Sawgrass above ground biomass from the Taylor Slough, Everglades National Park (FCE LTER), Florida, USA, August 1999 - ongoing

Sawgrass biomass is measured for TS/Ph-1, 2, 3, & 6 since 1999; TS/Ph-4 & 5 since 1997 to 2006; SRS-1b, 2, & 3 since 2000; SRS1c for 2005 to 2006, and SRS1d since 2006. Three 1 m2 plots are placed on each site. The sites are measured every two months. The number of sawgrass plants is counted for each 1 m2 plot and one third or a minimum of fifteen plants is measured. For each measured plant, measurements of the total number of live leaves, length of the live leaves, and culm diameter at the base are taken. From these measurements we calculate the average leaf length, and the sum of the length of the leaves. We created a model for biomass using a stepwise regression to see which of the variables measured and calculated are more correlated to explain plant biomass. Obtaining the mean biomass for the plants within the plot and multiplying it by the number of plants counted in the plot calculates biomass for each plot. The total biomass for each plot is summed with the other two plots in the same site, and they are averaged to obtain one biomass number per site. To validate our model, plant clippings are obtained in which four plants are clipped (small, medium, large, inflorescence) from each site. The same measurements are applied to the clipped plants as those applied to the measured plants in the plots. The plant clippings are oven dried at 70 degrees C and weighed.

自1999年起对TS/Ph-1、TS/Ph-2、TS/Ph-3及TS/Ph-6号样地的锯草（sawgrass）生物量（biomass）开展测定；TS/Ph-4与TS/Ph-5号样地的测定时段为1997年至2006年；SRS-1b、SRS-2、SRS-3号样地自2000年起启动测定；SRS1c号样地的测定时段为2005年至2006年，SRS1d号样地则自2006年起开始测定。每个样地布设3个1平方米（1 m²）样方，每两个月对所有样地进行一次测定。针对每个1平方米样方，先统计其内锯草植株总数，随后选取其中三分之一且不少于15株的植株进行详细测定。对每株被测植株，测定其活叶总数、活叶长度以及基部茎秆直径。基于上述实测数据，计算该植株的平均叶长与总叶长。本研究采用逐步回归法构建生物量预测模型，以筛选与植株生物量相关性最优的实测与计算变量。单个样方的生物量通过如下方式计算：先求取样方内被测植株的平均生物量，再将其与该样方内统计得到的植株总数相乘。将同一样地内3个样方的总生物量求和后取算术平均值，即可得到该样地的生物量数值。为验证所构建模型的性能，本研究从每个样地剪取4类植株样本：小型、中型、大型及具花序植株。对剪取样本执行与样方内被测植株完全一致的测定流程，随后将所有剪取样本置于70℃烘箱中烘干并称重。