Justification
Bulbophyllum aubrevillei, an epiphytic orchid endemic to Madagascar, occurs in humid, subhumid forests, montane and mossy forests of E and NE of Madagascar.
The species is known from 27 collections made between the 1950s (Kiener 526) and 2019 (Tsimbazaza Spirit Collection 6B47). It was impossible to assign coordinates to two collections among the 27: one collection (Kiener 526) which is the type specimen of the species synonym without precise localization and another one (Tsimbazaza Spirit Collection 6B47) which is from a cultivated plant at the Botanical and Zoological Park of Tsimbazaza (PBZT) with unknown provenance. One collection (Bosser 16458) representing one occurrence, has been recorded in an unprotected forest along the road Moramanga-Anosibe and should be considered as extirpated or as likely to be extirpated in the near future due to forest degradation from small-scale logging, wood harvesting for subsistence, and slash-and-burn agriculture (tavy). Two collections (Fischer 3013, Ravelonarivo 2291) representing two occurrences have been located in unprotected forests subjected to the same threats, forest degradation from small-scale logging, wood harvesting for subsistence, and slash-and-burn agriculture (tavy). Sixteen occurrences have been recorded within eight protected areas. In addition to these legally protected sites, one collection (one occurrence) has been made in the conservation zone surrounding the footprint of a mining project in Madagascar, which should be subject to protection in the near future. The species is thus known from 19 existing occurrences representing 13 subpopulations and one extirpated occurrence.
The extent of occurrence (EOO) of the species is estimated at 134,317 km2, far exceeding the upper limit for Vulnerable status under criterion B1 whereas its minimal area of occupancy (AOO) is estimated to be 64 km2, falling within the limits for Endangered status under criterion B2. The 19 existing occurrences represent a total of 12 locations (sensu IUCN 2022) with respect to the most serious plausible threat, forest clearing due to mining activities and forest degradation due to slash-and-burn agriculture (tavy). We infer that the ongoing loss of its habitat has and will induce a continuing decline in habitat extent and quality of the species and the two occurrences located in unprotected forests subjected to threats will be extirpated in the next ten years, and the species will move to a threatened category. The species is not severely fragmented and does not meet the threshold of any threatened categories under criterion B. The loss of one occurrence out of 66 cannot lead to considering the species under a threatened category according to criterion A. Bulbophyllum aubrevillei is therefore assigned a status of Near Threatened (NT).
Geographic Range Information
Bulbophyllum aubrevillei is endemic to Madagascar, where it occurs in six Regions: Alaotra-Mangoro, Analanjirofo and Atsinanana (Ambatovy, Analamazaotra, Ankerana, Anosibe An'Ala, Bandabe, Fierenana, Lakato, Mantadia, Maromizaha, road Moramanga-Anosibe) in the formerly recognized Province of Toamasina; Menabe (Vondrove) in the formerly recognized Province of Mahajanga; SAVA (Marojejy) in the formerly recognized Province of Antsiranana; and Vatovavy Region (Ranomafana) in the formerly recognized Province of Fianarantsoa (Madagascar Catalogue 2022). The species is known from the eastern and northeastern escarpment, mostly between 900 m and 1,300 m elevation and from south-western at elevation of 86 m.
Population Information
The population of Bulbophyllum aubrevillei is currently thought to be decreasing since its habitat is threatened by forest degradation due to selective logging, wood collection for small-scale subsistence and slash-and-burn agricultural practices (tavy), and by forest destruction due to mining activities. The number of mature individuals of B. aubrevillei is unknown and cannot be estimated because the species is an epiphytic plant on the trunk of trees or shrubs.
Habitat and Ecology Information
The species is an epiphytic orchid growing on the trunk of trees or shrubs c. 1 m above the ground, in humid and subhumid forests, mountain rainforest or lichen forest on ridges or exposed wind-swept ridges at elevations of c. 900–1,300 m, and on gallery forest bordering the river (Mangoky River) in subarid bioclimate at low elevation c. 86 m.
Threats Information
The species experiences continuing decline in its habitat quality because of habitat destruction or loss due to mining activities, logging, wood harvesting for subsistence, and slash-and-burn agriculture (tavy).
Use and Trade Information
There are no reported uses for this species, but may be sought after by specialist collectors.
Conservation Actions Information
Sixteen occurrences of Bulbophyllum aubrevillei have been recorded from eight protected areas: the Analamazaotra National Park, the Corridor Ankeniheny Zahamena Natural Resources Reserve (Ankerana forest and Main parcel), the Mangabe-Ranomena-Sahasarothra Natural Ressources Reserve, the Mangoky Ihotry complex Protected Harmonious Landscape, the Mantadia National Park, the Marojejy National Park, the Maromizaha Natural Resources Reserve, and the Ranomafana National Park. One collection (one occurrence) of this species has also been made in the Conservation Zone surrounding the footprint of a mining project undergoing intense human pressure such as forest clearing. This zone would be subject to protection in the near future. The species is listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). It has also been brought to cultivation at the Tsimbazaza shade houses.