Analysis of the geo-ecological controlling parameters for the distribution of forest and discontinuous permafrost under the influence of fire, exploitation and climate in the forest steppes of central Mongolia

在过去的几十年里，干旱、野火和不可持续的森林使用造成了蒙古森林的大量损失。这一仍在继续的损失并不是以统一的方式进行的。不同的因素，特别是地形、水文、冻土、土壤性质和人类影响，导致了空间分异。本项目的目的是一方面确定当地地质生态和人为因素的星座与不连续的永久冻土、森林分布、森林火灾的发生和火灾发生后植被演替(返回森林或进入草原)之间的因果关系。还将考虑各种因素(例如永久冻土-森林/森林-永久冻土)之间的相互作用。在六个假设的基础上，将结合几种方法分析蒙古森林丧失的因果链。将通过地貌测绘、用探地雷达确定永久冻土层的分布和深度、土壤和植被测绘、遥感数据分析、地形参数确定和生物量估计，对选定代表性地点的当地因素星座进行评估。选定的研究区位于北部的Tosontsengel定居点和南部的Kangai山脉主峰之间，是一个森林火灾频繁发生的地区。自上世纪中叶以来，该地区正在进行大规模的伐木活动。该地区的天然林和人为影响下的森林，都将受到森林利用和火灾历史、土壤性质、永久冻土层深度、水文参数和植被的分析。木炭、古土壤和风沙沉积，结合发光和放射性碳测年，将在人类影响开始之前用于重建森林和景观开发。这一古环境重建将允许在控制植被模式的一系列相互作用的因素中评估人类影响的维度。在下一步，将对识别和量化的地质生态参数进行地统计学分析。这一步骤将允许确定气候、地质、土壤和地形因素的当地星座与所产生的植被模式之间的关系。获得的关系将用于利用数字地形模型和卫星图像对整个地区潜在的森林分布模式进行建模。最后，我们将使用中尺度分辨率的卫星图像，测试将模拟扩大到区域尺度的可能性。根据已确定的因果关系，将确定可能受到干旱胁迫、野火和零碎林地演替障碍威胁的地区，并将制定植被和永久冻土进一步发展的预测。

Droughts, wildfires and non-sustainable forest use have caused substantial loss of forests in Mongolia over the past decades. This still ongoing loss does not proceed in a uniform way. Various factors, especially topography, hydrology, permafrost, soil properties and human impact, lead to spatial differentiation.The aim of this project is to identify causal relationships between the local constellation of geo-ecological and anthropogenic factors on the one hand, and patterns of discontinuous permafrost, forest distribution, occurrence of forest fires and succession of vegetation after fire events (back to forest or into steppe instead) on the other hand. Also interactions between the factors (e.g. permafrost - forest / forest - permafrost) will be considered. Based on six hypotheses, the causal chains underlying the loss of forests in Mongolia will be analysed by combining several methodological approaches. The local constellation of factors at selected representative sites will be assessed by geomorphological mapping, determination of the distribution and depth of the permafrost layer by ground penetrating radar, soil and vegetation mapping, analysis of remote sensing data, relief parametrisation, and biomass estimation. The selected study area, between the settlement Tosontsengel in the North and the main summit of the Khangai Mountains in the South, represents a region that experiences frequent forest fires. Extensive wood cutting is going on in the area since the mid-last century.Both, natural forests and forests under human influence in this area, will be subjected to analysis of forest-use and fire history, soil properties, depth of the permafrost layer, hydrological parameters and vegetation. Charcoal, palaeosols, and aeolian deposits, combined with luminescence and radiocarbon dating, will be used for reconstructing forest and landscape development prior to the onset of human influence. This palaeoenvironmental reconstruction will allow for evaluating the dimension of human impact within the bundle of interacting factors controlling the vegetation pattern.In the next step, the identified and quantified geoecological parameters will be analysed geostatistically. This step will allow for identifying relationships between the local constellation of the factors climate, geology, soils and relief on the one hand, and resulting vegetation patterns on the other hand. The obtained relationships will be used for modelling potential forest distribution patterns for the whole area, using digital terrain models and satellite images. Finally, we will test the possibility of upscaling the modelling to regional scale, using satellite images of medium scale resolution. Based on the identified causal relationships, areas that are potentially threatened by drought stress, wildfires and succession barriers for fragmented forest stands will be determined, and projections of the further development of vegetation and permafrost will be developed.