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

干旱、野火和不可持续的森林使用在过去几十年中造成蒙古森林大量流失。这种持续的损失并不以统一的方式进行。各种因素，特别是地形、水文、永久冻土、土壤特性和人类影响，导致空间差异，本项目的目的是确定一方面当地的地质生态和人为因素组合与不连续永久冻土、森林分布、另一方面，森林火灾的发生和火灾后植被的演替（恢复森林或变成草原）。还将考虑各因素之间的相互作用（例如，永久冻土-森林/森林-永久冻土）。根据六个假设，将通过结合几种方法来分析蒙古森林损失的因果链。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、地形参数化和生物量估计，对选定的代表性地点的当地因素组合进行评估。选定的研究区域位于北部的Tosontsengel定居点和南部的Khangai山脉主峰之间，是一个森林火灾频繁的地区。从上个世纪中期开始，该地区的木材砍伐量很大，对该地区的天然林和人为影响下的森林，将进行森林利用和火灾历史、土壤性质、冻土层深度、水文参数和植被的分析。木炭、古土壤和风成沉积物，结合发光和放射性碳测年，将用于重建人类影响开始之前的森林和景观发展。这一古环境重建将有助于在控制植被格局的一系列相互作用因素中评价人类影响的程度，下一步将对已确定和量化的地质生态参数进行地质统计学分析。这一步骤将有助于确定气候、地质、土壤和地形等因素的当地组合与由此产生的植被格局之间的关系。所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的潜在森林分布模式进行建模。最后，我们将使用中等分辨率的卫星图像，测试将模型扩大到区域规模的可能性。将根据已查明的因果关系，确定可能受到干旱压力、野火和零散林分演替障碍威胁的地区，并对植被和永久冻土的进一步发展作出预测。

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.