The importance of large trees for grazing ungulates in African savannas

大树对非洲稀树草原有蹄类动物放牧的重要性

• 批准号: 5455721
• 负责人: Dr. Anna C. Treydte
• 金额: --
• 依托单位: Resource Ecology Group
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2007-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5455721?language=en
• 关键词: importance; large; trees; grazing; ungulates

African savannas accommodate a high diversity of wildlife species utilising a mosaic of heterogeneous vegetation structure. Varying rainfall patterns and soil fertility create a continuous herbaceous layer, interspersed by large savanna trees. These trees can increase the nutrient content of their understorey vegetation and thereby generate attractive feeding sites for grazing wildlife. Large tree cover, however, is declining due to increased logging activities and elevated elephant densities in some protected areas. This may lead to a decline in the abundance of herbivorous ungulates that optimise their food intake by choosing high quality forage. We compile data on plant nutrient contents collected in Eastern and Southern Africa, together with estimates about minimal nutrient requirements of wild ungulate species. We will compare the nutrient quality of grasses underneath canopies with grasses in open savanna areas and use linear optimisation models to identify the importance of tree environments for grazing ungulate species. We hypothesize that these species will preferably feed beneath canopies due to the low quality of fodder grasses in surrounding savanna grasslands. We will combine information on different savannas along a gradient of rainfall and soil nutrient content with geographic maps of Africa. We then can identify areas where wildlife use underneath canopies should be high. Hence, we can predict future patterns of wildlife abundance with respect to tree cover in different savanna types such that management and conservation decisions can be applied accordingly.

非洲稀树草原利用异质植被结构的马赛克，容纳了高度多样性的野生动物物种。不同的降雨模式和土壤肥力创造了一个连续的草本层，散布着大草原树木。这些树木可以增加其林下植被的养分含量，从而为放牧野生动物提供有吸引力的觅食场所。然而，由于伐木活动的增加和一些保护区大象密度的增加，大型树木的覆盖率正在下降。这可能导致食草有蹄类动物的数量减少，这些有蹄类动物通过选择高质量的饲料来优化食物摄入。我们汇编了在东部和南部非洲收集的植物营养成分数据，以及对野生有蹄类动物物种最低营养需求的估计。我们将比较树冠下的草与开阔稀树草原地区的草的营养质量，并使用线性优化模型来确定树木环境对放牧有蹄类物种的重要性。我们假设，由于周围稀树草原的饲用草质量较低，这些物种更喜欢在树冠下觅食。我们将把联合收割机关于不同热带稀树草原的信息与非洲地理图结合起来，沿着降雨量和土壤养分含量的梯度。然后，我们可以确定在树冠下的野生动物使用应该是高的地区。因此，我们可以预测未来的模式，野生动物丰富的树木覆盖在不同的稀树草原类型，管理和保护决策可以相应地应用。