LTREB: A Long-Term Investigation of the Interplay of Biotic vs. Abiotic Factors in a Chilean Semiarid Community

本研究的目标是继续，并重新聚焦，一个长期的，大规模的实验，调查捕食，竞争和食草动物在智利半干旱社区的重要性。现有的结果表明，对植被最显着的影响是这一地区一直在响应与最近的厄尔尼诺-南方涛动（ENSO）事件，而不是草食动物或捕食增加降雨。这一发现表明，自下而上的影响结构这一社区在干旱年份的假设，而生物的相互作用（自上而下的监管）变得更加重要的动物数量增加，以提高生产力与降雨。这项研究的具体目的是继续我们的长期实验，以证实这种可疑的事件模式，并将我们的观察扩展到蜥蜴，鸟类和昆虫。从长远来看，这个实验有望提供一个有启发性的例子，说明直接和间接影响如何在社区中产生分歧，以及它们的重要性如何随着物理环境的变化而变化。除了解决基本的生态问题，这项研究提供了重要的基线数据，了解严重荒漠化的智利中北部半干旱区的生态系统变化。它仍然是智利和美国学生的宝贵培训基地，直接促进了两国的科学发展。

The goal of this study is to continue, and to refocus, a long-term, large-scale experiment that investigates the importance of predation, competition and herbivory in a Chilean semi-arid community. Existing results show that the most dramatic effect on vegetation is this area has been in response to increased rainfall associated with a recent El Nino-Southern Oscillation (ENSO) event, rather than to herbivory or predation. This finding suggests the hypothesis that bottom-up effects structure this community during dry years, while biotic interactions (top-down regulation) become more important as animal numbers increase in response to increased productivity associated with rainfall. The specific purpose of this study is to continue our long-term experiment to confirm this suspected pattern of events, and to extend our observations to lizards, birds, and insects. This experiment promises, over the long-term, to provide an instructive example of how direct and indirect effects diverge through a community, and how their importance shifts as the physical environment changes. In addition to addressing basic ecological questions, this study provides important baseline data for understanding ecosystem change in the heavily desertified north-central Chilean semi-arid zone. It continues to be a valuable training ground for Chilean and American students and contributes directly to the development of science in both countries.