Background and aims – Madagascar harbours high numbers of threatened orchid species, making it critical for orchid conservation. The Itremo Massif Protected Area (Itremo Massif PA), a Key Biodiversity Area in the Central Highlands, comprises diverse habitats essential for orchid survival. Previously, only 30% of the 83 orchid species recorded in the Itremo Massif PA had been assessed for the IUCN Red List. This research documents and analyses their habitats and threats to propose conservation approaches.

Material and methods – We compiled a dataset of orchid species native to the Itremo Massif PA, including information on endemicity, conservation status, habitats, and threats from IUCN Red List assessments and field observations. A species-by-habitat matrix was constructed, and species composition across habitats was analysed using a β-diversity framework. Overall β-diversity (β_SOR) was partitioned into species turnover and nestedness components. We also evaluated the proportion of threatened orchid species (Critically Endangered – CR, Endangered – EN and Vulnerable – VU) associated with the primary habitats and threats in the PA.

Key results – Of the 83 orchid species native to the Itremo Massif PA, 64% (53 spp.) are endemic to Madagascar and 41% (34 spp.) are threatened (1 CR, 16 EN, 17 VU). Species composition varies markedly between habitats (β_SOR = 0.83), primarily driven by species turnover (0.66). Bare soil and rock host the most orchid species (60%, 50 spp.). Bare soil and rock and grassland share the most species (14%, 12 spp.), while humid forest contains the most species restricted to a single habitat (16%, 13 spp.). Orchids are primarily threatened by mining and quarrying, increased fire intensity/frequency, logging and wood harvesting, and shifting agriculture.

Conclusion – Conservation should prioritise humid forest for its unique orchid species, and bare soil and rock for their richness in endemic and threatened species. Grassland also represents essential habitat for terrestrial orchids. Further research on population dynamics, pollination, and fungal interactions is needed to better assess extinction risk and manage conservation.

conservation, fire, habitat preference, Important Plant Area, IUCN Red List, mining, Orchidaceae

Orchidaceae is one of the most species-rich families of flowering plants with around 31,000 species (Fay and al. 2025; POWO 2026). At the same time, it is one of the world’s most threatened taxonomic groups (Wraith and Pickering 2018), as many species are vulnerable to habitat changes because of their strong ecological specialisation (Lussu et al. 2024). The IUCN Red List is regarded as the most comprehensive and authoritative source of global extinction risk for species (Nic Lughadha et al. 2020) and currently includes 2,123 orchid species, of which 1,062 (50%) are assessed as threatened (Critically Endangered – CR, Endangered – EN, or Vulnerable –VU; IUCN 2025; Fay et al. 2025). In response to these concerns, a global action plan was developed to identify the primary threats to wild orchid species and to provide recommendations for scientists, growers, and policymakers on how to protect orchid biodiversity (IUCN/SSC Orchid Specialist Group 1996). Given their exceptional diversity, vulnerability, and importance in cultivation and trade, orchids are recognised as a model group for biodiversity conservation (Hinsley et al. 2018). To mitigate the risks from unsustainable trade, international trade in orchids is regulated under the Convention of International Trade of Endangered Species (CITES 2024).

Madagascar is among the world’s important centres of orchid diversity and endemism. The island hosts a high number of threatened orchid species (Wraith et al. 2020), making it a global priority for conservation due to the intense pressures affecting its natural habitats (Vitt et al. 2023). However, only 30% (312 spp.) of Madagascar’s orchids have been published on the IUCN Red List (IUCN 2025), leaving major gaps in knowledge for conservation planning. Beyond the risks related to the collection and trade, many orchids occur in areas that are also important for agriculture, mining (Farminhão et al. 2024), and other subsistence activities (Droissart et al. 2023).

