SGS-LTER Long-Term Montioring Project: Arthropod Pitfall Trapping on Small Mammal Trapping Webs on the Central Plains Experimental Range, Nunn, Colorado, USA 1998-2006, ARS Study Number 118 (Reformatted to the ecocomDP Design Pattern)

This data package is formatted as an ecocomDP (Ecological Community Data Pattern). For more information on ecocomDP see https://github.com/EDIorg/ecocomDP. This Level 1 data package was derived from the Level 0 data package found here: https://pasta.lternet.edu/package/metadata/eml/knb-lter-sgs/134/17. The abstract below was extracted from the Level 0 data package and is included for context: This data package was produced by researchers working on the Shortgrass Steppe Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University. Long-term datasets and background information (proposals, reports, photographs, etc.) on the SGS-LTER project are contained in a comprehensive project collection within the Digital Collections of Colorado (http://digitool.library.colostate.edu/R/?func=collections&collection_id=3429). The data table and associated metadata document, which is generated in Ecological Metadata Language, may be available through other repositories serving the ecological research community and represent components of the larger SGS-LTER project collection. Additional information and referenced materials can be found: http://hdl.handle.net/10217/83450. With the exception of heteromyids, eg kangaroo rats and pocket mice, most small rodents in shortgrass steppe are omnivorous. Depending on season, arthropods (insects and arachnids) make up 40-85% of the diet of grasshopper mice and thirteen-lined ground squirrels, the most widespread rodents in northern shortgrass steppe. Small mammals are among the most important predators of ground-dwelling macroarthropods and herbivorous insects provide a direct resource link between weather and plant production. Understanding temporal variability in the abundance of arthropods is central to determining the mechanisms that drive small rodent populations. At present, there are no long-term studies of arthropods in shortgrass steppe, despite the important role that these taxa play in grassland food webs. Beginning in 1998, we implemented field protocols to track changes in relative abundance of terrestrial macroarthropods in grassland and shrub-dominated habitats of shortgrass steppe. Sampling was conducted on the six trapping webs (three upland prairie, three lowland saltbush) where we studied rodent populations, and was conducted approximately monthly from May-September (4-5 sessions/year). Ground-dwelling macroarthropods were sampled on each web using pitfall traps, set in one four-by-five grid, with 10 m between traps. Traps consisted of plastic cups (90-mm diameter, 120 mm deep), including a plastic funnel (90-mm diameter), buried flush with the ground surface. Traps were shaded with wooden covers held in place with nails; traps could be closed when not operational by nailing the cover flush to the ground. Traps were usually open for 4 consecutive days (ie 80 trap-days) during a trapping session. On the 4th day, captured arthropods were removed from the traps, identified and released. All arthropods were identified to the ordinal level; beetles (Coleoptera), crickets (Orthoptera), true bugs (Hemiptera) and spiders were identified to the familial level; and a few taxa, eg tenebrionid beetles, were identified to species. We also recorded any reptiles and amphibians captured. The number of individuals of each taxa captured per 