Seasonal Biomass and Seasonal and Annual NPP for Core Research Sites at the Sevilleta Wildlife Refuge, New Mexico

This long-term study at the Sevilleta LTER measures net primary production (NPP) across four distinct ecosystems: creosote-dominant shrubland (Site C, est. winter 1999), black grama-dominant grassland (Site G, est. winter 1999), blue grama-dominant grassland (Site B, est. winter 2002), and pinon-juniper woodland (Site P, est. winter 2003). 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.  While measures of both below- and above-ground biomass are important in estimating total NPP, this study focuses on above-ground net primary production (ANPP). Above-ground net primary production is the change in plant biomass, including loss to death and decomposition, over a given period of time. Volumetric measurements are made using vegetation data from permanent plots collected in SEV129, "Core Site Net Primary Productivity (NPP) Study" and regressions correlating biomass and volume constructed using seasonal harvest weights from SEV157, "Net Primary Productivity (NPP) Weight Data."

本研究依托塞维利塔长期生态研究站（Sevilleta LTER）开展长期监测，对四类典型生态系统的净初级生产力（Net Primary Production, NPP）进行量化测定：以三齿拉瑞阿为优势种的灌丛（Site C，1999年冬季设立）、以黑格兰马草为优势种的草原（Site G，1999年冬季设立）、以蓝格兰马草为优势种的草原（Site B，2002年冬季设立），以及矮松-桧木林（Site P，2003年冬季设立）。
净初级生产力是一项核心生态变量，可量化碳消耗与固持速率。NPP的估算结果对于解析群落层面的能量流动，以及阐释各类生态过程对应的时空响应均具有关键意义。
尽管地下与地上生物量的测定对总NPP的估算均至关重要，但本研究聚焦于地上净初级生产力（Above-ground Net Primary Production, ANPP）。
地上净初级生产力指特定时段内植物生物量的变化总量，涵盖死亡与分解过程造成的生物量损失。
本研究采用体积法开展测定：利用来自SEV129项目「Core Site Net Primary Productivity (NPP) Study」的永久样地植被调查数据，结合基于SEV157项目「Net Primary Productivity (NPP) Weight Data」的季节收获生物量-体积回归模型。