The Marsh Dock this morning
Although the Marsh Dock that hatched – sorry germinated – in my New Pond earlier in the year didn’t survive, the seedling we potted-up is looking pretty healthy and growing well.
With luck we’ll be able to add it to the New Pond sooner or later.
Our real aim, though, is to grow the plant on and return seeds or young plants to Pinkhill Meadow where the original seeds came from.
As far as we know, this is the only site in Oxfordshire where this plant grows.
Another nice piece in the Independent yesterday on the Million Pond Project.
Click here, and thanks to Gillian Orr, who wrote the article.
The Old Pond yesterday showing water conductivity values (and rather more Lemna than I'd expected this pond to have!)
One of the special things about ponds is how much they differ from place to place.
And the Old Pond is providing an excellent example of this phenomenon at the moment in its water quality.
Because the three basins of the pond – which have now been separate for about two months as a result of the dry weather – are showing big difference in water conductivity, considering how close they are to each other and that they have been supplied with exactly the same water throughout.
Yesterday the front small pool had a conductivity of 232 – that’s quite high, at the top end of what I’d expect to be unpolluted’; the middle right shaded pool was at 162 – a good low value; and the back Typha pool was a very low 53.
I was very surprised by the differences in the three ponds.
Conductivity is a very useful measure (and cheap) but it can’t tell you which dissolved chemicals are contributing to the overall score. To find that out you need a much more time consuming / expensive laboratory analysis.
So I don’t know what’s causing these differences.
But two things are interesting:
- the back Typha pool, which still has rich growths of moss – is cleaner than rainwater.
- designing the pond to have basins that separated when the water levels went down in summer was intended to create diversity in physical and chemical conditions.
At the moment it certainly seems to be working.
A typical scary picture of water fern
I notice silly season coverage of British Waterways kill-the-water-fern-using-weevils story:
The BBC and Independent both covered it. And it has propagated around the world too.
This is a case where the writers involved would do well to follow up the press release from the productive British Waterways PR team and dig a bit more deeply about the cause of plagues of water fern (Azolla filiculoides).
In fact, dense growths of water ferns usually occur only where there are exceptional levels of phosphorus pollution.
This is because water fern has a symbiotic relationship with an alga that can fix nitrogen from the air. So when there is a plentiful supply of the plant’s other main nutrient – phosphrous – it’s growth is effectively unlimited, and it can go wild. So in fact, this is another story about water pollution. Dense growths of Azolla are caused by pollution.
The problem is: it’s much easier to control the symptoms (the growth of water fern), than the cause (the pollution).
So is Azolla, and I quote from the BW press release, ‘a serious threat to waterway wildlife in the UK‘, or indeed any other, freshwater habitat? Not much. A far bigger impact on the canals is their generally poor water quality, and the constant churning up and down of boats which, together, virtually eliminates all underwater plants. But boaters can justifiably argue that this is what the canals are for.
In fact, water fern is petty rare and phosphorus pollution, although all pervasive and damaging, is still usually below the exceptional levels that allow water fern to grow explosively.
In ponds, where you might expect water fern to be most prevalent, we estimate it’s in about 1% of ponds nationally. Or put it another way, its absent from 99% of ponds – which is most of them! Although there are no equivalent statistics from canals, I would guess it’s equally infrequent there too.
But Azolla makes a a dramatic and deeply disturbing looking picture so it’s easy to get people exited about it.
(And for the headline, apologies to my German friends. I was unable to escape from my own cultural stereotype of constantly resorting to ancient World War II jokes – but I couldn’t resist the temptation).
After 10 days of the New Pond being pretty much bone dry, we had some heavy rain yesterday which has added about 5 cm of water.
Here’s how it looked before and after (though it was not a thing of beauty at either time, I will freely admit. But beauty will have to come later!).
So here it is before, about 10 days ago…
Dry as a bone, with the plants dead or dying. Surely nothing could be alive?
And after the rain we’ve now got a few centimetres of water.
After yesterday's heavy rain - the first here for a couple of months - we've got some water.
So after two weeks with the pond pretty much bone dry I didn’t expect much to have survived because, with a butyl liner, it really is dry. There’s very little damp cover in the pond – it has virtually no sediment and few water plants providing damp spots where creatures might hide away.
So I was quite surprised tonight to see that four species of water snail have survived, and also the aquatic larvae of a soldierfly (although unfortunately I don’t know which kind it is).
The survivors – below, for the record – are all pretty small specimens as well. I’d rather assumed that the small ones would be more vulnerable, but the opposite seems to be true.
So, here they are (sorry, not great pics, but I just wanted to document them)
Survivor number one: this tiny Smooth Ram's-horn is about 1.5 mm diameter. These are my best snails: like seeing a Turtle Dove or a Lesser Spotted Woodpecker in the average surburban garden
Survivor number two: a baby Marsh Snail, about 3 mm long
Survivor three: a Whirlpool Ram's-horn: this one is quite large, maybe 2/3rds grown (about 4 mm across) and should be maturing, and able to lay eggs, fairly soon.
I didn’t get a picture of the fourth survivor: a Contorted Ram’s-horn. But all in all, snails have come out of this surprisingly well, and look likely to rapidly repopulate the pond as water returns.
I also saw several of these:
Larval soldierfly: a bit more detection needed here as I'm not good with this group
On the other hand, perhaps unsurprisingly, there’s no sign of my Large Reds – and I found one small one dead. But they may hatch from eggs. It will be interesting to see if they can survive droughts in this way. No water slaters – no real surprise there, and no shrimps. Again no surprise. I also saw one very small young pond skater which, being flightless, had succumbed. I imagine all the beetles flew off, and any amphibious Horse Leeches would have made a break for it too.
