On Madagascar’s eastern coast, a small fragment of lowland rainforest shelters an astonishing diversity of amphibian life. Betampona Strict Nature Reserve covers less than 30 km² yet is home to at least 87 distinct amphibian lineages (some still unknown anywhere else on Earth). But this refuge is becoming increasingly threatened: climate change, invasive species and, most recently, a devastating cyclone are reshaping the forest, while a highly toxic invasive toad advances towards its boundary. The race is now on to keep it out. Madagascar Fauna and Flora Group (MFG) works in close partnership with the Reserve’s managers, Madagascar National Parks, and international partners to do just that.
Betampona’s remarkable amphibian biodiversity
What makes Betampona particularly remarkable is not only the diversity of its amphibian fauna, but also its exceptional levels of microendemism and taxonomic novelty. Frogs occupy almost every habitat throughout the forest, from fast-flowing streams and the forest leaf litter to tree holes, decaying trunks and Pandanus plants. This variety of habitats is reflected in a remarkably diverse amphibian community, including many lineages that remain poorly known to science.
Betampona is also an important centre of taxonomic novelty and microendemism. Continued field surveys and molecular analyses have added 14 lineages since the reserve’s first major amphibian inventory, and 30 of these lineages are still awaiting formal description or taxonomic revision. Seventeen are microendemic, having so far been found only within Betampona, and 13 of these have yet to be formally described or taxonomically resolved.
Some of Betampona’s most remarkable treasures are revealed in the extraordinary ways its frogs reproduce. One is a still-undescribed giant Mantidactylus frog, whose secretive breeding behaviour has only recently begun to come to light. During the cooler dry season, these frogs use burrows on the forest floor, where large eggs are laid. Males have been found attending burrows with egg clutches, suggesting a form of parental care. Later, these cavities fill with water, where the tadpoles continue their development.
At a different scale, the tiny Blommersia angolafa turns fallen palm leaves into miniature nurseries. Adults live and breed within rainwater-filled fallen palm sheaths, attaching their eggs to the inner walls, while the tadpoles complete their larval development in the tiny pools of water trapped inside. An entire reproductive world can therefore unfold within the confines of a single fallen palm leaf.
But the forest floor hides treasures smaller still. Among the leaf litter are minute Stumpffia frogs, some only as big as a fingernail, including two species known only from Betampona whose names tell stories of their own. Stumpffia davidattenboroughi was named in honour of Sir David Attenborough, recognising his extraordinary contribution to Natural History broadcasting and his long-standing role as an ambassador for Madagascar’s wildlife. Stumpffia jeannoeli, meanwhile, honours Jean Noël, a member of the local community and one of MFG’s long-serving conservationists, whose exceptional field knowledge and dedication to amphibian research have helped reveal many of the reserve’s species.
These are just a few glimpses of what makes Betampona’s amphibian fauna so extraordinary. Perhaps most strikingly, after more than three decades of dedicated survey work, new lineages and previously unknown aspects of the frogs’ lives are still being discovered. This small forest fragment harbours not only an exceptional amphibian diversity, but also species found nowhere else and remarkable behaviours that science is still only beginning to understand.
Threats to this amphibian oasis
Despite having the highest possible legal protection status as per the IUCN’s protected area designations (Strict Nature Reserve), Betampona is not insulated from the pressures affecting Madagascar’s remaining forests. The reserve is a residual of what was once a continuous low-altitude rainforest belt that stretched down the majority of the island’s east coast. As a result, its amphibian community is particularly vulnerable to environmental change. Long-term monitoring by the Madagascar Fauna and Flora Group (MFG) has revealed a shift towards hotter and drier conditions, with several streams and marshy areas within the reserve drying out completely. Declines have been observed across multiple lineages of amphibians, and MFG’s Head Conservation Agent for Betampona, Jean Noël, believes this is mainly due to the loss of breeding sites.
Invasive species add another layer of pressure. Domestic dogs and cats, small Indian civets and both black and brown rats have been recorded within the reserve. Their impacts on Betampona’s native fauna are still poorly understood, although several are likely to be having highly negative impacts on native species through direct predation. The growing presence of invasive animals, particularly feral cats and dogs, has already been identified as an emerging concern for the reserve’s biodiversity. Invasive plants are also altering parts of the forest and preventing natural forest regeneration.
More recently, a new and disturbing threat has arrived on the scene and has been advancing towards Betampona: the Asian black-spined toad (Duttaphrynus cf. melanostictus). The species is thought to have arrived in Madagascar via the port town of Toamasina around 2010 and has since steadily expanded its range. Highly toxic and invasive, this toad has clear parallels with the cane toad (Rhinella marina) in Australia. Today, the closest edge of the known invasion front lies just 2 km away from Betampona’s reserve limit. At Parc Ivoloina, MFG’s other main site of intervention, just 36 km from Betampona, declines in predatory snakes such as the Malagasy cat-eyed snake (Madagascarophis colubrinus) and in native frogs have been observed following the arrival of the toad. The causes for the decline of the native frogs are not yet understood, but predation, competition and potentially disease may all play a role.
