HCBL

Herpetological Conservation Breeding Laboratory (HCBL):

A 'One Plan' research approach on breeding ecology to inform the recovery of the Critically Endangered Bleeding toad (Leptophryne cruentata)

Leptophryne cruentata, or the bleeding toad, occurs in only two localities, at Gunung Gede Pangrango National Park and Gunung Halimun Salak National Park, in West Java, Indonesia. This species was listed as Critically Endangered by the IUCN SSC Amphibian Specialist Group in 2019 and became the first and only amphibian species protected under Indonesian law in 2018. L. cruentata is restricted to a narrow altitude range between 1,100 and 2,500 m asl, mostly in the boundary zone between moist mid-elevation and montane forest. To date, the only research conducted on L. cruentata was by Mirza Kusrini in 2004-2007, focussing on population presence and presence of chytridiomycosis (Kusrini et al. 2007, 2008, 2017). However, despite these efforts, the behavioral and ecological aspects of the species remain poorly understood, highlighting the urgent need for further in-situ, conservation-focused research in line with the 2021–2030 Action Plan.

Figure 1. Leptophryne cruentata © Ahmad Restu Dwikelana

To support the recovery of L. cruentata, conservation breeding has been identified as a critical strategy (following 2021-2030 Action Plan). In response, the Herpetological Conservation Breeding Laboratory (HCBL) was established through a collaboration among IPB University, Indonesia Herpetofauna Foundation, Chester Zoo, and the IUCN Asian Species Action Partnership. HCBL adopts a One Plan Approach, integrating in-situ conservation (e.g., habitat monitoring and protection) with ex-situ efforts (e.g., captive breeding), to ensure the species' long-term survival. A key goal of the ex-situ component is to establish an assurance population that can act as a safeguard against extinction. However, without simultaneous in-situ conservation actions, the success of future reintroduction efforts remains uncertain.

Given the critical status of L. cruentata and the absence of husbandry data for this genus, we began captive management trials using model species. Our first candidate was the hourglass toad (L. borbonica), a Least Concern species not under legal protection. Following successful trials, we plan to apply our learnings to L. javanica (Endangered), and ultimately to L. cruentata.

Figure 2. Herpetological Conservation Breeding Laboratory (HCBL) ©Briano Giovanny

In October 2023, we began keeping L. borbonica in captivity. Alongside our ex-situ efforts, we also conducted in situ observations to gather ecological and behavioral data that could inform captive management. Through many failures and re-evaluation of our husbandry practices, we are finally able to keep these frogs alive for long periods of time, and have even triggered amplexus several times, in January 2025, we found tadpoles in one of the tanks.

Figure 3. Leptophryne borbonica (adult) © Ahmad Restu Dwikelana

Figure 4. Leptophryne borbonica (tadpole) © Nathan Rusli

These successes demonstrate the viability of model species as a foundational step, bringing us closer to establishing a functional conservation breeding program for Leptophryne cruentata, and ultimately contributing to the species’ recovery in the wild. Building on this momentum, our activity plan for the next three years includes:

1. Carry out ecological studies on Leptophryne species
2. Develop a varied and sustainable ex-situ diet for Leptophryne species based on their natural prey items
3. Practice and understand the captive management of Leptophryne borbonica (LC) and L. javanica (EN), through successful breeding and rearing of young.
4. Develop best practice guidelines for Leptophryne borbonica and L. javanica.
5. Planning in preparation for a new herpetological facility to carry out conservation breeding of L. cruentata (CR).