Aerangis citrata, an epiphytic orchid endemic in humid and subhumid forests in Madagascar, between 3 and 1,600 m in elevation

 The species is known from 194 collections made between 1881 (Hildebrandt 3987) and 2019 (Antananarivo Spirit collection 542T186). Nine of these collections (Thompson s.n.; Herb. Jard. Bot. Tan. 2349; Peltier 2304; Forsyth-Major 114; Decary 7199, 10377; Cowan s.n.; Bréon 6 and Laan 382) were made with no precise locality information and thus were not taken into account for this assessment. The 185 collections represent 133 existing occurrences. Thirty four (34) occurrences of A. citrata are located outside protected area and are threatened by forest clearing due to shifting agriculture and forest degradation due to small scale agriculture practices, wood harvesting for subsistence and wildfires. Seventy three (73) occurrences, also present in protected areas are threatened by illegal logging. In addition to these officially protected sites, 11 occurrences  in a mining project footprint are facing human pressure such as forest clearing. These occurrences must be considered as extirpated. Moreover, six occurrences (Decary 7266, 7494, 10563; Scott Elliot 1880 and Catat 3206 and 3205) are facing forest clearing due to shifting agriculture and forest degradation caused by small scale agriculture and wood harvesting for subsistence should be also considered as extirpated. The remaining nine occurrences in the conservation zone of Ambatovy project surrounding the mining project footprint would be subject to protected in the near future. Aerangis citrata is a national ornamental species collected for horticultural purposes and trade . The species is thus known from 188 collections representing 116 existing and 17 extirpated occurrences.

The extent of occurrence (EOO) of A. citrata is estimated to be 235,545 km² (far exceeding the limits for Vulnerable status under criterion B1) whereas its area of occupancy (AOO) is estimated at 388 km² (which falls within the limits for Endangered status under criterion B2). The loss of the occurrences in the footprint of a mining project and in the outside of protected areas have induced a continuous decline of the AOO and EOO, the number of subpopulations and number of mature individuals. With regard to the most serious plausible threat of forest clearing and illegal logging, the 116 existing occurrences of the species represent 35 locations (sensu IUCN 2022), far exceeding the upper threshold for Vulnerable status under criterion B. Seventeen occurrences (17) of the species are considered as extirpated due to a mining project and shifting agriculture and forest degradation due to small scale agriculture, along with wood harvesting for subsistence and wildfires. Therefore, A. citrata could not be considered as threatened and is assessed as Least Concern (LC).

Aerangis citrata, an epiphytic orchid endemic in humid and subhumid forests, is known in Madagascar from 12 Regions: Analamanga in the formerly recognized Province of Antananarivo; Sava and Diana in the formerly recognized Province of Antsiranana; Atsimo-Atsinanana, Fitovinany, Ihorombe, Matsiatra Ambony and Vatovavy in the formerly recognized Province of Fianarantsoa; Sofia in the formerly recognized Province of Mahajanga; Alaotra-Mangoro, Analanjirofo and Atsinanana in the formerly Province of Toamasina; and Anosy in the formerly recognized Province of Toliara (Madagascar Catalogue 2022).

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

Aerangis citrata is an epiphytic herb on the trunks and branches of moss- and lichen-covered trees in humid, subhumid forests, and mossy high-land shrubland between 3 and 1,600 m elevation (Madagascar Catalogue 2022).

Thirty four (34) occurrences of Arerangis citrata are located outside protected area are threatened by forest clearing due to shifting agriculture and forest degradation due to small scale agriculture practices, wood harvesting for subsistence and wildfires. Seventy three (73) occurrences, also present in protected areas are threatened by illegal logging. In addition to these officially protected sites, 11 occurrences in Ambatovy mining project footprint are facing human pressure such as forest clearing. These occurrences must be considered as extirpated. Moreover, six occurrences (Decary 7266, 7494, 10563; Scott Elliot 1880 and Catat 3206 and 3205) are facing forest clearing due to shifting agriculture and forest degradation caused by small scale agriculture and wood harvesting for subsistence should be also considered as extirpated. The remaining nine occurrences in the conservation zone of Ambatovy surrounding the mining project footprint would be subject to protection in the near future. Aerangis citrata is an ornamental species collected for horticultural purpose and trade. It is inferred that ongoing loss of its habitat will induce a continuing decline in AOO and EOO, habitat extent and quality, and the number of subpopulations and mature individuals.

The species has national ornamental value and is collected for horticultural purpose and trade.

Aerangis citrata, an epiphytic orchid endemic to Madagascar, is known from 25 protected areas: Analamazaotra National Park, Andringitra National Park, Mantadia National Park, Natural Resources Reserve of the Ankeniheny-Zahamena Corridor , Montagne d'Ambre National Park , Lokobe National Park, Harmonious Protected Landscape of Ambohitr'Antsingy Montagne des Français, Ankarana Special Reserve, Marojejy National Park, Natural Resources Reserve of the Marojejy-Anjanaharibe South-Tsaratanàna Corridor - Northern Part, Masoala National Park, Analalava  Special Reserve, Manombo Special Reserve,  Anjanaharibe Sud Special Reserve, Harmonious Protected Landscape of the Anjozorobe-Angavo Complex, Ranomafana national Park, Makira Natural Park,  Ambatovaky Special Reserve, Natural Resources Reserve of Mangabe-Ranomena-Natural, Resources Reserve of Makirovana Tsihomanaomby, Ranomafana National Park, Natural Resources Reserve of the Tsitongambarika Natural Forest, Nosy Mangabe National Park, Andringitra National Park, National Park of Befotaka-Midongy du Sud,  Andohahela National Park, Zahamena National Park and Integral Nature Reserve of Betampona. Seeds are banked in the Ambatovy and Antananarivo seed bank. The species is also currently placed on Appendix II of CITES. Ex situ conservation is recommended (micro-propagation and living collections).