The Stangrove Pond Survey - 2006

Stangrove Pond Slide Show


There are several standard forms available for evaluating a pond's potential for wildlife. The one which I have used here is a basic system compiled by the Norfolk branch of FWAG (Farming and Wildlife Advisory Group) which relies on just seven factors: water quality, water level, profile & depth, pollution, light access to water surface, surroundings & links and rare species. Because of the potential duckweed and turbidity problems I have added 'light penetration', which I feel to be relevant in this case, making eight in total. By giving each factor a rating: High 3, Moderate 2 or Low 1, an overall evaluation is arrived at.

WATER QUALITY - 2: Moderate

High: Four or more aquatic plants including both submerged and emergent species. Teeming with a variety of invertebrates/amphibians.

Moderate: Less than four aquatic plant species. A few invertebrates/amphibians.

Low: Little plant/animal life. Overgrown e.g. common reed, reedmace, willow. Leaf litter problem.

WATER LEVEL - 2: Moderate

High: Reasonably stable. Little or no fluctuation.

Moderate: Fluctuation occurs but at least 0.3 to 0.6 metres at all times.

Low: Severe fluctuations. May dry out completely.


High: Gently shelving shore on at least one edge. Range of depths to 2 metres or more.

Moderate: Shelving edge but little range of depths.

Low: Steep bank all round. Shallow water severely silted up possibly with leaf litter.


High: Few or no algae. Clear water, no discolouration of water. No dumped rubbish.

Moderate: Probably some algae. Slight discolouration of water. Slight leaf litter.

Low: Algae abundant. Severe discolouration of water. Possibly dumped rubbish. Leaf litter serious.


High: Open to south but with some shaded areas.

Moderate: More shaded than open.

Low: Completely enclosed by surrounding or overhead growth. Little light access.


High: Full penetration of sunlight to pond bed, as far as observable.

Moderate: Penetration of sunlight to around 0.6 to 1 metre depth.

Low: Little penetration of light beyond around 0.1 to 0.3 of a metre.


High: Marginal vegetation with a range of native trees/shrubs but not causing too much shading over water nor producing undue leaf litter. Preferably linked with other habitat e.g. grassland, hedge, woodland edge. Buffered from spray, fertiliser, livestock, road run-off, rubbish and effluents.

Moderate: Marginal vegetation minimal. Linking with other habitats rather limited. Some buffering from sources of pollution.

Low: Trees/shrubs causing problem of light access and leaf litter or completely open e.g. mid-field arable with no protection from chemicals. Open to other sources of pollution. Few, or no, useful links with other habitats.


High: Presence of any rare plant/animal species.

This is the simplest form of evaluation that I was able to find. I am sure that you can see from it just what a subjective issue this kind of assessment is, and how difficult it is to apportion a rating within such a tightly drawn group of criteria, given fairly dramatic seasonal variations. Here I have chosen to take the late spring/early summer as typical and have ignored the dramatic decline experienced later in the year. It is, remember, the current potential, 'in an average season', that we are seeking to assess, not it's best, or worst, performance.

Using this system, as accurately as I was able to judge the situation, Stangrove Park Pond (there are many grey areas and in my view the end result is vastly over optimistic) currently scores roughly 1.9 or 'Low Moderate' for wildlife potential. Personally I feel that the requirement for a depth of two or more metres should not be taken too seriously and have scored accordingly. It is variety of depth which counts most, and shallow areas are the more important, particularly for invertebrates. Deeper parts only really become of value in times of extreme winter/summer weather or minor pollution incidents, when they offer a degree of protection to the aquatic inhabitants by buffering the more dramatic effects.