Herbivore outbreaks in warmer forests: soil biogeochemical responses to soil warming and an ephemeral, intense outbreak of leaf-feeding insect herbivores

温暖森林中食草动物的爆发：土壤生物地球化学对土壤变暖的反应以及食叶昆虫食草动物的短暂而强烈的爆发

• 批准号: 1242013
• 负责人: Jacqueline Mohan
• 金额: $ 16.41万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1242013&HistoricalAwards=false
• 关键词: Herbivore; outbreaks; warmer; forests; soil

This study uses a soil warming experimental facility in an oak-dominated forest to examine for the first time how insect outbreaks affect nutrient cycling and availability to trees under both current temperatures and warmer soils expected in the future. In the southeastern United States caterpillar outbreaks have inflicted high rates of damage to oak trees, including up to 100% defoliation of individual trees. Species involved in this outbreak, black-dotted brown (Cissusa spadix) and common oak moth (Phoberia atomaris), were never known to outbreak before (Cissusa) or only rarely (Phoberia). However, in May 2010 Cissusa broke out for the first time ever recorded in the southeastern U.S., and in May 2011 both caterpillars exhibited outbreak numbers and caused extensive defoliation. In April 2012 these caterpillars broke out again but a month earlier than previous years, likely due to the mild winter of 2011-2012. Such large numbers of leaf-eating insects in a few weeks produce large quantities of excrement (frass) and other soil nutrient additions that may impact nutrient biogeochemical dynamics over an entire year or more. This study will be the first to address how insect outbreaks and warmer soils affect the availability to trees of important nutrients.Insect outbreaks have been occurring more frequently and are projected to increase in frequency as climate warms. Understanding how forest ecosystems respond to outbreaks of foliage-eating insects concerns forest managers, timber harvesters, hikers, campers, and local and regional property owners. This work will have relevance for understanding soil nutrient availability to trees under current and future warmer conditions and, therefore, for future ecosystem services important to society. These services include, but are not limited to, provisioning of timber, forest carbon sequestration, wildlife habitat, and watershed integrity. During several weeks of outbreak each year, falling frass abundant enough to sound like drizzle and nightly climbing of thousands of caterpillars (per tree) up tree trunks garners much public interest and generates extensive media coverage, providing an excellent opportunity for discourse with the public.

这项研究使用橡树为主的森林中的土壤变暖实验设施，首次研究昆虫爆发如何影响当前温度和未来土壤变暖情况下的养分循环和树木的可用性。 在美国东南部，毛毛虫的爆发对橡树造成了很高的损害，包括单棵树高达 100% 的落叶。此次爆发涉及的物种包括黑点棕蛾（Cissusa spadix）和普通橡树蛾（Phoberiaatomaris），以前从未爆发过爆发（Cissusa）或很少爆发（Phoberia）。然而，2010 年 5 月，Cissusa 在美国东南部首次爆发，2011 年 5 月，两种毛毛虫均出现爆发数量并造成大面积落叶。 2012 年 4 月，这些毛毛虫再次爆发，但比往年早了一个月，可能是由于 2011-2012 年的暖冬所致。如此大量的食叶昆虫在几周内产生大量的排泄物（腐烂）和其他土壤养分添加物，可能会影响一整年或更长时间的养分生物地球化学动态。 这项研究将首次探讨昆虫爆发和土壤变暖如何影响树木获取重要养分的问题。昆虫爆发的频率越来越高，预计随着气候变暖，昆虫爆发的频率也会增加。 了解森林生态系统如何应对食叶昆虫的爆发涉及森林管理者、木材采伐者、徒步旅行者、露营者以及当地和区域业主。 这项工作将有助于了解当前和未来温暖条件下树木的土壤养分可用性，因此对于未来对社会重要的生态系统服务具有相关性。这些服务包括但不限于提供木材、森林碳固存、野生动物栖息地和流域完整性。每年爆发的几周期间，大量落下的虫草听起来像毛毛细雨，每晚有数千只毛毛虫（每棵树）爬上树干，引起了公众的极大兴趣并引起广泛的媒体报道，为与公众对话提供了绝佳的机会。