Doctoral Dissertation Research: Vegetation Change and Land Degradation in the Lake Baringo Ecosystem, Kenya, East Africa: Evidence from the Paleorecord.

孢粉学是重建地质和历史时期自然和人为环境变化的有用工具。本项目将通过检查湖泊沉积物岩心中的花粉化石、植物岩和微观木炭，研究东非肯尼亚巴林戈湖生态系统在全新世期间的植被变化和土地退化历史。巴林哥湖生态系统是500多种鸟类的重要栖息地，也是人类的生计来源，但由于东非人口压力日益增大，该生态系统正受到土地退化的威胁。尽管一些研究利用花粉重建了东非的古植被和古气候，但很少有孢粉学研究关注非洲最严重的环境问题之一——土地退化或荒漠化。研究人员将前往肯尼亚，从巴林哥湖收集一系列长芯和短芯以及地表沉积物样本。这些岩心和地表样本将提供一个扩展的年代学，也提供了这个大湖内花粉沉积和沉积速率的空间变化的信息。这项研究的一个关键目标是确定最近土地利用的变化和土地退化的加剧如何反映在湖泊沉积物记录中。研究人员将分析沉积物地层、微观木炭、花粉和植物岩组合，以记录巴林哥湖生态系统中土地退化、气候和植被变化以及火灾制度变化的历史。已经获得了湖泊集水区的卫星图像，为了提高分类精度，将在实地工作中获取GPS点进行地面真实性。这项研究将产生一份来自肯尼亚半干旱地区的高分辨率全新世花粉记录，这是东非仅有的几份记录之一。它将有助于了解全新世晚期东非一个关键环境带中自然原因与人为原因对环境变化的作用。其研究结果将对东非半干旱地区的生物多样性保护、湖泊恢复、土地使用规划和环境管理产生重大的政策影响。

Palynology is a useful tool for the reconstruction of environmental changes due to both natural and anthropogenic causes during geological and historical times. This project will study the history of vegetational changes and land degradation in the Lake Baringo ecosystem, Kenya, East Africa, during the Holocene through the examination of fossil pollen, phytoliths, and microscopic charcoal in lake-sediment cores. The Lake Baringo ecosystem, a critical habitat for more than 500 avifaunal species and a source of livelihood for humans, is threatened by land degradation as a result of mounting population pressure in East Africa. Although some studies have used pollen to reconstruct the paleovegetation and paleoclimate of East Africa, very few palynological studies have focused on land degradation or desertification, considered one of the most serious environmental problems in Africa. The researchers will travel to Kenya and collect a series of long and short cores and surface sediment samples from Lake Baringo. These cores and surface samples will yield an extended chronology and also provide information on the spatial variations of pollen deposition and sedimentation rates within this large lake. A key objective of the research is to determine how recent changes in land-use and increased land degradation are reflected in the lake-sediment records. The researchers will analyze the sediment stratigraphy, microscopic charcoal, and pollen and phytolith assemblages to document the history of land degradation, climatic and vegetational changes, and variations in fire regimes in the Lake Baringo ecosystem. Satellite imageries of the lake catchment area have been obtained and, to enhance accuracy in classification, GPS points will be obtained during fieldwork for ground truthing. The study will produce a high-resolution Holocene pollen record from the semi-arid region of Kenya and one of only a handful from East Africa in general. It will contribute to knowledge on the role of natural versus anthropogenic causes for environmental changes in a critical environmental zone in East Africa during the late Holocene. Its findings will have significant policy implications on the conservation of biodiversity, lake restoration, land-use planning, and environmental management in the semi-arid regions of East Africa.