The Stangrove Pond Survey - 2006

Diary of visits

30th November 2005 - Duration: 30 minutes

Made a cursory inspection of the pond on a dismal wet day. My overall impression was that the pond itself had weathered well since the last major works were carried out almost twelve years ago. There was plenty of open water and levels looked good considering that we are in the midst of the longest period of drought for over seventy years. The main problem seemed to be one of litter and dumping but nothing that could not soon be rectified by a good clear out using rakes and draglines.

18th January 2006 - Duration: 1 hour

Highslide JS
The duckweed already well in evidence - and covering most of the surface of the pond...
The duckweed already well in evidence...

A mild day with steady light rain (10°C).

I was surprised to find the duckweed (lesser I think) already well in evidence and covering most of the surface of the pond. I waded in at several points and found the depth of water to be good and still conforming to the re-profiling of the early nineties. Numerous copepods (predominately cyclops) were observable, moving jerkily about in the open water. I had a thorough look for frogspawn around the margins but none was to be found at this early stage in the proceedings.

Bank flora, at this time, (excluding trees) consisted of pendulous sedge, dock, cow parsley, great willowherb, cleavers, bramble and various indeterminate grasses.

While on site I also had a look at the shaw to the south of the pond, behind the children's play park (that which used to border the main road was mostly lost with the coming of the relief road). This is worthy of preservation/enhancement as an area of secondary habitat to the pond itself.

25th January - Duration: 30 minutes

Bitterly cold with a hard frost (-3°C)

Took some photographs around the pond, and of the southern shaw, while the vegetation was dormant and an overall impression of the site could be obtained.

No frogspawn.

1st February - Duration: 15 minutes

Cold and overcast but dry (3°C)

Had a quick look round. No frogspawn but a couple of new bits of emergent flora: flag iris, ribwort plantain and stinging nettle. A solitary heron was staring intently into the north-west corner of the pond. Given that there are no fish present I wonder if he had spotted a frog as it is too early for newts. They are not normally silly enough to waste their time. We shall see...

7th February - Duration: 15 minutes

Mild and overcast but dry (10°C)

Still no frogspawn. Made a note that the water level is six and half bricks down from the top of the overflow (this has been an exceptionally dry winter). The southerly wind had cleared the duckweed back and there appeared to be little in the way of submerged plant life to be seen, but a lot of fallen leaves, many of which are still piled up behind the bramble on the southern side, and were blowing into the pond in large numbers. They would seem to emanate from the shaw on that side of the park, the leaves from nearby trees having been cleared in autumn.

14th February - Duration: 15 minutes

Mild and sunny after a dismal start (10°C)

No frogspawn, but 14 mallard present

21st February - Duration: 15 minutes

Cold and windy with heavy showers of sleet (3°C)

After some heavy rain throughout last Sunday and overnight into Monday (first for quite some time) the pond had filled to within three bricks of the top of the outlet chamber and the island was almost flooding. The water was very turbid, suggesting that it had mostly filled with run-off from the sloping expanse of grass west of the pond, rather than any rise in the underlying water table. The wind had pushed all of the duckweed to the south-west corner and I would estimate that it covered no more than one twelfth of the surface area.

No frogspawn.

28th February - Duration: 15 minutes

Cold but fine (3°C)

Water level the same as previous visit. Duckweed covering about one fifth of the surface area and now in the south-east corner of the pond.

No frogspawn.

12th March - Duration: 15 minutes

Cold but fine (3°C)

Cold again after a wet, windy and mild interlude at the beginning of last week. Frogspawn was reported in many parts of Kent, but not yet showing here. Water levels remain high.

14th March - Duration: 15 minutes

Overcast and cold (4°C)

Water level still up at three bricks from top of overflow. 13 mallard and 5 moorhen in evidence. A lot of grain and chopped up bread on the bank. Signs of an attempt to rake off the duckweed at the north-west corner, with around 10% of surface area remaining covered. The western bramble bank is populated by a large colony of house sparrows, which is good, considering how they have declined over the last decade or so.

Still no frogspawn.

21st March - Duration: 15 minutes

Overcast and cold (5°C)

Water level now down to four bricks from the top of the overflow. Level on island confirms this as the optimum top-water mark. The water has cleared considerably, without recent input, which is a good sign. Only a tiny bit of duckweed remains, pinned on the south-west bank by the strong breeze.

Still no frogspawn. Starting to fear the worst.

22nd March - Duration: 1 hour

Cold but fine (0°C)

Arrived at 9pm and spent an hour torching for newts. Found none but this could be due to the extreme cold.

28th March - Duration: 15 minutes

Highslide JS
Frogspawn at last - better late than never...
Frogspawn at last...

Fine and mild but windy, after a warmer, wet, week (14°C)

Workmen were working on the overflow. No duckweed to be seen.

