With reference to the Qinghai-Tibetan Plateau boundary data (Zhang 2019), plants in the List (2021), distributed only in the Qinghai-Tibetan Plateau Region, were collected. First, based on the Flora of China (Wu et al. 1994), specimen information was obtained from the National Specimen Information Infrastructure (NSII, http://www.nsii.org.cn/2017) and the Chinese Virtual Herbarium (CVH, https://www.cvh.ac.cn/index.php). Combined with field scientific survey records collected in recent years, the family and species lists, as well as county-level distribution of key protected wild plants on the Qinghai-Tibet Plateau were, sorted out. Threatened status and endemism of species were confirmed from the IUCN Red List of Threatened Species 2021 (IUCN Red List of Threatened Species), China Red List of Biodiversity (Higher Plants Volume) (Ministry of Environmental Protection of the People’s Republic of China and Chinese Academy of Sciences 2018). Based on cataloguing, diversity characteristics of national key protected wild plants on the Qinghai-Tibetan Plateau were analysed and summarised, including family and genus composition characteristics, protection level, endemism, endangered status and geographical distribution characteristics. Floristic division scales of Qinghai-Tibetan Plateau were according to the Floristics of seed plants from China (Wu et al. 2010). The summarised checklist was arranged in order of Bryophyta, Lycopodiophyta, Pteridophyta, Gymnospermae and Angiospermae and the Angiospermae genera are arranged according to the APG IV system (The Angiosperm Phylogeny Group et al. 2016).

According to List (2021), the basic characteristics of key protected plants distributed on the Qinghai-Tibetan Plateau were summarised, including the quantity and proportion of families, genera and species, protection level classification, quantity of endangered plants and endemic species to China.

County-scale distribution data of key protected plants on the Tibetan Plateau were collected. The Qinghai-Tibet Plateau covers 221 county-level administrative regions (including municipal districts), including 45 in Qinghai Province, 74 in Tibet Autonomous Region, 48 in Sichuan Province, 28 in Gansu Province, 12 in Yunnan Province and 14 in Xinjiang Uygur Autonomous Region. The data collection sources of species distribution at the county level mainly included: (1) Annals and monographs, such as Flora of China (Wu et al. 1994), Flora of Qinghai (Northwest Institute of Plateau Biology, Chinese Academy of Sciences 1996), Flora of Sichuan (Volumes 1–21) (Editorial Committee of Flora Sichuanica 1981), Flora of Yunnan (Kunming Institute of Botany, Chinese Academy of Sciences 1977), Flora of Tibet (Wu 1983), Flora of Kunlun (Wu 2014), Vascular Plants and their Ecogeographical Distribution in the Qinghai-Tibet Plateau (Wu 2008) and the Second Survey of National Key Protected Wild Plant Resources in Gansu Province (Zhu and Kou 2020); (2) Online databases, such as National Specimen Information Infrastructure (NSII, http://www.nsii.org.cn/2017) and the Chinese Virtual Herbarium (CVH, https://www.cvh.ac.cn/index.php); (3) Field survey data of the Qinghai-Tibetan Plateau.

According to species in each county and floristic division, ArcGIS 10.6 was used to plot the diversity pattern of national key protected wild plants on the Qinghai-Tibet Plateau at county and floristic division scales.

There were 330 species, 18 varieties and two subspecies of national key protected wild plants on the Qinghai-Tibetan Plateau, belonging to 72 families and 130 genera, including five species of Bryophyta in three families and three genera, 27 species of Lycopodiophyta in two families and three genera, 11 species of Pteridophyta in three families and six genera, 25 species of Gymnospermae in five families and 12 genera, 262 species, 18 varieties and two subspecies of Angiospermae in 59 families and 106 genera (Suppl. material 1). These accounted for 1.43%, 7.71%, 3.14%, 7.14% and 80.57% of the national key protected wild plants on the Qinghai-Tibetan Plateau, respectively.

The List (2021) contains approximately 1,101 species (455 species and 40 categories), including five species of Bryophyta, eight species and seven categories of Lycopodiophyta and Pteridophyta (~ 106 species), 35 species and seven categories of Gymnospermae (~ 107 species), 397 species and 26 categories of Angiospermae (~ 830 species). According to the List (2021), the nationally protected wild plants distributed on the Qinghai-Tibetan Plateau accounted for 31.88% of the total in the List (2021), amongst which Bryophyta were all distributed on the Plateau, Lycopodiophyta and Pteridophyta, Gymnospermae and Angiospermae, accounted for 35.85%, 23.36% and 34.10% of the total species in the List (2021), respectively.

