LTREB: Climatic change and community organization across three trophic levels: long-term research at a sentinel site in semiarid north-central Chile

生态学家继续争论生物相互作用的相对重要性，如捕食，竞争和草食动物与非生物因素，如气候在调节人口和社区动态。这个项目，现在在其第二十个年头，开始作为一个大规模的调查，在智利半干旱的荆棘灌木社区的生物相互作用的重要性。排除捕食者对植物，食草动物及其捕食者产生了显著但短暂的影响，而高降雨事件导致所有社区成员的戏剧性反应。 在过去10年中，5次厄尔尼诺现象（高降雨量）中有3次预示着更频繁和更强烈的厄尔尼诺现象，这是全球气候变化的一个预测后果。 这些反过来又可能大大改变社区重要组成部分的动态。 该项目将根据最近降水状况的变化，评估降水模式的变化对本地物种和引进物种（特别是兔子和野兔）的影响。 新的实验将排除兔子或野兔，以及兔子或野兔和小型哺乳动物，使研究人员能够量化这些食草动物的影响，同时测试预测全球气候变化相关的降水变化将如何影响本地植物，主要消费者，它们的捕食者以及这些成分之间的相互作用。 越来越多的证据表明，厄尔尼诺现象在智利这个社区的影响更强和更频繁，这将为与全世界干旱和半干旱系统的持续变化进行比较提供一个基线。 该项目依赖于与智利科学家及其学生的强有力的智力合作，并为生态学，环境生物学，环境管理和保护以及全球变化领域的学生和技术人员提供了宝贵的培训。

Ecologists continue to debate the relative importance of biotic interactions such as predation, competition, and herbivory versus abiotic factors such as climate in regulating population and community dynamics. This project, now in its twentieth year, started as a large-scale investigation of the importance of biotic interactions in a Chilean semiarid thorn scrub community. Excluding predators has had significant though transient effects on plants, herbivores and their predators, while high rainfall events have resulted in dramatic responses by all community members. Three of 5 El Niño (high rainfall) events during the last 10 years portend more frequent and intense El Niños, a predicted consequence of global climate change. These in turn may significantly alter the dynamics of important community components. This project will assess the impact of changes in precipitation patterns on native vs. introduced species (especially rabbits and hares), in light of recent changes in the precipitation regime. New experiments will exclude rabbits or hares, and both rabbits or hares and small mammals, allowing the investigators to quantify the impacts of these herbivores while testing predictions for how global climate change-related alterations in precipitation will affect native plants, primary consumers, their predators, and interactions among these components. The increasing evidence for effects of stronger and more frequent El Niño events in this Chilean community will provide a baseline for comparison with ongoing changes in arid and semiarid systems worldwide. The project depends on a strong, intellectual collaboration with Chilean scientists and their students, and provides valuable training for students and technicians in the fields of ecology, environmental biology, environmental management and conservation, and global change.