27 clumps of frogspawn, at last! Better late than never.

29th March - Duration: 1 hour 30 minutes

Fine and mild (15°C)

Called in afternoon to photograph frogs and frogspawn. Went back after dark to torch for newts. None found. Lesser celandine and wild arum now showing.

11th April - Duration: 15 minutes

Cold and wet (8°C)

Minimal duckweed pinned on eastern bank by westerly wind. Creeping buttercup, germander speedwell, sorrel and marsh thistle now in evidence. Water a little clearer than of late.

20th April - Duration: 25 minutes

Intermittent drizzle (12°C)

Still little duckweed, and still no evidence of any newts. Creeping thistle, meadowsweet, shepherds purse and creeping jenny now showing. 10 ducks, 1 duckling and two moorhens to be seen. Water level has dropped to four and a half bricks from top of chamber. Water very much clearer.

23rd April - Duration: 1 hour

Steady drizzle (14°C)

Spent an hour observing and dipping in the company of Lyndsey Rule. Discovered some daphnia, freshwater shrimp, water boatmen, midge larvae, some indeterminate free swimming nematodes, lots of frog tadpoles and around a dozen newt eggs wrapped in submerged grass leaves, along the middle section of the northern bank (probably great crested, will investigate further). Wood avens now showing beneath trees on eastern bank.

28th April - Duration: 2 hours

Mild cloudy night (15°C)

Called at the pond from 11pm to 1am torching for newts. Found a maximum of seven great crested newts (3 male, 4 female) and one female common newt (conceivably palmate of either sex, impossible to distinguish at long range). All were located in the shallow margins along the entire northern bank. I found nothing around the rest of the pond. Two of the great crested females were in the act of laying eggs on submerged grass fronds.

5th May - Duration: 1 hour

Warm and sunny (22°C)

The pond has deteriorated dramatically since my last daylight visit on 23rd April. The water level has dropped to five bricks from the top of the overflow and the shallower eastern end begins to look a mess, with heavy growth of blanket weed now in evidence (classic symptom of enrichment) and much dumped rubbish showing. There is still no sign of any oxygenating plants within the pond. New species observed were woody nightshade, bindweed, orange tip, pond skater and whirligigs.

12th May - Duration: 1hour

Hot and sunny (25°C)

The pond looked slightly healthier after heavy rain on Monday 8th and through the early hours of Tuesday 9th, although the water level has fallen still further to almost six bricks from the top. Large red damselflies were to be seen mating in the margins with several orange tips on the wing. One patch of burdock coming into leaf, about two thirds west, on the north bank.

I had a good look at the surrounding trees and took some photos for identification of the more difficult species. There are a few typical clumps of elm suckers at the western end growing to around twenty feet and then succumbing to Dutch elm disease. A small leaved water lily is showing towards the eastern end of the north bank (which doesn't look too bad as regards marginals now), currently the leaves are a deep glossy red. I will do my best to get an accurate identification when it is more developed. 7 ducklings (10 adults) and 4 moorhen chicks (3 adults) were to be seen.

18th May - Duration: 30 minutes

Humid and showery (18°C)

Although the water has become quite turbid again after recent heavy rainfall the level remains unaltered from previous visit. The most mallard to date, with 15 adults and 21 duckling to be seen. There is still no duckweed in evidence.

20th May - Duration: 15 minutes

Much cooler than of late, 15°C during the day with heavy showers and around 11°C at time of visit (11pm)

Nothing to be seen, torching for newts, due to turbidity of water after recent heavy rainfall and possible cooling effect on ambient water temperature. Perhaps the wrong night to try.

3rd June - Duration: 2 hours

A perfect day, with unbroken sunshine (24°C)

After a protracted period of gales and rain with figures in the low teens. The level was at five bricks from top and turbidity was still very high. I noticed that efforts had been made, since my last visit, to clear rubbish and algae from the pond, with duckweed still barely noticeable.

There is a lot of stinging nettle now in evidence, possibly indicating high phosphates in the soil along the water's edge, particularly the northern bank. Flag iris just coming into flower.

I was fortunate enough to talk to several passers-by and it was interesting to hear their views and ambitions for the pond. One in particular (Mr A. D. Poupard) told me, at length, about the populations of both common and great crested newts using his garden ponds. I called round later but he was out, however, I was able to investigate the small pond in his front garden and found it to be teeming with common newts (at least fifty individuals). I have no doubt about his correct identification of great cresteds as he described them to me perfectly (they are more easily observed at night). This puts a different complexion on our population at Stangrove Park, as this and possibly/probably other garden ponds in the vicinity are well within striking distance of newts breeding and dispersing to and from the park pond. Indeed it may be that Stangrove pond is only a sink pond (newts exist in it but do not breed there in large numbers) and the outlying garden ponds, being better protected, are the source ponds (where newts breed and disperse successfully).

