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The role of plant functional diversity and soil amendments in regulating plant biomass and soil biogeochemistry in restored wetland ecosystems in the North Carolina piedmont.

机译:在北卡罗莱纳州皮德蒙特恢复的湿地生态系统中,植物功能多样性和土壤改良剂在调节植物生物量和土壤生物地球化学中的作用。

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摘要

This dissertation examines how soil amendments and planted herbaceous species diversity affect the restoration of ecosystem functions in wetlands, while also testing basic ecological questions that help us understand ecosystem function.; One unanswered question in the research relating biodiversity and ecosystem function is whether species diversity or species traits are more important drivers of ecosystem function. The first portion of my dissertation poses several hypotheses about how plant traits, plant trait diversity (calculated as a multivariate measure of plant trait diversity), and environmental conditions are likely to influence two ecosystem functions, biomass N and denitrification potential (DEA), and then examines these hypotheses in a restored wetland in the Piedmont of N.C. Using multiple linear regression, I demonstrate that functional diversity (FD), of traits important for plant growth had no effect on biomass N, but two plant traits, leaf area distribution ratio (LADR) and water use efficiency (WUE), had strong negative effects. Soil inorganic N also had a positive effect. For DEA, FD of traits related to denitrification also did not have a significant effect, but there was evidence of a weak positive effect. Two plant traits had positive effects on DEA, aboveground biomass and aboveground biomass C:N ratio; two traits, belowground biomass C:N ratio and root porosity, had negative effects. Soil inorganic N and soil organic matter also had positive effects on DEA. Results from a Principal Components Analysis (PCA) clustering plant species in trait-space, suggest that Carex, Scirpus, and Juncus species tend to be associated with traits that maximize biomass N, while there is no specific region of trait space or set of species that correspond to high DEA. Instead, there are multiple plant trait combinations that can lead to high DEA. These results suggest that, even though plant diversity (as measured by FD) does not significantly influence biomass N or denitrification, plant trait diversity is important to maintaining multiple ecosystem functions simultaneously.; Restored wetlands tend to have lower levels of soil organic matter than natural reference wetlands. Low soil organic matter can limit nutrient cycling as well as plant survival and growth in restored wetlands. In the second portion of my dissertation, I examine how soil compost amendments influence the development of soil properties and processes as well as plant communities at a restored wetland in Charlotte, NC. Using two-way analyses of variance, multiple comparisons of means, and regression, I determine that available N and phosphorus (P) increase with increasing soil organic matter in both the low and high marsh. Total microbial biomass (MB) and microbial activity (measured by denitrification potential (DEA)) also significantly increase with increasing organic matter in both marsh communities, as does soil moisture. Neither total plant biomass (in the low marsh), nor plant species richness (in the high or low marsh) demonstrate any consistent patterns with soil organic matter level in the first three years post-restoration. These results suggest that compost amendments can positively influence some soil properties (i.e. soil available N, P, microbial biomass, and soil moisture) and some ecosystem functions including nutrient cycling (such as denitrification potential), but may have limited early impacts on plant communities.; In restoration ecology there is a general assumption that restoring ecosystem structure will also restore ecosystem function. To test this fundamental assumption, I examine whether two restored wetlands demonstrate similar general relationships between soils variables (i.e. do the two systems have similar soil ecosystem structure), and whether the importance of each soil relationship is the same at both systems (i.e. do the two systems demonstrate the same soil function). I use structural equation modeling to both pose hypot
机译:本文研究了土壤改良剂和种植的草本物种多样性如何影响湿地生态系统功能的恢复,同时还测试了有助于我们理解生态系统功能的基本生态问题。在有关生物多样性和生态系统功能的研究中,一个尚未解决的问题是物种多样性或物种特征是否是生态系统功能的更重要驱动因素。本文的第一部分提出了几个假设,这些假设关于植物性状,植物性状多样性(作为植物性状多样性的多元衡量指标)和环境条件如何影响两个生态系统功能,即生物量氮和反硝化潜能(DEA),以及然后使用多重线性回归分析在北卡罗莱纳州皮埃蒙特恢复湿地中的这些假设,我证明了对于植物生长重要的性状的功能多样性(FD)对生物量氮没有影响,但是有两个植物性状,叶面积分布比( LADR)和用水效率(WUE)产生了很大的负面影响。土壤无机氮也有积极作用。对于DEA,与反硝化有关的性状的FD也没有显著作用,但有证据表明其正面作用较弱。两种植物性状对DEA有积极影响,地上生物量和地上生物量碳氮比;地下生物量碳氮比和根部孔隙度这两个性状具有负面影响。土壤无机氮和有机质对DEA也有积极影响。通过主成分分析(PCA)对性状空间中的植物物种进行聚类的结果表明,Carex,Scirpus和Juncus物种往往与使生物量N最大化的性状相关,而没有特定的特征空间区域或物种集对应于高DEA。相反,有多种植物性状组合可能导致较高的DEA。这些结果表明,即使植物多样性(通过FD测定)不会显着影响生物量氮或反硝化作用,植物性状多样性对于同时维持多种生态系统功能也很重要。恢复的湿地土壤有机质水平往往低于自然参考湿地。土壤有机质含量低会限制养分循环以及恢复湿地中植物的生存和生长。在我的论文的第二部分中,我研究了土壤堆肥改良剂如何影响北卡罗来纳州夏洛特市恢复湿地的土壤特性和过程以及植物群落的发展。使用方差的双向分析,均值的多次比较和回归,我确定在低沼泽和高沼泽地中,有效氮和磷(P)随土壤有机质的增加而增加。随着沼泽中有机物含量的增加,总微生物量(MB)和微生物活性(通过反硝化潜能(DEA)衡量)也显着增加,土壤湿度也随之增加。在恢复后的前三年中,植物总生物量(低沼泽地)或植物物种丰富度(高低沼泽地)均未显示出与土壤有机质水平一致的模式。这些结果表明,堆肥改良剂可以对某些土壤特性(即土壤中的有效氮,磷,微生物生物量和土壤水分)和某些生态系统功能(包括养分循环)(例如反硝化潜能)产生积极影响,但对植物群落的早期影响可能有限。 。;在恢复生态学中,通常假设恢复生态系统结构也将恢复生态系统功能。为了检验这一基本假设,我研究了两个恢复的湿地是否在土壤变量之间表现出相似的一般关系(即两个系统的土壤生态系统结构是否相似),以及每个土壤关系的重要性在两个系统中是否相同(即两个系统显示相同的土壤功能)。我使用结构方程建模来构成假设

著录项

  • 作者

    Sutton-Grier, Ariana E.;

  • 作者单位

    Duke University.$bEcology.;

  • 授予单位 Duke University.$bEcology.;
  • 学科 Biology Ecology.
  • 学位 Ph.D.
  • 年度 2008
  • 页码 212 p.
  • 总页数 212
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 Q14;
  • 关键词

  • 入库时间 2022-08-17 11:39:26

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