Overseen ecosystem services of ponds and their insects – their role for supporting terrestrial consumers and biodiversity "EUROPONDS"

Globally there’s an astounding and often underestimated number of ponds (small stagnant water bodies). Ponds, whilst directly providing habitats for a multitude of animals and plants, also contribute to habitat connectivity by enabling organisms to cross the landscape, acting as “blue stepping stones”. The diverse community of insects emerging from such ponds acts as a vector of dietary energy to the surrounding terrestrial environment. By providing highly unsaturated fatty acids, emerging insects constitute a high nutritional food resource for terrestrial (e.g. spiders, lizards) and avian (e.g. bats, birds) consumers. One important dietary resource these insects export is essential fatty acids. These are introduced initially into the local food web and then on into the main terrestrial cycle. However, knowledge about the exact ecological role of ponds, their contribution to beta- and gamma-biodiversity, and dietary energy transfer is limited. Herein, we present preliminary results for the first seasonal sampling (Autumn 2020) of our ongoing “EUROPONDS” project. EUROPONDS aims to fill this gap of knowledge on ponds by analyzing 55 ponds distributed across Europe from Sweden in the north to remote Mediterranean islands in the south, from rural areas to large cities, and including both artificial and natural ponds. EUROPONDS brings together around 80 European early-career limnologists and covers autumn, winter, spring, and summer sampling campaigns through 2020/21. Preliminary results from autumn 2020 indicate differences in emerging insect biomass, trophic status of ponds, and between artificial and natural ponds.