DOI: 10.5061/dryad.0p2ngf1xz
title: Energy-water and seasonal variations in climate underlie the spatial distribution patterns of gymnosperms species richness in China

description: Studying the pattern of species richness is crucial in understanding the
 diversity and distribution of organisms in the earth. Climate and human
 influences are the major driving factors that directly influence the
 large-scale distributions of plant species, including gymnosperms.
 Understanding how gymnosperms respond to climate, topography, and
 human-induced changes is useful in predicting the impacts of global
 change. Here, we attempt to evaluate how climatic and human-induced
 processes could affect the spatial richness patterns of gymnosperms in
 China. Initially, we divided a map of the country into grid cells of 50 ×
 50 km2 spatial resolution and plotted the geographical coordinate
 distribution occurrence of 236 native gymnosperm taxa. The gymnosperm taxa
 were separated into three response variables: (i) all species, (ii)
 endemic species, and (iii) non-endemic species, based on their
 distribution. The species richness patterns of these response variables to
 four predictor sets were also evaluated: (i) energy-water, (ii) climatic
 seasonality, (iii) habitat heterogeneity, and (iv) human influences. We
 performed generalized linear models (GLMs) and variation partitioning
 analyses to determine the effect of predictors on spatial richness
 patterns. The results showed that the distribution pattern of species
 richness was highest in the southwestern mountainous area and Taiwan in
 China. We found a significant relationship between the predictor variable
 set and species richness pattern. Further, our findings provide evidence
 that climatic seasonality is the most important factor in explaining
 distinct fractions of variations in the species richness patterns of all
 studied response variables. Moreover, it was found that energy-water was
 the best predictor set to determine the richness pattern of all species
 and endemic species, while habitat-heterogeneity has a better influence on
 non-endemic species. Therefore, we conclude that with the current climate
 fluctuations as a result of climate change and increasing human
 activities, gymnosperms might face a high risk of extinction.
description: Spatial distribution occurrence data of 236 native taxa of
 Chinese gymnosperm were obtained from the National Specimen Information
 Infrastructure (http://www.nsii.org.cn/; accessed between August 2017 and
 April 2018), Global Biodiversity Information Facility
 (https://www.gbif.org/; accessed between November, 2017 and February,
 2018), Chinese Virtual Herbarium (http://www.cvh.ac.cn/en/; accessed
 between August, 2017 and April, 2018), and relevant literature. The
 geographical distribution represent the point location denoted as
 longitude and latitude. There were 184 species and 52 varieties together
 represented “all species” while, 114 endemic and 122 non-endemic taxa in
 China. We used the geographical coordinate occurrence of a species to
 determine its presence or absence in the locality and plotted it at  the
 county level. The county-level distribution maps were then transferred
 into gridded distributions with a spatial resolution of 50 × 50
 km<sup>2</sup>. The number of individual taxa in each grid
 cell represent the species richness. The data represent here is the
 species richness of each grid cell including the longitude and latitude of
 a grid. Numerical One (1) denotes the presence of species while zero (0)
 is the absence of species in the grid.