Changes in plant functional diversity matters for peatland carbon cycling

碳（C）循环问题在科学和政治议程上占有重要地位，主要是因为人们担心生态系统在全球变化中储存C的能力。这一领域的大部分研究都集中在高沼地或泥炭地，因为它们是陆地碳的巨大储存地，目前估计占全球碳储量的三分之一。这里主要的担忧是气候和土地使用的变化将破坏这些储存的稳定性，将C以二氧化碳的形式释放回大气中，从而加剧全球变暖。迄今为止，这一领域的大多数研究都着眼于天气的变化，如气候变暖和干旱，可能会影响泥炭中这些重要的碳储存。然而，很少有人知道土地利用，以及管理导致的植被变化如何影响这些碳库。用于生产商品和服务的土地使用是人类对地球最重要的影响之一，影响到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，但它们受到林业、泥炭提取燃料和园艺、粗放牧和狩猎管理等许多土地使用活动的影响。所有这些活动都强烈地影响着植被的构成，往往增加了快速生长的植物，如草的生长，而损害了石楠花，这种植物通常与高沼地有关。从长远来看，这可能会影响生态系统的碳储量之间的平衡，从植物凋落物和根系材料，并通过分解和呼吸损失的C输入到土壤中。在这个建议中，我们解决这个问题，通过测试如何在植被的长期管理，即焚烧和放牧造成的变化，影响碳在泥炭地生态系统的循环。为此，我们将在英格兰北方的摩尔楼国家自然保护区进行一项长期（50年）的野外实验，采用各种放牧和焚烧处理。我们将操纵不同管理系统的植被，以测试这如何影响碳循环泥炭地。为此，我们将使用新的脉冲标记方法，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。

Summary 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.