Objective With climate change and other environmental problems becoming increasingly severe, the construction of China’ s ecological civilization has entered a critical period of green, low-carbon and circular development. Although garden plants are a key link in the carbon cycle of urban ecosystems, most of the plants cultivated in urban parks are ornamental ones that entail long-term, high-intensity maintenance management, which often consumes a large amount of resources and makes it difficult to balance the carbon emissions generated by human life. In this context, how to obtain maximum ecological benefits with minimum resource consumption has become an urgent task for the transformation and development of urban green space, and the resource saving rate and energy saving and emission reduction benefits of urban parks have become the focus of attention. Near-natural parks, as an effective solution, typically select low-maintenance or even self-maintained native plants with compound, heterogeneous and mixed community structures, and these parks only entail low-maintenance management. Meanwhile, self-maintained plants, as widespread urban native plants, do not require much maintenance management, and this feature, combined with the concept of low-cost management, has made them the ideal plant material used in near-natural parks and the focus of attention in traditional parks. The emergence of low-carbon gardens has put forward new ideas to meet the needs of low-carbon development, and near-natural parks are an important practice of low-carbon gardens that aim to explore the high carbon sink benefits of spontaneous plants during the planting, maintenance, and construction of plantscape dominated by native plant communities. Spontaneous plants are usually regarded as weeds, existing in areas of spontaneous growth in urban parks without proper care and management, and are the main targets for gardeners to remove.

Methods Taking the 13 urban parks in Xicheng District, Beijing as an example, this research, on the basis of combing domestic and international maintenance management policies and the current development situation, analyzes the impacts of the differences in the maintenance management of different types of parks on the species composition, diversity and community composition of spontaneous plants through the research methods of literature collection and field investigation, and puts forward a maintenance management system that is suitable for different types of parks.

Results Research findings are summarized as follows. 1) Urban parks in Xicheng District differ in terms of maintenance management strategies depending on the type of park. Near-natural parks and traditional parks differ primarily in terms of weeding and pruning, with the former not doing so to preserve the natural state of plants and the latter doing so on a regular basis to preserve the overall landscape effect. At other levels, such as irrigation, fertilizer application, and pest control, there are no appreciable differences between the two types of parks. 2) A total of 36 species of spontaneous plants classified into 32 genera under 17 families are recorded, with the near-natural parks having the highest number of species; under the influence of varying maintenance management, there is no discernible difference in the richness and diversity of spontaneous plants among the various park types, with the near-natural parks having the highest mean value; the spontaneous plant communities are impacted by the differences in maintenance management in terms of the composition of plant species, with traditional parks being dominated by annual or biannual plant communities and near-natural parks dominated by perennial plant communities; nevertheless, there is a significant difference in the homogeneity of the spontaneous plants, with large-scale traditional parks having the largest mean value. 3) Urban park maintenance management has two primary problems and difficulties: First, it is challenging to meet the needs of low-carbon development in urban parks due to the lack of specialized technical solutions for maintenance management and the obvious shortcomings in the application of policy measures in maintenance management; second, all types of parks contain spontaneous plants, which have large potential for gardening uses. It is critical to focus on applying spontaneous plant communities along with various maintenance management techniques and strategies to create plant communities that are appropriate for various environments. Based on the above findings, the research proposes the following optimization strategies for maintenance management applicable to different types of parks: clarify the maintenance management system; modify the species composition of plant communities; improve technical measures for maintenance management.

Conclusion This research emphasizes the key role of spontaneous plants in the maintenance management of urban parks, and the research results may provide new ideas and directions for the reform of park management, thus effectively promoting the low-carbon sustainable urban development.