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.

这项研究在以橡木为主的森林中使用土壤变暖的实验设施，首次检查昆虫暴发如何影响养分循环和在当前温度和将来预期的较温暖的土壤下的养分循环和可用性。 在美国东南部，毛毛虫的暴发对橡树造成了高度损害，包括多达100％的单个树木落叶。这次爆发，黑点的棕色（Cissusa spadix）和普通橡树蛾（Phoberia atomaris）涉及的物种从来没有以前爆发（cissusa）或很少（phoberia）爆发。但是，2010年5月，西苏萨（Cissusa）在美国东南部首次爆发，2011年5月，两家毛毛虫都表现出爆发的数量，并引起了广泛的脱叶。 2012年4月，这些毛毛虫再次爆发，但比往年早一个月，这可能是由于2011年至2012年的温和冬季。几周后，如此大量的食叶昆虫会产生大量的排泄物（FRASS）和其他土壤养分添加，这些昆虫可能会影响整整一年或更长时间的营养生物地球化学动态。 这项研究将是第一个解决昆虫暴发和温暖土壤如何影响重要养分树木的可用性的研究。疫苗暴发的发生频率更高，并且预计随着气候温暖的频率。 了解森林生态系统如何应对食肉昆虫的爆发涉及森林经理，木材收割者，徒步旅行者，露营者以及地方和地区财产所有者。 这项工作将与了解当前和未来温暖条件下的树木的土壤养分可用性有关，因此对于对社会很重要的未来生态系统服务。这些服务包括但不限于木材，森林碳固存，野生动植物栖息地和流域完整性的供应。在每年爆发的几周内，跌落的掉落足够丰富，听起来像毛毛雨和每晚攀登成千上万的毛毛虫（每棵树），树干升起，引起了公众的兴趣，并产生了广泛的媒体报道，为与公众提供了极好的机会。