The Norfolk Coast Area of Outstanding Natural Beauty (AONB) contains a rich array of habitats including shingle beaches, sandy beaches, mud flats, saltmarshes, freshwater grazing marsh and ditch systems, tidal rivers and estuaries, farmland, woodland and parkland.

Several conservation projects have been undertaken in the AONB, but thus far freshwater ponds have received relatively little attention. With rising sea levels and a consequent increased likelihood of sea floods into freshwater marsh and ditch systems, many coastal freshwater plants and animals will come under threat of decline or extinction in the coming years. Important and protected species in the AONB include natterjack toad, great-crested newt, palmate newt, European eel, crucian carp, and several specialist water plants and invertebrates. Coastal ponds, especially those located beyond the likely limit of sea floods, may help to conserve some of the aforementioned species. Currently, however, the pond resource in the AONB is poorly known

Objectives:

The objective of the project was to collate available information on ponds in the Norfolk Coast AONB, prioritise ponds for restoration and undertake restoration work in conjunction with interested landowners. The aim of the initial phase was to collate currently available information on ponds in the AONB, identify where further information, survey or ground-truthing is required and make a provisional prioritisation of ponds on which to focus initial restoration work, based on a range of factors, in preparation for future work (survey / ground truthing and restoration).

Methods:

Available information on ponds in the AONB past and present was collated from a variety of sources including UCL data holdings, data held by Norfolk Pond Project (NPP) partners and files held by key conservation landowners/land managers including the Holkham Estate, Norfolk Wildlife Trust, RSPB and The National Trust. In addition AONB pond species data were obtained from the Norfolk Biodiversity Information Service (NBIS).

GIS software was used to create a map containing multiple shapefiles showing all the known pond locations within the boundary of the Norfolk Coast AONB. Where possible, ponds, which have associated species records, were identified using the location data as provided by the data owner. Shapefiles were converted into compatible .kml files in order to upload them onto Google Maps, where a complete map could be viewed of all known pond locations and species data.

Three 5 x 5 km squares were randomly placed within the Norfolk Coast AONB boundary, using Google Earth Pro. High-resolution satellite imagery was used to locate any ponds that had not yet been identified on an Ordnance Survey (OS) map. The purpose of this exercise was to determine the error margin between identified ponds on OS maps and existing but unmapped ponds. In total, 204 known ponds (from the datasets queried) lie within the boundaries of the 5 x 5 km ground truthing squares. An additional 37 ponds were located within these squares using high-resolution satellite imagery, increasing the total number of identified ponds by a moderate 18%. This result implies that, although a significant number of ponds had already been identified prior to this exercise, the number of additional ponds subsequentlyidentified following desk-based ground truthing is large enough to justify more comprehensive, field based ground-truthing of the Norfolk Coast AONB. Although analysis of satellite imagery is a useful approach, it is recommended that ground-truthing should be completed in the field, using local knowledge, in order to ensure full coverage of sites within the Norfolk Coast AONB. Field ground truthing would also be useful where the GIS and satellite data make it difficult to differentiate between 'duplicates' ponds and those ponds that are very very close neighbours (e.g. where there is high tree coverage)

Results:

A total of 1307 ponds were identified following the data exercise. Pond type was broken down into a number of categories, including field ponds, gravel pit ponds, hedgerow ponds, estate lakes, woodland ponds and ghost ponds. Field pond and hedgerow pond were the most common types. Thus, from across the data sources we were able to obtain pond information from, 94 were characterised by species data. The table (below) summarises the number of ponds with data for different species groups.

Species Number of Ponds
Birds 22
Fish 10
Great Crested Newt 47
Invertebrates 20
Macrophytes 19
Mammals 7
Natterjack Toad 2

The data generated show that there is a real paucity of species data available relative to the number of ponds. This highlights;

  1. The problem of ineffective recording procedures (people record, but don’t effectively submit data)
  2. The need for a better (easier) reporting process to facilitate recording
  3. The AONB has a huge number of ponds without ANY data
  4. The number of ghost ponds show a large number of ponds have been lost
  5. But – the density of ponds suggest the AONB to have excellent potential as a biodiversity resource.

Recomendations

Currently the species data available for ponds in the AONB are scant/sporadic being largely limited to records for individual species with only a few ponds subjected to multi-species surveys. Nonetheless, there are large numbers of ponds in the AONB (1307 identified in this study) and it is clear that several key pond species are present which would benefit from future conservation work.

Important next moves and potential pond conservation

Farmland pond restoration. To date, pond management and restoration has received little attention in the AONB. Nonetheless, one flagship project, conducted at the landscape-scale where several overgrown ponds are managed to reduce terrestrialisation, might help to inspire future work.

Pond creation.

There would be huge benefits associated with focused pond creation within the AONB. This could take three major angles;

  1. Creation of ponds on and close to moraine deposits associated with the Cromer-Holt ridge - existing ponds on the Cromer Ridge are slightly more acidic (e.g. ponds at Kelling Heath Holiday Park) and thus suitable for the Palmate Newt an exceptionally rare species in East Anglia (only 2 known Norfolk sites until 2014).
  2. Creation of “compensation ponds” close to the coast – with the increasing threat of saline incursion due to climate change, many plant and animal species associated with coastal freshwater marshes (e.g. Blakeney Freshes) are potentially under threat of local extinction.
  3. Creation of floodplain ponds – due to a long history of drainage and agricultural land reclamation, ponds are currently rare habitats in river floodplains, with this especially the case for AONB rivers. The creation of lower floodplain ponds would greatly benefit river fishes through provision of flow refuges and additional food sources, as well as providing superb habitat for amphibians, dragonflies and wetland birds.

Surveys for rare species.
We suggest that more survey data is required to help target future pond conservation activities in the AONB. This is especially true of woodland and heathland ponds associated with the Cromer-Holt ridge, where the palmate newt may be much more prevalent (see above).

Better species recording.
We would therefore recommend that a simple data recording protocol be devised to facilitate recording and encourage individuals and organisations to submit data. This information then needs to be collected and collated and ideally this would be best achieved by individual collectors being able to upload data directly to a web site. This increases the opportunity for locating the records by using on-line mapping (e.g. Google Maps) to identify the sample point and would allow easy transfer of records to a central

Castle Lough 1