Rescue and reintroduction of the endemic lily- flowered hibiscus in the Grande Montage Nature Reserve, Rodrigues, Mauritius

Summary

The lily-flowered hibiscus, known locally as mandrinette, was feared extinct on Rodrigues when its last known individual died in 1981, until two more plants turned up in the Mourouk valley in 1983 and a third near Montagne Ursule in the 1990s. Since the mid-1990s, the Mauritian Wildlife Foundation and the Rodrigues Forestry Service have taken cuttings and seed from those three founders to build a protected gene bank at Solitude, nine of whose clones remain alive and productive in 2017, and used them to propagate plants for out-planting in the Grande Montagne Nature Reserve, where exotic vegetation is cleared in stages ahead of planting to aid soil recovery and limit erosion. Between 2008 and 2016 alone, MWF staff propagated and planted around 1,573 individuals, but three-year survival monitoring has consistently found low success, which the team attributes to the slow-growing hibiscus being outcompeted when planted at high density alongside faster-growing native species. Even so, the wild population has grown roughly tenfold, from four known individuals in the mid-1990s to at least 54 mature, fruit-bearing plants recorded in 2017, and the species is also held ex situ at botanical gardens in Mauritius and Hawaii. The project rates itself successful, while flagging reduced monitoring attention, spread across more than 40 threatened species, and the risk of hybridization with an introduced ornamental hibiscus as ongoing concerns.