北京城市公园环境下自生植物物种组成及多样性时空特征

城市绿地中的人工栽培植物景观已造成资源消耗过高、景观同质化等一系列问题。随着人类生态意识的提高,城市中可自播繁衍、无需过多养护管理同时可发挥生态效益的自生植物引起了国内外的广泛关注,但以往研究主要以整个城市环境作为基底,针对其在城市绿地中的分布特征鲜有报道。为揭示城市绿地中自生植物的多样性特征及其分布的时空格局以指导低维护景观的营建,本研究以北京奥林匹克森林公园为例,采用网格布样法,于2015年生长季的3—11月对所有样点重复调研七次,运用多样性指数、群落聚类、Duncan检验等统计计算方法针对物种组成、群落多样性及群落分类进行了深入探讨。结果表明:全园自生植物丰富,共记录到32科98属128种,其中乡土植物占76.56%,外来植物占23.44%,入侵植物占12.50%。在物种组成的时间变化上,各月份记录到的物种数呈单峰型分布,8月末物种数达到峰值,为98种;菊科(Asteraceae)植物物种数在整个生长季显著高于其他科,外来植物物种数及其所占比例均在夏季达到最高。从空间格局看,路边和林地是样方数量最多的生境类型,所容纳的物种数也最多,分别为109和106种。自生植物群落多样性在10月初显著高于其他月份,其次是8月末、4月末和6月初;各生境下的群落多样性排序较为不稳定,分析认为这是由于各季节不同程度的外界干扰所致。依据物种优势度,自生植物群落共被划分成了42个群落组,各季节和各生境下有其特定优势种和群落组合,其中有9个群落组在春、夏、秋三季均有出现,且大多数群落组随着季节变化景观呈现出丰富的野趣效果。这些研究结果在未来低维护、具有较高生物多样性及地域性特色的可持续性城市绿地植被景观营造中具有重要的参考价值。

Temporal and spatial characteristics of spontaneous plant composition and diversity in a Beijing urban park

The planted vegetation in urban green spaces results in high consumption of resources and landscape homogeneity. With the increasing ecological awareness, spontaneous plants have gained attention at home and abroad for their variety of positive attributes, including self-reproduction, low-maintenance, and ecological benefits; however, previous studies have primarily used the city environment as the study area. The distribution of spontaneous plants in urban green spaces has rarely been reported. To determine the diversity, as well as the temporal and spatial patterns of spontaneous plants in urban green spaces, we used the Beijing Olympic Forest Park as the study area for this research project. A total of 123 sample sites were selected using a 200 m grid placed over the park. Each site was a 20 m×20 m square, and all sample sites were surveyed seven times during the growing season from March to November, 2015. Combined with diversity, community cluster calculation, and Duncan tests, we analyzed the composition features, diversity, and community classification of spontaneous plants in this urban park. A total of 128 plant species were recorded, which belonged to 98 genera and 32 families. Among them, native plants accounted for 76.56% and alien species accounted for 23.44%, meanwhile, invasive species accounted for 12.50%. The species number of spontaneous plants exhibited a pattern with a single peak during the year, and the peak occurred in late August with 98 species. The number of species in the family Compositae was significantly higher than that in other families, and the percentage of foreign species increased in summer. The habitat of roadside and woodland contained the highest number of sample sites as well as more spontaneous species, 109 and 106, respectively. Community diversity was significantly higher in early October, followed by late August, late April, and early June. Community diversity among different habitats was not stable because of the varying degrees of external interference in different seasons. All communities were classified into 42 community groups based on species dominance. Each season and habitat had its own dominant species and communities, and nine community groups occurred in all the three seasons. With the variation among seasons, most groups presented a rich and colorful effect together with that of wildness. The results of this research will provide a reference for the future construction of sustainable urban vegetation with low maintenance, high biodiversity, and regional characteristics.