LTREB Renewal: Ecosystem Structure and Function in Palouse Grasslands

美国西部的蝗虫数量在不同年份和地点之间变化很大。同一年，蝗虫在一个地点的数量可能很高，而在附近的一个地点的数量可能很低，而在下一年，两个地点的数量可能会相反。这可能会给依赖可靠的天气和虫害预报的畜牧业生产者带来经济困难。蝗虫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。仅对一个可能的原因进行研究或在几年内仅在一个地点进行研究，不可能促进对蝗虫动态的了解，而需要在多个地点进行长期研究。 该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。该项目还将被编织成一个由圣母大学运行的既定夏季野外生态计划。该计划为本科生提供为期10周的实地研究经验，并专门招募美国原住民和非原住民学生，以帮助促进文化交流。该计划取得了成功，因为所有参与的美国原住民学生都完成了本科学位，其中一些人现在为部落自然资源机构工作。虽然天气不能通过实验改变，但不同年份和地点的结果将进行比较，以帮助解开食物和捕食对蝗虫种群在一系列天气条件下的影响。蝗虫也将进行实验研究，保持一些人口在大领域的笼子里，在不同的网站，植物的质量和数量和捕食相对于自然水平在任何给定的一年。蝗虫种群可以通过消费直接减少植物产量，也可以通过影响植物所需养分的循环间接减少植物产量。长期研究的结果表明，在某些地点的种群更频繁地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。该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作，并揭示气候变化造成的长期趋势。虽然较大的食草动物，如野牛、麋鹿、鹿或兔子的数量可能不像蚱蜢那样变化很大，但它们也可能在某些时间和地点受到食物供应的控制，或者在其他时间和地点受到捕食的控制。因此，蚱蜢系统是一个有助于更广泛地解决这一问题的模式。

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.