GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2024

A quadrat survey was conducted in October 2024 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.

2024年10月，研究人员针对奥塔莫希河（Altamaha River）河岸的3个采样点开展样方调查，以测定该区域的植物物种组成与大小分布。本次选取采样点的目的是覆盖两类植被演替过渡带：其一为互花米草（Spartina alterniflora）向互米花草（Spartina cynosuroides）的过渡带（对应位点SCSA），其二为互米花草（Spartina cynosuroides）向蔗状水葱（Zizaniopsis miliacea）的过渡带（对应位点ZSC1与ZSC2）。2012年10月，研究人员在各采样点的河岸沿线布设PVC桩，将样方设立为永久监测样地。样方间距均匀，但并非随机布设：因研究初衷为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，故未采用随机取样方案。因此，此类样地虽可有效用于监测植被动态变化，但并非对应位点植被的随机样本。每年将根据实际需求，替换因干扰受损的样地。研究人员采用目视调查法，对每个样方内高度超过10cm的每一株植物，分别记录其物种、株高及开花状态。受干扰样地的观测数据将单独整理为独立数据集。本调查将每年重复开展，以结合GCE LTER其他监测工作所记录的环境变化，评估植物分布与生物量的动态变化。