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

在过去20年中，在了解生物多样性和复杂性在自然和人为生态系统健康运作中的关键作用方面取得了巨大进展。然而，很少甚至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相互作用，影响生态系统功能，特别是在森林中。该研究项目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、花园和管理森林到面对全球变化在偏远地区设立的保护区。更准确地说，该项目解决了两个新颖且广泛互补的问题：(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（如干旱、土壤肥力、极端天气）相互作用，从而影响生态系统的功能、恢复力和生产力；(2)树木单独生活与在复杂社区中生活的功能成本/收益是什么，目的是弄清在树木群落中，积极的物种相互作用何时以及如何变得与竞争一样重要。我将利用我在美国、加拿大和欧洲帮助发起的一个世界独一无二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，该项目将测试关于以下方面的新假设：(1)非本地生物在多样化和复杂群落中的作用；(2)在无压力环境中的潜在促进作用；(3)复杂空间模式在增加树木群落资源利用互补性方面的作用。

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.