Shortgrass Steppe site, station Treatment 3 (nitrogen addition) for ESA study, study of plant density of Haplopappus spinulosus in units of numberPerMeterSquared on a yearly timescale

The EcoTrends project was established in 2004 by Dr. Debra Peters
(Jornada Basin LTER, USDA-ARS Jornada Experimental Range) and
Dr. Ariel Lugo (Luquillo LTER, USDA-FS Luquillo Experimental Forest)
to support the collection and analysis of long-term ecological datasets.
The project is a large synthesis effort focused on improving the accessibility
and use of long-term data. At present, there are ~50 state and federally funded
research sites that are participating and contributing to the EcoTrends project,
including all 26 Long-Term Ecological Research (LTER) sites and sites funded by
the USDA Agriculture Research Service (ARS), USDA Forest Service,
US Department of Energy, US Geological Survey (USGS) and numerous universities. Data from the EcoTrends project are available through an exploratory web portal
(http://www.ecotrends.info). This web portal enables the continuation of data
compilation and accessibility by users through an interactive web application.
Ongoing data compilation is updated through both manual and automatic
processing as part of the LTER Provenance Aware Synthesis Tracking
Architecture (PASTA). The web portal is a collaboration between the Jornada LTER
and the LTER Network Office. The following dataset from Shortgrass Steppe (SGS)
contains plant density of Haplopappus spinulosus measurements in numberPerMeterSquared units
and were aggregated to a yearly timescale.

EcoTrends项目由黛布拉·彼得斯博士（约纳盆地长期生态研究站（Jornada Basin LTER）、美国农业部农业研究服务局（USDA-ARS）约纳实验牧场）与阿里尔·卢戈博士（卢奎洛长期生态研究站（Luquillo LTER）、美国农业部林务局（USDA-FS）卢奎洛实验林）于2004年创立，旨在支撑长期生态数据集的收集与分析工作。该项目是一项大型综合研究计划，核心目标为提升长期生态数据的可获取性与应用价值。目前共有约50个州级与联邦资助的研究站点参与并为EcoTrends项目贡献数据，其中包含全部26个长期生态研究（Long-Term Ecological Research, LTER）站点，以及由美国农业部农业研究服务局（ARS）、美国农业部林务局、美国能源部、美国地质调查局（USGS）及众多高校资助的站点。EcoTrends项目的数据可通过探索性网络门户（http://www.ecotrends.info）获取。该门户依托交互式网络应用程序，支持用户持续开展数据汇编与数据获取工作。作为LTER溯源感知综合跟踪架构（Provenance Aware Synthesis Tracking Architecture, PASTA）的组成部分，持续推进的数据汇编工作通过手动与自动两种处理方式完成更新。该网络门户由约纳LTER站与LTER网络办公室联合打造。本次提供的短草草原（Shortgrass Steppe, SGS）数据集包含刺叶哈氏菊（Haplopappus spinulosus）的植株密度实测数据，单位为每平方米植株数，且数据已按年尺度聚合。