Biodiversity and ecosystem functioning in degraded and recovering Amazonian and Atlantic forests

热带森林比任何其他陆地环境拥有更多的动植物物种，并在树木和土壤中储存了大量的温室气体。然而，我们大多数人都意识到，它们也受到人类活动的严重威胁，媒体的注意力往往集中在森林砍伐上——当森林被其他土地用途所取代时，例如农业和畜牧业。然而，森林也在以其他方式被改造，当树木被砍伐用于商业木材提取，或者当森林在异常干燥的年份燃烧。这些事件被称为森林退化，影响的土地面积比森林砍伐本身更大。森林退化的广泛性意味着了解这些人为改造的森林是否与完整的原始森林发挥着类似的作用是非常重要的。它们含有多少碳和氮，这些营养物质在树叶和森林地面之间的循环速度是否与原始森林相似？这些生态系统的过程能否通过植被本身的特征（如叶片的形状和格式，以及进行光合作用的速率）来预测。至关重要的是，这些变化对这些森林的未来有什么影响——它们能够抵抗额外的修改吗？这个项目将在两个不同的巴西生物群落中回答这些问题，圣保罗的大西洋森林和圣塔伦市附近的亚马逊森林。我们在两年的野外工作中收集的数据将用于提高我们对森林功能的理解，并有助于开发森林的计算机模拟。然后，这些模拟可以用来研究森林如何对气候变化或其他人类影响（如伐木或火灾）作出反应。这些森林对生物多样性保护也至关重要，因为许多稀有和特有物种只在森林已经被人类严重改造的景观中发现。重要的是要评估它们在多大程度上有助于保护这些物种，以及哪些因素可以提高它们的保护价值。热带森林拥有数量多得令人眼花缭乱的物种，其中许多物种尚未被描述。因此，重点关注已知的物种群是很重要的，使鸟类和植物成为两个理想的物种群。关于森林功能的详细工作将在数量有限的森林地块上进行，因为我们受到许多需要在一段时间内采取的精确措施的限制。相比之下，生物多样性的采样速度要快得多，使我们能够在亚马逊和大西洋森林中检查大约100万公顷的更大区域。除了研究这些景观中的生物多样性外，该项目还将评估物种特征的变化，这些特征将物种与其在自然界中执行的许多任务联系起来。通过这样做，我们将能够检查人类改造的森林在多大程度上失去了关键的生态系统过程，比如长喙蜂鸟的授粉，或者树木吸收和储存大量碳的能力。这将使我们更好地了解不同种类的人类活动是如何影响生物多样性的，如果我们要设计有助于保护许多物种的景观，这一点很重要。长期以来，重要的科学知识一直被锁在学术期刊上，未能为政策提供信息和影响。我们决心在我们的研究中不让这种情况发生，因为我们相信它将产生重要的见解，可以帮助我们保护热带森林的生态稳定性及其所包含的生物多样性。为了促进这些影响，我们将尽一切努力传播我们的研究结果。这些活动包括为YouTube制作一系列短片，与当地学校建立联系，以及撰写政策简报。

Tropical forests hold more species of plant and animal than any other kind of terrestrial environment, and store large amounts of greenhouse gases in their trees and soils. Yet most of us are aware that they are also highly threatened by human activities, with media attention often focussing on deforestation - when forests are replaced with alternative land-uses, such as agriculture and cattle ranching. However, forests are also being modified in other ways, when trees are felled for the commercial extraction of timber, or when forest burn in abnormally dry years. These events are known as forest degradation, and affect a larger area of land than deforestation alone.The widespread nature of forest degradation means it is very important to understand whether these human-modified forests are performing similar roles as intact primary forests. How much carbon and nitrogen do they hold, and are these nutrients cycled between the leaves and the forest floor at similar rates as in primary forests? Can these ecosystem processes by predicted by characteristics of the vegetation itself (such as leaf shape and format, and the rate it carries out photosynthesis). And crucially, what are the implications of these changes for the future of these forests - are they able to resist additional modification? This project will answer these questions in two separate Brazilian biomes, the Atlantic Forests of Sao Paulo and the Amazon forests near the city of Santarem. The data we collect in two years of fieldwork will be used to improve our understanding of forest functioning, and can help develop computer simulations of forests. These simulations can then be used to examine how forests may respond to changes in climate, or other human impacts such as logging or fire.These forests are also crucial for biodiversity conservation, as many rare and endemic species are only found in landscapes where forests have already been heavily modified by humans. It is important to assess to what extent they help conserve these species, and what factors could be managed to improve their conservation value. Tropical forests hold a bewildering number of species, and so many of these species are yet to be described. It is therefore important to focus on groups of species which are well known, making birds and plants are two ideal species groups. The detailed work on forest functioning will take place in a limited number of forest plots, as we are limited by the many precise measures that need to be taken over time. In contrast, biodiversity is much quicker to sample, allowing us to examine much larger areas of around one million hectares in the Amazon and in the Atlantic Forest. As well as examining biodiversity in these landscapes, this project will also assess changes in species traits, which are characteristics that link species to the many tasks they perform in nature. By doing so, we will be able to examine the extent to which human-modified forests are losing key ecosystem processes, such as pollination from long-beaked hummingbirds, or the ability of trees to assimilate and store large quantities of carbon. This will provide us with a much better idea of how the many different kinds of human activity are affecting biodiversity, which is important if we are to design landscapes that help protect the many species of conservation concern. For too long, important scientific knowledge has remained locked away in learned journals, and has failed to inform and influence policies. We are determined not to let this happen with our research, as we believe it will produce important insights that can help us preserve the ecological stability of tropical forests and the biodiversity they contain. To facilitate these impacts, we will make every effort to disseminate our findings. These activities include producing a series of short films for YouTube, linking with local schools, and writing policy briefs.