Institut für Umweltsystemforschung

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© J. Berlekamp

Research group 'Applied Systems Science'


Head: Professor Frank Hilker

Group meeting 

Research profile

Our research group works on modeling environmental and ecological systems. These systems are experiencing a rapid rate of change, e.g. due to alterations in land and resource use, global mobility, pollution and climate change. If we are to effectively manage the emerging challenges and maintain the ecosystem services they provide, there is a pressing need to better understand how these systems respond to perturbations. Yet, environmental and eco-systems are complex and notoriously difficult to analyze.

Our work is interdisciplinary, at the interface of theoretical ecology, biogeochemistry, epidemiology, eco-toxicology, and applied maths. We use a variety of approaches, including mathematical modeling, tools from nonlinear dynamics and statistical physics, computer-based simulations, and data analysis.

Our research is "system-oriented". That is, we capture complicated system structures by focusing on selected components and their interactions with each other as well as with the environment. This allows us to identify and understand complex behavior that emerges from the interrelations of the system parts.

Current and ongoing research

  • Regime shifts and early-warning signals
  • Environmental flow requirements
  • Modeling biocontrol and integrated pest management
  • Species distribution and trophic interactions in streams and rivers
  • Spatial population models for conservation biology
  • Chaos control methods for stabilizing fluctuating populations
  • Epidemiological modeling: the complexity of wildlife diseases


  • Cecilia Berardo (Univ. Turin, Italy): April-September 2016
  • Martina Bulai (Univ. Turin, Italy): August-September 2016
  • Marta Paliaga (MSc student, U. Turin, Italy): April-September 2015
  • Federico Roccati (MSc student, U. Turin, Italy): April-September 2015
  • Anthony Sun (Univ. Rennes, France): January-June 2016
  • Vinicius Weide Rodrigues (Federal University of Rio Grande do Sul, Brazil): September 2017 - February 2018

Former group members

  • Christian Ehling
  • Dr. Nils Kehrein
  • Vanessa Schakau
  • Dr. Mickaël Teixeira-Alves

News from the research group

Visitor: Ezio Venturino (Turin)

It's our pleasure to host Prof. Venturino and continue collaboration on eco-epidemic models.

New postdoc

We are excited to welcome a new colleague, Dr. Matthew Adamson. Matthew recently graduated from the University of Leicester (UK) with a PhD in mathematics.

Visit to Alberta

Vanessa Schakau will be visiting the University of Alberta in Edmonton, AB, Canada for five weeks in September and October. She will be hosted by the Centre for Mathematical Biology under the direction of Prof. Mark Lewis.


Vanessa Schakau will be presenting at the international conference on "Mathematical Population Dynamics and Ecology" (MPDE) in Niteroi, Rio de Janeiro, Brazil. Fellow PhD student Michael Bengfort and Prof. Horst Malchow from the Theoretical Systems Science group will also attend and present joint work.

Visitors from Besançon, Cologne und Oldenburg

In June, we are thrilled to host three visitors: Virgile Baudrot (Université de Franche-Comté, Besançon, France), Fanny Groll (University of Cologne) and Daniel Ritterskamp (University of Oldenburg).

Visit to the Research Station Grietherbusch

Vanessa and Frank the Research Station of the University Cologne's Zoological Institute. Kindly hosted by Jost Borcherding, Lisa Heermann and Maxim Teichert, they discussed avenues in modelling fish leeches that have been observed in irregular patterns in the Lower Rhine.

Visitor: Eduardo Liz

We are delighted to have Prof. Eduardo Liz visiting from 10-17 May and giving a seminar on 12 May. Eduardo is Professor of Applied Mathematics and from the University of Vigo (Spain).

Welcome: Marta Paliaga and Federico Roccati

We are pleased to welcome Marta and Federico, who are visiting us from the University of Turin. They will write their Master theses under joint supervision from Frank Hilker (U Osnabrück) and Prof. Venturino (U Turin). They are supported by Erasmus+ grants.

Colloquium Cologne

Invited to give a presentation at the Ecological Colloquium in Cologne, Frank Hilker was excited to catch up with Prof. Hartmut Arndt and his research group.

Cooperation with Turin (Italy)

In April, Frank Hilker visited Prof. Ezio Venturino at the Department of Mathematics (University of Turin) to strengthen teaching activities and discuss jointly supervised student projects.

Research cooperation with Vigo (Spain)

Following up on recent work with Prof. Eduardo Liz, Frank Hilker was thrilled to visit the University of Vigo (Spain) to continue with and start new joint research projects.

European Society for Mathematical and Theoretical Biology (ESMTB)

Frank Hilker has been elected as a board member of ESMTB. At the inaugural board meeting in Vienna, Frank has been elected as the new treasurer.

