Making an impact on UK farmland pond conservation

Correspondence Carl Sayer, Pond Restoration Research Group, Environmental Change Research Centre, Department of Geography, University College London, Pearson Building, Gower Street, London, WC1E 6BT, UK. Email: c.sayer@ucl.ac.uk Abstract 1. It is of vital importance that aquatic conservation is evidence based, and in the field of farmland pond management and restoration evidence was largely lacking until an article published in Aquatic Conservation: Marine and Freshwater Ecosystems (AQC) in 2012. 2. To examine the influence of farmland pond management on aquatic biodiversity conservation, macrophyte and invertebrate diversity in ponds subject to traditional management involving scrub and occasional sediment removal at different time intervals in the past (0–2, 3–5, 6–10 years since management), were compared with a set of neighbouring, highly terrestrialized ponds that had not been managed for many decades. 3. With the exception of Mollusca, significantly higher species diversity was found for managed ponds compared with the late-succession unmanaged ponds, with invertebrate gamma diversity significantly lower for the late-succession ponds, compared with all the managed pond categories. 4. The AQC article was a key component of the Natural England (UK Government's adviser on the natural environment in England) ‘Freshwater and Wetland Conservation Narrative’ and has helped with integrating pond management into recent great crested newt Triturus cristatus mitigation policy as well as bringing it to the fore in past and evolving agri-environment policy. 5. The AQC article provided the evidence and in turn the confidence for the authors and a number of conservation partners to form a Norfolk Ponds Project. Since 2014, the Project has delivered or facilitated more than 100 pond restorations in Norfolk, eastern England, as well as educating conservation practitioners and farmers on the importance of farmland ponds via various events. 6. With good underpinning science it has been possible to achieve considerable impact in the field of farmland pond conservation. This study shows the importance of setting aside time and support for academic staff to translate applied research outputs into practical impact.


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To examine the influence of farmland pond management on aquatic biodiversity conservation, macrophyte and invertebrate diversity in ponds subject to traditional management involving scrub and occasional sediment removal at different time intervals in the past (0-2, 3-5, 6-10 years since management), were compared with a set of neighbouring, highly terrestrialized ponds that had not been managed for many decades.
3. With the exception of Mollusca, significantly higher species diversity was found for managed ponds compared with the late-succession unmanaged ponds, with invertebrate gamma diversity significantly lower for the late-succession ponds, compared with all the managed pond categories.
4. The AQC article was a key component of the Natural England (UK Government's adviser on the natural environment in England) 'Freshwater and Wetland Conservation Narrative' and has helped with integrating pond management into recent great crested newt Triturus cristatus mitigation policy as well as bringing it to the fore in past and evolving agri-environment policy.
5. The AQC article provided the evidence and in turn the confidence for the authors and a number of conservation partners to form a Norfolk Ponds Project. Since 2014, the Project has delivered or facilitated more than 100 pond restorations in Norfolk, eastern England, as well as educating conservation practitioners and farmers on the importance of farmland ponds via various events.
6. With good underpinning science it has been possible to achieve considerable impact in the field of farmland pond conservation. This study shows the importance of setting aside time and support for academic staff to translate applied research outputs into practical impact.
However, in the absence of natural disturbances (e.g. beavers, wild river flooding) capable of resetting succession (Sayer et al., 2013), the only truly sustainable solution to this problem is active scrub management and sediment removal. The latter approach is the focus of this impact case study, which examines the conservation impact of an article published in Aquatic Conservation: Marine and Freshwater Ecosystems (AQC) (Sayer et al., 2012).
To improve understanding on the role of pond management for aquatic biodiversity conservation in farmland, Sayer et al. (2012) compared macrophyte and invertebrate diversity patterns for a pond landscape subject to frequent interventions (scrub and occasional sediment removal) to re-set succession with a set of nearby highly terrestrialized late succession ponds. The study ponds were located at Manor Farm, Briston, a mixed (arable plus cattle) farm in north Norfolk, eastern England, where the farmer has managed at least three or 3-5 and 6-10 years since management, respectively) with six latesuccession ponds (two at Manor farm and four within a 10 km distance) typical of most ponds in the region ( Figure 1e). All ponds were old (probably >200 years), artificially created (dug for marl or for livestock watering), located in comparable arable settings, and they were F I G U R E 1 Four open-canopy, managed ponds at different stages of post-management succession at Manor Farm, Norfolk (a-d) and a nearby highly terrestrialized late-succession pond (Beckett's Farm Pond) (e) as studied by Sayer et al. (2012). Photo (f) shows Beckett's Farm Pond in 2016, 2 years after restoration by major scrub and sediment removal buffered by 7-10 m wide rough grassland headlands. The ponds were surveyed for aquatic macrophytes and key invertebrate groups (Mollusca, Coleoptera, Trichoptera, Ephemeroptera) using standard methods.
With the exception of Mollusca, significantly (P < 0.01) higher species diversity (estimated by Brillouin diversity and Simpsons D) was found for Manor Farm's managed ponds compared with unmanaged, late-succession ponds in the surrounding landscape. Species richness calculated for combined macrophyte and invertebrate data was significantly lower in the unmanaged ponds compared with ponds in all other management categories (P < 0.0001 - Figure 2).
Invertebrate gamma diversity, as estimated by rarefaction analysis, was also significantly lower for the late-succession ponds, compared with ponds in all management categories for all rarefied sample sizes.
Importantly, while many species were absent from the unmanaged ponds, especially in the macrophytes and Coleoptera, few species were unique to these ponds, suggesting that pond management was unlikely to lead to significant species losses from the pondscape. In combination, these analyses showed that, by arresting succession and maintaining large numbers of macrophyte-dominated early and midsuccession ponds in the landscape, pond management resulted in major benefits for landscape-scale aquatic diversity.