The main purpose of this visit was to continue dipping operations and record further species using the pond. I also checked the pH of the water, which I found to be 7.3, just slightly alkaline.

Dipping revealed huge numbers of daphnia and cyclops, a saucer bug nymph, some mosquito larvae (most probably Culex pipiens) and some chironomid or non-biting midge larvae (probably Chironomus luridus). Frog tadpoles were observable in great numbers, having now grown large with well-developed hind legs, they could be seen rushing to the surface to gulp in air and then quickly diving back down into the depths. Several banded agrion damselflies were also to be seen around the pond. These I believe to be vagrants from The River Eden rather than a breeding population.

8th June - Duration: 1hour

Hot and sunny (24°C)

Called back and had a chat with Mr & Mrs Poupard. Found some knotgrass and took some grasses away for identification. Water level still holding at the five brick mark. No duckweed to be seen but water looks in poor order, turbid, black and anaerobic with a great deal of willow seed floating on the surface.

16th June - Duration: 4 hours 30 minutes

Hot and sunny (24°C)

Spent all of the morning, and part of the afternoon, dipping in the pond and beating the surrounding vegetation for invertebrates. Greatly extended my list.

Christine Lane, the clerk of Edenbridge Town Council, came down at about one o'clock for a look around and to see what the most urgent needs may be.

Although the water level is still holding at about six bricks from the top of the outlet the water quality has declined dramatically over the past two weeks. The colour is black, very turbid, and looks completely anaerobic. There is very little life in the pond except sludge worms, a few midge larvae, water boatmen and daphnia. Even the daphnia are reduced in numbers on my previous forays. The only good news is that duckweed is still at a very low density (I am becoming suspicious about this!).

During the period of my visit members of the public threw four loaves of bread, i.e. one loaf every hour, and about half a kilo of grain into the pond. A body of water of these proportions cannot possibly sustain this volume of pollution!!!

28th June - Duration: 30 minutes

Warm and sunny (21°C)

Did not visit last week as the fair was in town. They cleared up well and there was no additional input of litter to be seen when I called. Half a days rain on Monday 26th did little to improve water quality, although there was absolutely no duckweed that I could find.

The purple loosestrife is just coming into flower.

Water level down to seven bricks from top of overflow.

6th July - Duration: 30 minutes

Cooler than of late with a few light showers (20°C)

Water quality slightly improved despite outflow now being down to eight bricks. Checked pH again at 7.4. No duckweed to be found.

The mallard's second brood was in evidence, with a further twelve plus ducklings to be seen and meadowsweet now coming into flower.

Recorded a few new species.

12th July - Duration: 1 hour

Hot and sunny (25°C)

Water level now at the very bottom of the overflow (8 bricks showing). Found a few new species: gipsywort, agrimony, cut-leaved crane's-bill, large red-tailed bumblebee.

19th July - Duration: 1 hour

Very hot and sunny (37°C)

Water level now out about a foot from the bottom brick. Did some dipping but found very little, apart from sludge worms, a few daphnia, and a couple of diving beetles, which avoided capture. I would guess they were Agabus bipustulatus, as I thought I glimpsed a transparency at the rear of the wing cases, which is diagnostic. Other new species included: water mint (Mentha aquatica), leaf-cutter bee (Megachile centuncularis), wool carder bee (Anthidium manicatum), common wasp (Vespula vulgaris), hover fly (Sphaerophoria scripta), codlin moth (Cydia pomonella), common blue damselfly (Enallagma cyathigerum).

There is still absolutely no duckweed, which, together with the total absence of all aquatics, makes me increasingly suspicious that some form of chemical treatment may have been applied earlier in the season.

26th July - Duration: 1 hour

Very hot and sunny (32°C)

Water level stable at level of last visit, despite this mornings heavy storm.

Christine has confirmed that a biological agent was applied to the pond earlier in the year, confirming my worst fears. Will check this out more thoroughly when I return from holiday.

The water quality is now quite appalling with the detritus on the bottom starting to ferment, which is stirring up the silt and intensifying the turbidity. The only aquatic life, to be found, are a few sludge worms.

16th August - Duration: 30 minutes

Warm and sunny (24°C)

Water level now about six feet out from the bottom brick. Fully 2.5-3 feet down on early spring level, in fact very little water remains at the eastern end at all.

17th August - Duration: 30 minutes

Cloudy with showers (22°C)

Returned to take a few photos. Decided to terminate the survey at this point, as there is no point in continuing further, with even sludge worms reduced to a single observable specimen.

1st September - Duration: 5 minutes

Broken cloud with a few showers (18°C)

Final look to see if there was any recovery of levels after recent rain. There was little perceptible change.