Identify a priority pond
So far, fewer than 2% of ponds in the UK have been identified as priority habitats, but the total is likely to exceed 20%.
Identifying and reporting new priority ponds helps to protect these sites and increases the likelihood that their freshwater species will continue to thrive in the landscape. Information about priority ponds is valuable to many public bodies, organisations and individuals.
Seven criteria for identifying a priority pond
1 Habitats of high conservation importance
These are ponds that meet the conditions for an Annex 1 Habitats Directive type. The following nine habitat types are the most relevant to ponds:
- 3110 Oligotrophic waters containing very few minerals of sandy plains (Littorelletalia uniflorae)
- 3130 Oligotrophic to mesotrophic standing waters with vegetation of the Littorelletea uniflorae and/or Isoeto-Nanojuncetea
- 3140 Hard oligo-mesotrophic waters with benthic vegetation of Chara spp
- 3150 Natural eutrophic lakes with Magnopotamion or Hydrocharition – type vegetation
- 3160 Natural dystrophic lakes and ponds
- 3170 Mediterranean temporary ponds
- 3180 Turloughs (mainly Ireland)
- 2190 Humid dune slacks
- 21A0 Machairs (in Scotland and Ireland)
Descriptions of these habitat types are given in the EU Habitats Directive interpretation manual (European Commission DG. 2013). For some freshwater habitats additional, UK specific, guidance has been developed. However, this is not true for ponds. For example, for lakes, the ‘Common Standards Monitoring Guidance for Freshwater Lakes’ includes UK interpretation of Habitats Directive assessment criteria, but acknowledges that they are not suitable for ponds under 1ha in area (Interagency Freshwater Group, 2015).
In the absence of other guidance, Freshwater Habitats Trust has produced a Guide to Annex 1 Habitats Directive pond types. This is based on the EU interpretation manual (2013) and focusses predominantly on the Habitat Directive pond types found in England and Wales. The criteria used to identify priority ponds were originally listed in the UK Biodiversity Action Plan, Priority Habitat Descriptions: Ponds BRIG (2008).
2 Ponds with species of high conservation importance
These are ponds with one or more national or UK Red Data Book species, BAP species, species fully protected under the Wildlife and Countryside Act Schedule 5 and 8, Habitats Directive Annex II species, a Nationally Scarce wetland plant species, or three* Nationally Scarce aquatic invertebrate species.
*Note: priority pond criteria were drawn up in 2007, prior to significant revisions of some Red Data Books. In particular, Garth Foster’s (2010) review of water beetle status substantially reduced the number of water beetles that classify as Scarce. The original qualifying level of three Nationally Scarce aquatic invertebrate species was heavily dependent on the large number of Scarce water beetles recorded in ponds at that time. Freshwater Habitat’s Trust originally suggested the ‘three Scarce invertebrate’ limit. However, following Foster’s review, we now believe it is more appropriate to treat ponds with one Nationally Scarce aquatic invertebrate species as a priority habitat.
3 Ponds with exceptional populations or numbers of key species
These are ponds that fulfil at least one of the following criteria:
- Criteria specified in guidelines for the selection of biological Sites of Special Scientific Interest (currently amphibians and dragonflies only).
- Exceptionally rich sites for plants or invertebrates (supporting 30 or more wetland plant species or 50 or more aquatic macroinvertebrate species).
4 Ponds of high ecological quality
These are ponds identified using the Predictive System for Multimetrics (PSYM), developed by Freshwater Habitats Trust for use in England and Wales. Ponds need to be assessed using standard PSYM methods.
To qualify as a priority pond, waterbodies need to be categorised as having ‘Good’ quality with a score of 75% or more.
5 Other important ponds
These are individual ponds or groups of ponds with a limited geographic distribution recognised as important because of their age, rarity of type or landscape context. For example, these could be pingos, duneslack ponds or machair ponds. There is now specific guidance for two types of important ponds: Ice Age ponds and ponds with floating mats. Find out more about irreplaceable ponds.
There are now two additional methods for identifying a potential priority pond:
6 Predictive methods (PASS)
The Priority Pond Assessment (PASS) system has been developed to use observations about the physical characteristics of a pond (such as surrounding land use) to rapidly identify if a pond is likely to qualify as a priority pond. The method picks up around 60% of priority ponds.
Read the Priority Pond Assessment manual for more details on this method.
7 Clean water
In agreement with Natural England, the presence of clean water can now be used to identify ‘Provisional Priority Ponds’.
Clean water (in this context) is assessed using two nutrients which can pose a major risk to freshwater wildlife: nitrate and phosphate.
To qualify as a Provisional Priority Pond both nitrate and phosphate need to be at low levels:
- Nitrate (nitrogen) levels need to be below 0.5 mg/l (or ppm), and
- Phosphate (phosphorous) levels below 0.05 mg/l (or ppm).
These pollutants can be measured using laboratory or other tests including the ‘quick kits’, as long as they are sensitive enough to show levels of 0.5mg/1 for nitrate and 0.05mg/1 for phosphate.