Functional roles of tree neighbourhood diversity and complexity in the face of global changes

在过去20年里，在理解生物多样性和复杂性在自然和人造生态系统的健康运行中的关键作用方面取得了很大进展。然而，很少或根本没有研究评估生物多样性和空间格局的复杂性如何在各种环境条件下影响生态系统的功能，特别是在森林中。这项研究计划旨在调查树木多样性和空间复杂性模式如何影响许多关键的生态系统过程，以及如何利用这些新知识更好地管理我们的自然世界，从我们最受欢迎的城市公园、农作物、花园和管理的森林，到面对全球变化而留在偏远地区的保护区。更准确地说，这个项目解决了两个新的和广泛互补的问题：(1)树木多样性(丰富度、功能和系统发育)如何与复杂的空间格局和各种环境压力(例如干旱、土壤肥力、极端天气)相互作用，影响生态系统功能、弹性和生产力，以及(2)树木单独生活相对于在复杂社区生活的功能成本/收益是什么，目的是弄清何时以及如何在树木群落中，积极的物种互动变得与竞争一样重要。我将利用我在美国、加拿大和欧洲发起的一个世界独特的高密度树木多样性实验网络。通过实验改变树木在不同土壤和环境条件下的密度、多样性和空间分布，该项目将检验关于(1)非本地生物在不同和复杂的群落中的作用，(2)在非压力环境中促进的潜在作用，以及(3)在树木群落中增加资源利用的互补性的复杂空间格局的影响。

Great progress has been made in the last 20 years towards understanding the key roles of biodiversity and complexity in the healthy functioning of both natural and man-made ecosystems. However, very little to no research has evaluated how both biodiversity and complexity of spatial patterns interact to affect ecosystem functioning under various environmental conditions, particularly in forests. This research program aims to investigate how tree diversity and spatial complexity patterns can affect many key ecosystem processes and how this new knowledge could be used to better manage our natural world, from our most popular urban parks, agricultural crop, garden and managed forests to conservation areas set aside in remote areas in the face of global changes. More precisely, this project tackles 2 novel and broadly complementary questions: (1) how does tree diversity (richness, functional and phylogenetic) interact with complex spatial patterns and various environmental stresses (e.g. drought, soil fertility, extreme weather) to affect ecosystem functioning, resilience and productivity, and (2) what are the functional cost/benefits for trees to live alone vs. in complex neighbourhoods with the aim of disentangling when and how positive species interactions becomes as important as competition in treed communities.I will make use of a world unique network of high-density tree diversity experiments that I have helped initiate in the USA, Canada and Europe. By varying experimentally the density, diversity and spatial distribution of trees under various soil and environmental conditions, this project will test novel hypotheses regarding (1 the role of non-native organisms in diverse and complex communities, (2) the potential role of facilitation in non-stressful environments, and (3) the effects of complex spatial patterns in increasing complementarity of resource uses in treed communities.