The Itremo Massif Protected Area (Itremo Massif PA), situated in Madagascar’s Central Highlands, represents an important focus for plant conservation due to its notable botanical richness including 749 plant species, 353 genera, and 103 families (Rakotonasolo et al. 2025). Orchidaceae is the second most species-rich family in the area, with 83 species recorded, following Poaceae with 111 species (Rakotonasolo et al. 2025). Located 117 km west of Ivato along the National Road (RN 35) to Malaimbandy, the Itremo Massif PA lies within the district of Ambatofinandrahana, Amoron’i Mania Region, in Fianarantsoa province. It is bordered by the rural commune of Itremo in the east, by Amborompotsy in the west, and by Mangataboahangy in the northwest (Fig. 1). Covering 24,788 ha at elevations between 1,500 and 2,100 m, the Itremo Massif PA comprises diverse habitats (Fig. 2) including grassland (70%), bare soil and rock (10.5%), tapia woodland (6.4%), humid forest (1.3%), and wetland (0.4%) (Kew Madagascar Conservation Centre 2012). Inselbergs in the Central highlands of Madagascar, characterised by bare soil and rock, harbour succulent plants, including orchids typically associated with arid environments, indicating unique microclimates and environmental stresses in these habitats (Porembski 2007; Rabarimanarivo et al. 2019). Tapia woodland is a characteristic element of the Malagasy flora occurring in the Central Highlands, consisting of a grassy herbaceous layer with a tree layer dominated by Uapaca bojeri Baill. (Phyllanthaceae), alongside species from families such as Anacardiaceae, Asteraceae, Asteropeiaceae, Rubiaceae, and Sarcolaenaceae. Designated as a protected area (PA) in 2005 and managed by Kew Madagascar, the Itremo Massif is classified as a protected harmonious landscape under IUCN Category V and was initially conceived as a PA through the Durban Vision initiative in 2003 (Ralimanana et al. 2022). It is recognised as an Alliance for Zero Extinction site (https://zeroextinction.org/), due to the presence of the endangered endemic plant Podocarpus capuronii de Laub. (Podocarpaceae). The Itremo Massif PA is also recognised as a Key Biodiversity Area (KBA) because it hosts endangered animals such as Verreaux’s sifaka (Propithecus verreauxi A.Grandidier, 1867) and the harlequin mantella frog (Mantella cowani Boulenger, 1882) (Rakotonasolo et al. 2025). Despite its botanical importance, the Itremo Massif PA has not yet been assessed using the criteria for Important Plant Areas (Darbyshire et al. 2017), leaving a significant gap in prioritisation of plant diversity conservation.

Figure 1. 

Location of the Itremo Massif Protected Area, in Amoron’i Mania region, South-Central Madagascar. The habit types by Moat and Smith (2007), such as the small patches of humid forest, tapia forest, and areas of bare soil and rocks that occur within the area are not clearly distinguished at the scale of the map and are included within the woodland grassland. Map prepared in QGIS Desktop v.3.34.1 (QGIS Development Team 2023).

Figure 2. 

Vegetation types in the Itremo Massif Protected Area. A, B. Humid forest in a valley in the middle of grassland in Antanimenahy. C. Quartzitic bare soil and rock in Antsirakambiaty. D. Tapia woodland in Antsirakambiaty. Photos by Landy R. Rajaovelona.

Of the 83 orchid species recorded in the Itremo Massif PA, only 34 species have been assessed on the IUCN Red List (IUCN 2025). Orchids are collected by local people and horticulturists for both local and international trade, with around 75% of species affected (Hermans and Rajaovelona 2022; UNEP-WCMC 2024). Expanding the number of species assessed on the IUCN Red List is critical, as it raises public awareness, unlocks conservation funding, guides prioritisation and site-based planning, and facilitates collaboration among stakeholders (Fay et al. 2025).

