林分空间结构与物种多样性随空间尺度变化的规律研究

目的 探究林分空间结构、物种多样性随尺度变化的规律及林分空间结构与物种多样性的相互关系,为鄂西南常绿落叶阔叶混交林可持续经营提供科学依据。 方法 以鄂西南七姊妹山自然保护区、木林子自然保护区和金子山国有林场3个研究区的典型植被——亚热带常绿落叶阔叶混交林为研究对象,基于各研究区大样地调查数据,分析从20 m × 20 m到200 m × 200 m不同尺度下,林分空间结构指标和物种多样性指数及其随尺度变化的规律,结合Pearson相关系数法解析尺度变化影响下的空间结构指标与物种多样性的相关性。 结果 鄂西南地区常绿落叶阔叶混交林中物种丰富,常见优势乔木树种为川陕鹅耳枥、多脉青冈和锥栗。林分空间结构特征在尺度 ≥ 120 m × 120 m后变化趋于稳定,整体表现出微聚集分布、大小分化中庸且混交良好的状态。不同尺度上林分空间结构参数角尺度与林分物种多样性存在中度相关性（P < 0.01）,其他结构参数与林分多样性不存在相关性。 结论 鄂西南亚热带常绿落叶阔叶混交天然林,林分空间结构调查的最适尺度为120 m × 120 m;不同研究尺度下,角尺度是林分空间结构影响物种多样性的一个关键因子。

Variations on Stand Spatial Structure and Species Diversity in Different Spatial Scales

Objective To provide a scientific reference for the sustainable management of evergreen deciduous broad-leaved mixed forest in southwest Hubei. Method The stand spatial structure and species diversity as well as their correlations in the different spatial scales ranging from the sample size 20 m × 20 m to 200 m× 200 m in the subtropical evergreen deciduous broad-leaved mixed forests in Qizimeishan National Nature Reserve, Mulinzi National Nature Reseve and Jinzishan National forest farm in southwest Hubei province were explored. Result The tree species were abundant in this study, and Carpinus fargesiana, Cyclobalanopsis multinervis and Castanea henryi were dominant tree species. The spatial structure diversities tended to be stable when the sample size ≥ 120 m× 120 m, showing the state of micro-aggregation distribution, moderate differentiation and good mixing. The Uniform angle index was correlated with species diversity (p < 0.01) at different scales, while other structural parameters had no correlations with species diversity. Conclusion The optimum investigation scale for the stand spatial structure of subtropical evergreen deciduous broad-leaved mixed forest in southwest Hubei is 120 m × 120 m. In addition, the Uniform angle index was a key factor of stand spatial structure affecting species diversity in different spatial scales.