How threatened are orchids? A review of the state of play and identification of gaps and priorities.

Orchidaceae, one of the largest plant families, have been predicted in several analyses to be under a higher level of threat than angiosperms as a whole. Despite this, compared to many other major groups of animals and plants, orchids are under-represented on the Red List of the International Union for the Conservation of Nature (IUCN). Since 2000, concerted efforts have led to the number of orchids on the Global Red List increasing from eight to > 2,000 species, but many of these assessments are now outdated, and 28,000 species remain to be assessed for the first time. Here we review the current knowledge of the conservation status of orchids based on Red Listing and other methods, including machine learning and EDGE (Evolutionarily Distinct and Globally Endangered). At the geographical level, Sub-Saharan Africa is relatively well sampled for the Global Red List, whereas South and Central America and tropical Asia are poorly sampled. With the existing Red List assessments, levels of threat vary widely between tribes and subtribes. Tribes and subtribes with no or low sampling are identified. We discuss the main threats, and we identify climate change and fire as emerging threats, the former due to the potential for disruption of critical associations with pollinators and mycorrhizal fungi.

Project(s)

Priority 4: Accelerated Taxonomy

Priority 1: Ecosystem Stewardship

Funder

Funder name	Awards
International Union for Conservation of Nature, Switzerland	Providing technical and scientific support in measuring the pulse of European biodiversity using the Red List Index (P03601)
Horizon 2020 Framework Programme, European Union	Marie Skłodowska-Curie grant agreement No. 101,031,324 (project FORECAST)
National Geographic Society, United States	Grant NGS-50970 C-19
American Orchid Society, United States	Grant C-2020-22
Plantlife Conservation Society, Canada	Grant Planta-001
Natural Environment Research Council, United Kingdom	NE/S007415/1
St Andrews Botanic Gardens, United Kingdom	CASE Partner
Australian Orchid Foundation, Australia
National Fish and Wildlife Foundation, United States
Ambatovy Minerals S.A., Madagascar