With the support of the Second Qinghai-Tibetan Plateau Integrated Scientific Expedition Project (2017QZKK0502), field investigations were conducted in June 2021 and June 2022 for Rhododendron auritum Tagg, which is categorized as Critically Endangered on The Red List of Rhododendrons (Gibbs et al., 2011, Botanic Gardens Conservation International). The type specimen of R. auritum was collected by Frank Kingdon-Ward in 1924 in Pemako Chung in Milin County, south-east Tibet, and was deposited in the Royal Botanic Garden Edinburgh in 1932. Since then, no more information on this species had been recorded in the wild. Although we were unable to explore the type location because Pemako Chung was seriously damaged during an earthquake that occurred in 1950, we have discovered two additional sites with the species, in Medog County, Tibet.
In June 2022, we discovered a previously unknown population of R. auritum, comprising < 100 individuals, in Gedang, at the edge of a fir forest. This population is exposed to disturbance from anthropogenic activities, including road construction. With a population comprising 29 individuals discovered in Lage in 2021, there are now two known populations of R. auritum in Medog county, 43 and 62 km from the type location.
Local authorities need to take action to conserve these two small populations. We have collected seedlings from Lage and planted them in the Kunming Botanical Garden, for ex situ conservation. We have also collected DNA material from both populations, for investigation of the species’ conservation genetics. Further investigations are needed to locate any other potential wild populations. In addition, we will perform propagation experiments once seeds are mature in the autumn, and some seeds will be preserved in the Germplasm Bank of Wild Species in Kunming Institute of Botany.
Flowers of Rhododendron auritum Tagg. Photo: Zi Wang.
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