Core Research Site Web Quadrat Data for the Net Primary Production Study at the Sevilleta National Wildlife Refuge, New Mexico (1999- )

This dataset is part of a long-term study at the Sevilleta LTER measuring 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.Above-ground net primary production is the change in plant biomass, represented by stems, flowers, fruit and and foliage, over time and incoporates growth as well as loss to death and decomposition. To measure this change the vegetation variables in this dataset, including species composition and the cover and height of individuals, are sampled twice yearly (spring and fall) at permanent 1m x 1m plots within each site. A third sampling at Site C is performed in the winter. The data from these plots is used to build regressions correlating biomass and volume via weights of select harvested species obtained in SEV157, "Net Primary Productivity (NPP) Weight Data." This biomass data is included in SEV182, "Seasonal Biomass and Seasonal and Annual NPP for Core Research Sites."This dataset is designated as NA-US-011 in the Global Index of Vegetation-Plot Databases (GIVD). To aid tracking of the use of databases in this index, please also reference this number when citing this data. The GIVD report for SEV129 can be found in: Biodiversity and Ecology 4 - Vegetation Databases for the 21st Century (2012) by J. Dengler et al.本数据集隶属于塞维利塔长期生态研究站（Sevilleta LTER）的长期研究项目，旨在测量4个独立生态系统的净初级生产力（Net Primary Production, NPP）：以石炭酸灌木为优势种的灌丛（C样地，1999年冬季设立）、黑格兰马草占优的草原（G样地，1999年冬季设立）、蓝格兰马草占优的草原（B样地，2002年冬季设立）以及矮松-杜松林地（P样地，2003年冬季设立）。 净初级生产力是衡量碳消耗与固碳速率的核心生态变量。对其进行估算，有助于理解群落层面的能量流动，以及生态过程对空间与时间维度的响应。 地上净初级生产力指植物生物量随时间的变化量，其表征指标涵盖茎秆、花朵、果实与叶片，既包含植物自身的生长增量，也计入因死亡与分解导致的生物量损失。为量化这一变化，本数据集针对各样地内的永久性1m×1m样方，每年开展两次植被调查（春季与秋季），采集的植被变量包括物种组成、植株盖度与高度。其中C样地额外在冬季开展第三次采样。 本样方的采集数据，将结合SEV157数据集《净初级生产力（NPP）称重数据》中获取的选定收获物种的生物量，构建关联生物量与体积的回归模型。该生物量数据收录于SEV182数据集《核心研究样地的季节生物量及季节、年度NPP》。 本数据集在全球植被样方数据库索引（Global Index of Vegetation-Plot Databases, GIVD）中的编号为NA-US-011。为便于追踪该索引内数据库的使用情况，引用本数据集时请一并标注此编号。GIVD中关于SEV129的相关报告可查阅：J. Dengler等人2012年发表于《生物多样性与生态学4：21世纪的植被数据库》的文献。