tree frog habitat is threatened by the destruction of its habitats because of human activities such as forest encroachment and illegal felling of trees. This frog species is threatened not only during adults but also during tadpole phase. High chances of survival from tadpoles into frogs will sustain the existence of this species in its habitats. The purpose of this study was to see the percentage of eggs survived in natural habitats and the survivalof R. margaritifer tadpoles in translocation habitat to reach metamorphosis. Additional purpose is also to analyze the microhabiotat of of R. margaritifer eggs and tadpoles in Mount Gede-Pangrango National Park (MGPNP). Eggs and tadpoles data in natural habitats was collected from Cibeureum area. Translocation of tadpoles were carried out in Ciwalen and Cibodas in the Mount Gede- Pangrango National Park. Data collected includes number of successful and failed eggs hatched into tadpoles, the percentage of tadpole that survive in each stage of metamorphosis , habitat characteristics (water temperature, water quality, air temperature, substrate), and the total area of habitat and density of tadpoles in its natural habitat. The percentage of R. margaritifer eggs becoming tadpoles was high in their natural habitat, however in two occasions the survival was nil since all eggs decayed and failed to become tadpoles due to extreme temperature conditions. Based on observation, the survival probability of R. margaritifer tadpoles in age class I (st 25) to age class II (st 26-30) was only by 0.4 and continued to decline in subsequent age classes in following orders 0.26 (stage 31-40), 0.2 (stage 41-45) and 0.18 (stage 46). This indicated that tadpoles in its early growth phase are susceptible to death. Eggs clutch of R. margaritifer in their natural habitat at the MGPNP was found on water plants such as kecubung (Brugmansia suaveolens) and babakoan (Eupatorium sordidum) which situated above the flowing river. Tadpoles usually found in temporary pool or on the banks of the river basin with main substrate of mud. The average of diameter of the pools was approximately 150 cm, with average depth of less than 20 cm. The highest density of tadpoles found in its natural habitat is in Curug III (120 ind/m3 ) and the lowest is in the Curug I pool (3 ind/m3).