Distribution and conservation of orchid species richness in China

Orchidaceae, the orchid family, is one of the species richest families and the most endangered plant groups. Most orchids are narrowly distributed in specific habitats because of their mycorrhizal specificity, pollinator specialization and limited seed germination rate; compared to plants from other families, orchids are extremely susceptible to habitat disturbance. However, little is known about how orchids are distributed and how they are protected at large scales. In this study, we developed a distribution database for all the 1449 orchid species in China. Using this database, we explored patterns of orchid richness in relation to climate, net primary productivity and habitat heterogeneity in China. We then evaluated the in situ conservation status of the orchids in China by overlapping the species distribution and the terrestrial national and provincial nature reserves (NNRs and PNRs) in China. We found that 90% of orchid species in China were distributed in 258,800 km2 (2.7% of China's landmass). Net primary productivity, elevation range, and temperature seasonality together explained 34.4% of variance in orchid richness. On average, NNRs covered 12.1%, NNRs and PNRs together covered 29.1%, of orchid distribution areas. However, there were still 154 (including 83 endemic to China) narrowly distributed orchid species not covered by NNRs; and 48 (including 28 endemic to China) were not covered by either NNRs or PNRs. We proposed that nature reserves specifically designed for orchids need to be established in Southwest China and Hainan Island.