黄河下游平原非农植物多样性拆分研究

Additive partitioning of non-agricultural plant diversity in the lower reaches of the Yellow River plain

非农生物多样性的存在是农业景观生态系统健康持续发展的基础,对农业景观非农生境中植物群落物种多样性特征分析将有助于可持续农业景观构建措施的科学提出。在黄河下游平原典型农业景观中采用栅格分区的方式布设样点(共54个),采用典型样地法对各样点内的林地、树篱、田间道路和沟渠等主要非农生境的植物群落进行调查,采用生物多样性加性分配的方法探讨不同空间尺度上生物多样性的组成特征。结果显示:(1)各非农生境间植物群落物种多样性特征存在较大的差异。(2)偶见种从数量上构成了各非农生境中植物物种丰富度的主体,而常见种则行使着群落优势种和构建者的角色。(3)总体上,β多样性在各空间尺度中均对总物种丰富度具有重要贡献。(4)常见种和偶见种中物种组成格局存在显著差异:常见种的物种丰富度主要由α多样性贡献,而β多样性则贡献了偶见种的绝大部分。简言之,β多样性对区内植物多样性的保护和维持意义重大,农业景观中非农生境类别的出现对总物种丰富度的提高具有重要作用;各生境中较高的样点间β多样性(β样点)意味着在看似均质化的农业景观背景中依然具有较高的区域差异;景观组成和构型的变化将对农业景观中植物群落特征和物种多样性产生重要影响,且对偶见种的影响更甚。未来,应从景观和区域等更大尺度上,基于农业景观生态系统功能和服务的综合考虑及可持续农业景观的建立来探讨农业活动与生物多样性保护的权衡。

Biodiversity plays a crucial role in producing and maintaining ecosystem functions and services, so biodiversity conservation and preservation are prerequisites for the sustainability of regional landscape ecosystems. The mechanisms determining spatial patterns of plant communities in non-agricultural habitats are the basis for the construction of sustainable agro-landscapes. To understand the composition of plant communities in non-agricultural habitats, 54 plots were established in Fengqiu County, Henan Province. Plant communities in non-agricultural habitats （planted forests, treelines, field roads, and ditches） were investigated using the Braun-Blanquet method, and the spatial pattern of plant species diversity was analyzed by additive partitioning. We found that species richness and diversity were significantly higher in planted forests and treelines than in field roads and ditches, and field roads had the lowest plant diversity. A comparative analysis of common and rare species showed that rare species were the main component of species richness in non-agricultural habitats, whereas common species were dominant in agricultural habitats. Additive partitioning of species richness showed that β diversity made an important contribution to total regional species richness across multiple spatial scales. At the quadrat scale, α diversity contributed about 50% of the total species richness of common species, and the contribution of α＋β1 was more than 75% of the total common species richness. For rare species, the contribution of α was less than 6% of total species richness in each habitat. In contrast, β2 contributed up to 97% of total rare species richness, especially in field roads. At the regional scale, the contribution of α was only 1.86%, while β2＋β3 contributed more than 95% of total rare species richness. According to the results, the emergence of non-agricultural habitat could play an important role in improving total species richness in agro-landscapes. In addition, changes in landscape composition and configuration could have a profound impact on plant diversity, and the effects would be stronger for rare species. In future, more attention should be paid to the tradeoffs between agricultural production and sustainability of ecosystem services on landscape and regional scales, and improvement of the ecological processes and ecosystem services controlled by biodiversity should be emphasized.