News & Events
Red listing of Hong Kong orchids
By Stephan W. Gale
23 June 2020

In order for conservationists to address the looming biodiversity crisis, it is useful to know which species are closest to the brink of extinction. Estimating a species’ extinction risk requires an objective method that can be applied universally, such that the resulting inferred status is directly comparable to that of another species. The International Union for Conservation of Nature (IUCN) developed the Red List Categories and Criteria precisely for this purpose.

Bulbophyllum tigridum has a very limited geographic range and a very small population size in Hong Kong, putting it a grave risk of regional extinction.

Red Listing involves quantifying various biological parameters pertaining to a species’ occurrence, abundance and population trend (whether stable, increasing or decreasing), as well as the severity of the threats it faces, to derive a relative indication of how perilous its status can be considered. The scale for this measure ranges from Least Concern (LC) for species that are doing well, to Critically Endangered (CR) for those perceived to be at imminent risk of extinction.

Some species, such as Bulbophyllum pecten-veneris, are feared regionally extinct in Hong Kong.

Normally, this approach is followed for any species (plant, fungus or animal) across its entire global range, regardless of which countries it is found in. However, in view of the fact that conservation is often administered within particular jurisdictions, the method can be adapted to generate a regional assessment for a species within a specific country or territory, such as Hong Kong.

Working with the Hong Kong SAR Government, botanists at Kadoorie Farm and Botanic Garden are currently preparing a comprehensive Red List of all of Hong Kong’s 135 native orchid species. The work falls within the scope of Hong Kong’s commitment to the development of a Biodiversity Strategy and Action Plan (BSAP). The results will highlight species most in need of conservation action.

By comparing the Red List status of different species and taking other factors into consideration, it is possible to define a shortlist of priority taxa. Bulbophyllum kwangtungense has declined dramatically in southern China due to collection for the ornamental plant trade, making the subpopulations in Hong Kong all the more important for species conservation.