DOI: 10.5061/dryad.1c59zw41z
title: Spatial patterns and drivers of native plant diversity in Hainan, China

description: The Hainan Island has the most extensive and well-preserved tropical
 forests in China. With rapid economic development of Hainan, biodiversity
 is increasingly at risk. Determining the spatial patterns of plant
 diversity in Hainan and explaining the drivers behind plant diversity are
 important considerations in assessing and maximizing the effectiveness of
 national parks, such as the newly designated Hainan Rainforest National
 Park. We assessed phylogenetic diversity patterns, and species richness
 using 106,252 georeferenced specimen records and a molecular phylogeny of
 3,792 native plant species. Based on phylogenetic range-weighted turnover
 metrics, we divided the Hainan flora into four major floristic units. The
 Grade of Membership model was used to further verify the four units and to
 understand their boundaries and the internal structure of each floristic
 unit. Finally, the best combination model was used to explore the driving
 mechanisms underlying the division. Our results reveal that central Hainan
 is the most important hotspot for plant endemism and diversity, followed
 by the southern. Environmental energy is the main factor determining the
 spatial patterns of native plant diversity on the island, and
 accessibility has the greatest impact on native plant diversity among
 social factors. We explore patterns of spatial phylogenetics and
 biogeography to identify potential priorities for management and
 conservation drivers of plant diversity patterns across Hainan, to provide
 the basis for the effective protection of native plant diversity and the
 improvement of national parks of Hainan Island.
description: In order to determine the
 taxonomic composition of Hainan's native plants, we compiled a list
 of 5,860 native plant species belonging to 285 families and 1,875 genera
 based on the plant species lists of Xing et al. (2012) and Yang et al.
 (2016). We then screened and removed exotic cultivated plants, exotic
 escaped plants and naturalized plants using checklists, and combined
 subspecies and variants at the standard taxon species level. In total, we
 identified 3,792 native plants belonging to 257 families and 1,804 genera,
 representing 64.71% of the total plant species, 96.21% of the total plant
 genera and 90.18% of the total plant families present on the island. On
 this basis, we have compiled a list of 93 recorded endemic species by
 referring to the Hainan Endemic Plant Directory.
 For locality information, we
 combined the geolocations of specimens from Xing et al. (2012) and Yang et
 al. (2016) with the National Specimen Information Infrastructure (NSII;
 www.nsii.org.cn),
 the China Plants Database (DCP; http://db.kib.ac.cn). We removed all occurrence records with latitude and longitude values ​​of "0" or "NA", and divided the coordinate records into two categories: Hainan Island and Chinese Mainland. We used five loci to reconstruct the phylogeny: the nuclear internal transcribed spacer (ITS) and the chloroplast loci t<em>rnL, matK, ndhF, </em>and<em> rbcL</em>. We extracted gene sequences from GenBank (Benson et al., 2017) following the methodology of Smith et al. (2011). We conducted a maximum-likelihood phylogenetic analysis (ML) in RAxML (Stamatakis, 2006) HPC2 within the CIPRES (Miller et al., 2010) Portal on XSEDE. We performed 1,000 bootstrap replicates with automatic termination (i.e., -l autoFC) (Zhu et al., 2021). We then used Figtree 1.4.4 (Zhu et al., 2021) to visualize the resulting topology and export the tree in Newick format.