LTREB Renewal: Climatic drivers of temporal and spatial dynamics of a focal herbivore

地球气候在超过40亿年的时间里持续变化。最近这种变化的步伐和方向加快了，对国家福利、农业经济和基本资源的管理提出了挑战。该项目提供了一个独特的机会来确定短期气候效应导致长期人口变化、影响当地人口之间的空间交流以及导致一些人口灭绝的机制。该项目的重点是一种常见的食草动物--毛熊毛虫，其结果有可能为有益和有害的食草动物的保护和管理提供信息。更重要的是，该项目将纳入高中课程，让学生和教师参与监测毛虫的丰度。来自科学领域代表性不足群体的本科生和研究生也将通过参与该项目接受科学实践方面的培训。毛熊蛾是加利福尼亚州羽扇豆属的主要食草动物。研究人员积累了长达30年的该物种及其种群动态的重要驱动因素的丰富数据，包括寄主植物、其他草食动物、捕食者、寄生蜂、运动和气候条件。该项目将启动短期实验，以确定气候因素与观察到的不同生境的丰度和分布模式之间的因果联系机制。这些研究将评估气候对捕食者的自上而下的影响，通过涉及第二种草食动物的促进互动而产生的自下而上的气候影响，以及洪水和垃圾堆积对毛毛虫死亡率的影响。统计分析和数学模型将检验这些实验的推论，评估假设的机制是否会导致物种数量的年际波动，并改变包括局部物种灭绝在内的空间动态。该项目将操纵性实验与模型开发和长期人口数据分析相结合的情况很少见。它将提供一个有据可查的源-汇动态的例子，这是一种数据仍然稀缺的生态现象，很可能成为气候变化对人口动态造成的后果的经典例子。

The Earth's climate has changed continually over 4 billion years. The recent increased pace and direction of this change challenge the nation's welfare, the economics of agriculture, and the management of essential resources. This project provides a unique opportunity to identify the mechanisms by which short-term climatic effects cause long-term population changes, affect spatial exchanges between local populations, and result in the extinction of some populations. The project focuses on a common herbivore, the wooly-bear caterpillar, and results have the potential to inform conservation and management of beneficial as well as pest herbivores. More importantly, the project will be integrated into high school curricula by involving students and teachers in monitoring caterpillar abundances. Undergraduate students from groups under-represented in science and graduate students will also receive training in the practice of science through their participation in the project The wooly-bear moth, Platyprepia virginalis, is a primary herbivore on lupines in California. The investigators have accumulated up to 30 years of abundance data for this species and for important drivers of its population dynamics, including host plants, other herbivores, predators, parasitoids, movement, and climatic conditions. The project will initiate short-term experiments to identify mechanisms that causally link climatic factors to observed patterns of abundance and distribution across habitats. These will evaluate top-down effects of climate on predators, bottom-up climate effects through a facilitative interaction involving a second herbivore species, and the effects of flooding and litter accumulation on caterpillar vital rates. Statistical analyses and mathematical models will test inferences from these experiments, evaluating whether the hypothesized mechanisms cause inter-annual fluctuations in abundance and changing spatial dynamics including local extinctions. The project's combination of manipulative experiments with model development and analyses of long-term demographic data is rare. It will provide a well-documented example of source-sink dynamics, an ecological phenomenon for which data remain scarce, and is likely to become a classic example of the consequences of climate change for population dynamics.