LTREB Renewal: Ecosystem Structure and Function in Palouse Grasslands

美国西部蚱蜢的丰度在不同年份和地点变化很大。同年，蚱蜢可能在一个地点数量多，而在附近的地点数量少，而在第二年，这些地点的数量可能会相反。这可能给依赖可靠天气和病虫害预报的畜牧生产者造成经济困难。蚱蜢数量变化大的可能原因包括天气模式、植物数量和营养质量以及捕食。了解蚱蜢的动态不能通过仅仅研究一个可能的原因或在一个地点进行几年的研究来推进，而是需要在许多地点进行长期研究。这个项目将涉及一些研究生，并向联邦、州和部落机构、非政府组织和民间团体提供外联服务。该项目还将被纳入由圣母大学（University of Notre Dame）运营的一个已建立的夏季野外生态项目。该项目为本科生提供为期10周的实地研究经验，并特别招募美国原住民和非原住民学生，以帮助促进文化交流。该项目取得了成功，因为所有参加项目的印第安学生都完成了本科学位，其中一些人现在正在部落自然资源机构工作。虽然天气不能在实验上改变，但不同年份和地点的结果将进行比较，以帮助理清食物和捕食在一系列天气条件下对蚱蜢种群的影响。蚱蜢也将被实验研究，通过在不同地点的大型野外笼子中饲养一些种群，在任何给定年份，植物的质量和数量以及捕食量都是相对于自然水平进行控制的。蚱蜢种群可以直接通过消耗和间接通过它们对植物所需养分循环的影响来减少植物产量。到目前为止，长期研究的结果表明，某些地点的种群更经常受到一种或另一种机制的控制，但所有地点的种群在任何一年都不受同一机制的控制。这个项目将增加长期记录，以回答为什么一种机制只在某些年份在某些地点运行，并揭示由于气候变化的长期趋势。虽然大型食草动物，如野牛、麋鹿、鹿或兔子的数量变化可能不像蚱蜢那么大，但它们也可能受到某些时间和地点食物供应或其他地方捕食的控制。因此，蚱蜢系统是一个可以更广泛地解决这个问题的模型。

Grasshopper abundance in the western United States varies dramatically across years and locations. Grasshoppers can have high numbers at one site and low numbers at a nearby site in the same year, while in the next year the numbers at the sites may be reversed. This can create economic hardship for livestock producers that depend on reliable forecasts of both weather and pests. Possible reasons for the large variation in grasshoppers include weather patterns, plant quantity and nutritional quality, and predation. Understanding grasshopper dynamics cannot be advanced by studies of only one possible reason or at a just one site over a few years, but requires long-term studies across a number of sites. This project will involve a number of graduate students and provide outreach to Federal, State and Tribal agencies, non-governmental organizations and civic groups. The project will also be woven into an established summer field ecology program run by the University of Notre Dame. This program provides 10-week field research experiences to undergraduates and specifically recruits Native American and non-Native students in order to help to promote cultural exchange. The program has been successful in that all of the participating Native American students have completed undergraduate degrees and a number are now working for Tribal natural resource agencies.While weather cannot be experimentally altered, results from different years and sites will be compared to help disentangle the effects of food and predation on grasshopper populations over a range of weather conditions. Grasshoppers will also be experimentally studied by keeping some populations in large field cages at different sites where plant quality and quantity and predation are manipulated relative to natural levels in any given year. Grasshopper populations can reduce plant production directly through consumption and indirectly through their effects on the cycling of nutrients needed by plants. Results of long term studies thus far indicate that populations at some sites are more frequently controlled by one or the other mechanism, but populations across all sites are not controlled by the same mechanism in any year. This project will add to that long term record in order to answer why one mechanism operates only in some years at certain sites, and also to reveal long-term trends due to climate changes. And while the numbers of larger plant-eating animals, such as bison, elk, deer, or rabbits, may not vary as much as grasshoppers do, they also may be controlled by availability of food at some times and places, or by predation at others. Therefore, the grasshopper system is a model useful for addressing this question more generally.