Visitor: Hans Joachim Poethke

We are excited to welcome Prof. Poethke (U. Würzburg, Germany), who will deliver a presentation in our Colloquium and visit our research group!

Inaugural lecture

On Wednesday, 10 December 2014, the Institute's two new chairs will give their inaugural lectures. Frank Hilker will present on «Modeling complex ecological systems», and Alexander von Humboldt-awardee Stefanie Engel will present on «Policy design for sustainable ecosystem services». The lectures will begin at 4:15pm in lecture hall 66/E33.

New PhD student

We are delighted that Vanessa Schakau has joined our group as a new PhD student and academic assistant. She recently graduated from Oldenburg University with an MSc in Marine Environmental Sciences and a focus on environmental modeling. At Osnabrück, she will working on modeling infectious diseases dynamics in streams and rivers.Welcome to our group and at the Institute, Vanessa!

For prospective undergraduate students

At the University Open Day, members of the research group informed local high school students about systems science and the degree programmes offered. Professor Frank Hilker introduced the undergraduate programmes «Applied Systems Science» und «Environmental Systems Science». Christian Ehling and Dr. Jörg Klasmeier ran a computer lab on cellular automata.

Alumni meeting

Every other year, the graduates of our study degree programmes are invited to the Alumni Meeting of the School of Mathematics and Computer Science. This year, Professor Frank Hilker introduced some of his research activities by delivering a presentation on «Chaos in Ecology: How “controllable” are outbreaks and extinctions?»

Visitor: Dr. Ivo Siekmann (U Melbourne, Australia)

We were delighted to host Ivo Siekmann, who graduated with a PhD in Applied Systems Science from our School in 2009. He gave a talk on "The Tyranny of the Masses - Population dynamics of individual-based models".

New paper

"Plankton blooms and patchiness generated by heterogeneous physical environments", to appear in Ecological Complexity, joint with local colleagues Michael Bengfort and Horst Malchow (Theoretical Systems Science) and Ulrike Feudel (U. Oldenburg).

Guest: Prof. Daniel Franco (UNED, Madrid, Spain)

Daniel Franco is with the Dept. of Applied Mathematics at UNED, an Open University. With more than 260,000 students, UNED is Spains largest and Europe's second largest university.

New publication

"A mathematical biologist's guide to absolute and convective instability", to appear in Bulletin of Mathematical Biology.

Guest: Prof. Thomas Hillen (U. Alberta)

Thomas Hillen will visit the Institute of Environmental Systems Research on 24 April and deliver a seminar on "Mathematical Modelling of Cancer", in which he will motivate the understanding of cancer as an ecosystem. Thomas Hillen is professor of mathematics at the University of Alberta in Edmonton AB, Canada.

Workshop: Predictive systems models for ecological risk assessment of chemicals

Frank Hilker attended an investigative workshop at the National Institute for Mathematical and Biological Synthesis (NIMBIoS) to develop models bridging the molecular, individual and population levels of chemical risk assessment. Following the workshop, he collaborated with Prof. Suzanne Lenhart and Eric Numfor from the University of Tennessee in Knoxville.

Publication: Linking hydrodynamics and population dynamics for environmental flow requirements

The interplay of temporal variability and spatial heterogeneity can give rise to a new phenomenon, the invasion ratchet, which drives the persistence of organisms in streams and rivers. This emerging behavior has been found in a novel bio-physcial hybrid model coupling hydraulics and ecological dynamics.

The paper is co-authored by Ju Yin (Lincoln-Nebraska), Frank Hilker, Peter Steffler, and Mark Lewis (Alberta). It has been accepted for publication in Bulletin of Mathematical Biology.

Workshop: "Simulation in den Umwelt- und Geowissenschaften"

Three members of the research group (Jörg Klasmeier, Jürgen Berlekamp, and Frank Hilker) attended a meeting on simulation in environmental and geo-sciences. Jörg Klasmeier delivered a talk on geo-referenced simulations of pharmaceuticals in watersheds in the context of decision support for risk management. The workshop took place at the University of Applied Sciences in Osnabrück.

Back to Osnabrück

Frank Hilker returned to his Alma mater as Professor of Applied Systems Science. He recently joined the Institute of Environmental Systems Research and School of Mathematics/Computer Science.

The Institute is a trans-departmental initiative and a vibrant place for interdisciplinary research. For students, there three degree programs on offer: Applied Systems Science (BSc), Environmental Systems Science (BSc), and Environmental Systems and Resource Management (MSc).

Previously, Frank Hilker was Assistant Professor (Lecturer) at the University of Bath (UK), a research fellow at Lisbon University, and a postdoc at the Gulbenkian Institute (Portugal) and the University of Alberta (Canada).