Elucidating the major drivers of bryophyte distribution is the first step to protecting bryophyte diversity. Topography, forest, substrates (ground, tree trunks, roots, rocks, and rotten wood), and spatial factor, which factors are the major drivers of bryophyte distribution? In this study, 53 plots were set in 400 m2 along the elevation gradient in Xiaoqinling, China. All bryophytes in the plots were collected and identified. Regression analysis was used to examine the relationship between bryophyte and substrate diversity. We compared the patterns of overall bryophyte diversity and diversity of bryophytes found on the ground, tree, and rock along elevational gradients. Canonical correspondence analysis was applied to relate species composition to selected environmental variables. The importance of topography, forest, substrates, and spatial factors was determined by variance partitioning. A total of 1378 bryophyte specimens were collected, and 240 species were identified. Bryophyte diversity was closely related to substrate diversity. The overall bryophyte diversity significantly increased with elevation; however, the response varied among ground, tree, and rock bryophytes. Tree diversity and herb layer were considered important environmental factors in determining bryophyte distribution. Species abundance was best explained by stand structure (17%), and species diversity was best explained by stand structure (35%) and substrate (40%). Results directly indicated that substrate diversity can improve bryophyte species diversity. The effects of micro-habitat formed by stand structure and substrate diversity were higher than those of spatial processes and topography factors on bryophyte distribution. This study proved that the determinant factors influencing bryophyte diversity reflect the trends in recent forest management, providing a real opportunity to improve forest biodiversity conservation.

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Aims Tree mortality is an important ecological process in forest ecosystems. The aims of this study were to determine how tree mortality influences the spatial patterns and interspecific associations of plant species, and what are the causes of tree mortality in a 1 hm 2 permanent plot in Baotianman National Nature Reserve, Nanyang City, Henan Province. Methods We conducted field investigations in the plot and used spatial point pattern analysis to examine the spatial patterns and interspecific associations of 17 species prior to and following mortality. Important findings (1) Most of the species in the study plot showed an aggregated distribution both pre-and post-mortality. However, the number of species showing aggregated distribution decreased and the number of species showing random distribution increased following the mortality event. (2) Most species were positively associated with Quercus aliena var. acuteserrata both pre-and post-mortality, while some had no apparent association. Following tree mortality, on fine scales, the number of species with positive associations increased, and the number of species with negative associations decreased. (3) Tree mortality was in consistency with the random death hypothesis. The interspecific associations of four species with Q. aliena var. acuteserrata completely changed following death. For most species, the spatial patterns and the interspecific association with Q. aliena var. acuteserrata either changed at minor scales or did not change. The variations in spatial patterns or interspecific associations were inconsistent among species. (4) The dead trees of Q. aliena var. acuteserrata were significantly