近自然社区公园的生物多样性特征——以北京市中心城区为例

城市绿地为城市动植物提供了重要栖息地,对城市生物多样性保护具有重要意义。然而,传统社区公园绿地（"传统绿地"）主要围绕安全、景观和游憩功能,植物种类偏少,群落结构单一,为城市野生动物提供食源和栖息地的资源有限。北京市以2035规划"留白增绿"为政策背景,在中心城区建设一系列小型近自然社区公园绿地（"近自然绿地"）,在植物物种组成、群落结构和管理方式上有别于以往的传统绿地。一般认为生物多样性在一定范围内随面积的增大而提高,那么对于受到高度干扰的小型绿地,"近自然"特征是否能够显著提高其包括昆虫、鸟类在内的生物多样性？为探究这类近自然绿地的生物多样性特征,在2020年8月至2021年3月,综合采用样方法、样线法,对北京市西城区2个近自然绿地及4个传统绿地的植物、昆虫和鸟类进行调查,分析比较其多样性特征。结果表明,近自然绿地的灌木和草本层丰富度和多样性显著高于传统绿地,均匀度则无显著差异;近自然绿地的昆虫和鸟类的丰富度、多样性显著高于传统绿地,均匀度则无显著差异。与传统绿地相比,近自然绿地具有更丰富的鸟类食源、蜜源植物,以及更为复杂的植被垂直结构。根据以上结果,近自然绿地具有比传统绿地更为显著的生物多样性优势,建议在进行城市绿地建设时,应增加植被结构复杂的近自然绿地的比例,增加绿地的灌木和草本层多样性。研究成果不仅丰富了小面积绿地的生物多样性内涵,且可为大都市近自然绿地营建提供理论依据。本研究还将为今后公园设计、改造和管理提供新的思路,引导绿地向基于生物多样性保护的方向可持续发展。

Biodiversity characteristics in near-natural community parks: A case study in the central area of Beijing

Urban green space provides an important habitat for urban flora and fauna, and is of great significance to the conservation of urban biodiversity. However, the traditional community green space ("traditional green space") mainly focuses on the functions of safety, landscape viewing and recreation, with fewer plant species, and single community structure, which makes it difficult for traditional green space to provide abundant food source and habitat for urban wildlife. Under the policy background of "building green space in the vacated space, where illegal construction was demolished" in Beijing Urban Master Plan (2016-2035), Beijing has built a series of small near-natural community green space ("near-natural green space") in the central city, with different species composition, community structure and management methods from the traditional green space. It is generally believed that biodiversity increases with the increase of green space area in a certain range. For small green space that is highly disturbed by urban surroundings, can the near-natural feature of it significantly improve its biodiversity, including insect and bird diversity? In order to explore the biodiversity characteristics of this kind of green spaces, we investigated the plants, insects and birds in two near-natural community gardens and four traditional community gardens, with sample method and transect method comprehensively, in Xicheng District, Beijing, from August 2020 to March 2021. The biodiversity characteristics between traditional and near-natural green space were analyzed and compared. The results showed that the richness and diversity of shrubs and herbs in the near-natural parks were significantly higher than those in the traditional green spaces, while the evenness of shrubs and herbs in two kinds of green space had no significant difference; the richness and diversity of insects and birds in the near-natural parks were significantly higher than those in the traditional green spaces, while the evenness of birds and insects in two kinds of green space had no significant difference. Compared with traditional green spaces, near-natural green spaces had significantly higher richness of bird-feeding plants and nectariferous plants. In addition, the vertical planting structure was significantly more complex in near-natural green spaces. According to the above results, it is suggested that the area ratio of multi-layered planting should be improved, and the diversity of shrubs and herbs should also be increased in the construction of urban green spaces. The research results not only enrich the biodiversity connotation of small green space, but also provide a theoretical reference for the construction of urban near-natural green space. The research will provide new thoughts for urban park design, reform and management, and guide the sustainable development of green space in metropolis based on biodiversity conservation.