白洋淀湿地不同生境植物群落功能多样性和功能冗余及其对环境因子的响应

Functional Diversity and Functional Redundancy of Plant Communities in Different Habitats of Baiyangdian Wetland and Their Responses to Environmental Factors

功能多样性和功能冗余与植物群落稳定性和抗干扰能力密切相关,评估植物群落功能多样性、功能冗余以及主要环境驱动因子能够为生物多样性保护和生态系统功能维持提供重要参考。文章针对白洋淀湿地水生植物群落和洲滩草本植物群落,选取比叶面积、叶绿素含量、叶干物质含量、植物氮含量、植物磷含量、植物钾含量6个植物功能性状,利用基于性状概率密度的功能指数评估白洋淀湿地不同生境植物群落功能多样性和功能冗余,利用多元回归检验影响植物群落功能多样性和功能冗余的关键环境因子。结果发现,白洋淀洲滩草本植物群落功能丰富度和功能冗余显著高于(P <0.05)水生植物群落,而功能均匀度和功能分散度显著低于水生植物群落。功能丰富度和功能冗余与物种丰富度显著正相关,功能分散度与物种多样性表现为显著负相关。生境中有效氮含量和磷元素含量是影响白洋淀湿地2种生境植物群落功能多样性和功能冗余的主要环境因子,另外,土壤自然含水量和pH值对洲滩草本植物群落功能特征也有显著影响,与水生植物群落功能特征显著相关的环境因子还包括化学需氧量、水体砷和底泥速效钾。研究结果表明丰富群落物种库、调节和改善生境条件是提高白洋淀湿地植物群落功能多样性和功能冗余水平的有效途径。

Functional diversity and functional redundancy are closely related to the stability and resilience to disturbance of plant communities. Assessing the functional diversity, functional redundancy and main environment-driving factors of plant communities can provide important references for biodiversity protection and ecosystem function maintenance. In this study, based on the aquatic plant community and the floodplain herbaceous plant community, six plant functional traits, including specific leaf area, chlorophyll content, leaf dry matter content, plant nitrogen content, plant phosphorus and plant potassium content, were selected to evaluate the functional diversity and functional redundancy of plant communities under different habitats in Baiyangdian wetland by using the functional indices based on trait probability density. Multiple regression was used to assess the effects of the environmental factors on the functional diversity and functional redundancy of plant communities. The results showed that the functional richness and functional redundancy of floodplain herbaceous plant community were significantly higher than those of the aquatic plant community, while functional evenness and functional divergence were significantly lower than those of the aquatic plant community. Functional richness and functional redundancy were significantly positively correlated with the species richness, functional divergence and species richness were significantly negatively correlated. The content of available nitrogen and phosphorous in the habitat were the main environmental factors affecting the functional diversity and functional redundancy of the plant communities in the two habitats of Baiyangdian Wetland. In addition, soil water content and pH value also had a significant effect on the functional characteristics of the floodplain herbaceous plant community, and the environmental factors significantly correlated to the functional characteristics of the aquatic plant community also included chemical oxygen demand, water arsenic and soil available potassium. The results suggested that enriching community species pool, regulating and improving habitat conditions was an effective way to improve the functional diversity and functional redundancy of plant community in Baiyangdian Wetland.