Orchid conservation in Madagascar’s Central Highlands faces multiple interacting challenges. High endemism and narrow habitat ranges make orchids sensitive to environmental changes (Swarts and Dixon 2009; Phillips et al. 2024). Seasonal fires, a traditional practice associated with pasture and agriculture, help maintain grassland but can also degrade forest fragments and threaten orchid survival and regeneration, although it may also trigger flowering in some orchids (Keeley et al. 2011; Andela et al. 2017). Invasive pines (Pinus kesiya Royle ex Gordon, P. elliottii Engelm, P. patula Schiede ex Schltdl. & Cham.) further impact orchids by altering fire behaviour and modifying soil properties, reducing habitat suitability (Downing 2016; Rajaonarivelo et al. 2022). Pine eradication was implemented as part of the 2017–2019 Kew Madagascar project in the Itremo Massif PA funded by the Critical Ecosystem Partnership Fund. Mining activities, such as tourmaline, crystal, and gold extraction, have been observed in the field (Landy R. Rajaovelona pers. obs. 2023).

These combined pressures highlight the urgent need for targeted conservation. This study aims to assess the conservation status and set conservation priorities for orchids in the Itremo Massif PA by answering the following questions: (1) How many orchid species native to the Itremo Massif PA are currently classified under IUCN threatened categories? (2) What are the primary habitats of Itremo orchids and how does species composition vary across habitats? and (3) What are the main threats to orchids in the Itremo Massif PA? Finally, we propose actions to preserve orchid biodiversity in the area.

Our research shows that the Itremo Massif Protected Area supports a rich orchid flora, with 53 species endemic to Madagascar—representing 64% of the 83 species recorded in the area. Of these, 34 species (41%) are classified as threatened according to IUCN Red List assessments. Although substantial, the proportions of endemic and threatened species in the Itremo Massif PA are lower than national estimates (83% and 76%, respectively; Droissart et al. 2023). These results provide essential baseline data for informing conservation planning (Ralimanana et al. 2022) and underscore the importance of integrating comprehensive biodiversity information—including habitat characteristics, species distributions, and threat patterns—into protected area management strategies (Cooke et al. 2022). Humid forest harbours unique, mostly epiphytic orchid species that depend on stable microclimate conditions and specific host trees; these species would not survive prolonged droughts and extreme temperatures (Linder et al. 2005). Humid forest is home to 13 species of epiphytic orchid that are restricted to this habitat. Other orchid species can occur across diverse habitats, including bare soil and rock, grassland, tapia woodland, wetland, and cultivation areas. In the Itremo Massif PA, bare soil and rock is the most species-rich habitat (50 spp.), highlighting the ability of orchids to withstand extreme conditions of drought, heat, and nutrient-poor soils (Pinheiro et al. 2014). Globally, endemic orchids are mostly threatened due to their limited geographic range and dependence on specific habitats such as forest and granitic outcrops (Fay 2018). This pattern is evident in the Itremo Massif PA, where 30 endemic species are threatened while only four non-endemic species are at risk.

Mining and quarrying, including extraction of stones like crystal and tourmaline, are the main threat to 21 threatened orchids in the Itremo Massif PA which aligns with findings by Nakade and Dhadse (2024), who reported that species with narrow ranges and small populations are particularly vulnerable to mining activities. Mosissa and Atinafu (2025) further demonstrated that habitat degradation from mining can deter mycorrhizal fungi necessary, for orchid survival.

Increase in fire frequency/intensity is the second most significant threat to orchids in the Itremo Massif PA, affecting 12 threatened species. Lithophytes, growing on exposed rocks, are vulnerable to fire as they lack underground tubers for resprouting after burning (Gill 1975; Whitman et al. 2011). Although fires threaten lithophytic orchids in the Itremo Massif PA, many terrestrial geophytic orchids are adapted to fire, and some require fire to stimulate flowering (Lamont and Downes 2011; Bowman et al. 2012; Abreu et al. 2017; Wieczorkowski et al. 2024). In open habitats including grassland, bare soil and rock, and tapia woodland, peak flowering occurs from January to March (Wieczorkowski et al. 2026) whereas fire in the Itremo Massif PA occurs between May and October with a peak from June to September (Fenonirina Rakotoarison pers. comm. 2024). Approximately 61% of orchid species in the Itremo Massif PA flower after the fires during the rainy season. Among these, geophytic orchid genera notably Benthamia, Cynorkis, Eulophia R.Br., and Habenaria Willd. are dominant.

