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.