Ponds are very special habitats and often act as hotspots for biodiversity. They provide a breeding ground for amphibians, drinking water for terrestrial mammals, shelter for a wide range of species, and act as a plentiful feeding ground due to their invertebrate and plant abundance. Not only that, but ponds also support over two thirds of all freshwater invertebrate species found in the UK - that’s pretty incredible!
Photo courtesy of DLL Scheme
Unfortunately, it is estimated that since agricultural intensification in the 1950s, when food production was upscaled, we have lost 50% of our farm ponds throughout the UK. The term ‘ghost pond’ refers to these historical ponds, that were filled in during reclamation of land for agriculture and development. Ghost ponds are often still visible in a landscape, either as slight bowl-shaped depressions in fields, or as damp circular areas in fields. Freely accessible LiDAR maps, which are high-resolution 3D representations of terrain, enables the possibility of spotting these depressions.
Due to difficulties in completely stopping historical ponds from collecting water, they often make poor agricultural land.
Photo provided courtesy of DLL Scheme
Whilst many small ponds were filled in to create more land for agriculture, some ponds were too large to fill and instead were left unmanaged. The effects of less management and reduced maintenance resulted in many ponds becoming heavily overgrown with trees and scrub. This greatly reduces the benefit of these ponds for wildlife as they are often species-poor. The Freshwater Habitats Trust estimate that of the remaining ponds in the UK, 80% of these are in poor condition.
A fantastic project, carried out in Norfolk by the Norfolk Ponds Project Restoring, resurrecting and conserving Norfolk's ponds, has been highlighting ghost ponds and their potential for biodiversity. One of the fascinating things that the Norfolk Ponds Project has found out is that ghost ponds often contain a viable seed bank. During the process of filling in ponds, pond sediments were often buried beneath topsoil. Previous ghost pond resurrections have shown that these pond sediments can hold a host of seeds - some of which will still be viable. This means that rare plants can be uncovered and start to grow again once a pond has been re-dug, allowing for rapid re-colonisation. One study found back in 2017 (Alderton et al., 2017) that the seed banks have germinated after 50-150 years of dormancy, in spite of being buried under intensive agricultural fields. Ghost ponds often have a negative message attached to them, but this offers a positive message, highlighting that aquatic species can survive prolonged burial!
A great website to look for these long-lost ponds is the National Library of Scotland’s Map images where you can compare historic Ordnance Survey maps with LiDAR data and satellite imagery, side-by-side. As you can see below from an example in Lancashire, we can see pond circled in red on the historic map (on the left), and the LiDAR data (on the right) highlights a slight depression in the same location as the pond. When comparing with current satellite imagery, this pond no longer exists so we can say that this is a ghost pond.
Photo courtesy of DLL Scheme
A count of ghost ponds in Norfolk revealed over 8,000 ponds had been lost between the 1950s and present day. We have not yet mapped the losses in Lancashire.
Lancashire Wildlife Trust is the Habitat Delivery Body for the Natural England District Level Licensing scheme in Lancashire. As part of the scheme, we can create and restore ponds in our area - at no cost to landowners. Through the District Level Licensing scheme, we are aiming to restore some of these ghost ponds.
If you are a landowner and you think you may have a ghost pond on your land and would be interested in restoring this amazing habitat, please do complete our online form and someone will be in touch.
