Doctoral Dissertation Research: Characterizing Land-Management Impacts on Ecosystem Structure in the Botswana Central Kalahari

博士论文研究：描述土地管理对博茨瓦纳中部卡拉哈里生态系统结构的影响

• 批准号: 1203580
• 负责人: Jennifer Miller
• 金额: $ 1.16万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1203580&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Characterizing; Land

Arid and semi-arid savanna ecosystems are globally significant and are an important element of the Earth system due to their major role in land-atmosphere energy balance as well as carbon and nutrient cycles. They are essential contributors to both productivity and biodiversity, especially in southern Africa, where they support high populations of economically critical domesticated livestock, some of the largest expanses of protected wildlife habitats, and wildlife-based tourism. Recent changes in land-use pressure, altered fire regimes, and climatic shifts have led to large-scale changes in the vegetation structural and functional attributes of xeric systems, which have important implications for both biogeochemical processes and the availability of habitat-related key structural resources, such as solitary nesting trees, foraging grounds, breeding zones, hiding places, and safe migration routes. This doctoral dissertation research project will focus on the semi-arid savanna system in the central Kalahari, Botswana, in order to examine the differential impacts of three dominant land-management strategies (protected areas, game ranching, and open access/cattle ranching) on ecosystem structure and function. The doctoral student will build on field-based data collection and subsequent analysis of areas within the Central Kalahari Game Reserve (CKGR) to extend sampling to neighboring and similar systems outside the reserve. He will use a bottom-up hierarchical approach to integrate field-derived vegetation measurements with spatio-temporally coincident data from high- and medium-resolution satellite imagery to quantify the vegetation and soil characteristics. Estimates derived from analysis of high-resolution imagery will be used to validate the estimates derived from spectral mixture analysis of medium-resolution imagery across the central Kalahari. To better understand the spatial heterogeneity of savanna systems, fractional estimates will be combined with other topographic and spectral variables representing slope, aspect, elevation, soil moisture and vegetative productivity) to map physiographic-physiognomic landscape units. Fractional cover and landscape units will be integrated and then parsed into the three land management designations to comparatively assess their impacts on savanna ecosystem structure in the central Kalahari.The results of this project will help to fill a void in the scholarly literature of savanna ecology, where structure assessments typically are conducted either remotely or in the field but rarely are integrated into a cohesive multi-scale sampling strategy. The project will generate both field- and satellite-derived ecosystem variables and test new research methodologies in an understudied and remote area that is functionally similar to savanna systems globally. Project results will be provided to wildlife, park, and agriculture government authorities, local researchers, ranching associations, and rural administrative district officers, thus facilitating the integration of lessons learned at this locale into the practice of rangeland ecology and conservation management. 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.

干旱和半干旱稀树草原生态系统具有全球重要意义，由于它们在陆地-大气能量平衡以及碳和养分循环中发挥着重要作用，因此成为地球系统的重要组成部分。 它们是生产力​​和生物多样性的重要贡献者，特别是在南部非洲，它们支持大量经济上至关重要的驯养牲畜、一些最大的受保护野生动物栖息地以及以野生动物为基础的旅游业。 最近土地利用压力的变化、火灾制度的改变和气候变化导致旱地系统的植被结构和功能属性发生大规模变化，这对生物地球化学过程和栖息地相关关键结构的可用性具有重要影响。资源，例如孤独的筑巢树、觅食地、繁殖区、藏身之处和安全的迁徙路线。 本博士论文研究项目将重点关注博茨瓦纳卡拉哈里中部的半干旱稀树草原系统，以研究三种主要土地管理策略（保护区、狩猎牧场和开放通道/养牛牧场）对生态系统的结构和功能。 该博士生将以实地数据收集和对中央卡拉哈里禁猎区（CKGR）内区域的后续分析为基础，将采样范围扩展到保护区外的邻近和类似系统。 他将使用自下而上的分层方法将实地植被测量与来自高分辨率和中分辨率卫星图像的时空一致数据相结合，以量化植被和土壤特征。 高分辨率图像分析得出的估计值将用于验证卡拉哈里中部中分辨率图像光谱混合分析得出的估计值。 为了更好地了解稀树草原系统的空间异质性，分数估计将与代表坡度、坡向、海拔、土壤湿度和植物生产力的其他地形和光谱变量相结合，以绘制地貌-地貌景观单元。 部分覆盖和景观单元将被整合，然后解析为三个土地管理名称，以比较评估它们对喀拉哈里中部稀树草原生态系统结构的影响。该项目的结果将有助于填补稀树草原生态学学术文献的空白，其中结构评估通常是远程或在现场进行的，但很少被整合到一个有凝聚力的多尺度抽样策略中。 该项目将产生现场和卫星衍生的生态系统变量，并在一个功能类似于全球稀树草原系统的未充分研究的偏远地区测试新的研究方法。 项目结果将提供给野生动物、公园和农业政府当局、当地研究人员、牧场协会和农村行政区官员，从而促进将该地区吸取的经验教训纳入牧场生态和保护管理的实践中。 作为博士论文研究改进奖，该奖项还将为有前途的学生建立强大的独立研究生涯提供支持。