喀斯特常绿落叶阔叶混交林生态系统稳定性及维持机制

It is the key to accelerate vegetation quick restoration and management of rocky desertification at different succession stages in karst regions that to reveal the stability maintenance mechanism of karst climax community, i.e., evergreen and deciduous broadleaf mixed forests. In the research, vegetation, soil, topography, and litterfall will be investigated and analyzed in the large dynamic monitoring plot with 25 ha area of karst evergreen and deciduous broadleaf mixed forests. The research intends to analyze the community characteristics of the karst evergreen and deciduous broadleaf mixed forests, the interspecific segregation and its internal causes, and the spatial pattern of vegetation community structure and diversity indexes and soil main properties. It plans to identify the potential key-stone species and to then demonstrate the spatial patterns and interspecific associations of these key-stone species. Principal component analysis method is applied to construct the indicator system of forest ecosystem stability which will be tested by Godron stability index method. Principal component analysis (PCA) and canonical corresponding analysis (CCA) are used to find out the major factors of influencing the forest ecosystem stability and to show interaction coupling relationships between stability, and vegetation, soil, topography, and litterfall. Detrended canonical correspondence analysis (DCCA) is used to demonstrate ecosystem stability along ecological environmental gradients and to caculate the relatvie contribution ratio of each group factors to the ecosystm stability. Meanwhile, the relative applicability of species diversity theory, redaduncy theory, and Gaia theory will be examined in the karst forest ecosytem. Finally, the stability maintenance mechanism of the karst forest ecosystem will be revealed, which will enrich the theory of karst forest community ecology and provide guidance for vegetation recovery and ecological restoration in degraded forests in the karst region in southwest China.

揭示喀斯特顶极群落—常绿落叶阔叶混交林的稳定性维持机制是加速喀斯特不同演替阶段植被的迅速恢复及石漠化治理的关键。本项目基于喀斯特常绿落叶阔叶混交林25 ha大型动态监测样地植被、土壤、地形、凋落物的全面调查，分析喀斯特常绿落叶阔叶混交林生态系统的群落特征，探寻种间分离特征及内在原因，研究植被结构和多样性指标以及土壤属性的空间分布格局；确定喀斯特森林生态系统潜在关键种，揭示其空间格局和种间关联；构建森林生态系统稳定性指标体系，并应用Godron指数测定法验证；找出影响喀斯特森林生态系统稳定的主导因子，阐明生态系统稳定性与植被、土壤、地形和凋落物之间的耦合关系，描述稳定性沿生态环境梯度的分布规律，量化各因子的相对贡献率，检验多样性、冗余理论、Gaia假说的相对适宜性，揭示其稳定性维持机制，丰富喀斯特森林群落生态学理论，同时为西南喀斯特地区退化生态系统植被的迅速恢复和生态重建提供科学依据。

揭示喀斯特顶极群落—常绿落叶阔叶混交林的稳定性维持机制是加速喀斯特不同演替阶段植被的迅速恢复及石漠化治理的关键。本项目基于喀斯特常绿落叶阔叶混交林25 ha大型动态监测样地植被、土壤、地形、凋落物的全面调查与分析，发现：喀斯特常绿落叶阔叶混交林生境异质性高，组成丰富，木本植物整体径级结构呈倒“J”形，更新良好；以优势度确定的潜在关键种有小果厚壳桂、香叶树、滇丁香等14种，其径级结构大都呈倒“J”型或“L”型分布，基于完全零随机模型在不同尺度下的空间格局所有物种呈聚集分布；群落物种间的总体表现为显著的正联结，物种之间的相关性随尺度的变化而变化；喀斯特常绿落叶阔叶混交林群落处于相对稳定状态（19/81），沿着坡度减小、土壤深度和养分增加的生态梯度植物群落向阳性和矮化方向发展，样地内中上坡部位群丛稳定性最高，洼地群丛稳定性最低，表明海拔在群落结构及组成中起着重要作用，可能是影响群落分布的重要因素。该研究结果可为维持或者促进西南喀斯特地区森林生态系统稳定、植被恢复提质增效提供科学支撑，同时也为西南喀斯特地区退化生态系统植被的迅速恢复和生态重建提供科学依据。