Bulbophyllum occultum, an epiphytic orchid, is known from Mauritius (Bel Ombre), La Réunion (St Phillipe), Comoros (Bahani) and widespread in Madagascar in 11 regions, in humid and subhumid forests.

The species is known from 163 collections made between 1907 (Perrier 1898) and 2020 (Ambatovy Spirit collection 3215A3626). The 163 collections represent 110 occurrences. Twenty two occurrences of B. occultum located outside protected areas are threatened by forest clearing due to shifting agriculture and forest degradation due to small-scale agriculture, along with wood harvesting for subsistence and wildfires. Other 53 occurrences, although present in protected areas, are threatened by illegal logging. In addition to these officially protected sites, 24 occurrences within the footprint of a mining project are undergoing intense human pressure such as forest clearing. The later occurrences must be considered as extirpated. The remaining 11 occurrences in the Conservation Zone surrounding the footprint of a mining project, would be subject to protection in the near future. The species is thus known from 163 collections representing 86 existing and 24 extirpated occurrences.

The extent of occurrence (EOO) of B. occultum is estimated to be 1,159,419 km² (far exceeding the limits for Vulnerable status under criterion B1) whereas its area of occupancy (AOO) is estimated at 284 km² (which falls within the limits for Endangered status under criterion B2). The loss of the occurrences in the mining footprint has induced a continuous decline of the AOO, the number of subpopulations, the number of locations, and the number of mature individuals. With regards to the most serious plausible threat namely forest clearing and illegal logging, the 86 existing occurrences of the species represent 32 locations (sensu IUCN 2022), far exceeding the upper threshold for Vulnerable status under Criterion B. B. occultum is not severely fragmented and does not meet the threshold of any threatened categories under criterion B. Twenty four occurrences of the species are considered as extirpated due to the threat of a mining project (12% of the total), which cannot lead to consider the species under a threatened category according to criterion A. Therefore, B. occultum is assessed as Least Concern.

Bulbophyllum occultum, an epiphytic orchid, is known from Mauritius (Bel Ombre), La Réunion (St Phillipe), Comoros (Bahani) and Madagascar in 12 Regions: Alaotra-Mangoro, Analanjirofo and Atsinanana (in the formerly recognized Province of Toamasina), Atsimo-Atsinanana, Fitovinany, Ihorombe, Matsiatra Ambony and Vatovavy (in the formerly recognized Province of  Fianarantsoa), Diana and Sava (in the formerly recognized Province of  Antsiranana), Sofia (in the formerly recognized Province of Mahajanga) and Anosy (in the formerly recognized Province of Toliara), in humid and subhumid forests (Madagascar Catalogue 2022). According to the Inventaire National du Patrimoine Naturel (INPN) (https://inpn.mnhn.fr/espece/cd_nom/705982/tab/statut#ancreStatutEspece), the presence of B. occultum in Grande Comore is doubtful but after checking the identifications of the specimens, it is confirmed that the specimens that were found there are indeed B. occultum.

The population of Bulbophyllum occultum is currently thought to be decreasing since its habitat is threatened by forest clearing due to mining activities, forest degradation by illegal logging, wildfires, timber harvesting for small-scale subsistence, and slash-and-burn agricultural practices (tavy). The number of individuals of B. occultum is not known and cannot be estimated since the species is an epiphyte on trunks or branches in humid, subhumid forests, and mossy shrublands.

Bulbophyllum occultum is an epiphytic herb growing on trunks and branches, on moss-and lichen-covering trees in humid and subhumid forests, mossy shrublands high-land between 10 and 1,500 m elevation (Madagascar Catalogue 2022).

Twenty two occurrences of Bulbophyllum occultum are located outside protected area and are threatened by forest clearing due to shifting agriculture and forest degradation due to small scale agriculture, along with wood harvesting for subsistence and wildfires. Other 53 occurrences, even if present in protected areas, are threatened by illegal logging. In addition to these officially protected sites, 24 occurrences have been made in the footprint of a mining project undergoing intense human pressure such as forests clearing, these occurrences should now be considered as extirpated. The last 11 occurrences have been made in the Conservation Zone surrounding the footprint of the mining project, which should be subjected to protection in the near future. It is inferred that ongoing loss of its habitat will induce a continuing decline in AOO, habitat extent and quality, and the number of subpopulations and mature individuals.

There are no reported uses of the species, although it may be sought by specialist collectors.

One occurence is located within Bel Ombre Nature Reserve in Mauritius. One occurrence is situated within Forêt de Département Domaniale du Sud in La Réunion and 51 occurrences of the species are situated within 19 protected areas in Madagascar: Ambatovaky Special Reserve, Analamazaotra National Park, Andohahela National Park, Andringitra National Park, Ankarana Special Reserve, Befotaka-Midongy du Sud National Park, Corridor Ankeniheny-Zahamena Natural Resources Reserve, Corridor Forestier Ambositra-Vondrozo Protected Harmonious Landscape, Corridor Marojejy-Anjanaharibe South-Tsaratanàna - Northern Part Natural Resources Reserve, Mangabe-Ranomena-Sahasarotra Natural Resources Reserve, Manongarivo Special Reserve, Mantadia National Park, Masoala National Park, Montagne d'Ambre National Park, Pointe à Larrée Special Reserve, Ranomafana National Park, Tampoketsa d'Analamaitso Special Reserve, Torotorofotsy Protected Area, Tsaratanàna Strict Nature Reserve, and Tsitongambarika Natural Resources Reserve. Seeds are banked in the Ambatovy seed bank. The species is also currently placed on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).