Plant interactions and ecosystem function in wetlands

湿地植物相互作用和生态系统功能

• 批准号: RGPIN-2014-05875
• 负责人: Brisson, Jacques
• 金额: $ 2.48万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=632083
• 关键词: Plant; interactions; ecosystem; function; wetlands

Over the last two decades, there has been accumulating evidence that the loss of biodiversity results in a reduction of the efficiency with which communities capture resources, produce biomass and recycle nutrients. Yet, there is an undisputed over-representation of studies on grasslands and primary production measures in the literature on this subject, and despite the recognized importance of wetlands in global biochemical cycles, our understanding of the fundamental relation between plant diversity and ecological attributes and function is still limited for this system. One property that may set wetlands apart in their relation between diversity and functions is the common, local domination of a single – often exotic – vascular plant species. The negative impact of invasive macrophytes on wetland diversity is well known, but it is unclear whether it is accompanied by a decrease in ecosystem processes and services. My research program focuses on competitive interactions between highly productive plant species and the impact of the loss of diversity caused by invasive species on ecosystem functions and services. For the current proposal, my students and I will test whether 1) ecological services in wetlands, as measured by nutrient cycles and water purification, increase with plant diversity due to complementarity effects and whether 2) expansion of competitive clonal species in wetlands reduces ecological functions and attributes associated with ecological services. For the first objective, we will evaluate the effect of plant diversity and composition on nutrient assimilation, mineralization and microbial activity using treatment wetland mesocosms as model ecosystems, with varying numbers of plant species and under several different nutritional conditions. A first experiment will use connected basins of Phalaris arundinacea and Phragmites australis, two wetland macrophytes that differ in root system architecture and seasonal activity. In a second experiment, we will use combinations of 1 to 4 floating plant species in free water wetland mesocosms. In both experiments, water quality parameters, plant parameters and microbial activity will be monitored to test the effect of plant diversity and combination on wetland processes. For the second objective, we will monitor ecological attributes and plant spatial dynamics in a large wetland area of southern Quebec, within and outside of dense, nearly monospecific patches of clonal species (Phragmites australis var. australis, Phragmites australis var. americana, Phalaris arundinacea). To complement the field survey, we will measure the effect of plant interaction on ecological attributes using an original mesocosm experiment designed to reproduce competition between wetland plant species with clonal growth. Results of our study will allow us to understand, at the fundamental level, how plant interactions and diversity influence wetland ecosystem processes. Furthermore, our findings will have implications for vegetation management, wetland restoration and constructed wetlands used for wastewater treatment.

在过去的二十年中，越来越多的证据表明，生物多样性的丧失导致社区获取资源、生产生物量和回收养分的效率降低。然而，毫无疑问，有关该主题的文献中对草原和初级生产措施的研究过多，尽管湿地在全球生化循环中的重要性已得到公认，但我们对该系统的植物多样性与生态属性和功能之间的基本关系的理解仍然有限。使湿地在多样性和功能之间的关系上与众不同的一个特性是单一（通常是外来）维管束植物物种的普遍的、局部的主导地位。入侵大型植物对湿地多样性的负面影响众所周知，但尚不清楚它是否伴随着生态系统过程和服务的减少。我的研究项目侧重于高产植物物种之间的竞争性相互作用，以及入侵物种造成的多样性丧失对生态系统功能和服务的影响。对于当前的提案，我和我的学生将测试：1）湿地的生态服务（通过养分循环和水净化来衡量）是否会因互补效应而随着植物多样性的增加而增加；2）湿地中竞争性克隆物种的扩张是否会降低与生态服务相关的生态功能和属性。对于第一个目标，我们将使用处理湿地中生态系统作为模型生态系统，在不同数量的植物物种和几种不同的营养条件下，评估植物多样性和组成对养分同化、矿化和微生物活动的影响。第一个实验将使用芦苇和芦苇的相连盆地，这两种湿地大型植物的根系结构和季节性活动不同。在第二个实验中，我们将在自由水湿地中生态系统中使用 1 到 4 种漂浮植物的组合。在这两个实验中，将监测水质参数、植物参数和微生物活动，以测试植物多样性和组合对湿地过程的影响。对于第二个目标，我们将监测魁北克南部大片湿地区域的生态属性和植物空间动态，该湿地区域位于密集的、几乎单一特异性的克隆物种斑块（芦苇、美洲芦苇、Phalaris arundinacea）的内部和外部。为了补充实地调查，我们将使用原始的中生态实验来测量植物相互作用对生态属性的影响，该实验旨在通过克隆生长重现湿地植物物种之间的竞争。我们的研究结果将使我们能够从根本上了解植物相互作用和多样性如何影响湿地生态系统过程。此外，我们的研究结果将对植被管理、湿地恢复和用于废水处理的人工湿地产生影响。