Temporary wetlands and ducklings: Evaluating the ecological importance of temporary ponds, beaver flood and vernal pools for waterfowl breeding success

Application summary

Wetlands are among the most threatened ecosystems globally, with Europe having lost over 70% of its wetland area. In Finland, insectivorous waterbirds are declining rapidly due to habitat loss, eutrophication, fish competition, and reduced breeding success. Temporary wetlands such as vernal pools and beaver ponds may provide crucial breeding habitats by offering abundant invertebrates and reduced predation risk, yet while beaver ponds are increasingly recognized, vernal pools remain poorly studied and unprotected. My PhD project in the Evo Natura 2000 area addresses this gap by comparing the ecological role of vernal pools, beaver ponds, and lakes during the waterfowl breeding season. The research has three main objectives: Investigate waterbird use of temporary versus permanent wetlands in relation to aquatic and emerging insect availability, using camera traps (20–30 units) and weekly bird surveys with invertebrate trapping during 2023–2025. Assess habitat quality for ducklings’ survival via controlled feeding trials with imprinted ducklings over 14 days, combined with invertebrate sampling to evaluate food supply and growth potential. Compare feeding behaviour of ducklings between habitats using scan sampling, providing insights into how prey availability and accessibility affect growth. A key innovation is using ducklings as direct indicators of habitat quality. By linking growth, survival, and foraging to invertebrate communities, the project provides a dynamic measure of habitat suitability complementing traditional surveys. Ultimately, this work fills critical knowledge gaps on temporary wetlands and supports conservation policies such as Finland’s Helmi–SOTKA wetland program and the EU Water Framework Directive.