黔中喀斯特次生林主要物种的生态位及种间联结性动态变化

Dynamic Changes in Niche and Interspecific Association of Major Species of Karst Secondary Forest in Central Guizhou

摘要:

为探讨黔中喀斯特次生林演替规律，基于2013-2019年的定点监测数据，从群落物种组成、生态位宽度、生态位重叠值、种间联结等方面研究了黔中喀斯特次生林生态位和种间联结性的动态变化。结果表明，7年间建群种的重要值占比减小，六月雪（Serissa japonica）、珍珠荚蒾（Viburnum foetidum）等物种优势度显著增加。竹叶椒（Zanthoxylum armatum）、小果蔷薇（Rosa cymosa）等占据较宽生态位，云南旌节花（Stachyurus yunnanensis）、六月雪等物种对资源的可利用量增加，使得其生态位变窄。生态位重叠值小于0.2的种对比例减少，种间竞争关系更为复杂。主要物种间的总体联结性由不显著正联结变为显著正联结，多数种对间的正负联结比例上升。黔中喀斯特次生林群落中种间竞争激烈且渐趋稳定，种间联结紧密性增强，在正向演替过程中，伴随着六月雪、珍珠荚蒾等耐阴种和中生性种的优势度和竞争力增大，小冻绿树（Rhamnus rosthornii）和杭子梢（Campylotropis macrocarpa）等先锋种竞争不足而衰退。这为喀斯特地区植被恢复和石漠化治理提供参考。

Abstract:

To explore the succession rule of karst secondary forest in central Guizhou, based on the fixed-point monitoring data in 2013-2019, the dynamic changes of niche and interspecific association of karst secondary forest in central Guizhou were studied, including community species composition, niche width, niche overlap and interspecific association. The results showed that the proportion of important value of constructive species decreased in 7 years, and the dominance of species, such as Serissa japonica and Viburnum foetidum, increased significantly. Zanthoxylum armatum and Rosa cymosa occupied a wide niche, while the niche width of Stachyurus yunnanensis and Serissa japonica and other species have increased resource availability, which narrowed their niche width. The proportion of species pairs with niche overlap less than 0.2 decreased, and the relationship of interspecific competition was more complex. The overall connectivity among main species changed from non-significant positive association to significant positive association, and the proportion of positive and negative association between most species increased. In the karst secondary forest community of central Guizhou, the competition among species was intense and gradually stable, and the connection between species was strengthened. In the process of positive succession, the dominance and competitiveness of shade tolerant and mesophily species, such as Serissa japonica and Viburnum foetidum increased, but some pioneer species, such as Rhamnus heterophylla and Campylotropis macrocarpa, declined due to insufficient competition. Therefore, these would provide a reference for vegetation restoration and rocky desertification control in karst areas.