Katja Schiffers
 

Research

What are the ecological and evolutionary mechanisms that shape species ranges in space and time? How can these biodiversity dynamics be modelled and projections of future scenarios be improved? And which factors modulate biotic interactions and thus species realised niches and community structure? These are the questions that incite most of my ecological research.
My work is mainly based on process-based simulation modelling, conceptual work on biodiversity models, phylogenetic approaches and the analysis of existent large-scale distributional data.

Improving biodiversity projections
Global biodiversity is declining rapidly, largely as a result of human activities. Effective policy and adaptive management strategies in the face of global change require anticipation of future changes. Mid- to long-term planning will therefore depend, at least in part, on model-based projections. The European cost-action HARMBIO, which I am currently working for, aims at harmonizing current models and datasets of terrestrial, freshwater and marine biodiversity to improve the reliability of future projections of biodiversity change. Our objective in workpackage 4, led by Prof. Dr. Katrin Böhning-Gaese and Prof. Dr. Andy Purvis, is to develop standards for systematic model intercomparison to explore and reducemodel-based uncertainty in biodiversity projections.

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Trait and niche evolution
Parts of the ERC project TEEMBIO (Towards Eco-Evolutionary Models of BIOdiversity, 2012-2016, FP7, led by Dr. Wilfried Thuiller) and my former Marie-Curie project EMMA (Evolution Meets MAcroecology, 2010-2012, FP7) aim at investigating the dynamics of rapid adaptation and niche evolution to assess the evolutionary potential of species subjected to environmental change. Together with my collaborators, I approach this topic from two angles: Coming from the process-based side, we use simulation modeling on allelic adaptive dynamics (download Aladyn source-code) to investigate how demographic parameters, populations genetics and abiotic conditions affect the rate of adaptation. For these studies, I am colaborating mainly with Dr. Justin Travis.
On the other side, comprehensive distributional and phylogenetic data allow us to infer patterns of past niche evolution across different taxonomic scales. Together with Florian Boucher, Dr. Sébastien Lavergne, Dr. Wilfried Thuiller and Dr. Cristina Roquet-Ruiz we develop new analytical pathways to test the hypothesis of niche conservatism and quantify rates and modes of evolution.

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Biotic interactions
Biotic interactions are important drivers of species coexistence and community assemblage. I am interested in how the intensity and mode of interactions depend on abiotic conditions and the spatial distribution, life-history-stage and morphological plasticity of interacting individuals.
The two studies on which I worked most are
(1) a neighbour-removal experiment along a climatic gradient in Israel demonstrating the existence of onthogenetic shifts from positive to negative interactions in two annual plant species (in the framework of the GLOWA Jordan River Project in collaboration with Prof. Dr. Katja Tielbörger: Schiffers and Tielbörger, 2006, Journal of Ecology PDF) and
(2) a semi-mechanistic simulation model fitted to experimental data on the uptake of nutrient tracers showing how the interactive effects of plants' spatial distribution and morphological plasticity affect intra-specific competition intensity (in collaboration with Prof. Dr. Katja Tielbörger, Prof. Dr. Britta Tietjen and Prof. Dr. Florian Jeltsch, Schiffers et al, 2011, Ecology PDF).
Other studies focus on the integration of positive interactions into ecological research and theory (Brooker et al. 2008, Journal of Ecology, PDF), the intensity of indirect interactions along climatic gradients (Deffozes et al, submitted) and the integration of biotic interactions into individual-based (Berger et al, 2008, PPEES, PDF) and macroecological models (Kissling et al, accepted, Journal of Biogeography).

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Katja Schiffers   •   katja.schiffers (at) gmail.com