Community Characteristics and Population Structure of Heptacodium miconioides within and around the Nanhe National Nature Reserve，Hubei

Heptacodium miconioides Rehder (Seven-son flower) is a vulnerable plant species on the IUCN Red List of Threatened Species and is also on the List of National Key Protected Wild Plants in China. This shrub or small tree species was first recorded in 1907 by Ernest Wilson in western Hubei, central China, and later found in Zhejiang and Anhui. However, after the first record, it was not found in the next 115 years and was presumed extinct in Hubei. Then, in August 2022, it was rediscovered in the Hubei Nanhe National Nature Reserve, which is ca. 100 km away from its type locality. The vegetation type is typical deciduous broad-leaved forest and dominated by Carpinus stipulata H. J. P. Winkl., Platycarya strobilacea Siebold & Zucc., H. miconioides, and Quercus variabilis Blume. Our surveys located 151 individuals at three localities with elevations of 1, 000-1, 300 m. The size class structure (main stem) of the rediscovered populations is spindle-shaped, indicating that populations are declining due to insufficient seedlings. The 151 individuals produced 936 sprouts, 91% of the individuals produced sprouts, and the number of sprouts per sprouting individual was 6.83. The abundant sprouting can compensate for the scarcity of seedlings, maintain populations, and enable the species to persist in the niche. Because the populations are at remote mountain ridges and cliffs with few human disturbances, the population decline may be mainly caused by internal factors. We recommend additional field surveys for other undiscovered populations and an integrated conservation plan, including in situ conservation, artificial cultivation of seedlings, ex situ conservation, and reintroduction.