Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, Hainan, China.
Key Laboratory of Wildlife Evolution and Conservation in Mountain Ecosystem of Guangxi, School of Environmental and Life Sciences, Nanning Normal University, Nanning, Guangxi, China.
PeerJ. 2023 Oct 27;11:e16331. doi: 10.7717/peerj.16331. eCollection 2023.
The seasonal rainforests distributed across the tropical karst hills of south China are of high biodiversity conservation value and serve many important ecosystem functions. However, knowledge surrounding distribution patterns of woody plants in tropical karst hills remains limited. In this study, we surveyed the distribution of families, genera and species of woody flora at four slope positions (depression, lower slope, middle slope, and upper slope), and analyzed the influence of topographic and soil variables on the distribution of woody plants in the tropical karst hills of south China. Forty forest plots (each 20 m × 20 m) contained 306 species of woody plants with a diameter at breast height (DBH) ≥1 cm, representing 187 genera and 66 families. As slope increased, the number of families increased slowly, and the number of genera and species followed a concave-shaped trend, with the lowest number of genera and species in the lower slope position. Differences in species composition were significantly stronger between slope positions than within slope positions. The topographic and soil variables explained 22.4% and 19.6%, respectively, of the distribution of woody plants, with slope position, slope degree, soil potassium and soil water content as the most significant variables. The results of generalized linear mixed model analysis showed that total R of fixed effects on variation of woody species richness was 0.498, and rock outcrop rate and soil total phosphorus were the best fitting effects. Our results help to explain the community assembly mechanism and to inform management and protection strategies for species-rich seasonal rainforests in the karst area.
中国南方喀斯特丘陵地区分布的季节性雨林具有很高的生物多样性保护价值，发挥着许多重要的生态系统功能。然而，关于喀斯特丘陵地区木本植物分布模式的知识仍然有限。在这项研究中，我们调查了四个坡面位置（洼地、下坡、中坡和上坡）的木本植物科、属和种的分布，并分析了地形和土壤变量对中国南方喀斯特丘陵地区木本植物分布的影响。40 个森林样地（每个 20 m×20 m）包含了 306 种胸径（DBH）≥1cm 的木本植物，代表了 187 个属和 66 个科。随着坡度的增加，科的数量缓慢增加，而属和种的数量呈凹形趋势，在较低的坡面位置属和种的数量最少。坡位之间的物种组成差异明显大于坡位内的差异。地形和土壤变量分别解释了木本植物分布的 22.4%和 19.6%，其中坡位、坡度、土壤钾和土壤含水量是最重要的变量。广义线性混合模型分析的结果表明，固定效应中对木本物种丰富度变化的总 R 值为 0.498，而露头率和土壤总磷是最佳拟合效应。我们的研究结果有助于解释群落组装机制，并为喀斯特地区物种丰富的季节性雨林的管理和保护策略提供信息。