Then, on 10th February 2026, Cyclone Gezani struck the region. This was the biggest cyclone to hit this region since the satellite era. This cyclone caused widespread devastation around Toamasina, leaving hundreds of thousands of people in need of urgent humanitarian aid, including the vast majority of MFG’s team. At the same time, it ravaged forest cover and severely damaged MFG’s project infrastructure at both Betampona and Parc Ivoloina. Within the reserve, large, mature trees that had survived multiple cyclones for hundreds of years were brought down and extensive gaps opened in areas of previously closed-canopy forest. For Betampona, this disturbance may have an additional and particularly concerning consequence. Asian black-spined toads favour more open and disturbed habitats. By opening the forest canopy, Cyclone Gezani may have made parts of the reserve more susceptible to invasion, just as the toad is approaching its boundary.
The conservation response
MFG staff and our partners have not stood by in the face of these growing threats. MFG has led the national response to the Asian black-spined toad invasion, working with Madagascar’s Ministry of Environment and Sustainable Development (MEDD) to develop the 5-year National Toad Action Plan and Madagascar’s first ever multi-ministry invasive species working group. The plan identified areas of high biodiversity most at risk from the invasion and set out priorities for monitoring, research, control and mitigation. At Betampona, the focus is increasingly on preventing the toad from becoming established. MFG and its partners have been developing and testing safe control methods and toad exclusion fencing, while acoustic recorders are being deployed in sensitive areas around the reserve. These devices can continuously monitor the soundscape for the toad’s distinctive call, providing an important early-warning system as the invasion front approaches.
Biosecurity measures and continued monitoring are also helping to slow its spread and reduce the risk of toads being transported into currently uninvaded areas. Local communities are central to this response. A large part of MFG’s drive has been to raise awareness of the toad, the risks it poses to people, domestic animals and wildlife, and the role communities can play in controlling its spread. To date, 286 posters have been distributed across 8 local fokontany (compositions of small villages forming a governmental unit), awareness activities have reached 63 villages, and 14 community members have been trained as awareness-raising agents. In total, 6,395 people have been directly informed about the threats of the toad and how they can help keep it under control.
MFG’s response extends beyond the Asian black-spined toad. For more than two decades, the team has carried out applied research to develop effective control methods for the most problematic invasive plants, while minimising damage to native species during the control work. This work has contributed to a forest restoration programme recognised by Missouri Botanical Garden as one of the best in Madagascar. Following Cyclone Gezani, that experience has become particularly important. The team is now ready and trained to step in and work proactively to prevent invasive plants taking over in the multiple new forest canopy gaps created by the storm.
Coupled with MFG’s long term ecological monitoring programme in Betampona, we are well placed to understand the impacts of these diverse threats, monitor the effectiveness of our responses and continue to adapt our conservation management strategies. MFG works in close partnership with Madagascar National Parks, which manages the reserve, to translate our research findings into conservation actions within and around Betampona. Long-term partners of MFG, Mahaliana Laboratories, are also now launching a new programme of neutering stray dogs around the reserve in collaboration with Mad Dog Initiative, which should in time help reduce the present rate of growth of the dog population around Betampona and, in turn, reduce some of the predation pressures from domestic species within the reserve.
The challenges facing Betampona and its amphibian fauna are many, but one lesson from almost four decades of conservation work is that we are not alone. MFG’s motto is “conservation through collaboration” and reflects the partnerships that have sustained work at the reserve through some exceptionally difficult circumstances. With the Asian toad right on our doorstep and Cyclone Gezani creating new opportunities for invasive species to spread, we will need help more than ever in the coming months and years. Please reach out to info@savethelemur.org if you feel you can help in any way! The amazing amphibian biodiversity of Betampona deserves all the help it can get!
Supporting literature
Andreone, F. (2014) Risk review is under way for invasive toad. Nature 512, 253. https://doi.org/10.1038/512253c
Licata, F., Harison, R.F., Ficetola, G.F., Freeman, K., Muller, B.J., Ponga, V.R., Andreone, F. & Crottini, A. (2022) Toad invasion of Malagasy forests triggers severe mortality of a predatory snake. Biological Invasions, 24 (4), 1189–1198.
Piccoli, C., Paoletti, A., Andreone, F., Freeman, K., Georges, Harris, D.J., Lava, H., Melo, M., Nöel, J., Ramamonjisoa, D.L., Randriamialisoa, Raselimanana, A.P., Rosa, G.M., Salvi, D., Scanarini, E., Velo, J.H. & Crottini, A. (2025) The amphibians of Betampona: an updated account of the remarkable diversity of Madagascar’s central-eastern Strict Nature Reserve, Systematics and Biodiversity, 23:1, 2505180. https://doi.org/10.1080/14772000.2025.2505180
Reardon, J.T.; Kraus, F.; Moore, M.; Rabenantenaina, L.; Rabinivo, A.; Rakotoarisoa, N.H.; Randrianasolo, H.H. (2018) Testing tools for eradicating the invasive toad Duttaphrynus melanostictus in Madagascar. Conservation Evidence 15, 12-19.
Rosa, G.M.; Andreone, F.; Crottini, A.; Hauswaldt J.S.; Noël, J.; Rabibisoa, N.H.; Randriambahiniarime, M.O.; Rebelo, R.; Raxworthy, C.J. (2012) The amphibians of the relict Betampona low-elevation rainforest, eastern Madagascar: an application of the integrative taxonomy approach to biodiversity assessments. Biodiversity and Conservation 21 (6): 1531-1559.