Changes in plant functional diversity matter for peatland carbon cycling

碳循环问题是科学和政治议程上的重要议题，主要是因为人们担心生态系统在面对全球变化时储存碳的能力。这一领域的大部分研究都集中在沼地或泥炭地，因为它们是陆地碳的巨大储存库，目前估计占全球碳储量的三分之一。人们主要担心的是，气候变化和土地利用会破坏这些储存，将碳以二氧化碳的形式释放回大气，从而加剧全球变暖。迄今为止，该领域的大多数研究都关注天气变化，如气候变暖和干旱，如何影响泥炭中这些重要的碳储存。然而，人们对土地利用和管理导致的植被变化如何影响这些碳储量知之甚少。用于生产货物和服务的土地使用是人类对地球最重大的影响之一，影响着三分之一至一半的陆地表面。虽然泥炭地被认为对农业的价值有限，但它们受到许多土地使用活动的影响，包括林业、提取泥炭作为燃料和园艺、粗糙放牧和狩猎管理。所有这些活动都强烈地影响了植被的构成，通常会增加快速生长的植物的生长，如草，以牺牲石南花为代价，石南花是与沼地最常见的植物。从长期来看，这可能会通过改变从植物凋落物和根系物质向土壤输入的碳与通过分解和呼吸损失的碳之间的平衡来影响生态系统的碳储量。在本提案中，我们通过测试长期管理（即焚烧和放牧）导致的植被变化如何影响泥炭地生态系统中碳的循环来解决这个问题。为了做到这一点，我们将在英格兰北部的摩尔屋国家自然保护区进行长期（50年）的实地试验，采用各种放牧和燃烧处理方法。我们将对不同管理系统下的植被进行操作，以测试这对泥炭地碳循环的影响。为了做到这一点，我们将使用新颖的脉冲标记方法，使我们能够追踪植物对C的吸收及其向土壤的转移，然后再回到大气中。

The issue of carbon (C) cycling is high on the scientific and political agenda, largely because of concerns over the ability of ecosystems to store C in the face of global change. Much of the research in this area is focussed on moorlands, or peatlands, because they act as vast stores of terrestrial C, currently estimated to be one-third of the global C stock. The main worry here is that changes in climate and land use will destabilise these stores, releasing C back into the atmopshere as carbon dioxide, thereby boosting global warming. To date, most research in this area has looked at how changes in weather, such as climate warming and drought, might affect these important C stores in peat. Very little, however, is known about how land use, and changes in vegetation that result from management, influence these C stores. Land use, for the production of goods and services, is one of the most substantial human influences on Earth, affecting one third to one half of the land surface. While peatlands are thought to be of limited value for farming, they are subject to much land use activity from forestry, peat extraction for fuel and horticulture, rough grazing and game management. All these activities strongly affect the make-up of the vegetation, often increasing the growth of fast growing plants, such as grasses, at the expense of heather, the plant most commonly associated with moorland. In the long-term, this could influence ecosystem C storage by changing the balance between C input to soil, from plant litter and root material, and its loss by decomposition and respiration. In this proposal, we tackle this issue by testing how changes in vegetation resulting from long-term management, namely buring and grazing, influence the cycling of C in peatland ecosystems. To do this, we will use a long-term (50 year) field experiment at the Moor House National Nature Reserve, northern England, with various grazing and burning treatments. We will manipulate vegetation of different management systems to test how this affects C cycling in peatland. To do this, we will use novel pulse labelling approaches which allow us to trace the uptake of C by plants and its transfer to soil, and then back to the atmopshere.