Oeonia rosea, an epiphytic orchid native but not endemic to Madagascar, is also known from the Mascarenes. It is known from 114 collections, six of which, as well as one observation, were made without accurate locality information in Madagascar, and thus are not taken into account for this assessment. Four observations were made in La Réunion. The remaining 108 collections and four observations represent 88 occurrences.

Thirty-eight collections were made in eleven protected areas. In addition to these legally protected sites, 18 collections representing 17 occurrences were made within the footprint of a mining project that has undergone and is undergoing intense human pressure from forest clearing, and should now be considered as extirpated. Moreover, three collections in the footprint are likely to be extirpated soon. Five collections (five occurrences) have been made in the Conservation Zone surrounding the mine footprint. This zone should be protected in the near future. O. rosea is also known from three collections made from Andranomilolo, Bekora, and Torotorofotsy (three occurrences), in unprotected forests subjected to timber harvesting for small-scale subsistence use, and slash-and-burn agricultural practices (Tavy), these occurrences should also be considered as extirpated. The species is thus known from 108 collections and three observations with precise locality information, representing 23 extirpated and 88 existing occurrences that are threatened by small-scale agriculture, wood harvesting for subsistence use, and fire, inducing a decline in the habitat quality of the species.

The extent of occurrence (EOO) of O. rosea is estimated to be 675,990 km² (far exceeding the upper limit for vulnerable status under criterion B1) whereas its area of occupancy (AOO) is estimated at 220 km² (within the limits for Endangered status under the criterion B2). These 88 existing occurrences represent a total of 70 locations (sensu IUCN 2022) with respect to the most serious plausible threat, forest clearing due to mining activities, far exceeding the upper limit for vulnerable status under criterion B. Despite a continuing decline of its AOO, habitat quality, and the number of locations and mature individuals, any conditions for applying subcriterion under criterion B2 are not met and the species is not severely fragmented and does not meet the threshold of any threatened categories under criterion B. It is inferred that these threats have induced a decline of 12% in the AOO of the species, which cannot lead to considering the species under a threatened category according to criterion A. Due to the wide distribution and population size of the species, criteria C and D cannot be applied. Therefore, despite the projected continuing decline in the quality of its habitat, O. rosea is assessed as Least Concern (LC). The species is also assessed as LC in La Réunion.

Oeonia rosea, an epiphytic orchid native to Madagascar and the Mascarenes, is known from 14 Regions: Alaotra-Mangoro (Ambatovy, Analamazaotra, CAZ, CFAM, Mantadia , Tororofotsy, and Zahamena), Analanjirofo (Makira and Masoala) Antsinana (CAZ), in the formerly recognized Province of Toamasina; Amoron’I Mania (Ambohimitombo), Atsimo-Antsinana (Midongy du Sud), Fitovinany (COFAV), Haute-Matsiatra (Ialatsara), Ihorombe (Kalambatritra), and Vatovavy (Ranomafana) in the formerly recognized Province of Fianarantsoa , Vakinankaratra (Faratsiho), Analamanga (Mandraka) in the formerly recognized Province of Antananarivo, Anosy (Tsitongambarika), Diana (Montagne d’Ambre), and Sava (COMATSA Nord and Marojejy) in the formerly recognized Province of Antsiranana.

The population of Oeonia rosea is currently thought to be decreasing since 20 occurrences on the mine footprint have been extirpated as well as three occurrences in unprotected forests. The number of mature individuals was not estimated.

Oeonia rosea is an epiphyte herb growing on branches of trees in humid forests of the East and Highlands, in Madagascar and Réunion Island between 500 and 2,000 m elevation.

The species is threatened by forest clearing due to mining activities, forest degradation due to small scale agriculture, and wood harvesting for subsistence use.

There are no reported uses of this species, but it may be sought after by specialist collectors.

Thirty-eight collections were made in eleven protected areas in Madagascar, Analamazaotra National Park, Andrigintra National Park, Befotaka-Midongy du Sud National Park, COMATSA Nord National Park: Ivohibe Special Reserve, Mantadia National Park, Masoala National Park, Marojejy National Park, Montagne d’AmbreNational Park, the Torotorofotsy Protected Area, and Zahamena National Park. Three human observations are known from La Réunion, two of which are made in two protected areas: National Park of La Reunion, and National Seaside and Lakeside Conservancy. The species is also currently placed in Appendix II of the CITES.