3.1. Conifer species richness pattern and hotspot ecoregions
In the current investigation, four distinct conifer richness centres identified: the central and northern parts of Sichuan including Qionglai-Minshan ecoregion; the northern part of Yunnan including Nujiang Langcang Gorge ecoregion; and the south part of Hengduan Mountain ecoregion. The species richness per grid cell of all conifers ranged from 1 to 30 (Fig. 1A). Two endemic centres (IPAs) were identified (Fig. 1B) with richness ranged from 1 to 24: central Sichuan and the north part of Qionglai-Minshan ecoregion. Regarding the threatened species richness (1-17 species per grid), two centres (IPAs) in central Sichuan and northern Yunnan (Nujiang Langcang Gorge ecoregion) (Fig. 1C). Furthermore, one centre (central Sichuan) for the endemic threatened species richness: (Fig. 1D), which ranged from 1 to 14 species per grid. The species richness of all categories was highly right-skewed (see Table S2, Appendix A). Four nature reserves with the highest richness of conifers (IPAs), located in the central part of Sichuan (giant panda area) and the northern part of Yunnan (Fig. 1E). Furthermore, a four distinct area (IPAs) with a high richness of conifers were located outside the national nature reserve system representing the proposed nature reserves (Fig. 1E). The results of correlation analysis showed moderate to high concordance between all conifer richness and the four categories (r = 0.68 – 0.90; see Table S3, Appendix A), implying that the factors driving conifer richness are possibly the same among the different richness categories.