Rediscovery of the mistletoe Bakerella hoyifolia subsp. bojeri (Loranthaceae) on Reunion Island: population status assessment for its conservation

The mistletoe Bakerella hoyifolia subsp. bojeri (Baker) Balle was presumed extinct from Reunion Island, where it is native, for over 50 years. We recently found B. hoyifolia plants in a well-preserved forest stand in the southeastern part of the island. The small population consists of six individuals, distributed in two groups, ca. 50 m apart, growing on five host plant species from different families, suggesting a low host specificity. Each group is structured vertically with a large mistletoe established on an emerging tree while smaller mistletoes are seen on the trees below. Moreover, we observed the Reunion grey white-eye, Zosterops borbonicus (J. R. Forster, 1781) visiting flowers of these mistletoes found on Reunion. Further investigations are required in order to clarify the genetic isolation and taxonomic position of this population relative to those in Mauritius and Madagascar, and the mechanisms that have caused its decline on Reunion. Two possible mechanisms are discussed. The loss of most frugivorous vertebrates on Reunion Island soon after human settlement, may have driven this mistletoe to extinction. Among rapid conservation actions, propagation from seeds should be carried out in order to prevent the extinction of this native plant population