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Pond Restoration Research Group

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Background bannerThe UCL Pond Restoration Research Group uses scientific research to underpin practical pond conservation and restoration action, especially in agricultural landscapes. Currently the group aims are to understand: the chemical and ecological changes that accompany pond terrestrialisation; the influence of pond restoration and management on landscape scale biodiversity, including aquatic and terrestrial species; the influence of fish on landscape-scale aquatic diversity; the causes of decline of lesser studied pond fishes and amphibians; the culture history of ponds.

    The UCL Pond Restoration Research Group is comprised of a diverse group of staff, researchers and research students each providing their own unique contribution.

    Crucian Carp ConservationCrucian carp banner

    The crucian carp (Carassius carassius) is a small greeny-gold, beautiful little cyprinid fish that is in a steep decline across large tracts of Europe. Its stronghold in the UK is eastern England, especially Norfolk, where in the past it was widespread in farmland ponds. Since 2008, inspired by an Environment Agency announcement, that the species was “thought to be virtually extinct in Norfolk”, we have been searching for the crucian carp and concerned with its conservation. To this effect the crucian carp was established as a Biodiversity Action Plan (BAP) species in Norfolk in 2010 (Copp & Sayer, 2010), its first formal conservation designation in the UK.

    Responding to the crucian carp’s decline and with a view to recovering the species, the Norfolk Crucian Carp Project was established in 2009. With much support from Cefas (Gordon Copp) and Bedwell Fisheries (Keith Wesley) we have now undertaken fyke-net surveys of 90+ Norfolk farmland ponds, many of which are known to have contained the species in the 1970s-1980s. This work shows an approximate 75% decline in the species over the last 30-40 years (Sayer et al. 2011). Currently we know of 24 wild populations of crucian carp in Norfolk, although many of these populations are either dwindling (consisting of a few old individuals), or contaminated by crucian carp hybrids with goldfish and/or common carp. We believe the major cause of crucian carp decline to be pond terrestrialisation, which prevents them from recruiting.

    To help fulfil the requirements of the Norfolk crucian carp BAP, we have enacted a programme of pond restoration and crucian carp re-inroduction, using the few remaining healthy wild crucian populations as donors. To date the Norfolk Crucian Carp Project has undertaken 8 pond restorations and crucian carp re-introductions to 11 ponds, many of which are known to have been successful.  Recently our work was covered in an article by angling author John Bailey in the Anglers Mail and has helped to inspire a National Crucian Conservation Project run by the EA and the Angling Trust (Carl Sayer & Dave Emson are project members).


    Farmland Pond RestorationFarmland banner

    Norfolk holds more ponds than any other English county with over 23,000 currently present. Most of these ponds are located in farmland, and have their origins as marl or clay pits and in some cases livestock-watering ponds dug in the 17th to 19th centuries. Ponds can provide vital clean freshwater environments in farmland and can be wonderful habitats for aquatic biodiversity covering plants, invertebrates, amphibians, fishes, and mammals. Nonetheless, despite all of this, farmland ponds are severely threatened by land reclamation, inappropriate encroachment of trees (especially over the last 30-40 years), nutrient-enrichment and invasive species.

    Using a combination of before and after studies and comparisons of managed, open canopy and non-managed overgrown ponds, our research is investigating the response of pond ecosystems to restoration involving scrub and sediment removal. In addition, we have examined the influences of native fish (e.g. crucian carp, tench, 9-spine stickleback) and pond terrestrialisation on biodiversity in pond landcapes. This work alludes to the importance of a mosaic approach to pond conservation with a landscape containing ponds at different stages of succession (a continuum from open to overgrown ponds) and native fish, enhancing aquatic biodiversity (Sayer et al. 2012; 2013).

    Our research shows rapid and dramatic increases in biodiversity following pond restoration, with ponds colonised by several aquatic plant and invertebrate species within less than 6 months. In addition recent studies show open-canopy managed ponds to be important for populations of farmland birds, likely through enhanced provision of insect (emerging adults) and plant seed food.

