GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2021

A quadrat survey was conducted in October 2021 to measure the species and size distribution of plants at 3 sampling sites on the creekbank of the Altamaha River. The sites were chosen to capture the transition from Spartina alterniflora to Spartina cynosuroides (site SCSA) and the transition from Spartina cynosuroides to Zizaniopsis miliacea (sites ZSC1 and ZSC2). The quadrats were established as permanent plots in October 2012 by placing PVC stakes along the creekbank at each site. Plots were evenly spaced, but were not randomly located because the goal was to start with mixtures of vegetation in most of the plots, and vegetation was distributed in patches along the creekbanks. Therefore, these plots provide useful measures of vegetation change, but are not a random sample of the vegetation at the site. Plots will be replaced each year as necessary to replace any lost to disturbance. The plots were visually surveyed and the species, shoot height, and flowering status was recorded individually for each shoot over 10 cm in height present in each plot. Observations from plots exhibiting signs of disturbance were noted in a separate data set. This survey will be repeated annually to assess changes in plant distribution and biomass in relation to environmental changes documented by other GCE LTER monitoring efforts.2021年10月，研究团队于阿尔塔马哈河（Altamaha River）河岸的3个采样点开展样方调查（quadrat survey），以测定区域内植物的物种组成与体型分布特征。本次选取的采样点分别覆盖互花米草（Spartina alterniflora）向鸭茅状米草（Spartina cynosuroides）的群落过渡带（站点SCSA），以及鸭茅状米草向粟状水禾（Zizaniopsis miliacea）的群落过渡带（站点ZSC1与ZSC2）。样方于2012年10月设立为永久样地，研究人员在各站点河岸布设PVC桩以确定样方位置。样方间距均匀，但并非随机布设：因研究初衷是在多数样地中保留植被混合群落，而河岸植被呈斑块状分布，故未采用随机取样策略。因此，尽管该样地体系可有效用于监测植被动态变化，但并非对应站点植被的随机样本。每年将根据实际需求，更换因干扰受损的样地。研究人员对样地开展目视调查，逐一记录样地内所有高度超过10cm的植株的物种、茎高及开花状态。存在干扰迹象的样地的观测数据，将单独存入独立数据集。本调查将每年重复开展，以结合其他GCE LTER监测项目所记录的环境变化，评估区域内植物分布与生物量的动态变化。