PEATBOG: Pollution, Precipitation and Temperature Impacts on Peatland Biodiversity and Biogeochemistry (Biodiversa Programme)

PEATBOG的目标是，首先，了解整个欧洲泥炭地的生物多样性和生态系统功能如何受到氮污染和气候变化的影响，其次，制定有意义的风险指标。北欧的泥炭地是全球主要的碳汇，并支持着一个独特的生物群落。然而，气候变化和空气污染威胁着这些生态系统的结构和功能。活性氮和其他污染物的空中沉降已经导致欧洲部分地区泥炭地的多样性和功能显著下降。还有证据表明，气候变化将通过广泛的夏季干旱扰乱泥炭地水文，从而减少净碳固存。本项目旨在了解氮污染和气候变化的综合压力如何影响泥炭地的生物多样性和生态系统特性。我们假设超过氮沉降的临界阈值，所有物种的多样性都会减少，其中苔藓植物尤其敏感。随着敏感类型的丧失，将有更多的喜氮物种取代，这些变化将有助于加速氮和碳循环的速度。这将导致氮和碳在环境中的损失增加，主要表现为水流中氮含量升高以及释放到大气中的温室气体（N2O、CO2、CH4）浓度上升。我们预计，这些对氮污染的负面反应将在气候变化下恶化，因为微生物活动增加，特别是在温暖的夏季条件下，泥炭地地下水位下降。为了解决这些问题，我们将确定整个北欧泥炭地物种丰富度与氮沉积之间的关系。利用野外操作改变地下水位和温度，我们将测量氮污染与气候对泥炭地生物多样性和生物地球化学的相互作用的本质。物种多样性对生态系统元素循环的重要性将在控制实验和跨调查点进行评估。我们还将确定植被丰富度和土壤微生物多样性之间的关系，以及它们如何受到氮污染和气候变化的影响。加深了解将有助于我们开发生物指标，以评估氮沉降升高和气候变化对泥炭地生态和功能完整性造成的风险。例如，我们将能够在设定氮临界负荷阈值时更好地解释气候变化，反过来，更准确地评估氮污染如何影响泥炭地对特定程度的变暖和夏季干旱的脆弱性。本研究首次探讨了氮沉降与气候对沼泽生物多样性的交互作用，将植物多样性与微生物多样性联系起来。进一步的新颖方面是在不同尺度上进行的生物地球化学研究，这些研究协调良好，结合了实地调查和相关的营养分析、实地操作研究和涉及稳定同位素技术和分子技术的实验室实验。这项研究将采用创新的方法，利用关系数据库和地理信息系统，加强数据分析，并方便与持份者和最终用户沟通研究结果。

The aims of PEATBOG are, firstly, to understand how the biodiversity and ecosystem functions of peatlands across Europe are impacted by nitrogen pollution and climate change, and secondly, to develop meaningful indicators of risk to these impacts. The peatlands of northern Europe are major global sinks for carbon and support a unique biological community. Climate change and air pollution, however, threaten the structure and function of these ecosystems. Aerial deposition of reactive nitrogen and other pollutants has already caused a significant drop in diversity and functioning of peatlands in parts of Europe. There is also evidence that climate change will disturb peatland hydrology, through widespread summer drying, thus reducing net carbon sequestration. This project aims to understand how the combined stresses of nitrogen pollution and changing climate will affect biodiversity and ecosystem properties of peatlands. We hypothesize that above critical thresholds of nitrogen deposition, there will be reductions in the diversity of all species, with bryophytes being particularly sensitive. Accompanying a loss of sensitive types, there will be replacement by more nitrogen-loving species and both these changes will contribute to accelerated rates of nitrogen and carbon cycling. This will result in increased losses of nitrogen and carbon to the environment, seen principally as elevated levels of nitrogen in stream-water and rising concentrations of greenhouse gases (N2O, CO2, CH4) released to the atmosphere. We anticipate that these negative responses to nitrogen pollution will worsen under climate change due to increased microbial activity seen particularly in warm summer conditions as peatland water tables fall. To address these concerns, we will determine the relationship between peatland species richness and nitrogen deposition across northern Europe. Using field manipulations to alter water table and temperature, we will measure the nature of the interaction between nitrogen pollution and climate on peatland biodiversity and biogeochemistry. The importance of species diversity for ecosystem elemental cycles will be assessed within controlled experiments and across survey sites. We will also identify the associations between vegetation richness and soil microbial diversity, and how these are affected by nitrogen pollution and climate change. Increased understanding will help us develop bio-indicators of risk to peatland ecology and functional integrity caused by elevated nitrogen deposition and climate change. For example, we will be able to better account for climate change in the setting of nitrogen critical loads thresholds, and conversely, assess more accurately how nitrogen pollution affects the vulnerability of peatlands to specific degrees of warming and summer drought. This is the first study investigating the interactive effects of N deposition and climate on bog biodiversity, linking plant diversity with microbial diversity. Further novel aspects are the biogeochemical studies carried out at different scales in a well-coordinated combination of field surveys and associated nutrient assays, field manipulation studies and laboratory experiments involving stable isotope technology and molecular techniques. The study will adopt an innovative approach in using relational databases and GIS to strengthen data analysis and facilitate communication of the results with the stakeholder and end-user community.