Plant diversity and ecosystem services in wetlands

湿地中的植物多样性与生态系统服务 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、生产生物质、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的不同而不同。例如，在营养有限的环境中，例如天然草原，多样性效应可能更加重要，因为在这些环境中，对资源的竞争是对称的。相比之下，自然湿地是地球上生产力最高的生态系统之一，部分原因是它们从排水的分水岭获得沉积物和养分。然而，生态学文献报道，在湿地进行的多样性实验几乎没有经验证据。因此，人们对这一高产生态系统中的“多样性生态系统功能”关系知之甚少。 我的研究项目重点是生物多样性驱动湿地生态过程和支持生态系统功能和服务的机制。对于目前的建议，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，以及2)测试湿地的生态服务(通过水质净化衡量)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Institut de Recherche en Biologie Végétales研究站点进行群落恢复中游实验。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，我们将在三年内调查群落重组和入侵植物物种的建立。这将使我们能够确定物种和官能团特性、物种和官能团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来确定生物抗性。 对于第二个目标，我们将评估植物多样性和组成对不同数量漂浮植物的湿地中隔生态系统养分同化和矿化的影响。我们还将比较不同植物丰富度和功能多样性的湿地土壤中生态过程的测量，包括实验中的中观系统和魁北克南部的一个大型湿地。由于去除污染物的过程不同，我们的湿地实验将为检验关于生物多样性生态系统的多功能性的假设提供一个理想的环境，即植物多样性如何同时影响几个生态功能。 我们研究项目的结果将不仅让我们了解，在 在基本层面，植物相互作用和多样性如何影响湿地生态系统过程，但也将对植被管理、湿地恢复和用于废水处理的人工湿地的设计产生影响。

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.