SGS-LTER Standard Production Data: 1983-2008 Annual Aboveground Net Primary Production on the Central Plains Experimental Range, Nunn, Colorado, USA 1983-2008

The objective of the long-term ANPP study is to monitor long-term net above ground primary production of the shortgrass steppe community. There are 6 sites: ridgetop (ridge), midslope (mid), swale, ESA (replicate 1 not 2), Section 25 (SEC 25), and owl-creek (OC). Each site is located in a different landscape position or soil type on the shortgrass steppe and may be grazed or not. Ridgetop, midslop and swale are grazed and are sampled along a catena. Section 25 is grazed and is located in an upload grassland. ESA is an ungrazed upland grassland an is the control from the Ecosystem Stress Area experiment. Owl Creek is ungrazed and is located in the lowlands along the owl creek drainage. There are 3 transects with 5 plots in each transect. Plots in the grazed locations are protected by cages. Chose a random direction and distance to move the cages for the LTNPP harvest next year and re-stake the cages. Plots in the ungrazed locations are chosen randomly each year. The 3 transects are marked by rebar. Measure the distance to the random location of the five plots along each transect. Because this is a monitoring effort, true replicates across the landscape are not available and it is recommended that the transect be used in calculating mean production at each sampling location. Our harvesting protocol is: Use equipment including .25 meter metal ring, shears, paper bags and sharpies. Bring knee pads to stay comfortable while working. Clip just above crown-level, except for shrubs (shrub data have been removed from the dataset). All live plus recent dead material needs to be harvested from the plot. Both recent dead and old standing-dead are standing and both are dead, but they are not the same. You can brush the basal old-dead material away from the clipped material with your fingers and sort out other taller stems. -- check your plot over before moving to next one. Plots are clipped by species. It is usually easier to first clip species other than BOGR-BUDA. There are three cactus species on the site. Only current year growth of OPPO is clipped - these are the small pads. (OPPO data have been removed from the dataset) The two 'barrel' cactus are not clipped. There are only some times when combining of species may be done, but it is important that the following 'combining-rules' be followed: 1) The only time combining is allowed is when two species are each less than a gram (this is a few leaves, or one very small stem of an individual). 2) Some species are never combined even if there is only a very small quantity - these are BOGR, BUDA, SPCO, and CAHE. 3) When combining, never combine forbs with shrubs, grasses with forbs, etc. Only combine grasses with grasses, forbs with forbs, shrubs with shrubs. Envelopes with combined species should have codes for all species on the envelope. Do not clip on an ant mound or large disturbance. Note all small mammal, ant, and any other disturbances on the bag. Place all envelopes or small bags from each plot into the largest sample bag from that plot. This is usually, but not always, the BOGR bag. If there happen to be two or more large bags from one plot, try to keep them together. If there are, for example, three bags for one species, label the bags "1 of 3, 2 of 3, and 3 of 3".长期净地上初级生产力（Net Above Ground Primary Production, ANPP）研究的目标是监测短草草原群落的长期净地上初级生产力。本研究共设置6个样地：山脊顶（ridgetop, ridge）、坡中部（midslope, mid）、洼地（swale）、ESA（重复样地1而非2）、25区（Section 25, SEC 25）以及猫头鹰溪（owl-creek, OC）。各采样点分别位于短草草原的不同景观位置或土壤类型，且存在放牧与未放牧两种利用方式。 山脊顶、坡中部与洼地为放牧样地，沿土壤链（catena）设置采样样带。25区为放牧样地，位于高地草原（upland grassland，原文疑似笔误为upload）区域。ESA为未放牧的高地草原，是生态系统胁迫区（Ecosystem Stress Area）实验的对照样地。猫头鹰溪为未放牧样地，坐落于沿猫头鹰溪水系分布的低地生境。 本研究共设置3条样带，每条样带包含5个样方。放牧样地的样方采用围栏（cages）进行保护。明年开展LTNPP采样时，需随机选择移动方向与距离，重新固定围栏。未放牧样地的样方则于每年随机选取。3条样带均采用钢筋（rebar）标记。需沿每条样带测量至5个随机样方位置的距离。由于本研究属于长期监测项目，无法获取跨景观的真实重复样地，因此建议通过样带计算每个采样点的平均生产力。 采样操作规程如下：使用0.25平方米金属环、修枝剪、牛皮纸袋与油性马克笔（sharpies）作为采样工具。请佩戴护膝以提升作业舒适度。在植物冠层以上高度进行剪切取样，灌木除外（灌木相关数据已从本数据集移除）。需采集样方内所有活体及近期枯死的植物材料。近期枯死与长期直立枯亡的植物均为死体，但二者存在显著差异：可通过手指将基部的长期枯亡植物碎屑与剪切下的材料分离，并分拣出其他较高的茎秆。完成当前样方的检查与采样后，再前往下一个样方。 样方采样需按物种分别进行。通常优先剪切除BOGR-BUDA之外的物种。本样地共分布3种仙人掌科植物。仅剪切OPPO当年生的小型垫状枝条——此类数据已从本数据集移除。两种“桶状”仙人掌无需剪切。仅在部分特定场景下可合并物种，且需严格遵循以下合并规则： 1. 仅当两个物种的单株生物量均小于1克（对应少量叶片或单株极小茎段）时，方可进行合并。 2. 部分物种无论生物量多寡均不得合并，包括BOGR、BUDA、SPCO及CAHE。 3. 合并物种时，严禁跨功能群进行合并，仅可将草本与草本、杂类草（forbs）与杂类草、灌木与灌木进行合并。装有合并物种的信封需标注所有参与合并的物种代码。 请勿在蚁丘或大型扰动区域开展采样。需在采样袋上记录所有小型哺乳动物活动、蚂蚁巢穴及其他扰动痕迹。将单个样方的所有信封或小包装袋放入该样方对应的最大规格样品袋中——通常为BOGR对应的样品袋，但并非绝对。若某一样方存在2个及以上大规格样品袋，请尽量将它们归置在一起。例如，若某一物种对应3个样品袋，则需标注为"1 of 3、2 of 3及3 of 3"。