START Project
Global change - including climate change, pollution, habitat loss and other stressors - is proceeding at an ever-faster pace and threatens organisms, communities, ecosystems and, ultimately, human wellbeing. For an accurate risk assessment and to inform conservation and mitigation strategies, we urgently need a deeper understanding of how species, communities and ecosystems respond to global change.
Recent research has shown that ecological and evolutionary changes can occur rapidly and that, if they occur on contemporary timescales, they can influence each other. Understanding these eco-evolutionary interactions and feedbacks is essential for assessing how past disturbances may affect todays’ responses to ecological changes. Likewise, identifying the traits of organisms mediating these interactions is key to gaining mechanistic insight.
In this START project funded by the Austrian Science Fund (FWF), we use the Daphnia longispina species complex system and peri-Alpine lake ecosystems as a model system to tackle these questions. Daphnia water fleas feed on microbes (algae, bacteria, protists) which they filter from the lake water and are themselves an important prey for invertebrates and fish and thus important ecological interactors in lake food webs. Cultural eutrophication, caused by anthropogenic increase of nutrients in lakes, has resulted in species invasions followed by hybridization and admixture in the Daphnia longispina complex in different lakes. We hypothesize that this evolutionary change in response to an ecological change has changed important traits in Daphnia such as body size and filter apparatus, and has thus affected the way they interact with their biotic and abiotic environment.
Within this project, we characterize these changes and interactions to assess whether and how they affect the response of water flea populations, communities and the ecosystem to a new, emerging stressor: heat waves in lakes. Heat waves are an aspect of climate change and have recently been shown to constitute a major stressor for lake ecosystems with direct and indirect effects on organism and communities.
We combine field surveys, geno- and phenotyping, and lab and mesocosm experiments to explore how two ecological stressors - eutrophication and heat waves - interact through time via their effects on eco-evolutionary dynamics and how such interactions may modulate responses to global change stressors.