100 trap-days was used as an index of relative abundance, with adjustments made for traps that were flooded or disturbed by cattle or for changes to the number of days that traps were open (range 4-7 days). We sampled grasshoppers by counting the numbers flushed from 0.78-m2 circular plots (hoops) placed on each web. Hoops were set out on the day that pitfall traps were opened and were surveyed on the day that traps were closed. A technician used a wooden lath to flush and count all grasshoppers from each hoop. Grasshoppers were not identified to species. Surveys were conducted in 1998, then were discontinued until 2002. In 1998 and from 2002-2005, nine hoops were sampled on each web. Beginning in 2006, we sampled a total of 20 hoops on each web. The Shortgrass Steppe Long Term Ecological Research (SGS-LTER) project was funded by National Science Foundation as one of the first sites in the US LTER Network in 1982. This collaborative, interdisciplinary research project was established in the Natural Resource Ecology Lab at Colorado State University by ecosystem scientists who learned novel approaches to study grassland ecosystems during the International Biome Program (IBP) (1968-1974). The SGS-LTER project was built upon the foundation of data and information obtained during IBP, as scientists sought to identify and follow, and often manipulate in experiments, important ecosystem processes over the long-term. The objectives of the SGS-LTER project were to investigate what mechanisms regulate processes in the shortgrass steppe. Research questions focused on how biotic and abiotic components of the ecosystem are coupled, where and when ecosystem components are most vulnerable to perturbations, disseminating information that would be helpful for rangeland management and assessing impacts of climate change. Scientists explored variations in the structure and function of the ecosystem over space and time and sought to understand how these aspects are governed by climate, natural disturbance, biota, physiography, and human use. Scientists at the SGS-LTER integrated long-term monitoring data, designed experimental studies, performed and advanced modeling techniques, and synthesized data to conduct innovative research, education, and outreach. The core SGS-LTER research site was established on the Central Plains Experimental Range (CPER) in Nunn, Colorado, part of the United States Department of Agriculture’s Agricultural Research Service. The research site sits in the rain shadow of the Rocky Mountains at the western edge of the shortgrass steppe of North America. The shortgrass steppe ecosystem evolved with grazing by the American bison, which has now been replaced by cattle. Grazing by domestic livestock is the primary land use of native grassland, which occupies about 60% of the land area of the shortgrass steppe. Short grasses dominate the vegetation community, which have adapted to grazing and less than 400 mm of annual rainfall. The topography is characterized by gently rolling hills, broad ephemeral stream courses and low flat-topped terraces. Aspects of physiography regulate the shortgrass steppe ecosystem, including landscape position, soil age, water holding capacity, soil depth and surface texture which, in turn, determine such properties as soil moisture storage, net primary productivity and the distribution of small mammals such as prairie dogs and pocket gophers. SGS-LTER scientists have expanded their research studies beyond the CPER to identify similar or different patterns in ecosystem