Net Primary Productivity (NPP) Weight Data at the Sevilleta National Wildlife Refuge, New Mexico (1999 - )

Several long-term studies at the Sevilleta LTER measure net primary production (NPP) across ecosystems and treatments. Net primary production is a fundamental ecological variable that quantifies rates of carbon consumption and fixation. Estimates of NPP are important in understanding energy flow at a community level as well as spatial and temporal responses to a range of ecological processes. Above-ground net primary production (ANPP) is the change in plant biomass, including loss to death and decomposition, over a given period of time. To measure this change, vegetation variables, including species composition and the cover and height of individuals, are sampled up to three times yearly (winter, spring, and fall) at permanent plots within a study site. The weight data presented here is obtained by harvesting a series of covers for species observed during plot sampling. These species are always harvested from habitat comparable to the plots in which they were recorded. This data is then used to make volumetric measurements of species and build regressions correlating biomass and volume. From these calculations, seasonal biomass and seasonal and annual NPP are determined.塞维利塔长期生态研究站点（Sevilleta LTER）的多项长期研究，针对不同生态系统与实验处理措施测定了净初级生产力（Net Primary Production, NPP）。净初级生产力是衡量碳消耗与固持速率的核心生态变量，其估算结果对于理解群落层级的能量流动，以及各类生态过程驱动下的时空响应模式均具有重要意义。地上净初级生产力（Above-ground Net Primary Production, ANPP）指特定时段内植物生物量的变化总量，涵盖植株死亡与分解所导致的生物量损耗。为量化该变化，研究人员会在研究样地的永久样方内，每年至多开展三次植被调查（冬季、春季、秋季），采集物种组成、单株盖度与株高等植被参数。本数据集提供的重量数据，通过收割样方调查中记录到的物种的对应盖度梯度样本获取，且所有采样物种均取自与对应记录样地生境条件相仿的区域。随后利用该数据开展物种的体积测量，并构建生物量与体积的回归模型，通过上述计算即可得到季相生物量、季相净初级生产力与年度净初级生产力。