Santa Rita Experimental Range site, station Pasture 2N at Santa Rita Experimental Range, study of plant density of Prosopis velutina 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 Santa Rita Experimental Range (SRE)
contains plant density of Prosopis velutina measurements in numberPerMeterSquared units
and were aggregated to a yearly timescale.

生态趋势（EcoTrends）项目由黛布拉·彼得斯博士（乔纳达盆地长期生态研究站，美国农业部农业研究局（USDA-ARS）乔纳达实验牧场）与阿里尔·卢戈博士（卢奎洛长期生态研究站，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。本项目为大型综合研究计划，致力于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生态趋势项目贡献数据，其中涵盖全部26个长期生态研究（Long-Term Ecological Research，简称LTER）站点，以及由美国农业部农业研究局（USDA-ARS）、美国农业部林务局（USDA-FS）、美国能源部、美国地质调查局（US Geological Survey，简称USGS）及众多高校资助的相关站点。生态趋势项目的数据集可通过探索性网络门户（http://www.ecotrends.info）获取，该门户依托交互式网页应用，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，简称PASTA）的组成部分，正在推进的数据汇编工作通过人工与自动处理两种方式完成更新。该网络门户是乔纳达LTER站点与LTER网络办公室的合作成果。本次所用数据集取自圣丽塔实验牧场（Santa Rita Experimental Range，SRE），包含以每平方米株数为单位的绒叶牧豆树（Prosopis velutina）植株密度测量数据，且已按年度时间尺度完成聚合。