Artificial Pond Habitats Placed in an Australian Berry Farm Support Invertebrate Diversity Including Pollinating...

Artificial ponds in agricultural landscapes may provide critical microhabitats for aquatic and semi-aquatic invertebrates, including pollinating flies that require water for larval development. To test this idea, we deployed eight artificial ponds, comparing water-only controls with ponds containing decomposed blackberry plant material, at four farm blocks within a commercial berry farm located in New South Wales, Australia. Ponds were inspected every 3-4 days to monitor pond taxa appearance alongside eristaline (Diptera: Syrphidae) fly oviposition, larval development and pupation. Over 43 days, we recorded 40 invertebrate taxa from nine orders; seven taxa were observed only 1-3 times during the 43-day trial and were not present in the final sampling period. In total, 33 taxa colonised the artificial ponds for the entire trial period including three eristaline flies (Eristalis tenax, Eristalinus punctulatus and Austalis copiosa). Eristaline fly eggs appeared within 9 days of deployment, larvae within 17 days, and pupation occurred within 38 days of deployment within the adjacent soil and grass. Overall, this study demonstrates that artificial ponds could act as multifunctional habitats that support invertebrate communities and provide a simple, scalable way to enhance on-farm insect biodiversity while supporting pollinating flies. Future research directions could include broader-scale designs that maintain eristaline populations while reducing pest taxa.