(2010) studied the Dinghushan plot and indicated that shrubs had weaker dispersal limitations than arbors and subarbors. The dispersal ability of plant species is frequently predicted to influence species turnover, but only limited tests have been performed to confirm this the results of these tests have been inconsistent ( Qian, 2009 Elgar et al., 2014). Therefore, the relative role of the environment and neutral processes in governing species turnover may vary ( Liu et al., 2015 Valladares et al., 2015). Moreover, results vary because of differences in the methods, including the spatial extents and the measures of species turnover. Alternatively, neutral processes state that species coexistence results from biogeographic barriers and low dispersal abilities ( Hubbell, 2001 Jia et al., 2015). Several research studies have indicated that species coexistence is attributed to different environmental factors species have different resources, time, and space to achieve coexistence ( Jia et al., 2015 Escudero and Valladares, 2016). The underlying mechanisms governing large-scale species turnover are ambiguous and poorly studied ( De Cáceres et al., 2012) despite several and recent efforts to describe large-scale species turnover patterns of plant ( De Cáceres et al., 2012 Tang et al., 2012a, b Wang et al., 2012b Xu et al., 2015). The drawbacks of this method include coarse spatial resolutions spatial heterogeneity among species composition has been smoothed out, and spatial autocorrelation has increased ( Wang et al., 2012b). Moreover, in the few studies about the patterns of species turnover across latitudes, a great majority is based on the space-filling species of range maps. However, the studies on the patterns of species turnover across latitudes are relatively few. (2009) have shown that the similarity coefficients of North American mammals and African amphibians decrease with increasing spatial distance. (2012) have found that the environmental dissimilarity coefficient of lizards and frogs increased with changing geographical distance and habitat Qian et al. On a large scale, recent studies have demonstrated that species spatial turnover is a key factor for both plants and animals ( Kreft and Jetz, 2007 Qian and Ricklefs, 2008). However, species turnover patterns have received less attention than alpha diversity ( Koleff et al., 2003), and most studies on species turnover have been conducted locally ( Kraft et al., 2011 Wang et al., 2012a). Species turnover pattern (or beta diversity) is a basic pattern in biogeography and macroecology ( Gaston, 2000), and it provides fundamental insights into mechanisms of community assembly, especially on a large scale ( Anderson et al., 2011). Therefore, trees and shrubs should be subjected to different protection strategies in future biodiversity conservation efforts. Neutral processes explained more variation for turnover of tree species, and environmental factors explained more variation for the turnover of shrub species on a large scale. Our results support the hypothesis that the effect of neutral processes on woody species turnover is more important than the effect of the environment. The effects of pure spatial and spatially structured environments were stronger than pure environmental effects for overall woody species. Spatial factors explained 47.92, 48.39, and 41.38% of the total variance in β j, β s, and β sim, respectively. For overall woody species, environment explained 36.30, 37.20, and 48.48% of the total variance in Jaccard’s (β j), Sorenson’s, (β s), and Simpson’s dissimilarity (β sim). The patterns of woody species turnover increased significantly with increasing latitude differences in East Asia. In this study, we explored the large-scale patterns of woody species turnover across the latitude gradient based on eight large stem-mapping plots (covering 184 ha forest) in East Asia. In addition, the determinants of species turnover depend on the dispersal ability of growth forms. However, few studies have described and interpreted large-scale spatial variation in plant species turnover, and the causes of this variation remain elusive. Species turnover is fundamental for understanding the mechanisms that influence large-scale species richness patterns. 3Educational Administration Department, Henan University of Finance and Banking, Zhengzhou, China.2College of Life Sciences, Henan Agricultural University, Zhengzhou, China.1College of Forestry, Henan Agricultural University, Zhengzhou, China.Yun Chen 1†, Zhiliang Yuan 2†, Peikun Li 2, Ruofan Cao 2, Hongru Jia 3 and Yongzhong Ye 2*
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