中国五类重要桦木属植物群系气候生态位

Several important Betula Linn. biomes climatic ecological niches and potential distribution areas

选择我国面积大、分布广泛、资源数量多的五类桦木属植物群系(白桦(Betula.platyphylla)、黑桦(B.dahurica)、红桦(B.albosinensis)、亮叶桦(B.luminifera)、枫桦(B.costata)),在群系水平上探讨其气候生态位,通过拟合Weibull概率密度函数,定量分析其地理分布与各气象指标间的关系,据此估计其气候生态位核心分布区与最大分布范围,并以ROC曲线法检验各类桦木属植物群系的超体积生态位模拟的准确程度,结果均为极满意。说明综合文中几项气象指标可以较为准确的模拟五类桦木属植物群系(亚群系)的气候生态位模型。应用PCA双序分析,探讨了不同气象指标最适生态位与生态幅宽度对桦属植物分布的影响。显示,白桦属低温、低湿、宽生态幅种,红桦属高温、高湿、宽生态幅种;枫桦与黑桦属低温、低湿、窄生态幅种;亮叶桦属高温、高湿、窄生态幅种。白桦、红桦群系表现出较宽生态幅,与最适生态位指标相关性相对较弱。枫桦、黑桦群系分布特征受极端低温(T_(min))、最冷月均温(Tc)、年均降雨量(AP)、Kira温暖度指数(W_I)四项生态幅指标相关性较强,与最低温和蒸发量指标存在较强的正相关性,与年均温存在较强负相关。亮叶桦群系分布与最热月均温(Tw)、湿润指数(HI)、温暖指数(WI)及年均降雨量(AP)存在较强正相关,与极端低温(T_(min))、最冷月均温(Tc)等存在强负相关。研究成果可用于指导各类桦属植物的种质保护、引种绿化,同时在全球气候变化的背景下,可为五类桦属植物的潜在种质区域迁移提供科学依据。

Five widely distributed and resources abundant Betula[Betula platyphylla,B.dahurica,B.albosinensis,B.luminifera,B.costata]in China were chosen and their climatic ecological niche in formation level were studied.Weibull probability density function was used to quantitative analyze the relationship between each geographical distribution and climatic indices,and climatic niche core distribution area and maximum distribution range were estimated.The accuracy of the ultra-volume niche simulation of various species of Betula genus was tested by ROC curve method,and the results were extremely satisfactory,that indicated that several meteorological indicators in the comprehensive text can accurately simulate the climate niche model of five types of birch vegetation groups(sub-groups).PCA double-sequence analysis was used to explore the effect of the optimal niche of different meteorological indicators on the distribution of birch plants.The results showed that B.platyphylla belongs to low temperature and low humidity wide niche species,B.costata and B.dahurica belong to low temperature,low humidity and narrow niche species;B.luminifera belongs to high temperature,high humidity and narrow niche species.B.platyphylla and B.albosinensis showed a wider niche,and have relatively weak correlation with the optimal niche index.The distribution of B.costata and B.dahurica are strongly correlated with the four ecological indicators:extreme low temperature(Tmin),coldest monthly average temperature(Tc),annual average precipitation(AP),and Kira warmness index(WI).B.platyphylla and B.albosinensis show a strong positive correlation with the lowest temperature(Tmin)and evaporation,and a strong negative correlation with the annual average temperature(T).There is a strong positive correlation between the distribution of B.luminifera and the hottest monthly mean temperature(Tw),wetness index(HI),warming index(WI)and average annual precipitation(AP),while a strong negative correlation with extreme low temperature(Tmin)and coldest monthly average temperature(Tc).The research results can be used to guide the germplasm protection,introduction and greening of various birch plants,and provide a scientific basis for the migration of potential germplasm regions of five species of Betula in the context of global climate change.