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首页> 外文学位 >Soil nutrient heterogeneity and root foraging in a Nicaraguan rainforest: Patterns, processes and potential implications for competitive dynamics.
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Soil nutrient heterogeneity and root foraging in a Nicaraguan rainforest: Patterns, processes and potential implications for competitive dynamics.

机译：尼加拉瓜雨林的土壤养分异质性和根觅食：竞争动态的模式，过程和潜在影响。

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摘要

Soil nutrient heterogeneity at spatial scales that allow individual plants to experience multiple belowground environments is potentially an important influence on the competitive dynamics of plant communities. I investigated three topics related to soil heterogeneity in a Nicaraguan rainforest: spatial and temporal soil heterogeneity, morphological root foraging by plants, and the interaction between nutrient heterogeneity and root foraging on belowground competition.; In the field, I examined soil properties to quantify their heterogeneity, and to determine the influence of aboveground plant inputs and natural wildfires on soil nutrients. Both univariate and geostatistical methods were used to quantify the forests heterogeneity. Variability as measured by the coefficient of variation ranged between 12% and 92%. While N and K variability tended to be low, leaf litter and P tended to be on the high end of this range. The range over which soil components were autocorrelated (patch size) for the majority of soil properties in the forest was ≤20 meters. Burning altered the spatial variability by decreasing average patch size (12m vs. 7m). However, it had a variable effect on soil nutrient availability. Burning increased P, left K unchanged, and increased N at one site but decreased it in a second. It appears that site differences in N values were due to variable fire temperatures at the two locations.; Overall, plants in this forest forage morphologically for nutrients by growing roots prolifically into nutrient-rich substrates though a greenhouse study showed this to be a species-specific response. In addition, evidence was found that roots of some species are finer when growing into nutrient-rich substrates and that growing in a heterogeneous soil environment may be advantageous to some species.; In greenhouse experiments, I examined how soil heterogeneity and root foraging may interact to influence competition within plant populations through an effect on the size-symmetry of belowground competition. This work found that when combined with morphological root foraging, soil heterogeneity increases the symmetry of competition. This result goes in a direction contrary to traditional theory and suggests the nature of belowground competition is more complicated than previously thought.
机译：在空间尺度上允许单个植物经历多种地下环境的土壤养分异质性可能对植物群落竞争动态产生重要影响。我研究了尼加拉瓜雨林中与土壤异质性相关的三个主题：时空土壤异质性，植物的形态根觅食，养分异质性与地下竞争中的根觅食之间的相互作用。在野外，我检查了土壤特性，以量化它们的异质性，并确定地上植物的投入和自然野火对土壤养分的影响。单变量和地统计方法都用于量化森林的异质性。通过变异系数测得的变异性在12％至92％之间。尽管N和K的变异性趋于较低，但凋落物和P的变异性往往处于该范围的高端。森林中大部分土壤特性的土壤成分自相关（斑块大小）的范围≤20米。燃烧通过减小平均斑块尺寸（12m对7m）来改变空间变异性。但是，它对土壤养分的有效性具有可变的影响。燃烧使P增加，使K保持不变，并在一处增加N，但在一秒内减少N。看来N值的位置差异是由于两个位置的着火温度不同所致。总体而言，该森林中的植物通过将根大量繁殖到富含营养的底物中而在形态上寻找营养，尽管温室研究表明这是特定物种的反应。另外，有证据表明，某些物种的根系生长到富含营养的基质时更细，在异质土壤环境中生长可能对某些物种有利。在温室实验中，我研究了土壤异质性和根觅食如何通过影响地下竞争的大小对称性而相互作用，从而影响植物种群内部的竞争。这项工作发现，当与形态根系觅食相结合时，土壤异质性会增加竞争的对称性。这一结果的方向与传统理论相反，表明地下竞争的性质比以前认为的要复杂。

著录项

  • 作者

    Blair, Brent C.;

  • 作者单位

    University of Michigan.;

  • 授予单位 University of Michigan.;
  • 学科 Biology Ecology.; Agriculture Soil Science.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 214 p.
  • 总页数 214
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 生态学（生物生态学）;土壤学;
  • 关键词

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