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30th Systems Science Colloquium
Winter semester 2023/24
The colloquium takes place on Wednesdays from 16:15 to max. 17:45.
- Onsite colloquia take place in room 35/E16 (biology building, Barbarastraße 11).
- Online colloquia take place via a videoconference in BigBlueButton.
Link: https://studip.uni-osnabrueck.de/plugins.php/meetingplugin/room/index/4406fa0a5de3fae78d07fe80a02a07cd/413a6f247904fd6265876dd9d13712f1?cancel_login=1
Please see the program below for which colloquia will be held on-site or online.
PDF file of the program for download
Program
18 October 2023, onsite
Preparatory meeting for students
25 October 2023, 16:00, online
Prof. Dr. Takeshi Miki, Ryukoku University, Center for Biodiversity Science and Faculty of Advanced Science and Technology (Japan)
Epidemics in phytoplankton and their microscale characteristics
1 November 2023, onsite
Dr. Alexis Synodinos, Helmholtz Centre for Environmental Research (UFZ) and German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig
Trophic interactions in a warming world: Integrating theory and (some) data
22 November 2023, onsite
Dr. Paulien Adriaanse, Wageningen Environmental Research, Wageningen University & Research (The Netherlands)
29 November 2023, onsite
Prof. Dr. Georg Jäger, University of Graz, Institute of Environmental Systems Sciences (Austria)
Replacing rules by neural networks: Using artificial intelligence for agent-based modeling
20 December 2023, online
Prof. Dr. Raul P. Lejano, New York University, Steinhardt School of Culture, Education, and Human Development (USA)
Caring, empathy, and the commons
10 January 2024, onsite
Prof. Dr. Frank H. Westerhoff, University of Bamberg, Department of Economics
A new kind of economic dynamics: Interactions between real and virtual fixed points
24 January 2024, onsite
Prof. Dr. Sandrine Charles, Claude Bernard University Lyon 1, Laboratory of Biometry and Evolutionary Biology (France)
Modelling at the heart of environmental risk assessment
Abstracts of presentations
25 October 2023
Prof. Dr. Takeshi Miki, Ryukoku University, Center for Biodiversity Science and Faculty of Advanced Science and Technology (Japan)
Epidemics in phytoplankton and their microscale characteristics
Parasites, ubiquitous in ecosystems, play a pivotal yet relatively unexplored role in the dynamics of plankton and material transfer within aquatic environments. Fungal parasites in freshwater ecosystems are one of the major parasites, which not only regulate phytoplankton bloom but also contribute to the maintenance of the whole food webs by diversifying the material transfer pathways. In this presentation, I will begin by providing a brief introduction to the ecology of parasitic fungi in phytoplankton. Subsequently, I will provide an overview of mathematical and modeling methodologies aimed at enhancing our understanding of the epidemic dynamics of these parasitic fungi. Particular emphasis is placed on the microscale characteristics, involving individual-level heterogeneity within host-parasite populations.
1 November 2023
Dr. Alexis Synodinos, Helmholtz Centre for Environmental Research (UFZ) and German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig
Trophic interactions in a warming world: Integrating theory and (some) data
Temperature regulates the physiology and behaviour of many species, in particular ectotherms. Trophic interactions between ectotherm primary producers and their predators (consumer-resource interactions) modulate the flow of energy and materials into ecological communities and ecosystems, more broadly. Therefore, the documented increase in mean temperatures almost globally will have direct implications for these interactions, scaling up to whole ecosystems. Thus, an important question is, how will warming impact the structure and dynamics of consumer-resource interactions? Unfortunately, a conclusive answer still eludes us. In this talk, I will describe how a gap between the existing theory and experimental data hinders the generation of reliable, generalisable predictions. I will, then, present frameworks that aim to facilitate the integration of data into the theory.
22 November 2023
Dr. Paulien Adriaanse, Wageningen Environmental Research, Wageningen University & Research (The Netherlands)
Tiered risk assessment for pesticide registration: Principles and application on exposure in surface water in the EU
Application of pesticides is recognized as one of the main reasons for declines of farmland biodiversity. Despite regulatory risk assessment procedures are conducted to avoid unacceptable damage to wildlife resulting from environmental release of pesticides, there is evidence that protection is not guaranteed under certain scenarios. One of main problems behind the sometimes-low efficiency of environmental risk assessment of pesticides is that the procedures are usually limited to simplistic scenarios and ignore the complexity of the ecosystems. Scaling-up ecotoxicological data to the ecological level is therefore necessary to increase the relevance of the research results and to maximize their applicability to develop an efficient and protective risk assessment for wildlife. Our team has been investigating, for more than one decade, on different case studies about incidents in wildlife associated with pesticide use, from the initial description of toxicity and hazards to the characterization of population-level effects. Over the course of those studies, the abovementioned need to focus on ecologically relevant assessments has been revealed, and in this context we continue working to provide appropriate tools for improvement of risk assessment efficacy. During this seminar, we will review some of these case studies reflecting different problematics; on the one hand, that of an under-represented group in risk assessment procedures, such as amphibians, which are however highly sensitive to, and globally threatened by environmental pollution. On the other hand, the case of pesticide-coated seeds and granivorous birds, which represents a very particular risk when as animals become susceptible of ingesting toxic doses of pesticides in a short term when consuming these seeds. Strategies to integrate individual- with population-based effects will be reviewed and discussed.
