北京城市蝴蝶蜜源植物网络特征及重要蜜源植物识别

物种间相互作用网络研究能为物种多样性的保护、城市生态系统稳定性的维持提供指导。基于群落水平的城市蝴蝶蜜源植物互作网络的研究较少，对城市蝴蝶蜜源网络结构缺乏深入认识。研究在国内城市生态系统中构建蝴蝶蜜源网络，并探讨不同类型植物对网络特征的影响。2020年6-9月，在北京26个城市公园中记录访花蝴蝶和蜜源植物物种及互作频次，采用交互多样性（ID）、交互均匀性（IE）、专业化程度（H2''）定量化生态网络结构特征，采用Kruskal-Wallis秩和检验和变差分解分析不同生长型、起源、栽培方式的植物类型对网络结构的影响差异。采用物种的伙伴多样性（PD）和专业化程度（d''）识别重要蜜源植物。研究结果表明：（1）北京城市公园中22种蝴蝶与81种开花植物的交互作用，形成趋于泛化的生态网络结构；（2）不同生长型及不同起源的植物-蝴蝶网络的交互多样性及专业化程度有显著差异，草本及乡土植物对丰富网络中交互多样性和支持专业性更高的蝴蝶物种具重要作用，而植物的栽培方式对蜜源网络结构影响较小；（3）伙伴多样性高且专业化程度高的植物可被视为重要蜜源植物。基于蝴蝶多样性保护的目标，在城市生态系统中，绿色空间应注重构建乡土草本植物群落，优先选择重要蜜源植物。我们的发现印证了蝴蝶-蜜源植物生态网络方法作为联结生态研究和城市绿地实践管理的有效工具，能为城市生态系统中生物多样性保护提供科学策略，具有重要意义。

Characteristics of butterfly-nectar plant network in Beijing's urban parks and identifying important nectariferous plant species

Study on ecological networks about species interactions provides a basis for species diversity protection, and it is beneficial for the maintenance of urban ecosystem stability. However, urban ecological network study between butterfly and plant based on community level still leaves a huge blank, therefore, the knowledge of butterfly-nectar plant network structure needs an in-depth understanding. To our knowledge, ours is the first study focusing on butterfly-nectar plant network in urban ecosystems in China and evaluating the effects of different type of plants on butterfly-nectar plant network. In this study, we surveyed flower visiting butterfly species and nectariferous plant species and the interaction frequency in 26 urban parks in Beijing, China from June to September in 2020. The butterfly-nectar plant bipartite network was built. We identified five quantitative metrics on two hierarchical levels (network and species) to describe network patterns and species'' interaction. Metrics on network level were interaction diversity (ID), interaction evenness (IE) and network specialization (H2''). Moreover, we analyzed the effect of different vegetation types on the network structure differences, including different type of growth form, origin, and cultivation plant, using Kruskal-Wallis test and variance partitioning analysis. Metrics on species level were partner diversity (PD) and species specialization (d'') for identifying important nectariferous plant species that provide a key and central role to the stability of the structure of network. The results are as follows: (1) 22 species of butterfly and 81 species of flowering plants of interaction were observed and the butterfly-nectar plant network tended to be generalized. (2) The interaction diversity and specialization of two growth form plant-butterfly network were significantly different (P<0.01), and same to of two origin plant. Furthermore, herbs and native plants played an important role in maintaining the interaction diversity and specialized butterfly species in the network. Interestingly, cultivation type of plants had little effect on nectar network structure. (3) Plants with high partner diversity and high degree of specialization could be regarded as important nectariferous plant species. Consequently, in order to protect butterfly diversity, native herbaceous plant community should be constructed in green space of urban ecosystem, and important nectariferous plant species should be given top priority to grow. Our findings confirm that the butterfly-nectar plant ecological network can provide a scientific strategy for biodiversity conservation in urban ecosystems. It could be an effective tool to link ecology research with urban green space practice management.