International action required to rescue world's rarest plant

To the Editor — The last individual of Hyophorbe amaricaulis, a palm endemic to Mauritius, is this year celebrating 73 years as the rarest species on record worldwide¹. The species was thought to be extinct until the discovery of this individual in a botanic garden in 1942¹. Attempts to propagate the protandrous plant, which produces female and male flowers at different times, have so far failed. However, despite recent breakthroughs and promising results², Mauritius has devoted little meaningful effort towards averting the extinction of this species, which could happen anytime, for example through senescence, disease or during the next cyclone that impacts the island.

As consciousness about the global extinction crisis grew during the twentieth century, the lonely palm started to inspire propagation efforts³. The most successful of these were achieved outside Mauritius through international collaborative projects, one of which resulted in the production, in vitro, of small plants. Although these plants did not survive transplantation out of the sterile medium, the production of complete plantlets represented a significant step towards successful propagation². Despite these encouraging results, Mauritius did not deepen the collaborations with further propagation attempts and thus failed to capitalize on this breakthrough. This failure to act coincided with a weakening commitment towards biodiversity conservation in Mauritius more generally^4–6.

An international approach now appears necessary to help save the species. The will and technology (such as embryo culture) exist to propagate the species and avoid the plant's extinction⁷, but time seems to be running out given its now advanced age. Because progress made locally towards saving the lonely palm has been insignificant over the past seven decades, the best chances of success seem to reside with Mauritius not only intensifying its efforts, but also, most importantly, resolving to meaningfully collaborate with international institutions that have a greater capacity to propagate rare plants.

Before it becomes too late, the international community should encourage and help Mauritius to maximize such collaborations, so that the current situation can be changed into a conservation success story that showcases the power of cooperative efforts. Such efforts could prove fruitful for similar conservation issues; the species-rich tropics, for instance, faces pressing plant conservation problems, but for the most part lacks the resources to rise to these challenges.