Research and teaching unit “Physical Geography and Land Use Systems”
The research unit consists of the chair for physical geography and land use systems (Prof. Dr. Julia Pongratz), the professorship for soil geography (Prof. Dr. Eileen Eckmeier) and the research activities in geomorphology (apl. Prof. Dr. Carola Küfmann). Key focus is the influence of humans on the Earth system through land use, from changes in the regional and global energy and carbon cycle to soil degradation. Furthermore, we perform fundamental research in the area of geomorphodynamics with applications in land use in different regions (e.g., karst landscapes, alpine mountains). The research unit “Physical Geography and Land Use Systems” excels in a wide range of methodologies, from global climate and vegetation modeling to laboratory experiments and field measurements.
These research topics find their way into teaching. Here, we aim at assessing the main drivers of global change and revealing interactions between climate, humans, and vegetation. We provide the methodological tools to understand and quantify them. The research and teaching unit furthermore hosts didactics of geography, which is essential for the training of teachers at a wide range of types of schools.
Human influence on vegetation and climate
Three quarters of the ice-free land surface are used by humans in one way or the other. This has substantial consequences on climate because land use alters land cover, which in turn alters the exchange of energy, momentum, heat, moisture, carbon and other matter between vegetation and atmosphere. One third of anthropogenic CO2 emissions until today were caused by deforestation and other land use changes. Locally, altered energy and heat fluxes due to a forest being transformed to pasture or a cropland being afforested may change surface temperatures by several degrees.
In our research we aim at (1) a better understanding of the processes through which land use influences climate from local to global scale (2) a more accurate quantification of the human disturbance of the Earth system. A key focus lies on the global carbon cycle – land use substantially alters the terrestrial carbon sinks and sources, yet is the most uncertain term in the global carbon budget.
Our most important tools are global vegetation modeling, climate modeling, and Earth system modeling. These numerical models are used to simulate different scenarios, including mitigation efforts through land use, and to switch on and off individual processes. Recently we have shown that supposedly subtle changes in vegetation through wood harvest and other land management practices have impacts on surface climate similarly strong as those of deforestation.
Human influence on soils and landscapes
Soils have always been altered by human activities, which became evident especially since the development of agriculture demanded soil as a necessary resource. Incorporated residues of settlement life or land use activities, like waste, fertilizers or charred materials, alter the characteristics of soils, while soil management techniques can lead to soil degradation or erosion. Soil properties are therefore not only related to natural factors, but also to human activities.
The resulting specific sedimentological, elemental or molecular patterns are archived in soils or sediments, and they can deliver information about specific activities or even the intensity of human influence. But also recent processes that are related to land use can influence the usability of soils, now and in the future, by changing their characteristics and quality. We therefore investigate the effects of land use and climate change on pedogenesis and soil characteristics, and on soil degradation processes, mainly in the Eurasian steppes and (semi)arid regions. An important area of research is to investigate those changes in the past, using a geoarchaeological approach, with a main focus on landscape and site formation history and in cooperation with the archaeological disciplines.
Recent research focuses on the quantification of land-forming processes, their related landforms and substrata by using various methods in the field and the laboratory. The main aims are the identification of these basic components (process, form, substratum) and the knowledge about their interactions during Earth surface genesis depending basically on geology and climate. The evaluated data provide the fundamental input for related research activities in applied natural hazard science and georisk management to face the obvious influences of global change. The increase and frequency of mass movements (e.g. mudflows, debris flows) due to climatic changes interfere prevalently with human activities in rural and urban areas (e.g. Tien Shan, Pamir, Alps). Climatic variations also affect weathering processes in karstic regions; as a result water and land use patterns have to be adapted.
Moreover, the geomorphologic research focuses on atmospheric influences. The results reveal obvious effects of recent Saharan dust inputs on the development of vegetation and soils types in the high-mountainous zones of the Alps.
As mountain systems in general offer and at the same time have to face the variety of geomorphodynamics in interaction with human activities, the research expands now into the Kilimanjaro Region (Tanzania). There, climatic and hydrological changes induce e.g. erosion processes to start land degradation. Thus, questions about sustainable land use strategies integrating the traditional agriculture need to be answered to maintain stable agriculture in this outstanding East African ecosystem.
Further information is available in German: Lehrstuhl für Physische Geographie und Landnutzungssysteme