The role of large mammals in determining forest structure, microclimate, and carbon storage potential

在整个欧洲，大型哺乳动物的数量正在增加，它们的数量经常受到控制，以实现森林恢复的目标，因为高浏览压力损害了树苗的招募。在某些情况下，哺乳动物被完全排除在森林之外，以允许树木再生。然而，食草哺乳动物是森林生态系统的关键组成部分，通过直接和间接途径影响植被多样性和结构，并影响碳和养分循环。此外，大型哺乳动物造成的小规模干扰现在被认为在创造和维持古代森林结构特征和相关生物群落方面起着关键作用。尽管人们越来越认识到大型哺乳动物在林地生态系统中的重要性，但我们对森林中哺乳动物活动如何影响小气候条件、土壤生物群落、植被结构和枯木量的认识仍然存在空白。因此，将哺乳动物排除在外或控制其数量的生境管理技术缺乏强有力的证据基础，无法据此决定如何最有效地实现森林恢复、保护和碳储存目标。本研究的主要目的是了解大型食草哺乳动物如何影响森林生态系统中的植被结构3,4、小气候5,6、土壤生物群落和枯木量7。为了实现这一目标，候选人将在芬兰，德国，罗马尼亚，意大利和英国的地点进行大规模哺乳动物排除实验，并使用地面激光扫描（TLS），广泛的土壤数据记录器网络和土壤eDNA测序相结合。这一令人兴奋的野外工作、新技术和实验操作的结合将使候选人能够解决与欧洲森林中哺乳动物作用有关的几个关键问题，并为政策、森林管理和恢复活动提供证据基础。示例问题包括：大型哺乳动物对土壤小气候和生物群落、植被结构复杂性和森林地上碳储量有什么影响？“老生长”特征，如残余的老树和枯木，如何应对以控制哺乳动物密度为重点的恢复行动？哺乳动物管理方法、干预措施和技术在提高树木和森林（所有年龄）对生物多样性的价值方面有多有效？在更广泛的项目范围内，将鼓励潜在的候选人积极参与塑造研究的确切方向和性质，以最适合他们的技能和兴趣。

Project backgroundLarge mammal populations are increasing across Europe and their numbers are often controlled to realise forest restoration objectives because high browsing pressure impairs tree seedling recruitment. In some cases, mammals are completely excluded from forests to allow tree regeneration. However, mammalian herbivores are key components of forest ecosystems affecting vegetation diversity and structure, and C and nutrient cycling via direct and indirect pathways 1. Furthermore, small scale disturbances created by large mammals is now thought to play a key role in creating and maintaining ancient forest structural characteristics and associated biotic communities 2. Despite a growing appreciation of the importance of large mammals in woodland ecosystems, there remain gaps in our knowledge of how mammal activity in forests influence microclimatic conditions, soil biotic communities, vegetation structure and volume of deadwood. Therefore, habitat management techniques that exclude mammals, or control their numbers, lack a robust evidence base from which to make decisions on how to most effectively realise forest restoration, conservation and carbon storage objectives. Project Aims and Methods The overarching aim of the studentship is to understand how large mammalian herbivores influence vegetation structure 3,4, microclimate 5,6, soil biotic communities and deadwood volume 7 in forest ecosystems. To achieve this, the candidate will work within a large-scale mammal exclusion experiment with sites in Finland, Germany, Romania, Italy and the UK, and use a combination of terrestrial laser scanning (TLS), an extensive network of soil data loggers and soil eDNA sequencing. This exciting combination of field work, new technologies and experimental manipulations will allow the candidate to address several key questions relating to the role of mammals within the forests of Europe and provide an evidence base to inform policy as well as forest management and restoration activities. Example questions include: What impact do large mammals have on soil microclimate and biotic communities, vegetation structural complexity and above-ground carbon stocks in forests? How do 'old growth' characteristics, such as remnant old trees and deadwood, respond to restoration operations, which focus on controlling mammal densities? How effective are mammal management approaches, interventions, and techniques for enhancing the value of trees and woods (of all ages) for biodiversity? Within the broader remit of the project, prospective candidates will be encouraged to take an active role in shaping the exact direction and nature of the research to best suit their skills and interests.