Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, 530004, China.
Laibin Jinxiu Dayaoshan Forest Ecosystem Observation and Research Station of Guangxi. No, Jinxiu County, 95 Gongde Road, Laibin, 545700, Guangxi, China.
BMC Ecol Evol. 2024 Mar 28;24(1):40. doi: 10.1186/s12862-024-02229-y.
Species and structural diversity are important for understanding the formation of forest communities, key ecological processes, and improving forest ecological functions and services, but their spatial characteristics have received little attention. Based on the spatial relationships among neighbouring trees, we proposed to divide trees within a structural unit into 15 structural types, and used the univariate distributions of the uniform angle index (W), mingling (M), and dominance (U), along with four common species diversity indices, to analyse the diversity of structural types in natural forests near the Tropic of Cancer.
Only a portion of clumped class maintained aggregation, most exhibited a random pattern. Species mixture increased exponentially across distribution classes, and abundance and richness exhibited an initial increase followed by a slight decrease. The distribution patterns of mixture classes varied from highly clustered to random, and M distributions gradually shifted from an inverted J-shaped curve to a J-shaped curve. Abundance and richness exhibited an exponential distribution, whereas the Shannon-Wiener index increased linearly. The W distribution of differentiation classes approximated a normal distribution, whereas M distributions exhibited a J shape. The U distribution of each structure type was approximately 0.2.
These results reveal the species and structural diversity characteristics of trees at the structural type level and expand our knowledge of forest biodiversity. The new method proposed here should significantly contribute to biodiversity monitoring efforts in terrestrial ecosystems, and suggests that higher standards for the simulation and reconstruction of stand structure, as well as thinning in near-natural forests, is warranted.
物种和结构多样性对于理解森林群落的形成、关键生态过程以及提高森林生态功能和服务至关重要，但它们的空间特征尚未得到充分关注。基于相邻树木之间的空间关系，我们提出将结构单元内的树木划分为 15 种结构类型，并使用均匀角指数 (W)、混交度 (M) 和优势度 (U) 的单变量分布以及四种常见的物种多样性指数来分析近热带地区天然林的结构类型多样性。
仅部分聚集类保持聚集，大多数呈现随机模式。物种混合度随分布类别的增加呈指数增长，丰度和丰富度先增加后略有减少。混合类别的分布模式从高度聚集到随机变化，M 分布逐渐从倒 J 形曲线变为 J 形曲线。丰度和丰富度呈指数分布，而香农-威纳指数呈线性增加。分化类别的 W 分布近似正态分布，而 M 分布呈 J 形。每种结构类型的 U 分布约为 0.2。
这些结果揭示了树木在结构类型水平上的物种和结构多样性特征，并扩展了我们对森林生物多样性的认识。这里提出的新方法应该会极大地促进陆地生态系统的生物多样性监测工作，并表明需要更高的标准来模拟和重建林分结构，以及对近自然林进行疏伐。