| Farmland pond conservation and the Norfolk Ponds Project
Given an overwhelming dominance of highly terrestrialized ponds in the UK lowlands (Alderton, 2016;Sayer et al., 2013) and with pond creation largely failing to keep pace with the loss of open-canopy, macrophyte-filled ponds to successional processes (Mainstone, Hall, & Diack, 2016), there is a clear need for conservation intervention involving large-scale removal of woody vegetation and accumulated sediments from tree-and scrub-dominated ponds. As detailed by Sayer et al. (2012), it is essential that farmland ponds are managed to maintain early and mid-succession ponds in the pond network. The key mechanism for achieving effective farmland pond conservation in the UK is the incorporation of pond options into agri-environment schemes (AESs). At the time of Sayer et al. (2012), however, the authors felt that pond restoration and management was insufficiently promoted both in AESs and in turn by agri-environment advisers. Furthermore, it was believed that guidance on pond management was not well informed by science and that, despite recognition of their high importance in the farmed landscape, most UK conservation organizations (both statutory and non-governmental organizations The NPP was set up with two major aims: (i) to restore and conserve ponds (especially farmland ponds) in the county of Norfolk for the benefit of wildlife conservation; and (ii) to engage and educate farmers and the public as well as conservation practitioners and policy-makers on the importance of pond restoration and F I G U R E 2 Differences between nonmanaged ponds and ponds managed during different time intervals in the mean number of macrophyte and invertebrate species (selected groups Mollusca, Coleoptera, Trichoptera and Ephemeroptera) recorded. The letters (A, B) reflect statistically significant differences (P < 0.05) in mean diversity values between the different pond management categories based on an ANOVA with a subsequent Scheffé test. Error bars indicate one standard deviation management for biodiversity conservation. On the NPP's inception a 5-year plan was written, a website was constructed and social media channels were opened (Twitter). In addition, UCL and Norfolk Wildlife Trust co-designed a 'Restoring Norfolk Ponds' booklet providing a step-by-step guide to pond restoration. From the outset it was agreed that the NPP would promote the incorporation of ponds into individual partners' projects and it was hoped that, with the Manor Farm example and associated PRRG science as support, it would be possible to enact some successful pond conservation work and to undertake, through Before-After Control-Impact (BACI) studies of restored ponds, further research to measure the multi-species benefits of landscape-scale pond restoration.
To achieve its aims the NPP has used a range of approaches.

