Institute for Biodiversity and Ecosystem Dynamics

Three ERC Advanced Grants for IBED scientists

19 November 2012

Three scientists connected to the Institute for Biodiversity and Ecosystem Dynamics (IBED), André de Roos, Gerard Muijzer and Hal Caswell, each acquired one of the very prestigious Advanced Grant of the European Research Council (ERC).


ERC Advanced Grants are awarded annually to a select group of excellent established scientists, with an aim of giving them the opportunity to perform ground-breaking pioneering research in their area of expertise.  The excellence of the applying scientist and the excellence of the scientific proposal are both considered in the awarding of the grants with a maximum of 2.5 million euros.

ERC Advanced Grants are amongst the most prestigious scientific awards. The fact that in the 2012 round three ERC Advanced Grants were awarded to scientists connected to IBED is testimony to the scientific excellence of both the applying scientists and the institute itself.

André de Roos

André de Roos

André de Roos

André de Roos is Full Professor and Chair of the research group Theoretical Ecology. In his research, De Roos focusses on the dynamics of animal (mainly fish) populations, how it relates to the life history of the individuals making up the population and how these dynamics are influenced by environmental factors like productivity or human influences like harvesting. De Roos holds an honorary doctorate of the University of Umeå in Sweden and won several international grants and awards. With his ERC Advanced Grant, De Roos will study the eco-evolutionary dynamics of ontogenetic asymmetry and complex life cycles.

Most of the existing ecological and evolutionary theory is based on the simplifying assumption that individuals within a species are (more or less) equal. However, individuals of almost all species exhibit substantial growth and development throughout their life. As a consequence, asymmetric competition may develop between individuals in different life stages, for example when young individuals are more efficient in converting their food into biomass than mature individuals of the same species. Recently we have shown that such ontogenetic asymmetry can lead to surprising community dynamics, for example, that a predator can affect the size-structure of its prey population and thereby increase its own food supply.

Ontogenetic asymmetry is particularly prominent in species with a complex life cycle, such as amphibians and insects, because the different stages feed on different food resources, in addition to being morphologically different. In most animal groups the evolution of complex life cycles started out as an ecological specialization of individuals in different life stages (juveniles, adults) feeding to a varying extent on multiple resources. This provided under certain conditions a selective advantage for individuals to switch to an alternative food source entirely when reaching a certain size or age. The shift in diet has subsequently led to further specialization and a separation of the various life stages by metamorphosis. Asymmetry between life stages has hence been at the root of the evolution of complex life cycles. Fossil data suggest that complex life cycles have been ecologically and evolutionarily very successful, but there is no obvious explanation for this success. It seems clear, though, that the evolutionary advantages and disadvantages of ontogenetic asymmetry have at least played a crucial role.

 In the proposed research financed by the ERC Advanced Grant, both the ecological and the evolutionary effects of ontogenetic asymmetry will be studied. The study aims to obtain more insights in the current functioning of ecological communities on the one hand, and the evolutionary success of complex life cycles on the other.

dr. G. (Gerard) Muyzer

Gerard Muijzer

Gerard Muijzer

Gerard Muijzer is Full Professor of Microbial Systems Ecology at IBED, in the research group of Aquatic Microbiology. Muijzer’s research interest develop from describing diversity to understanding the mechanisms of diversification and the effect of diversity on ecosystem functioning and biotechnological processes. In addition to his Full Professorship at the UvA, Muijzer is visiting professor at the University of Milan, Italy. He is also the lead author of the most cited article ever in the prestigious journal Applied and Environmental Microbiology (vol. 59: 695-700) describing the denaturing gradient gel electrophoresis to study microbial communities that is currently used by many researchers(cited 4510 times ). With his ERC Advanced Grant, Muijzer will study ‘The paradox of sulfur bacteria in soda lakes’.

Soda lakes are extreme environments with a pH between 9-11 and salt concentrations up to saturation level. In spite of these extreme conditions, soda lakes harbor a large diversity of bacteria responsible for cycling of chemical elements. The sulfur cycle, driven by sulfur-oxidizing and sulfate-reducing bacteria, is one of the most active elemental cycles in soda lakes. However, normally extreme environments are characterized by low species diversity. Because live at conditions of high salt concentrations and high alkalinity is very energy consuming, the enormous diversity of sulfur bacteria in soda lakes is a big paradox.

The aim of the present study is to increase our understanding of the diversity, physiology and ecological role of sulfur bacteria in soda lakes, and the molecular mechanism that allows these bacteria to adapt to the extreme conditions. To this end, bacteria will be studied using a so-called Systems Biology approach, where bacteria are grown under specific conditions and analyzed using modern genome techniques. The results of these experiments will be used to construct mathematical models that can predict the metabolism of the various bacteria and their interactions.

The project will not only yield important insights in the ecology of sulfur bacteria in soda lakes, but is also important for the application of these bacteria for the removal of harmful sulfur components from waste water, essential to maintain a clean and healthy environment.

Hal Caswell

Hall Caswell

Hal Caswell

Hal Caswell is Senior Scientist in the Biology Department of the Woods Hole Oceanographic Institution in the United States of America. Caswell is a mathematical ecologist and demographer, and is particularly known for research on matrix population models, models for spatial processes and invasions, sensitivity analysis, and for applications to conservation biology, ecotoxicology, evolutionary demography, and human demography. Caswell is a Fellow of the American Academy of Arts and Sciences, and has received many international awards and fellowships. He will use his ERC Advanced Grant to study individual stochasticity and population heterogeneity in plant and animal demography at IBED.

Heterogeneity is always present in populations. If you look around you, it will be obvious that we are not all identical. The same is true in populations of birds, or fish, or trees, although they are presumably more skilled at recognizing this heterogeneity among their peers than we are.  Some of the differences among individuals are obvious and measurable: the young differ from the old, the large differ from the small, the caterpillar is strikingly different from the butterfly. Population biologists have long used such traits to develop models that classify individuals on the basis of age, or size, or developmental stage.  However, some forms of heterogeneity are more cryptic. Even among individuals of the same age, size, and stage, there will still exist variation that translates into differences in mortality and reproduction, which are the currency of population dynamics.

This ERC Advanced Grant will develop and apply new mathematical theory to analyze the consequences of both kinds of heterogeneity: the observed and the unobserved. Among the most important of those consequences is random (or stochastic, to be slightly more precise) variation in the structure and dynamics of the population resulting from individuals taking different pathways through their life cycles on the basis of chance events.

Population biology asks about both the trends in populations (increase or decrease, extinction or persistence) and fluctuations around those trends, including the stochasticity of individual development. The results of this project will provide new theory for analyzing these questions, applicable by a wide range of population scientists. Among the specific applications to be considered are the extinction of small isolated populations, the variation among individuals in lifetime reproduction in plants, animals, and humans, and the prospects for healthy aging in humans.

The Institute for Biodiversity and Ecosystem Dynamics (IBED)

The Institute for Biodiversity and Ecosystem Dynamics (IBED) is one of eight research institutes of the Faculty of Science at the University of Amsterdam. IBED was founded in 2000 by merging research groups from biology, environmental chemistry and earth sciences.

The mission of IBED is to increase our understanding of the diversity and dynamics of ecosystems from the level of molecules and genes to entire ecosystems.

Boris Jansen

Published by  IBED