Contemporary and long-term erosion in a pristine African Savanna, Kruger National Park, Republic of South Africa

可持续土壤管理需要关于当今自然侵蚀率的资料，以便制定普遍接受的管理目标。不幸的是，在当前气候条件下，关于未开垦土地自然侵蚀率的数据很难找到。这一点在南部非洲尤其适用，在那里，人类引起的土壤侵蚀据信比自然速率高出一到两个数量级，这取决于方法方法。在这里，我们建议通过调查克鲁格国家公园（KNP）自然保护区的长期剥蚀、当代产沙量和沉积物来源，建立并比较非洲稀树草原环境的当代和长期自然侵蚀率。KNP位于南非共和国东北部干燥的Lowveld稀树草原上，特别适合这项研究，因为该地区在100多年前被留出用于野生动物保护，从未经历过农业发展。此外，KNP是一个非常有记录的地区，Skukuza的SANParks科学服务提供了对其数据库的完整访问，包括与该侵蚀研究相关的许多数据集（例如，dem、地质、土壤、植被和植被变化、火灾记录、降水、排水、航空照片）。考虑到侵蚀的内因（地质、土壤和地形）和外因（气候和植被）驱动因素的变化，本联合研究项目的目标是：1)基于40至80年前建立的水库沉积的体积测绘和评估，确定流域尺度上的当代平均近自然产沙率。2)利用宇宙成因核素测定低起伏热带稀树草原环境的晚第四纪侵蚀速率，并与当代侵蚀速率进行比较。3)利用沉积物指纹法对流域内主要沉积物来源进行识别和量化，以便在流域贡献区分配产沙量。预期的结果将促进对晚第四纪热带稀树草原地貌动力学演化和环境轨迹的认识。与丰富的耕地土壤侵蚀数据相比，它们将为评估自然保护区的土壤保持生态系统服务提供有价值的数据。此外，研究结果通过提供当代和长期自然侵蚀基线率，对南非和邻国干旱稀树草原地区土壤和水管理目标的基础和合理性具有重要意义。

Sustainable soil management requires information on present day natural rates of erosion in order to develop generally accepted management goals. Unfortunately, data on rates of natural erosion from uncultivated land under current climate conditions are difficult to find. This holds especially for southern Africa, where human induced soil erosion is believed to exceed natural rates by one or two orders of magnitude, depending on the methodological approach. Here, we propose to establish and compare contemporary and long-term natural erosion rates for an African savanna environment by investigating long-term denudation, contemporary sediment yield and sediment sources in a nature conservation area, i.e. the Kruger National Park (KNP). The KNP, located in the dry Lowveld savanna in the NE part of the Republic of South Africa is particularly suited for this study because the area was set aside for wild life conservation over 100 years ago and never experienced agricultural development. Furthermore, KNP is an exceptionally well documented area and SANParks Scientific Services at Skukuza provides full access to its data base, including a number of data sets relevant to this study on erosion (e.g., DEMs, geology, soils, vegetation and vegetation change, fire records, precipitation, drainage, aerial photos).Taking into account variation in endogenetic (geology, soils and relief) and exogenetic (climate and vegetation) drivers of erosion the objectives of this joint research project are:1) The determination of contemporary average near-natural sediment yield rates on the catchment scale based on volumetric mapping and assessment of the sediment deposited in reservoirs established 40 to 80 years ago. 2) The determination of the late Quaternary rates of erosion in this rather low relief savanna environment using cosmogenic nuclides and a comparison with the contemporary erosion rates. 3) The identification and quantification of major sediment sources within the catchments using sediment finger printing methods in order to apportion sediment yield to contributing areas of the catchment. The anticipated results will advance the understanding of the late Quaternary geomorphodynamic evolution and trajectories of savanna environments. They will provide valuable data for an assessment of the soil preservation ecosystem services of a nature conservation area when compared to the abundant data on soil erosion from cultivated land. In addition, the results are of importance for the foundation and justification of soil and water management goals in the dry savanna regions of South Africa and neighboring countries by providing contemporary and long-term natural erosion baseline rates.