DISSERTATION RESEARCH: Earthworm invasions as drivers of soil carbon sequestration in north temperate forests

北美温带森林对碳的吸收和储存是一项重要的生态系统服务，它锁住了一部分原本会以二氧化碳（一种强效温室气体）的形式积聚在大气中的碳。北半球的森林每年吸收数百万吨碳，其中约一半储存在土壤中。各种因素可以影响森林碳储量的速率，包括入侵物种，它们可以极大地改变地上和地下的过程。其中一种具有巨大潜力影响森林土壤碳储量的入侵者是外来蚯蚓，它们的挖洞和取食对土壤功能和土壤碳分布至关重要。过去一个世纪的人类活动已经导致一些蚯蚓物种被引入北美温带森林。虽然最近有很多关于蚯蚓入侵的研究，但没有一项研究调查了可能受到影响的所有土壤碳库的变化。此外，没有其他研究调查过不同蚯蚓物种之间的相互作用如何影响碳储存。该项目将回答有关多种蚯蚓入侵时森林碳储量变化的未解决问题。本研究对评估外来蚯蚓入侵对温带森林碳平衡的影响具有重要意义。此外，研究结果将提高我们对温带森林生物入侵及其对森林环境、经济和文化价值的影响的认识。该项目还有一个重要的国际合作组成部分，包括法国的研究人员，这些蠕虫很久以前就侵入了法国的森林。结果将对科学政策产生影响。例如，目前没有限制进口外来蚯蚓物种到美国，也没有现行的立法来限制它们的进一步传播。

The uptake and storage of carbon in North American temperate forests is an important ecosystem service, locking up a portion of the carbon that would otherwise accumulate in the atmosphere as carbon dioxide, a potent greenhouse gas. Forests in the northern hemisphere take up many million tons of carbon annually and store about half of it in soils. Various factors can affect rates of forest carbon storage, including invasive species, which can dramatically change above and below-ground processes. One such invader that has tremendous potential to affect carbon storage in forest soils is the exotic earthworm, whose burrowing and feeding are central to soil function and soil carbon distribution. Human activities of the past century have led to introductions of several earthworm species into North American temperate forests. Although there has been a lot of recent research on earthworm invasions, no single study has examined changes in all pools of soil carbon that may be impacted. Further, no other study has examined how interactions among different earthworm species will affect carbon storage. This project will answer unresolved questions regarding changes in forest carbon storage in response to invasions involving multiple earthworm species. This research will have important implications for assessments of exotic earthworm invasion impacts on forest carbon balances in temperate regions. Further, results will improve our understanding of biological invasions on temperate forests and their impacts on forest environmental, economic, and cultural values. The project also has an important international collaboration component that involves researchers in France, where these worms invaded forests long ago. Outcomes will have implications for science policy. For example, there are no current restrictions on the importation of exotic earthworm species to the U.S., nor is there current legislation designed to limit their further spread.