The role of fire is also linked to the spread of invasive Pinus L. species, which have been increasingly recorded in tapia woodland in Madagascar’s Central Highlands (Rajaonarivelo et al. 2022). Reduced burning causes pine establishment (Flanary and Keane 2019), and expanding pine stands can alter forest structure and microclimatic conditions, reducing habitat suitability for epiphyte orchids (Besi et al. 2023). Although invasive species and disease affect only one threatened orchid species in the Itremo Massif PA (Angraecum coutrixii), pine invasion may further represent an emerging threat. Indeed, pines already represent a threat to tapia woodland vegetation in the Itremo Massif PA.

Shifting agriculture, and logging/wood harvesting represent the third major threat in the Itremo Massif PA, each affecting nine threatened orchid species. These threats mostly impact epiphytic species in the genera Aerangis Rchb.f., Aeranthes Lindl., and Bulbophyllum Thouars, which are restricted to humid forest and tapia woodland in the Itremo Massif PA. Shifting agriculture and logging/wood harvesting reduces canopy cover, increases exposure to heat and drought, and disrupts the fine-scale microhabitats for epiphytes (Zotz and Bader 2009). In addition, shifting agriculture fragments forest patches, and reduces the availability of mature host trees, limiting orchid dispersal and promoting small, isolated subpopulations of orchids dependent on forest (Harper et al. 2007; Besi et al. 2019).

Conservation priorities and actions

Protecting orchid diversity in the Itremo Massif PA requires habitat conservation strategies that address the ecological requirements of species and the varied threats across habitats. We suggest the following actions to preserve the orchid diversity in the Itremo Massif PA.

Research and citizen science

Further fieldwork is strongly recommended to better document rare orchids (Fig. 6) with a small distribution range, e.g. to locate additional subpopulations. Refined data on population size and distribution may affect the assessment of the extinction risk of orchids. There are significant gaps in knowledge concerning species distribution, natural history, taxonomy, and molecular phylogeny, which make prioritisation difficult (Vitt et al. 2023). To speed up the update of data on orchid distribution, iNaturalist (2024) offers an unparalleled opportunity to accelerate data collection while engaging scientists, local community members and orchid enthusiasts to upload photos from their field expeditions on the platform. Botanists, researchers and field experts and local observers regularly review the contributions added by other users to verify the identifications.

Figure 6. 

Examples of orchids occurring in the Itremo Massif Protected Area. A. Cynorkis cinnabarina (VU). B. C. melinantha (EN). C. Neobathiea grandidieriana (LC). D. Angraecum rutenbergianum (LC). E. A. coutrixii (CR). F. Jumellea spathulata (EN). G. Cynorkis cardiophylla (VU). H. Benthamia bathieana (VU). Photos by Narindra Romer Rabarijaona (A, C) and Landy R. Rajaovelona (B, D–H).

Habitat protection and restoration

The highest concentration of threatened orchids is found in the bare soil and rock, humid forest, and grassland habitats and these are therefore the highest priority for conservation.

Sustainable fire management

Installing firebreaks around sensitive habitats, fire patrolling, and planning early season burns (May–July) to prevent high-intensity fires.

Reducing mining impacts

Designate orchid-rich outcrops, humid forest, and tapia woodland as strict no mining zones because mining practices are a major driver of biodiversity loss (Nakade and Dhadse 2024). In areas where extraction is permitted, enforce low-impact techniques, limit removal of only the necessary material, and avoid disturbance of surrounding soil and vegetation.