In terms of family composition, the national key protected wild plants on the Qinghai-Tibetan Plateau belonged to 72 families. Orchidaceae was the only family with over 100 species, with 103 species accounting for 29.34% of the national key protected wild plants (350 species) on the Qinghai-Tibetan Plateau. This was followed by Lycopodiaceae (24 species) and Melanthiaceae (21 species), which accounted for 6.83% and 5.98% of the national key protected wild plant species (350 species), respectively. Families with over 10 species also included Liliaceae (15 species), Poaceae (13 species), Rosaceae (11 species) and Taxaceae (10 species). A total of 33 families had only one species, accounting for 45.83% of all families (Fig. 1).

Figure 1.  

Statistics of the proportion of each family of national key protected wild plants on the Qinghai-Tibetan Plateau.

In terms of genus composition, the national key protected wild plants on the Qinghai-Tibet Plateau belonged to 130 genera. Genera with more than 20 species included Cypripedium (29 species), Dendrobium (24 species) and Paris (21 species), accounting for 8.26%, 6.84%, and 5.98% of the total species (350 species) on the Qinghai-Tibetan Plateau, respectively. However, the genus with only one species included 77 genera, accounting for 59.23% of all the genera (Fig. 2).

Figure 2.  

Statistics of the proportion of each genus of national key protected wild plants on the Qinghai-Tibetan Plateau.

According to statistics, there are 14,939 species of endemic seed plants in China and 3,764 species of endemic seed plants in the Qinghai-Tibetan Plateau (Yu et al. 2018). The national key protected wild plants distributed on the Qinghai-Tibetan Plateau included 168 species endemic to China, including 16 species of Lycopodiophyta, three species of Pteridophyta, 14 species of Gymnospermae and 135 species of Angiospermae. The species of seed plants (Gymnospermae and Angiospermae) endemic to China (149 species) accounted for 1.00% of the total species endemic to China. There were 57 species endemic to the Qinghai-Tibetan Plateau, including eight species of Lycopodiophyta, three species of Gymnospermae and 46 species of Angiospermae. The species of seed plants (Gymnospermae and Angiospermae) endemic to the Qinghai-Tibet Plateau (49 species) accounted for 1.30% of the total seed plants endemic to the Plateau.

In terms of protection level, there were 22 species of Class-I protected plants, including two species of Lycopodiophyta, one species of Pteridophyta, nine species of Gymnospermae, nine species of Angiospermae and one species of Cyanophyta. There were 328 species of Class II protected plants, including five species of Bryophytes, 24 species of Lycopodiophyta, 10 species of Pteridophyta, 16 species of Gymnospermae and 273 species of Angiospermae.

In terms of endangered status, one species, Cystopteris chinensis, was extinct in the wild (EW), 17 species were critically endangered (CR), such as Calanthe dulongensis, 91 species were endangered (EN), such as Cephalotaxus lanceolata, 90 species were vulnerable (VU), such as Cypripedium henryi and 30 species were near threatened (NT), such as Paris polyphylla var. yunnanensis, 60 species were of least concern (LC), such as Huperzia selago and 62 species had data deficiency.

On the Qinghai-Tibetan Plateau, the diversity distribution pattern of national key protected wild plants showed a decreasing trend from the southeast to northwest. There were 169 species and 13 varieties in the Yunnan Province, with 13 Class-I and 156 Class-II species. In Sichuan Province, 169 species, 12 varieties and one subspecies were distributed, including nine Class-I species and 173 Class-II species. In the Tibet Autonomous Region, 155 species and five varieties were distributed, including nine Class-I species and 151 Class-II species. In Gansu Province, 75 species, five varieties and one subspecies were distributed, including six Class-I species and 75 Class-II species. In Qinghai Province, 46 species were distributed, which were all Class-II species. Eighteen species were distributed in the Xinjiang Uygur Autonomous Region, including 18 Class-II species.

From the distribution at the county-level (Fig. 3), the distribution of nationally protected wild plants on the Qinghai-Tibetan Plateau was the highest in Gongshan and Yulong counties in Yunnan and Motuo County in Tibet, with at least 80 species. Species distribution in Deqin, Weixi and Fugong counties of Yunnan; Chayu County of Tibet; and Kangding, Luding and Tianquan counties of Sichuan was concentrated, with 51–80 species. The species distribution in most areas from southeast to northwest Tibet was very low, with fewer than 10 species.

Figure 3.  

Number of national key protected wild plants on the Qinghai-Tibetan Plateau, based on county-level distribution.

From the floristic distribution (Fig. 4), the species distributed in the Sanjiang Valley subregion (IIIE14a) and the South Hengduan Mountain subregion (IIIE14b) were the most dense, with more than 160 species, followed by species distributed in Southeast Asia of Tibet (IIIE15b) and Taohe-Minshan subregion (IIIE14d). Only less than 10 species were found in the Qaidam Basin subregion (IIC6b) and Pamir-Kashi Kunlun subregion (IIF17c).

Figure 4.  

Distribution and quantity of number of national key protected wild plants on the Qinghai-Tibetan Plateau, based on the floristic scale.