Study on population and distribution of Paphiopedilum helenae Aver. in Trung Khanh district, Cao Bang province

Paphiopedilum helenae Aver. is one of the smallest slipper orchids among paphiopedilums. The combination of surprisingly miniature plants with large yellow flowers makes Paphiopedilum helenae being collected for ornamental purpose and commercial use. According to previous researches, the primary forests on limestone mountain landscape of Cao Bang, Bac Kan, Lang Son provinces of Vietnam and South China near the border are home to P. helenae. Just like other paphiopedilums, this slipper orchid species has been seriously exploited in most of its natural range that leads to the significantly decrease of population. The previous study estimated that the number of mature individual reduced of 85-90% over the last decade. The decline is continuing and there is a projected decline of 80-90% of remaining individuals in the next 25 years. Because of facing severe threat, this dwarf lady’s slipper orchid is listed as “Critically Endangered” (CR) on both IUCN Red List (IUCN 2019) and Vietnam’s Red Data Book (2007). Moreover, P. helenae is also being protected by national and international regulations such as: in Group IA of Decree 06/2019/ND-CP on “Management of endangered, precious and rare wild fauna and flora and Implementation of the Convention on International Trade in Endangered Species of Wild Fauna and Flora”, Appendix I of Decree 64/2019/ND-CP on “List of endangered, precious and rare species prioritized for protection” and Appendix I of Convention on International Trade in Endangered Species (CITES). Due to the fact of population decline and the need for studies to provide scientific information, appropriate management and conservation measures, Center for Nature Conservation and Development (CCD) is implementing study to assess distribution and identify threats to P. helenae population in Trung Khanh district of Cao Bang province. In October 2020, CCD conducted a field survey in some forest areas of Trung Khanh district (including some communes of previous Tra Linh district). The survey was carried out using transect survey method. Survey team recorded at least 172 individuals situated in 53 collected points along eight of nine survey transects. P. helenae were observed to grow on top and vertical limestone cliffs near tops of mountain peaks, on vertical ledges ranging from 75 to 90^o with a northern exposure in limestone karst mountain. Individuals are situated on open vertical limestone walls or slightly shade of primary mixed forest or broad-leaf forest mix with conifers that are dominated by Pseudotsuga brevifolia and Pinus wangii subsp. varifolia at the elevation from 700m to 850m above sea level. Besides, survey team visited three orchid collected gardens. There is only one nursery garden growing 1-2 P. helenae individuals. Result of Interviewing local people revealed that P. helenae orchid collecting is still happening in study area with small quantities. CCD is continuing to conduct further field surveys on population and especially collecting and trade status of paphiopedilums to gain comprehensive information to propose proper protection and recovery measures in their distribution areas. Research and conservation of endangered orchids is part of Plant Conservation Programme, which CCD is implementing in many regions of the country.