Shortgrass Steppe site, station Treatment 4 (water and 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项目由德布拉·彼得斯博士（乔纳达盆地LTER站点，美国农业部农业研究服务局乔纳达实验牧场）与阿里尔·卢戈博士（卢奎洛LTER站点，美国农业部林务局卢奎洛实验林）于2004年创立，旨在支撑长期生态数据集的采集与分析工作。该项目是一项大型综合研究项目，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个州立及联邦资助的研究站点参与并为EcoTrends项目贡献数据，其中涵盖全部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）和多所高校资助的研究站点。EcoTrends项目的数据集可通过探索性网络门户（http://www.ecotrends.info）获取，该门户依托交互式Web应用程序，为用户持续提供数据汇编与数据访问服务。作为LTER溯源感知综合跟踪架构（Provenance Aware Synthesis Tracking Architecture, PASTA）的组成部分，持续的数据汇编工作通过人工与自动处理相结合的方式完成更新。本网络门户由乔纳达LTER站点与LTER网络办公室联合开发。本次提供的短草草原（Shortgrass Steppe, SGS）数据集包含Haplopappus spinulosus的植株密度测量数据，单位为numberPerMeterSquared，且已按年度时间尺度进行聚合。