上海环城绿带群落植物多样性20年动态及其对干扰响应

Dynamics of Plant Diversity in 20 Years and Its Response to Disturbance in Green Space Communities in the Greenbelt Around Shanghai

城市植物群落的动态特征是城市绿地科学营建与管护的重要依据。文章以1999年营建的上海申纪港段环城绿带为研究对象,分别于2001年、2011年和2021年对绿地内8个植物群落进行3次动态变化调查分析,探讨新建绿地人工植物群落的演变特征及其对人工干扰的响应,以期为城市绿地科学管护和植物多样性保育提供借鉴。结果表明:2001—2021年,总体物种数量变化较小,3次样方调查到植物分别为72、72、78种,乔木种类增加7种,主要以灌草层更新苗为主;2011年各群落多样性指数较高,2021年除日本晚樱群落外,乔木层多样性均降低,大多数群落灌木层在2011年后被清除,草本层多样性较高,种类组成比较丰富;植物群落结构变化较小,多以乔草或乔灌结构为主,乔木层大多为单一种或显著优势种;人工干预影响植物群落自然发育过程,林下清除自生植被、引种植物和密植地被等人为干扰措施导致林下植被自然发育和自我更新被抑制,林下植被物种多样性降低。

The dynamic characteristics of urban plant community are the important basis for the science-based establishment and management of urban green spaces.This paper takes Shenji Port section of the Greenbelt in Shanghai,which has been established since 1999,to investigate 8 plant communities in 2001,2011 and 2021,respectively,and explore the evolution characteristics of plant communities in the newly established green space and its response to human interventions,with the expectation to provide references for the science-based management and maintenance of urban green spaces and the conservation of plant diversity.The results demonstrate that the number of plant species has changed little during the last two decades,and 72,72 and 78 plant species were identified in the three quadrat investigations identified,respectively,among which 7 additional arboreal species were found,mainly in the shrub layer.The diversity index of each plant community was relatively high in 2011,but the diversity in the arbor layer of all communities was found decreased in 2021 apart from the Prunus serrulata var.lannesiana community,the shrub layer of most communities has been removed since 2011 while the diversity of herb layer was relatively higher compared to other layers,with rich species composition.Plant community structures have also changed little,mainly arbor+herb or arbor+shrub,while the arbor layer is found composed of either single species or significant dominant species.Human interventions affect the natural development process of plant community,and the natural growth and self-renewal of understory vegetation has been inhibited due to the interventions such as the removal of understorey spontaneous vegetation,introduction of species and dense understory planting,which leads to the decreased diversity of species in understorey vegetation.