    Our work is informing pond biodiversity conservation strategies in farmland and underpins the work of the Norfolk Ponds Project.


    Ghost Ponds ProjectGhost Ponds banner

    The Ghost Ponds Project is exploring a completely novel approach to pond conservation; the re-excavation of ponds filled-in (especially since the 1950s) for agricultural land reclamation. These lost ponds are what we have call “Ghost Ponds”.

    It is often difficult to completely erase a pond from the landscape.  Even after a pond has been in-filled, a damp depression, or circular crop mark often remains, a lingering 'ghost' of the former habitat. These ghost ponds are abundant and easy to identify in certain areas of the UK, including Norfolk, where we have thus far undertaken most of our research. Ghost ponds hold an exciting potential; buried within these sites are the historic sediments from the former pond, and within these sediments the seedbank of past pond plants. We are investigating the viability of these historic seedbanks, and exploring how re-exposing them contributes to the re-colonisation of aquatic plants. A combination of pond ‘resurrections’ and restorations, field mesocosms, and greenhouse germination trials have been used to uncover the role the historic seedbank could play in pond conservation.  Remarkable, we have found that excavated ghost ponds, even those which have been buried for over a century, re-colonise rapidly with aquatic plants, due to a still viable seedbank covering various pondweeds (Potamogetonaceae) and stoneworts (Characeae).

    For more information on the Ghost Ponds Project see some recent coverage in New Scientist and The Conversation.

    Events and WorkshopsEvent banner

    Each year the Pond Restoration Research Group aims to reach out to local community groups, farmers and conservation organisations. For example, in June 2019 the group ran a practical pond restoration work for CIEEM.

    Each year the group also attends the Royal Norfolk Show to promote the Norfolk Ponds Project


    In 2019 Helen Greaves co-organised the first UK Pond science gathering at Huddersfield

    In 2021 UCL hosted the 9th European Pond Conservation Network meeting (on-line) as well as a series of follow-up seminars

    Gathering of UK pond scientists in Huddersfield, 2019


    Our research group is keen to share our research with other organisations, environmental volunteer groups and other sectors of society. Whenever possible, members of the Pond Restoration Research Group are willing to provide short talks about our work. Please contact us for more information.

    Learn more - MSc Aquatic Conservation, Ecology and Restoration

    Team leader, Carl Sayer, convenes UCL's MSc Aquatic Conservation, Ecology and Restoration course.

    The MSc Aquatic Conservation, Ecology and Restoration provides an ideal foundation for PhD research, or for employment within environmental protection and conservation agencies, the water industry and environmental consultancies.

    Norfolk Ponds Project

    The Norfolk Ponds Project (NPP) was launched in June 2014 at the Royal Norfolk Show and involves several conservation partners:

    The NPP aims to reverse the decline of Norfolk’s ponds so that agricultural landscapes contain a mosaic of clean water ponds with fewer ponds overgrown by trees and bushes. The project was conceived by Carl Sayer and Helen Greaves and inspired by the wonderful pond conservation work undertaken at Manor Farm, Briston (Norfolk) by the late and wonderful Richard Waddingham. Through many years of careful management Richard created a network of 40 high quality ponds which are full of species and afford exemplary high diversity clean water pond habitats. The Manor Farm ponds show that pond conservation and intensive agriculture can happily co-exist – a key message of the NPP. 

    For more information about the Norfolk Ponds Project please visit its website, Facebook page or follow the project on Twitter @norfolkponds. You can also find more information in our NPP leaflet and Guide to Pond Restoration.

    Research Blog banner

    As a team, we are continuously learning more and more about ponds, pond restoration and the conservation of pond flora and fauna. You can keep up to date with our most recent research and field visits on our Pond Restoration Research Group Blog.


    Previous Blog Posts

    Contact us bannerIf you would like to contact the pond restoration research group, you can email us at

    You can also keep in touch with our most recent activities by following our blog and Twitter accounts.


    Tweets from @UCLponds