The theoretical and practical significance of tree species and functional diversity in designing novel forest ecosystems

由于人类的直接和间接干预，世界各地的自然森林生态系统正以惊人的速度逐步消除和/或大大简化。剩余的天然林和管理林正受到与全球变化有关的因素(入侵物种和害虫；气候变化)的影响。由于人口压力的增加和全球变化的加速，这一趋势在未来可能会增加。考虑到森林为65%以上的陆地生物多样性提供了栖息地，并且是许多生态系统服务的主要提供者，这些压力更加令人担忧。然而，令人信服的科学证据现在表明，自然生态系统和管理生态系统的生产力和弹性在很大程度上依赖于生物多样性和复杂性的维持。在这个项目中，我们将重点研究提供两种主要森林生态系统服务的机制：木材和土壤固碳方面的初级生产力。来自4所加拿大大学(舍布鲁克大学、拉瓦尔大学、UQAR大学和UQAM大学)的科学家将与来自美国和波兰的合作者合作。这项研究将比较树种、系统发育和功能特性多样性在以下方面的作用：(1)维持健康的天然和受管理的森林；(2)促进更多生产力和更具弹性的新型森林生态系统；(3)最大限度地实现碳封存。核心办法将是在美国东北部的三个不同地区和波兰的一个地区建立和监测一系列世界独一无二的试验性高密度单一和混合本土和外来树种种植园。该项目将评估各种本地和外来树种的混合对：(1)地上和地下的生物量和根的分布；(2)细根的生长、形态和结构动态；(3)碳、氮、磷和碱基的循环、土壤中的储存和淋溶以及分解；(4)营养互补。该项目的成果将为政府和私营利益攸关方提供必要的知识，以制定关于利用混合物种种植园和外来物种作为可持续森林管理的一部分的知情的创新政策和做法。

Natural forest ecosystems worldwide are being gradually eliminated and/or greatly simplified at an alarming rate by direct and indirect human interventions. Remaining natural and managed forests are being impacted by factors associated with global change (invasive species and pests; changing climate). This trend is likely to increase in the future due to increasing human population pressures and accelerating global change. These stresses are even more alarming considering that forests provide habitats for more than 65% of the terrestrial biodiversity and are key providers of many ecosystem services. Yet, compelling scientific evidence now shows that the productivity and resilience of natural and managed ecosystems are greatly dependent on the maintenance of biodiversity and complexity. In this project, we will focus on mechanisms involved in supplying two major forest ecosystem services: primary productivity in terms of wood and soil carbon sequestration. Scientists from 4 Canadian universities (Sherbrooke, Laval, UQAR & UQAM) will work together with collaborators from the US and Poland. The research will compare the role of tree species, phylogenetic and functional trait diversity in (1) maintaining healthy natural and managed forests; (2) contributing to more productive and resilient novel forest ecosystems; and (3) maximizing carbon sequestration. The core approach will be the establishment and monitoring of a series of world-unique experimental high-density single and mixed native and exotic tree species plantations in three different regions of north-eastern America and in one region of Poland. The project will evaluate how various mixtures of native and exotic tree species affect: (1) above and below-ground biomass and root distribution; (2) fine-root growth, morphological and architectural dynamics; (3) C, N, P and base cycling, storage and leaching in soils and decomposition; and (4) trophic complementarity. The results of this project will provide both government and private stakeholders the necessary knowledge to develop well-informed innovative policies and practices regarding the use of mixed species plantations and exotics as part of sustainable forest management.