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

干旱和半干旱稀树草原生态系统具有全球意义，是地球系统的重要组成部分，因为它们在陆地-大气能量平衡以及碳和养分循环中发挥着重要作用。 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和以野生动物为基础的旅游业。 最近的变化，土地利用的压力，改变火灾制度，气候变化导致了大规模的变化，在干旱系统的植被结构和功能属性，这两个生态地球化学过程和生境相关的关键结构资源，如孤立的筑巢树，觅食地，繁殖区，藏身之处，和安全的迁移路线的可用性具有重要意义。 本博士论文研究项目将集中在中部卡拉哈里，博茨瓦纳的半干旱稀树草原系统，以研究三个主要的土地管理战略（保护区，游戏牧场，开放获取/养牛）对生态系统结构和功能的差异影响。 博士生将建立在基于实地的数据收集和随后的分析中卡拉哈里野生动物保护区（CKGR）内的区域，以扩大采样到保护区外的邻近和类似的系统。 他将使用自下而上的分层方法，将实地得出的植被测量结果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。 通过分析高分辨率图像得出的估计数将用于验证通过对整个卡拉哈里中部的中分辨率图像进行光谱混合分析得出的估计数。 为了更好地了解稀树草原系统的空间异质性，将把分数估计数与代表坡度、坡向、海拔、土壤湿度和植被生产力的其他地形和光谱变量结合起来，绘制自然地理地貌景观单元图。 部分覆盖和景观单元将被整合，然后解析到三个土地管理指定比较评估其对热带稀树草原生态系统结构的影响，在中央Kalahari.The结果这个项目将有助于填补一个空白，在热带稀树草原生态学的学术文献中，结构评估通常进行远程或在外地，但很少被整合到一个有凝聚力的多尺度采样策略。 该项目将产生实地和卫星衍生的生态系统变量，并在一个功能上类似于全球热带草原系统的未得到充分研究的偏远地区测试新的研究方法。 项目成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，从而促进将在该地区学到的经验教训纳入牧场生态和保护管理实践。 作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。

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.