LTER Cross-Site: Ecological Stoichiometry of North American Grassland Grasshoppers (Acrididae) Along a Latitudinal Gradient

LTER 跨站点：北美草原蚱蜢（蝗科）沿纬度梯度的生态化学计量

• 批准号: 0087253
• 负责人: Anthony Joern
• 金额: $ 8.48万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-10-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0087253&HistoricalAwards=false
• 关键词: LTER; Cross; Site; Ecological; Stoichiometry

JOERN, ANTHONYDEB 0087253"Ecological stoichiometry of North American grassland grasshoppers (Acrididae) along a latitudinal gradient"Insect herbivores in grassland ecosystems encounter widely varying food quality embedded in a variable mosaic of primary production, plant species composition and nutrient dynamics. The PI's asked: how similar or how different are the underlying processes mediating these interactions in southern arid grassland compared to northern mixed-grass prairie? Do patterns associated with larger scales provide insight that cannot be obtained by studying a single or nearby grasslands? As dominant and diverse aboveground herbivores, grasshoppers are an excellent model insect herbivore to evaluate these processes for a wide array of native North American grasslands. The PI will examine constraints on grasshopper secondary production resulting from limiting nutrients across twelve sites ranging from arid grasslands in Texas to New Mexico, through a highly dynamic mid-continent set of sites comprising tallgrass, shortgrass and mixed grass prairies in Oklahoma, Kansas, Colorado and Nebraska until northern mixed grass systems in South Dakota and Canada are encountered. Four LTER sites will be included in this transect (Jornada, Sevilleta, Shortgrass Steppe and Konza Prairie).Ecological stoichiometry provides the primary conceptual framework for addressing these key issues, employing the principle of mass balance to account for the regulation of limiting elements in their transfer between trophic levels. This research will examine stoichiometric elemental ratios (C:N:P) as a constraint on secondary production in grasshoppers. A series of predictions will be tested using C:N:P ratios of common grasshopper species, ingested food and grass from each of twelve sites. Sites that manipulate food quality with large experiments (fire, grazing and/or nutrient additions) provide an opportunity to better identify causal relationships.

JOERN, ANTHONYDEB 0087253“北美草原蚱蜢（Acrididae）沿纬度梯度的生态化学计量”草原生态系统中的食草昆虫遇到的食物质量差异很大，这些食物质量嵌入初级生产、植物物种组成和营养动态的可变镶嵌中。 PI 提出的问题是：与北部混草草原相比，南部干旱草原调节这些相互作用的基本过程有何相似或不同？与较大尺度相关的模式是否提供了通过研究单个或附近草原无法获得的洞察力？作为占主导地位且多样化的地上食草动物，蚱蜢是一种极好的模型昆虫食草动物，可以评估各种北美本土草原的这些过程。该项目负责人将审查十二个地点养分限制对蚱蜢二次生产的限制，这些地点从德克萨斯州的干旱草原到新墨西哥州，一直到俄克拉荷马州、堪萨斯州、科罗拉多州和内布拉斯加州的高草、短草和混合草草原，直到遇到南达科他州和加拿大的北部混合草系统。 该样带将包括四个 LTER 站点（Jornada、Sevilleta、Shortgrass Steppe 和 Konza Prairie）。生态化学计量学为解决这些关键问题提供了主要概念框架，采用质量平衡原理来解释限制元素在营养级之间转移的调节。 这项研究将研究化学计量元素比率（C:N:P）作为蚱蜢二次生产的限制。 将使用十二个地点中每个地点的常见蝗虫物种、摄入的食物和草的 C:N:P 比率来测试一系列预测。 通过大型实验（火灾、放牧和/或营养添加）来控制食品质量的场所提供了更好地识别因果关系的机会。