南昌城市河道自生植物多样性研究

Spontaneous Vegetation Diversity in Urban River Corridors of Nanchang

摘要:

河流廊道是城市自生植物重要的栖息地，揭示不同等级河道自生植物多样性特征及成因，有助于完善城市植被研究体系、指导河流廊道的低维护与可持续景观营造。本研究采用典型样地取样法，于2023年3月—11月对赣江(干流)和乌沙河(支流)样段330个样方进行全面调查，共记录自生植物240种，隶属于49科169属，以草本植物为主。结果表明，两河段在高频种的数量及其生活型组成上均存在差异，支流的高频植物数量较干流多；季节动态主导群落格局，形成春秋季单优势群组连续分布和夏季双群组片段化分布。不同河岸梯度中，除支流Margalef丰富度指数呈现市政道路边>水边的特征外，其余α多样性指数均表现为下段>上段>中段>水边>市政道路边的空间差异特征。Shannon-Wiener多样性指数和Pielou均匀度指数在极端和轻微干扰下呈现出显著差异。城市河岸带自生植物多样性是河岸环境异质性与人为干扰梯度共同作用的结果。因此，生态保护与修复应维系从水边至路边的纵向河岸梯度，尊重群落的季节性动态，并实施以干扰分级为基础的管理方法，即保护轻微干扰、利用中度干扰、疏导高强度干扰。因此，将各梯段的优势乡土植物作为景观资源进行应用，能够使河流廊道的生态修复、低维护管控与特色景观营造协同发展。

Abstract:

River corridors are important habitats for spontaneous plants in cities. Revealing the diversity characteristics and causes of spontaneous plants in different grades of rivers can help improve the urban vegetation research system and guide the low-maintenance and sustainable landscape creation of river corridors. This study adopted the typical plot sampling method to conduct a comprehensive investigation of 330 plots in the sample sections of the Ganjiang River (mainstream) and Wusha River (tributary) from March to November 2023. A total of 240 species of spontaneous plants were recorded, belonging to 49 families and 169 genera, with herbaceous plants being the majority. The results showed that there were differences in the number of high-frequency species and their life form composition between the two river sections, with more high-frequency plants in the tributary than in the mainstream. Seasonal dynamics dominated the community pattern, forming a continuous distribution of single dominant groups in spring and autumn and a fragmented distribution of double groups in summer. Among different riverbank gradients, except for the Margalef richness index of the tributary showing the characteristic of municipal road side>water side, the other α-diversity indices all presented a spatial difference feature of lower section>upper section>middle section>water side>municipal road side. The Shannon-Wiener diversity index and Pielou evenness index showed significant differences under extreme and mild disturbances. The diversity of spontaneous plants in urban riverbanks is the result of the combined effect of riverbank environmental heterogeneity and human disturbance gradients. Therefore, ecological protection and restoration should maintain the longitudinal riverbank gradient from water side to road side, respect the seasonal dynamics of communities, and implement management methods based on disturbance grading, that is, protect mild disturbances, utilize moderate disturbances, and guide intense disturbances. Therefore, applying the dominant native plants of each gradient as landscape resources can promote the coordinated development of ecological restoration, low-maintenance management, and characteristic landscape creation of river corridors.