LTREB Renewal: Ecosystem Structure and Function in Palouse Grasslands

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)资助的。这项更新提案继续对蝗虫、它们的敌人(捕食者和寄生虫)、它们的食物植物以及这些植物在蒙大拿州帕劳斯草原生态系统中的营养进行长期实验研究。蝗虫是这个生态系统中的主要食草动物，对生态系统的功能(养分循环和初级生产)有很大的影响。以前的研究表明，经典的食物链或食物网理论不足以解释蝗虫如何影响营养循环和初级生产，因为随着时间的推移，这些相互作用在生态系统中的特定生境(植被类型)内以及组成该生态系统的四个生境之间的空间上都是如此。正在进行的实验将继续进行，以确定食物网动态如何在空间和时间上变化，以及这种变化是否与自然气候周期或人为气候变化有关。这项研究将产生一些更广泛的影响。首先，像这样的长期研究对于评估气候变化的影响和预测气候变化的未来影响至关重要。自1908年以来，这些草原的平均日气温上升了0.4摄氏度，年降水量减少了30%(11.1厘米/年)。影响蝗虫丰度及其生态系统影响的主要因素(食用植物可获得性和天敌)显然受到气候变化的影响。这项研究的结果也将为牧场管理和保护计划提供参考，特别是在气候变化和正在进行的生态系统修改方面。这项研究被整合到圣母大学和南部萨利什部落和库特奈部落创建的本科项目中，以促进更好的资源管理和与美洲原住民的文化交流。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This renewal proposal continues a long-term experimental study of grasshoppers, their enemies (predators and parasites), their food plants and nutrients for these plants in a Montana Palouse grassland ecosystem. Grasshoppers are the dominant herbivores in this ecosystem and strongly influence the ecosystem?s functioning (nutrient cycling and primary production). Previous research has showed that classic food-chain or food-web theories are insufficient to explain how grasshoppers affect nutrient cycling and primary production, because these interactions very over time within a particular habitat (vegetation type) in the ecosystem as well as spatially among the four habitats comprising this ecosystem. Ongoing experiments will be continued in order to determine how food web dynamics vary over space and time, and whether this variation is associated with natural climate cycles or with anthropogenic climate change. This study will have a number of broader impacts. First, long-term studies like this are critical to assess the effects of climate change and to forecast future impacts of climate change. Since 1908, these grasslands have experienced a 0.4 degree Centigrate increase in average daily temperature and a 30% (11.1 cm/yr) decrease in annual precipitation. The main factors (food plant availability and natural enemies) that influence grasshopper abundance and their ecosystem impacts have clearly been influenced by climate changes. Results from this study will also inform range management and conservation programs, particularly with respect to climate change and ongoing ecosystem modification. The study is integrated into an undergraduate program created by the University of Notre Dame and the Confederated Salish and Kootenai Tribes to foster better resource management and cultural exchange with Native Americans.