Trade-offs between biodiversity and soil carbon storage in grasslands due to cattle grazing

放牧引起的草原生物多样性与土壤碳储量之间的权衡

• 批准号: RGPIN-2022-03683
• 负责人: Carlyle, Cameron
• 金额: $ 2.4万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=743333
• 关键词: Trade; offs; between; biodiversity; soil

Grasslands provide ecosystem goods and services (EGS), including: carbon storage, forage for livestock and biodiversity. The primary use of most grasslands is livestock grazing, and while grasslands evolved with grazing (i.e. bison), it can alter plant communities and ultimately affect multiple EGS. But rarely has the provision of multiple EGS been examined simultaneously. Thus, this program will examine the effects of grazing on the relationships and trade-offs among EGS with a focus on the role of grazing driven plant shifts in mediating these effects. We ask 1) what is the relationship among multiple EGS at multiple scales as affected by livestock, and 2) what are the roles of plant species in responding to grazing and affecting responses in EGS. The responses of individual EGS to grazing have been studied, however the pattern of trade-offs among EGS less so. It is often assumed that plant productivity and soil carbon are correlated. However, there are weak and highly noisy relationships between these variables and for some plant species the relationship between diversity, productivity and carbon do not follow these patterns. We will measure these patterns at small scale to relate plant species composition to localized EGS and large scale (pasture management) to examine affects resulting from altered landscape heterogeneity. A trait-based approach will be used to examine the functional role of plants in driving effects on EGS. Plants are key providers of EGS, and individual species may be better providers of different EGS or respond differently to grazing. To understand the effects of grazing on EGS we will measure plant traits that are directly related to ecosystem function (e.g. decomposition rate of leaves) and response traits, such as sensitivity to grazing. These traits will be linked to grassland community composition and ecosystem function, as well as preference by livestock. We will follow this approach with functional "knock-out" experiments designed to examine the impacts of grazing and global change process on EGS. This program will begin resolving how grazing alters multiple EGS through plant community changes. Such research is critical as societal awareness of grasslands increases, and policy to increase soil carbon storage is implemented through grazing management, which may have unintended consequences for biodiversity. Second, it will provide a mechanistic understanding of how individual plant species, through their traits, both respond to grazing and lead to changes in soil carbon storage in grasslands. We currently have an incomplete and sometimes opposing set of patterns in which grazing may or may not be beneficial for grassland ecosystems and ultimately these effects are driven by the selection of different plant species by grazing animals that leads to changes in their relative abundance, but why a particular species shift alters EGS is not always clear.

草原提供生态系统产品和服务（EGS），包括：碳储存、牲畜饲料和生物多样性。大多数草原的主要用途是放牧牲畜，虽然草原随着放牧（即野牛）而演变，但它可以改变植物群落并最终影响多种EGS。但很少同时审查多个EGS的提供。因此，本项目将研究放牧对EGS之间的关系和权衡的影响，重点关注放牧驱动的植物转移在调节这些影响中的作用。我们将探讨：1)受牲畜影响的多尺度EGS之间的关系；2)植物物种在EGS中对放牧的响应和影响响应中所起的作用。虽然研究了个别EGS对放牧的响应，但对EGS之间的权衡模式研究较少。人们通常认为植物生产力与土壤碳是相关的。然而，这些变量之间存在微弱且高度嘈杂的关系，对于某些植物物种，多样性、生产力和碳之间的关系不遵循这些模式。我们将在小尺度上测量这些模式，以将植物物种组成与局部EGS联系起来，并在大尺度上（牧场管理）研究景观异质性改变带来的影响。基于性状的方法将用于研究植物在驱动EGS效应中的功能作用。植物是EGS的主要供给者，不同的物种可能是更好的EGS供给者，或对放牧的反应不同。为了了解放牧对EGS的影响，我们将测量与生态系统功能直接相关的植物性状（如叶片分解率）和响应性状（如对放牧的敏感性）。这些性状与草地群落组成、生态系统功能以及牲畜偏好有关。我们将遵循这一方法，进行功能性“淘汰”实验，旨在研究放牧和全球变化过程对EGS的影响。该项目将开始解决放牧如何通过植物群落的变化改变多种EGS。随着社会对草原意识的提高，以及通过放牧管理实施增加土壤碳储量的政策，这可能对生物多样性产生意想不到的后果，此类研究至关重要。其次，它将提供对单个植物物种如何通过其特征对放牧做出反应并导致草原土壤碳储量变化的机制理解。我们目前有一套不完整的，有时是相反的模式，其中放牧可能对草地生态系统有益，也可能无益，最终这些影响是由放牧动物对不同植物物种的选择驱动的，导致它们的相对丰度发生变化，但为什么一个特定的物种转移会改变EGS并不总是清楚的。