Plant diversity and ecosystem services in wetlands

湿地的植物多样性和生态系统服务越来越多的证据表明，生物多样性的丧失导致社区捕获资源、生产生物量、回收养分或抵御入侵的效率降低。多样性与生态系统功能和服务之间的这种关系可能因土壤肥力而异。例如，多样性效应在营养有限的环境中可能更为重要，如天然草地，那里对资源的竞争是对称的。相比之下，自然湿地是地球上最具生产力的生态系统之一，部分原因是它们从排水流域获得沉积物和营养物质。然而，生态文献报道很少有经验证据，从多样性的湿地进行的实验。因此，人们对这一高产生态系统中“多样性-生态系统功能”的关系知之甚少。 我的研究计划侧重于生物多样性驱动生态过程和支持湿地生态系统功能和服务的机制。对于目前的提案，我和我的学生将1）评估物种丰富度和功能多样性对湿地中外来植物物种入侵的生物抵抗力的影响，2）测试湿地的生态服务，如水净化，是否因互补效应而随着植物多样性的增加而增加。 对于第一个目标，我们将在植物生物学研究所的研究地点进行社区恢复中型生态系统实验。我们将通过应用不同丰富度和功能多样性的种子混合物来操纵初始物种组成。然后，我们将调查社区重组和入侵植物物种的建立超过三年。这将使我们能够建立物种和官能团身份，物种和官能团的相互作用和非生物条件的贡献，以及这些因素如何相互作用，以确定生物抗性。对于第二个目标，我们将评估植物多样性和组成的营养同化和矿化的湿地围隔不同数量的漂浮植物物种的影响。我们还将比较湿地土壤中的生态过程与不同的植物丰富度和功能多样性的措施，无论是在实验中围隔和在南部魁北克的一个大湿地。由于去除污染物的过程不同，我们的湿地实验将提供一个理想的情况下，测试假设的生物多样性生态系统的多功能性，即植物多样性如何可能同时影响几个生态功能。我们的研究计划的结果不仅使我们能够了解，在基本水平上，植物的相互作用和多样性如何影响湿地生态系统过程，但也将有植被管理，湿地恢复和用于污水处理的人工湿地设计的影响。

Plant diversity and ecosystem services in wetlands There is accumulating evidence that the loss of biodiversity results in a reduction of the efficiency with which communities capture resources, produce biomass, recycle nutrients or resist invasion. This relationship between diversity and ecosystem functions and services may vary depending on soil fertility. For example, diversity effects may be more important in nutrient limited environments, such as natural grasslands, where the competition for resources is symmetric. In contrast, natural wetlands are among the most productive ecosystems on earth in part because they receive sediments and nutrients from the drained watershed. Yet, the ecological literature reports little empirical evidence from diversity experiments conducted in wetlands. As a result, little is known about the "diversity - ecosystem functions" relationship in this highly productive ecosystem. My research program focuses on the mechanisms by which biodiversity drives ecological processes and supports ecosystem functions and services in wetlands. For the current proposal, my students and I will 1) evaluate the effect of species richness and functional diversity on biotic resistance to invasion by exotic plant species in wetlands and 2) test whether ecological services in wetlands, as measured by water purification, increase with plant diversity due to complementarity effects. For the first objective, we will conduct a community restoration mesocosm experiment at the Institut de recherche en biologie végétale research site. We will manipulate initial species composition by applying seed mixtures of varying richness and functional diversity. We will then survey community reassembly and invasive plant species establishment over three years. This will allow us to establish the contribution of species and functional group identity, species and functional group interactions and abiotic conditions, and how these factors interact to determine biotic resistance. For the second objective, we will evaluate the effect of plant diversity and composition on nutrient assimilation and mineralization in wetland mesocosms with varying numbers of floating plant species. We will also compare measures of ecological processes in wetland soils with varying plant richness and functional diversity, both in experimental mesocosms and in a large wetland in southern Quebec. Because the processes for removing pollutants differ, our wetland experiments will offer an ideal situation for testing hypotheses on the multifunctionality of biodiversified ecosystems, i.e. how plant diversity may simultaneously affect several ecological functions. The results of our research program will not only allow us to understand, at the fundamental level, how plant interactions and diversity influence wetland ecosystem processes, but will also have implications for vegetation management, wetland restoration and design of constructed wetlands used for wastewater treatment.