We will have to wait to see which of the plants have survived.
White water lilies growing vigorously on the mud in a drying out pond
It’s natural to assume that drying our is bad for freshwater wildlife, a view often reinforced by environmental organisations, as you can see here and here.
Of course it’s nothing like as simple as this: water levels naturally go down in summer, rivers flow less and ponds and small streams often dry out. It’s something that’s been happening for millions of years, and quite a few plants and animals are well-adapted to this.
A classic example can be seen with water lilies, plants which you might assume needed water all the time.
In reality, lilies don’t mind low water and in summer are quite happy when there’s virtually no water left at all in a pond, as were these white water lilies (above) photographed this weekend in a pond naturally drying out at Woodcote, near Reading.
This same pond also had some nice patches of Gipsywort (below) growing in the drawdown zone – that naturally rich part of ponds and lakes which is exposed when the water levels drop in summer.
Gipsywort (Lycopus europaeus) growing at the Greenmoor Ponds, Woodcote (July 2010)
Mind you I wouldn’t mind a bit of water here in Abingdon – where there’s no sign that this is the wettest July of all time!
This Marsh Harrier photo can be seen in its natural habitat on Steve Tomlinsons Margate Cemetery Wildlife Blog
A few years ago I remember stumbling across the nest of a Marsh Harrier in the reedy edges of what, at first sight, looked like a pretty ordinary field pond in the eastern Polish countryside.
I was pretty amazed – but that was eastern Poland, where the ordinary countryside is still of a quality which we would automatically slap every protective designation we could find in this country.
So it was exiting this weekend, if not quite so unexpected, to see the nesting site of Marsh Harriers beside a pond at……..
Well, for obvious reasons, I’m going to be a little bit coy here other than saying that this was on a farm on the edge of some well-known areas of wetland in southern England.
In fact the nest site was in an established pond on the edge of an arable field which itself was next to a group of recently-made new ponds, created with funding from the Higher Level Stewardship scheme.
Marsh Harriers have nested for two years close to these new ponds
The ponds were constructed by a pair of farmers who are typical of the new generation – lovers of the countryside, aware of both the natural environment and farming, confident enough to listen, and personally committed too. Helped by local advisors with a detailed knowledge of what makes ponds tick the site is a classic example of the kind of pond creation we’re encouraging in the Million Ponds Project.
And it’s because of projects like this that Baroness Miller of Chilthorne Domer was able to say last week in the House of Lords that ‘….the Million Ponds Project is going well….’ and that ‘A pond, no matter how small, is an exciting example of something that individuals, schools and local authorities can all create.’
Well, the individuals concerned have done an excellent job here.
Thanks to Mike McCarthy, Environment Editor in the Independent, for the nice write up last week.
Picking up one of the themes of the article – that it’s only in Britain that you can imagine an organisation starting up that is concerned with little ponds – I think Pond Conservation is as much part of the long tradition of Britons being at the forefront of environmental activism, as much as ponds being a specially British peculiarity.
Because in fact we have colleagues throughout Europe who are also interested in ponds – in an organisation called the European Pond Conservation Network – and in the States too.
And a couple of years ago it was an America biologist John Downing who wrote one of the most important technical reports so far on ponds which showed that one third of the area of standing water in the world is in water bodies less than 10 ha in area.
So perhaps it’s distinctively British to be first to spot the environmental problem (in this case that little ponds are important) – but as on many other occasions, we’re not alone.
And just to prove it, in a couple of weeks we’re off on holiday to a region of northern France – the regional park known as the ‘Caps et Marais d’Opales‘, the bit of northern France you normally drive straight through on the way to somewhere more interesting – where they have a strong interest in ponds, as you can see from the manual they publish on the conservation of ponds (in France ponds are mainly called ‘mares’).
Only the crazy French could be interested in such little things.
Another exiting freshwater find today: this time it’s new pond sites for the extremely endangered Tadpole Shrimp (Triops cancriformis).
Until today’s reports this animal was known only in the New Forest in two, or perhaps three, ponds, and along the Solway coast in one single pond.
It’s survival in the UK is remarkable – not least because one of its sites is within 2 m (yes 2 m) of a road.
I’ve featured the Solway site before, which was originally discovered by the staff of the Wildfowl & Wetlands Trust.
Now there are reports of two new sites, also on the Solway – covered by the BBC here, the Guardian here and the Mail.
I thought readers of the blog might be interested to see the messages to RSPB members, Wildlife Trust members and members of the British Association for Shooting and Conservation from the Environment Secretary Caroline Spelman to get involved in designing the new White Paper on the Natural Environment (a White Paper is the traditional precursor to a new Act of Parliament).
It will probably be a good idea for all of us to get behind Caroline Spelman as she argues the case for wildlife and the environment over the next few months.
And for members of the the Wildlife Trusts…..
And for the members of the British Association for Shooting and Conservation (known as BASC).
Is there a connection to garden ponds?
Well, of course. Making top quality garden ponds is one way of putting back into the landscape something that has become extremely rare in much of England: clean, unpolluted, water – a very real way of making your own personal contribution to increasing the extent of good quality wildlife habitats.
And out in the countryside, making ponds looks like a remarkably good way of protecting freshwater biodiversity more generally, as important as trying to clean up rivers, create new wetlands and improve degraded lakes.