29 November 2023
Prof. Dr. Georg Jäger, University of Graz, Institute of Environmental Systems Sciences (Austria)
Replacing rules by neural networks: Using artificial intelligence for agent-based modeling
When dealing with complex dynamic systems that are comprised of many interacting and interconnected parts, agent-based modelling is a viable way to gain new insights by means of a computer simulation. The main idea of this approach is to model a system from the bottom up, i.e. by describing the individual components (called agents) and defining rules how they interact and behave. These microscopic rules can lead to the emergence of complex macroscopic behaviour. Agent-based modelling is especially useful if the agents represent human beings following simple rules, like for example in a traffic model or an evacuation model. However, once human behaviour becomes too complex to be described by simple rules, traditional agent-based modelling cannot be applied. Artificial Intelligence (AI) gives us new tools to describe and predict human behaviour. Using AI in the context of agent-based modelling (AI-ABMs) allows us to investigate systems out of scope for traditional models. To make AI-ABMs more accessible, I work on developing a generic and universal framework that can be used to investigate all kinds of systems where human decision play a crucial role, which is the case for many systems related to sustainability and sustainable development.
20 December 2023
Prof. Dr. Raul P. Lejano, New York University, Steinhardt School of Culture, Education, and Human Development (USA)
Caring, empathy, and the commons
People are not autonomous individuals but connected beings. Curae ergo sum – we care, therefore we are. The concept of relationality – which refers to the ethic and manner by which relational considerations govern decisions and institutional arrangements can take advantage of the power of connection– uncovers how social connection, across divides, moves people to act for the other. Drawing from research on empathy, social networks, and determinants of pro-social behavior, Lejano will discuss his new book (Caring, Empathy, and the Commons), which builds on Ostrom’s Governing the Commons. The theory offers a different mechanism by which collective action is induced, arguing that, sometimes, the individual thinks not in terms of individual gain but in terms of the other. In game theoretic terms, the underlying model involves decision functions with vector payoffs. Lejano will examine how this idea might be used to foster collective action around climate, species protection, fair trade, and other dilemmas of the commons.
Bio: Raul P. Lejano is Professor of environmental policy and education at New York University. His research revolves around two sides of relationality: how connectedness fosters collective action and disconnectedness increases vulnerability. He is a coauthor, with Wing Shan Kan, of a book entitled Relationality: The Inner Life of Public Policy (Cambridge University Press).
10 January 2024
Prof. Dr. Frank H. Westerhoff, University of Bamberg, Department of Economics
A new kind of economic dynamics: Interactions between real and virtual fixed points
We begin by examining several piecewise-linear discontinuous maps that correspond to simple economic models. These models might offer new insights into why many economic systems exhibit excessive volatility. Following this general overview, we delve deeper into one of these maps/models. Specifically, we analyze a stock market model involving chartists, fundamentalists, and market makers. Chartists chase stock price trends, fundamentalists bet on mean reversion, and market makers adjust stock prices with respect to the current excess demand. However, fundamentalists’ perception of the stock market’s fundamental value is subject to animal spirits. As long as the stock market is relatively stable, fundamentalists neutrally believe in a normal fundamental value. But when the stock market increases (decreases) strongly, fundamentalists optimistically (pessimistically) believe in a high (low) fundamental value. Our framework may give rise to boom-bust stock market dynamics that coevolve with waves of optimism and pessimism for parameter settings that would ensure globally stable stock market dynamics in the absence of animal spirits. Responsible for such a surprising outcome is the destabilizing nature of temporarily attracting virtual fixed points, brought about by animal spirits.
24 January 2024
Prof. Dr. Sandrine Charles, Claude Bernard University Lyon 1, Laboratory of Biometry and Evolutionary Biology (France)
Modelling at the heart of environmental risk assessment
In general terms, environmental risk assessment (ERA) is the process of evaluating the potential effects of substances, activities or natural phenomena on the environment and the living organisms within it. With a specific focus on chemical substances, ERA requires predicting and evaluating the likelihood and magnitude of potential adverse effects that these substances may cause on ecosystems. Since its inception, ERA has used models to quantitatively analyze toxicity test data. Since the 1970s, the models used have evolved greatly, from simple statistical approaches to high-dimensional, sophisticated mechanistic models. This talk invites the audience on an introductory journey through the modelling landscape of ERA, with the aim of convincing them why models are crucial for ERA, which models form the core of ERA today, and what the models of ERA tomorrow would be. This journey will be punctuated by methodological stops (opening the box of some typical models), but also by relaxing breaks (illustrating the use of models with case studies), to conclude with the identification of some key challenges that could animate the academic research sphere in the coming years.