| Agri-environment policy and practice
In the current (since 2014) Countryside Stewardship AES both farmland conservation advisers and farmers have been able to draw on NPP guidance on farmland pond restoration and management. In addition, for the forthcoming Environmental Land Management Scheme AES (likely to be launched in 2025 with pilots running from 2021 to 2024), Sayer et al. (2012), together with subsequent research on ghost pond resurrection (Alderton et al., 2017) and the benefits of pond restoration for farmland birds (Davies, Sayer, Greaves, Siriwardena, & Axmacher, 2016;Lewis-Phillips et al., 2019;Lewis-Phillips et al., 2020) and pollinators (Walton, Sayer, Bennion, & Axmacher, unpublished data), is being used to shape the overall approach and prescriptions for ponds. As Ruth Hall, Standing Waters Senior Specialist for Natural England, stated on 7 November 2019: 'The research evidence base you have produced has been fed into the development of agri-environment schemes and it continues to influence them, providing further justification for pond restoration to be To date all of the restored ponds have become macrophytedominated (compare Figure 1e,f) and BACI studies have shown significant landscape-scale increases in aquatic diversity for a range of biological groups, including aquatic plants, invertebrates and amphibians (Siggery, 2018;Sayer et al., unpublished data). A number of rare species have colonized some of the restored ponds, including nationally scarce submerged aquatic plants such as Oenanthe aquatica (n = 5), Hottonia palustris (n = 1), Tolypella glomerata (n = 5) and Najas marina shows Norfolk to have twice as many pond-containing stewardship agreements compared with Cheshire, Lancashire, Suffolk and Essex. It is not possible, of course, to be certain that higher engagement with AESs in Norfolk is the direct result of the lessons afforded by Sayer et al. (2012) and the work of the NPP, but it is suspected that both have been critical; as Lucy Hatcher, an NE Farm Adviser in Norfolk commented on 13 November 2019: 'There is a considerable awareness of the work of the NPP and the benefits that ponds provide to a whole breadth of farmland wildlife within the farming community in Norfolk. This is reflected in the high number of ponds being managed, restored or created within Higher Tier Countryside Stewardship schemes, which are supported by Natural England advisers many of whom have also received farmland pond training from the NPP' .
In terms of the NPP's aim of engaging and educating the general public, farmers and conservation practitioners on farmland pond management, impact is best assessed by measures of participant learning during events. Example questionnaire responses from two NPP fieldbased pond restoration workshops in June 2019 for local farmers and members of CIEEM (Figure 4) clearly suggest a previous lack of confidence with farmland pond conservation. Following the events, however, substantial learning was evident from questionnaire responses, with participants reporting that they were better able to understand important pond species and the science and practicalities of best practice farmland pond management at the landscape scale.

| CONCLUSIONS
The bottom-up and top-down approaches to achieving conservation impact outlined here are clearly synergistic, with the practical work and social media promotion of the NPP (bottom up) helping to raise the profile of a landscape-scale pond restoration and management approach, thus increasing knowledge among conservation practitioners and policy makers (top-down). Equally, it is clear that, at a local level, an active NPP was able to achieve a great deal in a short time, with the 100+ farmland ponds restored almost matching the number of Norfolk ponds restored via the top-down AES route over the same period. None of the aforementioned impact could have been achieved without the underpinning science provided by Sayer et al. (2012) in AQC, which provided a platform of confidence and a key site for demonstrating the huge potential of farmland pond management for biodiversity conservation.