\"Ghost ponds\" - How to resurrect in-filled farmland ponds to assist aquatic biodiversity conservation in agricultural landscapes

Growing recognition of the importance of ponds for landscape-scale biodiversity has led to considerable interest in their conservation, focusing on new pond creation, or existing pond restoration. However, there is a third approach; the re-excavation of ghost ponds - former ponds deliberately filled-in due to agricultural intensification. Previous work has shown ghost ponds to retain viable sediment propagules of many aquatic plants for over a century, allowing for the rapid re-colonisation of resurrected pond sites. Here we detail the practicalities of the ghost pond resurrection approach, describing how to locate, identify, and excavate ghost ponds in agricultural land. We also report on colonisation by aquatic macrophytes and water beetles (Coleoptera) for three ghost pond resurrections in Norfolk, eastern England and make comparisons with neighbouring extant ponds restored to open-canopy conditions via major scrub and sediment removal at the same time. Ecologically important macrophyte taxa, including charophyte and Potamogeton species, successfully established in the ghost ponds and within one year they supported a comparable species diversity to the adjacent restored ponds. Our findings show that, where appropriate to land management goals, ghost pond resurrection could be a very valuable conservation approach within farmed landscapes.