Control of Pinus invasion

The removal of invasive Pinus species combined with appropriate fire management is necessary to maintain the open structure of tapia woodland, which is essential for conserving orchid diversity. Epiphytic orchids depend on microhabitats shaped by canopy openness and light conditions, making them sensitive to changes in forest structure (Johansson 1974).

Ex situ conservation

Ex situ conservation is feasible for orchids when local communities are actively engaged in the maintenance of shade houses and/or nurseries, combined with understanding of orchid ecological requirements. This is particularly important for terrestrial and lithophytic orchids which have complex growth cycles, including seasonal dormancy, tuber formation, making their long- term cultivation challenging due to specific substrate, light and moisture requirements. Local shade houses and nurseries play a role in maintaining living collections, producing material for restoration or reintroduction, and supporting seed banking (Stévart et al. 2020; Fay et al. 2025).

Public awareness and education

To achieve successful conservation outcomes, it is important to promote stakeholder-inclusive and participatory conservation (Lees et al. 2021). Outreach activities include the production of educational leaflets, and posters similar to previous initiatives on one threatened orchid Angraecum longicalcar (Bosser) Senghas, (Rajaovelona and Gardiner 2016), as well as field guides, tailored to local communities, include photographs, vernacular and scientific names, and IUCN conservation status of orchids of the Itremo Massif PA.

Recognition of Itremo Massif PA as an Important Plant Area

Already recognised as a Key Biodiversity Area (KBA), we suggest its designation as Important Plant Area (IPA) to strengthen site-specific plant management (Darbyshire et al. 2017). The recent plant checklist by Rakotonasolo et al. (2025), documenting endemic and threatened species including orchids, provides strong evidence to support the IPA designation and can guide future conservation priorities.

Orchidaceae are the second most species-rich family after Poaceae in the Itremo Massif PA. This study provides the first assessment of orchid extinction risk within the PA, located in the Madagascar Central Highlands, characterised by various habitats such as grassland, bare soil and rock, humid forest, and tapia woodland. Understanding habitat diversity, species composition, extinction risk and associate threats are essential for informing effective management strategies of this plant group. The Itremo Massif PA harbours threatened orchid species, which have restricted distributions and small population sizes. These species require urgent conservation actions, including habitat protection and both in situ and ex situ measures. Humid forest is particularly important as it hosts orchid species not found in other habitats. Grassland also represents essential habitat for terrestrial orchids in the Itremo Massif PA. Orchids of bare soil and rock are vulnerable to mining activities and increase in fire intensity/frequency. Long-term conservation actions include controlling pine invasion in the tapia woodland combined with implementing fire management.

Orchidaceae are among the most threatened plant families in part due to their complex life histories and highly specific interactions with pollinators and mycorrhizal fungi (Fay et al. 2025). Research on orchid fungal associations remains limited in Madagascar. Further research should therefore prioritise reproduction success, population viability, pollination ecology, and fungal interactions to support long term conservation of the region’s orchid flora.

The authors express their gratitude to all who help on providing data and facilities for conducting this research: Jack Plummer and Amy Baker, in the Plant Assessment Unit of the Royal Botanic Gardens, Kew and Dr Solohery Rapanarivo and Dr Franck Rakotonasolo from the Parc Botanique et Zoologique de Tsimbazaza, Antananarivo. We also thank the Direction des Aires Protégées, des Ressources Naturelles Renouvelables et des Ecosystèmes (DAPRNE) at the Ministère de l’Environnement et du Développement Durable for delivering research and export permits. We are grateful to the local guides in the Itremo Massif PA who have supported our field work. Our warmest thank to the colleagues from Kew Madagascar for all their help. This research was funded by the Today’s Flora for Tomorrow project funded by a generous donor through Kew Development, allowing the first author to pursue a PhD at the University of Antananarivo in collaboration with Royal Botanic Gardens, Kew.