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Environmental and Adaptive Buffers that Mediate the Response of Subalpine Ecosystems to Environmental Change.

机译：介导亚高山生态系统对环境变化的响应的环境和自适应缓冲。

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摘要

This document reports the results of 4 studies of subalpine ecosystem ecology, describing ways that spatial heterogeneity in soils and plant communities mediate ecosystem responses to environmental change. Ecosystem responses to environmental change are also mediated by regional climate patterns and interannual variability in weather. In the first chapter we report the results of an experiment to test for the mediating effects of associational resistance in a forest community that experienced wide-spread beetle kill. We found that Engelmann spruce were more likely to survive a beetle outbreak when growing in low densities (host dilution) and not through other types of associational resistance that relate to higher tree-species richness or greater phylogenetic diversity of the forest community. In the second chapter we report the effects of early snowmelt on soil moisture in subalpine meadow and aspen communities. We found that soil organic matter, soil texture, and forest cover mediated the effects of early snowmelt and were more important drivers of growing-season soil moisture than was snow-free date. In the third chapter we report the effect of early snowmelt on growth and seed production of early-season and midsummer herbaceous species. We found that the primary effect that snowmelt timing had on plant growth was through its effect on species distribution. Changes in the timing of snowmelt had limited effect on the growth, flowering, and seed count of species after they were established. In the final chapter, we report the effect of early snowmelt on soil respiration, microbial biomass, dissolved organic carbon and soil organic carbon. We found that early snowmelt resulted in warmer soil temperatures compared to neighboring snow-cover plots, and that microbial biomass and soil respiration showed no signs of a snowmelt legacy effect during the growing season. Soil organic carbon in rapid and slow-turnover pools was affected more by plant community than by snowmelt timing, and the primary drivers of soil respiration during the snow-free period were first soil organic matter and second soil temperature. Taken together, this dissertation reports our findings that subalpine ecosystems are resilient to environmental change in part because organisms in these systems are adapted to environmental conditions that are highly variable between sites, seasons, and years.
机译：该文件报告了4个亚高山生态系统生态学研究的结果，描述了土壤和植物群落中空间异质性介导生态系统对环境变化的响应的方式。生态系统对环境变化的反应还通过区域气候模式和天气的年际变化来调节。在第一章中，我们报告了一个实验结果，以测试在经历了甲虫广泛杀灭的森林社区中，联合抗性的介导作用。我们发现，恩格尔曼云杉在低密度（寄主稀释）下生长时更有可能幸存于甲虫暴发中，而不是通过与森林树种丰富度更高或系统发育多样性相关的其他类型的抗性。在第二章中，我们报告了早期融雪对亚高山草甸和白杨群落土壤水分的影响。我们发现，土壤有机质，土壤质地和森林覆盖率介导了早期融雪的影响，并且比无雪期更重要地是生长季节土壤水分的驱动因素。在第三章中，我们报告了早期融雪对早期和仲夏草本植物的生长和种子生产的影响。我们发现融雪时间对植物生长的主要影响是通过其对物种分布的影响。融雪时间的改变对物种建立后的生长，开花和种子数量的影响有限。在最后一章中，我们报告了早期融雪对土壤呼吸，微生物生物量，溶解有机碳和土壤有机碳的影响。我们发现，与邻近的积雪地块相比，早期融雪会导致土壤温度升高，并且微生物生物量和土壤呼吸没有迹象表明在生长季节出现融雪的遗留效应。快速和慢周转池中的土壤有机碳受植物群落的影响大于融雪时间，而无雪时期土壤呼吸的主要驱动力是第一土壤有机质和第二土壤温度。综上所述，本论文报告了我们的发现，即亚高山生态系统具有抵御环境变化的能力，部分原因是这些系统中的生物适应了地点，季节和年份之间变化很大的环境条件。

著录项

  • 作者

    Conner, Lafe G.;

  • 作者单位

    Brigham Young University.;

  • 授予单位 Brigham Young University.;
  • 学科 Ecology.;Botany.;Hydrologic sciences.
  • 学位 Ph.D.
  • 年度 2015
  • 页码 169 p.
  • 总页数 169
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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