UFZ Environmental Modeling & Monitoring Lecture

Upcoming event:

25 January 2018, 10 - 12 am, KUBUS Hall 2AB

FRANK HILKER, Institute of Environmental Systems Research, Osnabrück University (Germany)

Dynamics and tipping points of exploited biological resources: Insights from mathematical modelling

The exploitation of biological resources is a pertinent issue in fisheries, forestry, grazing systems, wildlife management and pest control. Anthropogenic impact is increasingly recognized to put pressure on ecosystems, which is why there are different types of harvesting and management strategies aimed at sustainable exploitation. At the same time, ecological systems are inherently complex in themselves, giving rise to tipping points and unpredictable dynamics for example. How do management strategies interact with ecosystem dynamics and prevent –or even drive– ecological regime shifts? In this lecture, I will address this question with mathematical models that represent the dynamics of a biological resource in generic form (e.g., simple difference equations for fish stock or population size), but account for complexities like inherent oscillations and alternative stable states. I will pull together insights gained from mathematical analysis and simulations, and synthesize how different management strategies and intervention timing affect the persistence, constancy stability and resilience of the exploited resource.

 Past events:

RUTH DELZEIT, Kiel Institute for the World Economy (Germany)

Global economic-biophysical assessment of midterm scenarios for agricultural markets - biofuel policies, dietary patterns, cropland expansion, and productivity growth


Land-use decisions are made at the local level. They are influenced both by local factors and by global economic and political drivers and trends. These will most likely change over time e.g. due to political shocks, market developments or climate change. Hence, their influence should be taken into account when analysing and projecting local land-use decisions. We provide a set of mid-term scenarios of global drivers (until 2030) for use in regional and local studies on agriculture and land-use. In a participatory process, four important drivers are identified by experts from globally distributed regional studies: biofuel policies, increase in preferences for meat and dairy products in Asia, cropland expansion into uncultivated areas, and changes in agricultural productivity growth. Their impact on possible future developments of global and regional agricultural markets, food production and food prices are analysed with a modelling framework consisting of a global computable general equilibrium model and a crop growth model. Global trends as shown in the Business As Usual (BAU) scenario lead to an increasing scarcity of fertile land with rising prices for primary agricultural products as well as a shift towards the production of vegetable oils. It also leads to a conversion of pasture land to cropland. Under different scenarios, global crop price changes range between -42 and +4% in 2030 compared to the BAU. The comparison of the scenario simulations with the BAU highlights the impact of specific policy as well as supply- and demand-side changes. It turns out that supply-side effects have a stronger impact than changes on the demand side.

THORSTEN WAGENER, Department of Civil Engineering, University of Bristol (UK)

Some thoughts on building parsimonious models of complex environmental systems


“How can we build environmental and earth system models that are more integrated, more detailed and covering larger domains, while also being parsimonious? How can we assess what additional data we should collect to better evaluate these models and to reduce the uncertainty in their predictions? These are questions we are currently wrestling with across a range of application areas linked to understanding the water environment under current and potential future climate and land use conditions. Our approach to this problem is a focus on understanding dominant controls on relevant variables across space and time scales using both empirical and model-based strategies. Variables we currently investigate include those from hydrology, like groundwater recharge, and others that are partially controlled by hydrologic processes, such as infectious disease risk. In this talk I will describe the modelling-based strategies we use to understand these controls. These strategies are centred around our Global Sensitivity Analysis Toolbox, SAFE (www.safetoolbox.info), which has already been adopted by over 1000 researchers worldwide. I will use examples in which we try to understand the impact of subsurface heterogeneity on groundwater recharge, attempt to understand the impact of different uncertain data sources on flood inundation predictions, and (briefly) try to understand hydrologic controls on liver fluke infection risk in the UK.” (Prof. Thorsten Wagener)

SANDER VAN DER LEEUW, Center for Biosocial Complex Systems, Arizona State University & Sante Fe Institute (USA)

Integrated Modeling of the Future of Socio-environmental Dynamics


"As part of an effort to develop tools that may help us further the above agenda, I held a workshop at IASS Potsdam in March 2017 that was the third in a series of workshops on integrated modeling of socio-environmental phenomena. Aim was to bring together an open source community striving to develop, in particular, approaches to model transitions in complex systems, considering decisions concerning land use as the interface between societal and environmental dynamics. In this lecture, I will discuss the general approach, some conceptual and methodological challenges as well as ways forward to reach this goal."