SPP 1704:  Flexibility Matters: Interplay Between Trait Diversity and Ecological Dynamics Using Aquatic Communities as Model Systems (DynaTrait)

We aim to improve our understanding of the extremely important but severely understudied feedback loop of biodiversity-related flexibility and ecological systems, which enables adjustment to altered abiotic and biotic conditions. Depending on the different facets of biodiversity (e.g., genetic, phenotypic and species diversity), individuals, populations and communities possess an inherent flexibility, which allows them to adjust to ambient conditions improving their fitness. This influences their dynamics and consequently those of the entire food web. For example, enhanced grazing may lead to a higher proportion of less edible algae. This, in turn, dampens the reduction of algal biomass, which likely will have a feedback on the biomass and community composition of herbivores, e.g., the share of herbivorous species able to exploit less edible algae may increase. As a result, the advantage of less edible algae compared to edible ones is reduced, which promotes the coexistence of different algal types and hence biodiversity.
The Priority Programme moves away from the classical static species-based approach where rigid properties are assigned to each organism or species independent of ambient conditions, to an innovative, flexible, trait-based approach. It considers functional traits, which are measureable properties (e.g., edibility of prey, selectivity of consumers) that may change over time depending on the prevailing conditions.
We want a mutually stimulating interplay between experimental approaches, field measurements and mathematical modelling using mostly plankton and biofilms. These microbial food webs comprise multiple trophic levels with internal feedbacks and their small size and short generation times enables measuring and manipulating trait variations and estimating the major trade-off(s) among traits. Population dynamics can be quantified for many generations, which reveals the effect of eco-evolutionary feedbacks within feasible time scales. We want to broaden our very limited quantitative knowledge and predictive power on how biodiversity affects the type of ecological dynamics (e.g., static or oscillating) and responses to environmental changes. This will likely call for a profound reconsideration of classical "well-established" theoretical concepts and will enable us to identify and experimentally test mechanisms maintaining biodiversity that can then be implemented in (applied, forecasting) models to improve their validity.

DFG Programme Priority Programmes

International Connection Denmark, France, Japan, Netherlands, Spain, Sweden, Switzerland, USA

• Adaptive trait dynamics of lake phytoplankton at short time scales (Applicant Blasius, Bernd )
• Alternative states of a simple predator-prey system induced by competition between small edible and large inedible algae and fungal parasitism (APPS) (Applicants Grossart, Hans-Peter ;  Wollrab, Ph.D., Sabine )
• Comparing phenotypic plasticity in bacterial prey traits and ecological consequences by using specialist vs. generalist strains and organic aggregates as model systems (Applicant Grossart, Hans-Peter )
• Consumer diversity effects in multispecies predator-prey systems: Relevance of inter- and intraspecific consumer trait variation (Applicant Moorthi, Stefanie )
• Coordination Funds (Applicant Gaedke, Ursula )
• Diversity effects of trait-based zooplankton feeding interactions in a global ecosystem model (Applicant Prowe, Friederike )
• Diversity loss and trait dynamics in natural plankton communities (Applicants Fink, Patrick ;  Stibor, Herwig ;  Stockenreiter, Maria )
• Does stoichiometric variation in primary producers mediate coexistence in grazers? (Applicant Boersma, Maarten )
• Dynamics of phytoplankton size-structure as explained by bio-physical principles and ecological history: a trait based adaptive dynamics modeling approach (Applicants Kerimoglu, Onur ;  Wirtz, Kai )
• Ecoevolutionary feedbacks of phenotypic plasticity and mono- vs polyclonal communities in bi- and tritrophic systems (Applicants Tollrian, Ralph ;  Weiss, Linda Carolin )
• Effect of trait variability on the dynamics of coupled, bi-trophic plankton - biofilm systems (Applicants Berendonk, Thomas U. ;  Gaedke, Ursula ;  Weitere, Markus )
• Exploring the adaptive within- and between bloom dynamics of heterogenic dinoflagellate population of the toxigenic Alexandrium ostenfeldii in field and laboratory experiments. (Applicant John, Uwe )
• Flexible until it snaps: Dynamics of genes & traits, densities & diversity in communities challenged by environmental change (Applicants Boenigk, Jens ;  Rahmann, Sven ;  Sures, Bernd )
• Indirect response to external drivers through trait variation in predator-prey systems (Applicant Becks, Lutz )
• Inducible chemical defences in primary producer - herbivore interactions: effects on population dynamics as a function of consumer trait diversity (Applicant von Elert, Ph.D., Eric )
• Influence of chaotic dynamics on the coexistence of traits: Experimental studies with aquatic microbes (Applicant Arndt, Hartmut )
• INter- and intra-specific SIze Diversity of phytoplankton and its impacts on Ecosystem functions (INSIDE) (Applicants Acevedo-Trejos, Esteban ;  Hillebrand, Helmut ;  Striebel, Maren )
• Interplay between trait variation, food web dynamics and maintenance of biodiversity (Applicant Gaedke, Ursula )
• Modelling Seasonal Vertical Migration in Marine Zooplankton (Applicant Pahlow, Markus )
• Nutrient uptake-related trait variability and trade-offs - adaptive evolution and community functioning in competing phytoplankton species (Applicants Matthiessen, Birte ;  Reusch, Ph.D., Thorsten )
• Seasonal and long-term phytoplankton trait dynamics during trophic change and a regime shift in phytoplankton biomass (Applicant Peeters, Ph.D., Frank )
• The adaptive capacity of multitrophic plankton communities in a changing ocean (Applicant Merico, Agostino )
• The determinants of algal trait dynamics in phytoplankton communities over vertical, seasonal, and inter-annual gradients (Applicants Jäger, Christoph ;  Rinke, Karsten )
• The influence of environmental changes and individual trait variability (phenotypic plasticity) on biodiversity and ecosystem stability (Applicants Tollrian, Ralph ;  Weiss, Linda Carolin )
• The relevance of consumer competition and feeding traits, as well as their trade-offs, in determining multispecies trophic interactions (Applicant Moorthi, Stefanie )
• Trait-based biodiversity and multitrophic dynamics under external forcing: a combined planktotron and modelling approach (Applicants Hillebrand, Helmut ;  Singer, Gabriel ;  Striebel, Maren ;  Wacker, Alexander )
• Trait heterogeneity effects on trophic interactions: the role of essential nutrients (Applicants Martin-Creuzburg, Dominik ;  Wacker, Alexander )
• Trait-related feedback dynamics in natural plankton communities (Applicants Fink, Patrick ;  Stibor, Herwig ;  Stockenreiter, Maria )
• Trait shift history: Do grazing induced trait shifts in phytoplankton determine the sensitivity to nutrients and sinking? (Acronym: TraitHist) (Applicant Sommer, Ulrich )
• Trait variability and defense costs in coupled bi-trophic plankton - biofilm systems: effects on predator-prey dynamics and coexistence (Applicants Berendonk, Thomas U. ;  van Velzen, Ellen ;  Weitere, Markus )

Spokesperson Professorin Dr. Ursula Gaedke