Thursday 21 May 2009

Fancy A Spot Of Pond-Dipping?

In the months of April and May, the Barleycorn ponds are awash with golden cups of sunshine of the caltha palustris plant, more commonly known as marsh marigolds. In churches in medieval times, they were given in tribute to the Virgin Mary at Easter and were called Mary Gold. I grow them because they remind me of happy childhood days when my brother and I would take our nets and go pond-dipping and I would gather a little bunch of sunshine to take home to my Mum.
Although the lily flowers are not yet in bloom, I find the beautiful shapes and hues of the leaves so attractive. Covering roughly a third of each pond, they help to keep out the light which enables algae to grow. They also provide hiding places for the many creatures which live in the ponds.

Unlike their garden cousins which will devour fresh young shoots, the lymnaea stagnalis or great pond snails mostly tend to live on decaying plants, algae and debris in the pond, which makes them very useful. The two in this photo are foraging on the roots of a ranunculus plant which has come adrift from its mooring in the soil. They are greyish-brown in colour and around 60mm in length.

I find them fascinating to watch as they come part-way out of their shells to feed and often float upside down on the surface of the water as they go about their business acting as pond dustmen clearing up the rubbish and keeping everything clean and healthy. Because they absorb oxygen through their skin, they can live underwater for several months. I feel glad when I find a long string of their eggs under the leaves of aquatic plants because it is proof that they are thriving. In Winter they hibernate in the mud at the bottom of the ponds.

This tiny creature is a ramshorn snail and belongs to the family Planorbidae. There are many of these little snails in the ponds. Their shells are coiled into flat spiral discs. They are also vegetarian and graze on algae covering the plants, as this photo shows. They tend to grow to 18mm. What amazes me is the fact that all the creatures found their own way into the ponds.

If you are interested in looking at the creatures in more detail, click on each photo to get up close and personal. This photo shows the larva of the great diving beetle. They are voracious carnivores, feeding mainly on tadpoles and other insects - including their own brothers and sisters - which they grab with their pincer jaws. They look like scorpions as they keep their tails upright while swimming. They push their tails up out of the water to take in oxygen through an air hole in their tails.

This photo shows a pair of dytiscus marginalis, great diving beetles, at the breeding time in April. As it was a cloudy day, the water looks dark and murky. They are the adults of the larva in the previous photo. They actually pupate on land and then return to the water, though I have often had a fright when I have seen them flying as they look a bit like cockroaches.

The water boatman is hilarious to watch as it swims along upside down carrying a bubble of air on its abdomen. It has two pairs of legs- a short front pair, and a strong hind pair - which it paddles like oars. They grow to around 20mm in length. I would need an underwater camera to show you his large red eyes. They live on tadpoles and insects, and can eat fish too, though we have none in our ponds. The adults can fly and move between ponds.

Here we have a pair of Gerris lacustris, pond skaters. They are mating while resting on a lily pad. Normally, they are seen skating across the surface of the ponds. They are around 20mm long and move very quickly. If their bodies and legs did not have velvety hairs, they would sink through the water. Their diet consists of insects. I often see them jumping to avoid being eaten by predators.

At this time of year there are often wasps taking in water from the surface of the ponds. They are fetching water to cool and fan their nests. Birds, of course, use the ponds for drinking and bathing and often come in little groups. In fact, there is year-round activity of one kind or another at our watering-holes from visiting wildlife.

Over the years we have seen a huge increase in newt population in our ponds. The male in the photo is curled inside a red lily leaf. You might want to enlarge the picture to see him more clearly.

Spring is the best time to see them in the water as they live most of their life on land. Triturus vulgaris is the scientific name for the smooth or common newt. When they come to the surface to breathe, there is a little popping sound as they gulp air.

Depending on the sunshine and shade, the newts can appear to be black in colour. However they are actually pale brown or olive green. Both the males and females have orange bellies covered in black spots, though the females' are paler orange.

If you can get close enough to see, the males have fringed toes, which helps to distinguish them from the females. The males also have long wavy, rather than crested, backs and tails. They have tiny teeth to catch tadpoles and insects.

They breed in the ponds in Spring and are able to feast on frog tadpoles. They can lay around 400 eggs on the leaves of the waterplants. It takes around 10 weeks for their young to emerge as juveniles.

Adult newts can shed their skin once a week. Athough I have never seen any lying around, I have frequently seen casings of dragonflies. In late July they return to the land and become mainly nocturnal.

The frogs spawned one week earlier this year than in the previous three years. In spite of that, we had lots of frost and the ponds were partially frozen many days. As a result, the tadpoles hatched at the usual time.

When the sun's rays managed to penetrate the jelly, we noticed slight movement from some of the tadpoles, whereas the tadpoles in the frozen parts of the pond seemed in suspended animation.

It was interesting to watch different batches hatch and mature at different times. At first the jelly looked clear. As time went on it became green. I was fascinated seeing tails twitching, watching gills appear and finally legs.

At one point we had a writhing mass of taddies with gills, eyes and long tails, while, at the same time, there were also later batches still inside the spawn. Around this time I watched and waited for the newts to appear.

Sure enough I was not disappointed. Although the water was a dark green murky colour at this stage, you can still pick out the long, dark shape of the newt across the top of the photo. At this stage the tadpoles were coming up for air and leaving lots of bubbles on the surface of the pond.

The newt down the middle of this photo is extremely well camouflaged. There was still a loose jelly around the tadpoles at this stage and the newts would come swishing up from underneath the mass and grab some lunch.

Over the years I have been scattering forget-me-not seeds under the weeping birch tree outside our back door. Though there are so many pictures I could have shown you of how our garden looks at the moment - as opposed to what is happening in our ponds - choosing these little flowers over grander specimens was easy, for they have a simple beauty of their own and very much typify the Spring in our garden at Barleycorn.
The footage in the little video below was taken from the 3rd to the 12th April. There are six little videos joined together to show you the progress of the tadpoles. There is a little footage of newts amongst them towards the end of the video. Now that the tadpoles are swimming freely across the pond, it is difficult to catch sight of them.

Caltha Palustris, Marsh marigolds
Pond lilies
Lymnaea Stagnalis, Great Pond Snails
Planorbidae, Ramshorn Snail
Dytiscus Marginalis, Great Diving Beetle
Larva of Great Diving Beetle
Notonecta Glauca, Water Boatman
Gerris Lacustris, Pond skater
Vespula Vulgaris, Common Wasp
Triturus Vulgaris, Common Newt
Myosotis, Forget-me-nots