Land-use legacies in ecosystems: impacts of historical land use on carbon storage and species composition in Quebec

人为土地利用是生态系统变化最普遍和最持久的驱动因素。在全球范围内，土地利用是大气二氧化碳净排放量的第二大来源，也是生物多样性丧失的最重要驱动因素。此外，通过改变营养循环和物种组成，土地利用遗产可能会在直接利用停止后持续数千年。尽管土地利用遗产在生态系统中的重要性，但许多潜在的机制仍然没有得到很好的理解。例如，土地利用历史在驱动关键的陆地碳汇方面的作用仍然不确定，土地利用历史影响生物多样性的机制也是不确定的。 因此，我的研究计划的长期目标是研究历史土地利用遗产对生态系统结构和功能变化的程度和影响，以期展示这些知识如何加强碳和生态系统管理。短期内，研究将集中在魁北克，鉴于魁北克300年的土地利用历史，该地区非常适合这些问题。我将回答以下问题：(1)自欧洲人定居以来，历史上的土地利用如何影响整个魁北克的森林范围、组成和空间格局？(2)土地利用历史如何影响森林碳储量？森林的再生是否提供了一个重要的碳汇？未来森林封存的潜力是什么？(3)推动森林生物多样性和恢复途径变化的机制是什么？特别是，历史和当前的景观配置和连通性起到了什么作用？ 这项研究对加拿大南部地区的森林管理具有重要的政策应用，包括加强森林碳固存以帮助实现气候缓解目标，并为优先保护森林以加强农业景观中的生态系统功能提供经验规则。

Anthropogenic land-use is the most pervasive and persistent driver of change in ecosystems. At the global scale, land-use is the second greatest source of net carbon dioxide emissions to the atmosphere and the most important driver of biodiversity loss. Moreover, land-use legacies can persist for thousands of years after direct use has ceased through altered nutrient cycling and species composition. Despite the importance of land-use legacies in ecosystems, many of the underlying mechanisms are still not well understood. The role of land-use history in driving the critical terrestrial carbon sink, for example, remains uncertain, as do the mechanisms by which land use history affects biodiversity. The long-term objective of my research program is thus to examine the extent and influence of historical land-use legacies on changes in ecosystem structure and function, with a view to demonstrating how this knowledge can enhance carbon and ecosystem management. In the short term, the research will be focused in Quebec, a region well suited to these issues given its 300+ years of varied land-use history. I will address the following questions: (1) How has historical land use affected forest extent, composition, and spatial pattern across Quebec since European settlement? (2) How has land-use history impacted forest carbon storage? Has forest regrowth provided a significant carbon sink? What is the potential for future forest sequestration? (3) What are the mechanisms driving changes in forest biodiversity and pathways of recovery? In particular, what is the role of historical and current landscape configuration and connectivity? The research has important policy applications for forest management in southern Canadian landscapes, including enhancing forest carbon sequestration to help meet climate mitigation targets and providing rules of thumb for prioritizing forest protection to enhance ecosystem functioning in agricultural landscapes.