Throughout the Great Plains, aboveground annual net primary productivity (ANPP) is a critical ecosystem service supporting billions of dollars of commerce and countless stakeholders. Managers and producers struggle with high interannual change in ANPP, which often varies 40% between years due to fluctuating precipitation and drought. To quantify ANPP trends and evaluate interannual and spatial variation, we created the Rangeland Production Monitoring Service (RPMS), a spatially explicit database with automatic annual updates of ANPP for all rangelands in the conterminous United States. The RPMS establishes relationships between normalized difference vegetation index (NDVI) from remote sensing data and ANPP from soil ecological site descriptions. These relationships were applied to NDVI data in each year from 1984 to present, although the present assessment focuses on the period from 1984 to 2017. Validation metrics include an r² of 89% between predicted and observed ANPP at three locations in the Great Plains. For this special issue, we assess data from the RPMS to quantify trends and variation of ANPP in the Great Plains region for four major grassland types, smaller-scale ecological subsections, and national grassland units. Significant (α ≤ 0.05) increases in ANPP since 1984 were observed across all major grassland types in the Great Plains, particularly the northern mixed-grass prairie, which also had the greatest interannual variation (21%) from 1984 to 2017. Corresponding significant increases (P < 0.1) in growing season precipitation were found in all grassland types except the shortgrass steppe. Spatial variation decreases from west to east and tallgrass prairie exhibited the lowest temporal and spatial variation of 8% and 21%, respectively, from 1984 to 2017. Grazing allotments in the National Grasslands exhibit differential recovery after drought ranging from about 15% to 350%.

在整个大平原上，地上的年度净初级生产力（ANPP）是一项至关重要的生态系统服务，可为数十亿美元的商业活动和无数的利益相关者提供支持。管理者和生产者都在为ANPP的高年际变化而苦苦挣扎，由于降水和干旱的波动，其年间变化通常在40％之间。为了量化ANPP趋势并评估年际和空间变化，我们创建了Rangeland生产监视服务（RPMS），这是一个空间明确的数据库，具有针对美国本土所有牧场的ANPP的年度自动更新。RPMS建立了基于遥感数据的归一化植被指数（NDVI）与来自土壤生态站点描述的ANPP之间的关系。从1984年至今，每年都将这些关系应用于NDVI数据，在大平原的三个位置，ANPP的预测值和观测值之间的89％的r ²。对于此特刊，我们评估了RPMS的数据，以量化大平原地区四种主要草地类型，小规模生态分区和国家草地单位的ANPP趋势和变化。自1984年以来，在大平原的所有主要草地类型中，特别是北部混合草草原，ANPP的观测值均显着增加（α≤0.05），其在1984年至2017年之间的年际变化也最大（21％）。 （P在生长季节，除短草草原外，所有类型的草地均出现<0.1％的降水。从西到东，空间变化减小，高草草原在1984年至2017年间表现出最低的时空变化，分别为8％和21％。国家草原的放牧分配在干旱后表现出差异恢复，范围从15％到350％不等。 。