How many kinds of dragonflies in your garden pond?

Broad-bodied Chaser (left) and Common Darter larvae from the pond this morning

I thought I was doing quite well having three different kinds of dragonfly using my pond:

- Broad-bodied chaser

- Large Red Damselfly

- Common Darter

But Helen at Frog End has twice this number.

She’s got six, and its not a big pond either.

The not-invasive Bulrush

My naturally colonised Bulrush, a widely hated ‘invasive’ plant, is still showing none of its reputed triffid nature in my pond.

It’s now midsummer and we’ve got a total of five stems.

Most interesting, the plants are practically dwarfs – mine are about 70 cm tall,

My Bulrush 28 June 2009

only a quarter of the 3 m they can reach.

I think – though I’ve no proof of this – the very low levels of nutrients in the pond are keeping them stunted. I still don’t really anticipate them taking over, not for a few years yet anyway.

Some questions

Matt asks:

M: Do the larvae of Broad-bodied Chasers live in streams?

J: No, they seem never to be found in streams and rivers. Your’s must have come from another pond, lake or very slow moving ditch somewhere.

M: Can sticklebacks live happily alongside other creatures or are they also quite voracious?

J: Lots of animals do live alongside sticklebacks but I think the effect they have will depend a lot on the size of pond. In a local pond down by the river near us in Abingdon, there’s a good range of animals living in a pond that also has 3-spined sticklebacks. But I suspect that when you put the sticklebacks in a small pond they’re likely to have a much bigger impact.

Sticklebacks are notorius for exterminating Great Crested Newt larvae; no doubt they would have the same effect on the smaller newts too. People sometimes go to considerable lengths to get rid of them from crested newt ponds.

Do tadpoles make ponds go green?

This excellenmt picture is from Matt Wilsons Blog: http://mwilsonherps.wordpress.com/

The pond had a bad couple of weeks during the first half of June when it was looking disappointingly green (so disappointing I couldn’t bear to photograph it!).

You can get a hint of it in the first picture of the dragonfly in the previous post.

Yuk.

But why did this happen: well I blame the tadpoles.

There have been so many tadpoles in the pond that I have a feeling that, as they munched their way arround the pond, they have simply overwelmed the mosses that would otherwise be taking up nutrients.  Tadpoles aren’t meant to eat plants (only tiny algae) but mine have certainly tucked into the mosses in the pond. At times you can see them savaging the delicate mosses like a jackal stripping the carcass of a wildebeest.

At the same time the amount of tadpole poo meant that there’s probably been a superabundance of nutrients encouraging the little green monsters.

And there was a downturn in water fleas too – so nobody there to filter the algae out of the water either.

Result: very soupy water.

BUT….the good news is now the water’s beautifully clear again. Water fleas are back, and there’s maybe not such a big tadpole impact as some have become baby frogs and others the dinner of my voracious backswimmers (but don’t worry tadpole lovers – I’ve still got loads!).

At least, its a plausible theory.

Emerging dragonflies

Emerging broad bodied chaser dragonfly in grass at the pond margin

I’ve had probably 10 or a dozen broad bodied chaser dragonflies emerge from the pond so far.

Here’s a quick snap of one from a couple of days ago, shortly after emergence before the wings had hardened.

Large red damselflies are around most days too, at least when its sunny,  so there should be a good crop of larvae later in the summer.

A quick snap (which is another way of saying it's out of focus!)

I was wrong

Remember these eggs?

I said they were the eggs of alderflies – but they’re not (as any alderfly expert could probably have told you).

Actually they’re almost certainly the eggs of the hoverfly Helophilus pendulus – there’s a brilliant picture here – which is a regular around the pond.

They turn into the babies of the animal with just about the least attractive name in the animal kingdom – what we popularly call rat-tailed maggots.

If ever an animal needed brand makeover, it’s this one.

And it’s why Alisdair had the eggs but not the alderflies (see the comments).

Froggiemergency

Emergency lawnmowing (mind you, is there any other kind?)

I’m never one to choose a gardening job before some other (unless it’s to do with the pond).

So last night’s lawn mowing had nothing to do with keeping up appearances and everything to do with an impending frog emergency.

The reason – baby frogs are imminent.

Katy and I found at least 3 fully formed baby frogs yesterday; so-called ‘metamorphs’ – because they have metamorphosed from their aquatic form to begin their land-based lives.

They are of course utterly cute – but more seriously last year we had a real panic at emergence time when the baby frogs came out and headed for the long grass – which meant the whole of the lawn!

Because once they were out there, and lurking in that long grass (their favoured spot) that was the end of lawn mowing, unless we wanted a large supply of frog mince.

And the other thing I will be much more careful of this year is any buckets of water: young frogs are very good at climbing into buckets of water but they are very bad at climbing out again.

Last year quite a few drowned in our experimental buckets. This year I will make sure I keep them out.