Katja Schiffers


How do plant species respond to changing environmental conditions? This is the question that incites most of my scientific work. I combine empirical data with process-based models to better understand patterns of species' trait and niche evolution, range shifts and phenotypic plasticity.
I am also interested in a better integration of monitoring and modeling of biodiversity to improve projections of future scenarios.

Phenological responses to environmental change
In the frame of the PASIT Project, together with Prof. Dr. Eike Lüdeling, Dr. Cory Whitney and our project partners, we aim at advancing the understanding of climate change impacts on fruit and nut farming communities in Tunisia and Chile. To that end, we integrate phenological dormancy research and modeling of fruit and nut tree development with comprehensive socio-economic and behavioral data collection and analysis.

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Improving biodiversity monitoring and modeling
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 well-designed biodiversity monitoring as well as the anticipation of future changes. In the sMon Synthesis project of the iDiv, led by Dr. David Eichenberg Prof. Dr. Aletta Bonn Prof. Dr. Florian Jansen and Prof. Dr. Helge Bruelheide we aim at combining and harmonizing exemplary datasets of different taxa and habitats and to evaluate the potentials and limits for analysing changes in the state of biodiversity in Germany. We are using Bayesian hierarchical modells to account for observer bias and will derive perspective for future biodiversity monitoring programs in Germany.
In two other projects, we used synthetic data to test how well different biodiversity metrics reflect changes in biodiversity metrics (Santini et al. 2017 Biological Conservation) and how a set of novel modelling approaches for species range dynamics perform under different assumptions for demographic and community processes (Zurell et al, 2016, Global Change Biology, PDF).
Doing some conceptual work, together with Dr. Wilfried Thuiller and co-authors we formulated a road map for integrating eco-evolutionary processes into biodiversity models (Thuiller et al, 2013, Ecology Letters PDF.

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 Dr. 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 (but not working a lot in this field anymore) 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 (Defossez et al, 2015, Oikos, PDF), the influence of interspecific interactions on species range expansion rates (Svenning et al. 2014, Ecography, PDF), and the integration of biotic interactions into individual-based (Berger et al, 2008, PPEES, PDF) and macroecological models (Kissling et al, 2011, Journal of Biogeography).

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