Microcoelia macrantha is know from Madagascar and Comoros. The species is known from 66 collections (38 occurrences). One of these collections, Bosser 21141 were made with no precise locality information and thus not taken into account in this assessment. This species is also known from four observations recorded on iNaturalist. However, because precise GPS coordinates are not available, these observations were not considered in this assessment. It is also known from two collections representing two occurrences in Comoros. Twelve collections representing 10 occurrences, and seven locations have been recorded in seven protected areas, the Marojejy National Park (one occurrence, one location), the Masoala National Park (one occurrence, one location), the Zahamena National Park (one occurrence, one location), the Torotorofotsy Protected Area (one occurrence, one location), the Analamazaotra National Park (three occurrences, one location), the Vohibe forest Ankeniheny- Zahamena Natural Resources Reserve Corridor (two occurrences, one location) and the Harmonious Protected Landscape of Mandena (one occurrence, one location). In addition to this officially protected site, 46 collections representing 20 occurrences have been made on the footprint of a mining project undergoing intense human pressure such as forests clearing. These occurrences should be considered as extirpated due to habitat destruction by the mining project’s activities. Microcoelia macrantha is also known from two collections representing two occurrences and one location made in the conservation zone surrounding the footprint and this forest should be subject to protection in the near future. It is also known from three collections representing three occurrences made from Ambodimandresy (one occurrence, one location), Onive-Mangoro (one occurrence, one location), Maroantsetra (one occurrence, one location) in unprotected forest that are subjected to selective logging, timber harvesting for small-scale subsistence, production of charcoal and slash-and-burn practices (tavy). Overall, this species, is thus known from 65 collections (37 occurrences) with precise location information representing 17 existing and 20 extirpated occurrences.

The extent of occurrence (EOO) of M. macrantha is estimated to be 477,893 km² (far exceeding the limits for Vulnerable status under criterion B1) whereas its area of occupancy (AOO) is estimated to be 64 km² (which falls within the limits for Endangered status under the criterion B2). These 17 remaining occurrences represent a total of 13 locations (sensu IUCN 2019) with respect to the main threat, mining activities, which is over the upper limit for Vulnerable status. Despite our inference of a loss of its habitat that will induce a strong continuous decline in EOO, AOO, habitat extent, and quality, the number of subpopulations and mature individuals in the next ten years, this widespread species, with many subpopulations encompassed within the protected areas network, will still not qualify for a threatened category by then. Microcoelia macrantha is therefore assigned a status of Least Concern.

Microcoelia macrantha is known from Madagascar where it occurs in the former provinces of Antsiranana in Diana Region (Marojejy), of Fianarantsoa in Ihorombe Region (Bekora), of Toamasina in Alaotra-Mangoro, Analanjirofo, Atsinanana Regions (Ampasimpotsy, Analamazaotra, Moramanga, Zahamena, Sahavary, Maroantsetra, Vohibe), of Toliara in Anosy Region (Mandena). It has also been recorded from the Comoros and Mayotte.

The population of Microcoelia macrantha is currently thought to be decreasing since the species habitat is threatened. The number of mature individuals of M. macrantha is not known and cannot be estimated since the species is an epiphyte and without leaves (aphyle).

Microcoelia macrantha is an epiphytic herb growing on the trunks or branches of trees or shrubs in humid and sub-humid forests between 50 and 1,404 m elevation (Madagascar Catalogue 2021).

This species is threatened by mining and selective logging. Twenty occurrences of this species have been collected on the footprint of a mining project undergoing intense human pressure such as forests clearing. It is also known from three occurrences in unprotected forests subject to selective logging, timber harvesting for small-scale subsistence, production of charcoal, and slash-and-burn practices (tavy).

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

Microcoelia macrantha has been recorded from in seven protected areas, the Marojejy National Park (one occurrence), Masoala National Park (two occurrences), Zahamena National Park (one occurrence), Torotorofotsy Protected Area (one occurrence), Analamazaotra National Park (three occurrences), Vohibe forest Ankeniheny-Zahamena Natural Resources Reserve Corridor (two occurrences) and the Harmonious Protected Landscape of Mandena (one occurrence). Two occurrences of this species have also been made in the conservation zone surrounding the footprint of a mining project undergoing intense human pressure such as forests clearing. This conservation zone should be subjected to protection in the near future. This species is included in Appendix II of CITES. Several individuals of this species have been brought to cultivation in the Ambatovy shade houses. Ex situ conservation is recommended (micro-propagation, seed banking). Further awareness building is recommended for local communities and national authorities.