Doctoral Dissertation Research: Vegetation Dynamics and Biogeomorphic Influences in a Highly Eroded Landscape

博士论文研究：高度侵蚀景观中的植被动态和生物地貌影响

• 批准号: 9900967
• 负责人: Kathleen Parker
• 金额: $ 1万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-01 至 2001-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9900967&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Vegetation; Dynamics

Although the impact of vegetation cover on erosional processes has been studied extensively, far less attention has been given to the effects of accelerated soil erosion on vegetation structure and composition. Research in relatively stable, arid badlands suggests that the steep environmental gradients caused by fluvial erosion create correspondingly graded vegetation communities, but few studies have examined vegetation responses to the frequent geomorphic disturbance that occurs in actively eroding landscapes as well as relationships among geomorphic processes, topographic variables, and edaphic (soil-related) characteristics, and vegetation patterns in humid environments. This doctoral dissertation research study will investigate those relationships through a case study in Providence Canyons, Georgia, a landscape that has experienced severe soil erosion and deep gully incision over the last 150 years because of careless cotton-farming practices. Aerial photographic analysis will be used to characterize vegetation and geomorphic change occurring both spatially and temporally on a landscape scale over the past 60 years. Complementing this broader-scale analysis will be focused examinations of geomorphic, topographic, and edaphic variables that have primary influences on vegetation patterns, including the nature and frequency of geomorphic disturbance that characterize a particular portion of the landscape; slope aspect, configuration and steepness; gradient; elevation above the valley floor; valley width; soil texture; and soil nutrient levels. The doctoral candidate will measure vegetative and soil characteristics in a broad range of sites exhibiting differing geomorphic disturbance regimes and topographic position and will relate the variables using canonical correspondence analysis, classification analysis, and discriminant function analysis. On an applied level, this study will assist landscape managers in the restoration of severely eroded landscapes. More broadly, because of the unique blend of geomorphic and topographic variables present in these landscapes, this study will increase our understanding of the influence of those variables on vegetation composition, structure, and dynamics. This study will strengthen existing links between geomorphologists and biogeographers and will enable geomorphologists to refine erosion models with more specific vegetation variables. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.

尽管已经对植被覆盖对侵蚀过程的影响进行了广泛的研究，但对加速土壤侵蚀对植被结构和组成的影响的关注得多。 在相对稳定的研究中，干旱的荒地表明，河流侵蚀引起的陡峭环境梯度会产生相应的分级植被群落，但很少有研究检查对植被对频繁的地貌干扰的反应，而植被的反应在积极侵蚀景观中发生的频繁的地貌干扰以及地质过程，地球，超图像变量和土壤的杂物（和土壤和土壤）的形式（杂物和土壤中）的杂物（杂物）（杂物）（杂物）（杂物）（杂物）的特征（杂物）（杂物）（杂物）（杂物）（杂物）和杂种杂种（杂种）杂物（杂物）和杂种构成了杂种的杂物。 这项博士学位论文研究将通过在佐治亚州的普罗维登斯峡谷（Providence Canyons）的案例研究中调查这些关系，这种景观在过去150年中经历了严重的土壤侵蚀和深处的沟渠切口，这是由于粗心的棉花养育习惯。 航空照相分析将用于表征在过去60年中在景观尺度上在空间和时间上发生的植被和地貌变化。 对这种广泛的分析的补充将是对对植被模式产生主要影响的地貌，地形和质量变量的重点检查，包括地貌干扰的性质和频率，表征了景观的特定部分；斜率方面，配置和陡度；坡度;山谷地板上方的海拔；山谷宽度；土壤质地；和土壤养分水平。 博士候选人将在具有不同的地貌干扰方案和地形位置的广泛地点中测量营养和土壤特征，并使用规范对应分析，分类分析和判别功能分析将变量联系起来。 在应用水平上，这项研究将帮助景观经理恢复严重侵蚀的景观。 更广泛地说，由于这些景观中存在的地貌变量和地形变量的独特融合，这项研究将增强我们对这些变量对植被组成，结构和动态的影响的理解。 这项研究将加强地貌学家与生物地理学家之间的现有联系，并使地貌学家能够完善具有更具体的植被变量的侵蚀模型。 作为博士学位论文研究改进奖，该奖项还将提供支持，使有前途的学生能够建立强大的独立研究职业。