关键词: β多样性, 周转, 嵌套, 广义相异性模型 (GDM), 环境异质性

Abstract:

【Objective】This study explored the patterns and environmental factors that drived β diversity and its components in plant communities on the northern slope of Changbai Mountain, to provide a theoretical basis for biodiversity conservation and ecosystem management in the area.【Method】The betapart package of R was used to decompose the components (turnover and nestedness) of β diversity. The generalized dissimilarity modelling (GDM) was used to explore the environmental factors that drived β diversity and its components.【Result】Decomposition of the β diversity components revealed that the β diversity of the plant communities was dominated by the turnover, indicating that species replacement leads to differences in species composition among communities. The results of GDM analysis showed that 13 environmental variables explained 32.63%-66.52% of the β diversity and the turnover components of the plant communities. The mean annual air temperature significantly influenced the arbor β diversity. The arbor β diversity was significantly affected by the annual precipitation and soil bulk density when they reached values higher than 710.00 mm and 1.07 g/cm³, respectively. The turnover components of arbor β diversity were primarily affected by the mean annual air temperature, soil bulk density, and slope. The turnover rate increased with an increase in the values of the predictive variables once the threshold was surpassed. The growth rate of shrub β diversity and its turnover components exhibited a downward, constant and upward trend, respectively, for shrub plants following an increase in air temperature seasonality, slope and mean annual air temperature. However, in response to the major determinants, the gradient changes in the β diversity of herbs and its turnover components increased with altitude, decreased with rising isothermality, and initially increased and then decreased following an increase in soil organic carbon.【Conclusion】Altogether, the findings revealed a turnover pattern in the species composition of plant communities in the northern slope of Changbai Mountain, indicating that biodiversity conservation efforts should focus on multiple species and at multiple regions. The β diversity patterns are primarily affected by environmental factors. The arbor β diversity and its turnover components are primarily affected by the mean annual air temperature, while those of shrub plants are mainly affected by seasonal variations in air temperature, and those of herbs are primarily limited by the altitude.

Key words: β diversity, turnover, nestedness, generalized dissimilarity modelling (GDM), environmental heterogeneity