Inter- and intraspecific zooplankton trait changes during four decades of environmental changes (ZoopTraits)

• Applicant: Privatdozent Dr. Dietmar Straile
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions ; Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 577571558

The study of traits provides a direct link between the characteristics of organisms and their ability to survive in a specific environment. Consequently, trait-based analyses received increased interest in ecological and evolutionary studies during the last decade. More recently, also the importance of within-species trait-variability has been recognized as an important driver of ecological dynamics. However, especially the latter has been rarely studied for plankton organisms. In this proposal, we will study long-term inter- and intra-specific traits variability of the crustacean zooplankton in Lake Constance during 4 decades, in which zooplankton was affected by huge environmental changes (oligotrophication, warming and neozoa invasions). The proposal will make use of the archive of zooplankton samples of the Limnological Institute of the University of Konstanz, which dates back to 1987. Using an automated imaging system (ZooScan) we propose to measure the traits from ca. 500 000 zooplankton specimen from 10 species in ~500 samples during the time period 1987-2024. Depending on the specific trait and zooplankton species, trait measurements will be done either semi-automatically, or manually at the microscope. After establishing this unique data set, we will perform analyses at the community level and at species and trait - levels. Specifically, we will ask at the community level whether trait diversity and the community size – abundance relationships are influenced by environmental changes. At the species level, we will 1) compare cyclomorphosis over several years and between different species (which factors determine the extent of cyclomorphosis, e.g. in Daphnia versus Bosmina in different study years), 2) the dynamics of eye sizes in cladoceran species (to what extent are changes in eye size influenced by environmental factors and species characteristics) and 3) examine the dynamics of life cycle characteristics , e.g. the size at first reproduction of cladocerans, and for copepods, the size at metamorphosis and the size of adults in response to environmental changes. These analyses will improve our understanding of the regulation of these populations and of the entire pelagic ecosystem. Overall, this proposal will enable us to conduct analyses that have not yet been possible for any plankton community. In addition, we will provide other plankton ecologists and theoretical ecologists with a unique data set that will certainly be used beyond our own analyses.

• DFG Programme: Research Grants