structure and function in North American grasslands; across the Great Plains region and along the latitudinal gradient from Wyoming to Mexico. They also conducted cross-site collaborative research and compared their results and tested theories in grasslands located in South America, Asia and Africa. Funding from NSF for the SGS-LTER project ends in 2014, but over thirty years of research has resulted in a scientific team with diverse expertise, which produced over 1200 journal publications, almost 400 book chapters and over 200 theses. Data, products and other information produced from the SGS-LTER are available through the LTER Network Information System, Digital Collections of Colorado at CSU or upon request through [e-mail].

本数据包采用ecocomDP（Ecological Community Data Pattern，生态群落数据模式）格式进行组织。有关ecocomDP的更多详情，请访问：https://github.com/EDIorg/ecocomDP。
本一级数据包源自此处提供的零级数据包：https://pasta.lternet.edu/package/metadata/eml/knb-lter-sgs/134/17。以下摘要提取自该零级数据包，用于提供背景信息：本数据包由参与短草草原长期生态研究（Shortgrass Steppe Long Term Ecological Research, SGS-LTER）项目的研究人员编制，该项目由科罗拉多州立大学负责管理。SGS-LTER项目的长期数据集及背景资料（包括研究提案、报告、影像资料等）均收录于科罗拉多数字馆藏的综合项目库中：http://digitool.library.colostate.edu/R/?func=collections&collection_id=3429。本数据表及采用生态元数据语言（Ecological Metadata Language, EML）编制的关联元数据文档，亦可通过其他服务于生态研究社区的仓储平台获取，且均属于SGS-LTER项目综合馆藏的组成部分。更多相关信息及参考资料可访问：http://hdl.handle.net/10217/83450。
除异鼠科动物（heteromyids，如更格卢鼠与囊鼠）外，短草草原中的多数小型啮齿动物均为杂食性。根据季节差异，节肢动物（昆虫与蛛形纲动物）在食蝗鼠和十三线地松鼠——北短草草原分布最广的啮齿类——的饮食中占比可达40%至85%。小型哺乳动物是地表大型节肢动物的重要捕食类群之一，而植食性昆虫则构成了天气变化与植物生产力之间的直接资源纽带。明确节肢动物丰度的时间变异规律，是解析小型啮齿动物种群驱动机制的核心所在。然而截至目前，学界尚未开展针对短草草原节肢动物的长期研究，尽管该类群在草地食物网中扮演着关键角色。
自1998年起，我们启动野外采样方案，以追踪短草草原草地与灌丛生境中地表大型节肢动物的相对丰度变化。采样工作在6个诱捕网格（3个位于高地草原、3个位于低地盐生灌丛）开展——该网格同时用于啮齿动物种群研究——并于每年5月至9月间每月开展1次（每年4至5次采样周期）。
每个网格均采用陷阱诱捕器（pitfall traps）采集地表大型节肢动物，诱捕器布设为4×5的网格布局，陷阱间距为10米。诱捕器由直径90毫米、深120毫米的塑料杯搭配直径90毫米的塑料漏斗组成，埋置至与地面齐平。陷阱上方采用木质盖板遮蔽，并用铁钉固定；非作业时段可将盖板钉平至地面以封闭陷阱。单次采样周期内，陷阱通常连续开放4天（即累计80个陷阱日）。在第4天，将陷阱内捕获的节肢动物取出、鉴定后放生。所有节肢动物均鉴定至目级阶元；甲虫（鞘翅目Coleoptera）、蟋蟀（直翅目Orthoptera）、半翅目异翅亚目昆虫（true bugs）及蜘蛛类群可鉴定至科级阶元；部分类群（如拟步甲科tenebrionid beetles）可鉴定至物种级。此外，我们还记录了捕获的所有爬行类与两栖类个体。
我们以每100个陷阱日捕获的各分类群个体数作为相对丰度指标，并针对陷阱被洪水淹没、受牲畜干扰或陷阱开放天数变化（范围为4至7天）的情况进行了校正。
我们还通过计数放置于每个网格的0.78平方米圆形样方（采样圈）中惊飞的蝗虫数量开展采样。采样圈于陷阱开放当日布设，并于陷阱闭合当日完成调查。一名技术人员使用木质板条惊飞并计数每个样方内的所有蝗虫，且未对蝗虫进行物种级鉴定。该采样工作于1998年开展，随后暂停至2002年。1998年及2002年至2005年期间，每个网格布设9个采样圈；自2006年起，每个网格的采样圈总数增至20个。
短草草原长期生态研究（SGS-LTER）项目于1982年由美国国家科学基金会（National Science Foundation, NSF）资助，是美国长期生态研究网络（Long Term Ecological Research Network, LTER）首批设立的站点之一。该跨学科合作研究项目由科罗拉多州立大学自然资源生态实验室的生态系统科学家牵头建立，这些科学家曾在国际生物群系计划（International Biome Program, IBP，1968-1974）期间掌握了研究草地生态系统的创新方法。SGS-LTER项目依托IBP期间获取的数据与信息基础开展研究，科学家们旨在长期识别、追踪乃至通过实验操控关键生态系统过程。
SGS-LTER项目的目标是解析调控短草草原生态系统过程的机制。研究问题聚焦于：生态系统的生物与非生物组分如何耦合？生态系统组分在何时、何地最易受扰动？如何为牧场管理提供实用信息并评估气候变化的影响？科学家们探索了生态系统结构与功能的时空变异规律，并试图理解这些特征如何受气候、自然干扰、生物类群、地形地貌及人类活动的调控。SGS-LTER的研究人员整合长期监测数据、设计实验研究、运用并改进建模技术，同时综合各类数据开展创新性研究、教育与科普推广工作。
SGS-LTER的核心研究站点设立于科罗拉多州努恩市的中央平原实验牧场（Central Plains Experimental Range, CPER），该站点隶属于美国农业部农业研究服务局。研究站点位于北美短草草原西缘的落基山脉雨影区。短草草原生态系统随美洲野牛的放牧活动演化而来，而如今野牛已被牲畜取代。家畜放牧是原生草原的主要土地利用方式，原生草原约占短草草原总面积的60%。植被群落以短草植物为主，这些植物已适应了放牧环境与年均不足400毫米的降水条件。地形以缓坡丘陵、宽阔的季节性河道与低平的台地为特征。地形地貌特征调控着短草草原生态系统，包括景观位置、土壤年龄、持水能力、土层深度及地表质地，这些因素进而决定了土壤水分储量、净初级生产力以及草原犬鼠与囊鼠等小型哺乳动物的分布格局。
SGS-LTER的研究人员已将研究范围拓展至CPER以外，以识别北美草原、大平原区域以及从怀俄明州到墨西哥的纬度梯度上生态系统结构与功能的异同模式。他们还开展了跨站点合作研究，对比研究结果并在南美、亚洲及非洲的草原生态系统中验证相关理论。
美国国家科学基金会对SGS-LTER项目的资助于2014年终止，但历经三十余年的研究已打造出一支具备多元专业技能的科研团队，累计发表超过1200篇期刊论文、近400个图书章节以及200余篇学位论文。SGS-LTER项目产生的数据、产品及其他信息可通过LTER网络信息系统、科罗拉多州立大学科罗拉多数字馆藏获取，或通过发送邮件至[e-mail]申请获取。