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

生态学家继续就生物相互作用(如捕食、竞争和草食)与非生物因素(如气候)在调节种群和群落动态方面的相对重要性进行辩论。该项目目前已进入第20个年头，最初是对智利半干旱荆棘灌木丛群落中生物相互作用的重要性进行的大规模调查。将捕食者排除在外对植物、草食动物及其捕食者产生了重大而短暂的影响，而高降雨量事件导致了所有社区成员的戏剧性反应。在过去10年的5次厄尔尼诺(强降雨)事件中，有3次预示着厄尔尼诺现象将更加频繁和强烈，这是全球气候变化的预测后果。这些反过来又可能极大地改变重要社区组成部分的动态。该项目将根据最近降水制度的变化，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草食动物的影响，同时测试全球气候变化相关的降水变化将如何影响本地植物、初级消费者、它们的捕食者以及这些组成部分之间的相互作用的预测。越来越多的证据表明，在智利这个社区发生更强烈和更频繁的厄尔尼诺事件的影响，将为与世界各地干旱和半干旱系统正在发生的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，并在生态、环境生物学、环境管理和保护以及全球变化领域为学生和技术人员提供宝贵的培训。

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.