Tag Archives: ponds

Pond plants

The most obvious thing people think about in relation to pond plants is usually the flowers – water lilies reflected in the water, stately bullrushes or yellow irises growing along the bank. But there’s much more to plants than meets the eye. From the point of view of the creatures which depend on ponds there’s a whole network of plants, above and below the surface, which are of vital importance to them for food and shelter.

These plants can be split roughly into four groups depending on the part of the pond in which they grow: those which are submerged; those with floating-leaves; those emerging from shallow water; and those on the margins. A balance between all these types ensures a healthy pond with plenty of wildlife.

Submerged plants +

Submerged plants are adapted to grow entirely below the surface, some of them not even rooted. They maintain oxygen levels in the water and provide shelter for invertebrates in the deeper parts of the pond. Examples are the native hornworts, which actually flower under water; water-milfoils, and water crowfoot, which has delicate white flowers on the surface of the water.

One particularly unusual and uncommon submerged plant is Bladderwort which occurs in a few sites in Herefordshire. It is carnivorous, bearing small bladders which suck in & trap small creatures. Attractive yellow flowers appear above the surface.

Plants with floating-leaves +

Plants with floating-leaves are rooted in the mud at the bottom of the pond but their broad leaves cover the water surface, cutting out light and so reducing the growth of algae. The leaves also provide cover for invertebrates and amphibians. Lift a lily leaf in early summer and you’re likely to find a newt sheltering beneath. Common plants in this group are broadleaved pondweed, amphibious bistort and of course, water-lilies, the native ones being the vigorous White water-lily and the globe shaped Yellow water-lily.

There are also a few free floating plants in this group like Frogbit (see image on left) which has small lily-shaped leaves and white flowers; and the duckweeds which can completely cover the surface of nutrient rich ponds.

Emergent plants +

Emergent plants have their roots in water and can grow out into the pond, sometimes completely taking over shallow ponds. Tall emergents like Branched Bur-reed and Reedmace (often called bulrush) are particularly invasive, but provide protection for nesting moorhens and places for dragonfly nymphs to emerge from the water. On windy days numerous damselflies can be found taking shelter among the tall stems.

Marginal plants +

Marginal plants grow in the marshy areas around the pond and out into the water. Many pond animals live in dense vegetation in very shallow water, often only a few centimetres deep, so the low growing plants, rushes and grasses around the edges of the pond forming a tangled network of stems and roots are very important for wildlife. Great Crested Newts lay their eggs on flat leaves like Water Forget-me-not, Water Parsnip or Flote Grass. The mauve flowers of Water Mint attract bees and butterflies.

Continuing outwards from the margins of the pond are plants of damp ground and marshy areas. Here there are many with colourful flowers, like Marsh Marigold, Ragged Robin (see image on left), Purple Loosestrife (image at head of page), and Hemp Agrimony, whose large flat pinkish flowers are irresistible to bees and butterflies.

Problem plants +

As well as these native plants which have adapted to life in British ponds over thousands of years, there are a number of vigorous introduced species which have escaped into the countryside from garden ponds and aquaria and now pose a serious threat to our plants and wildlife. Many form dense mats of vegetation which smother native plants, deplete oxygen levels in the water and create a poor environment for amphibians, fish and invertebrates.

Those which particularly need to be watched out for are:

  • New Zealand Pigmyweed (Crassula helmsii or Tillaea recurva as it’s sometimes known).
  • Parrot’s Feather
  • Water Fern
  • American Pennywort

For more information on these plants click here.

Plants for wildlife +

A balance between the types of plant listed creates a habitat which will attract wildlife, but some plants are particularly important for certain species.

Great Crested Newts choose plants with flat leaves to lay their eggs, particularly Flote Grass and Water Forget-me-not, whereas Smooth and Palmate Newts prefer small leaves of submerged weeds.

▸ Follow the link for more information about pond creation and management.

Dragonflies need plenty of submerged plants for their developing larvae, while their emerging larvae need tall emergent plants, which also provide sheltered places for perching and roosting. A variety of plants is also required for egg laying, some dragonflies and damselflies laying their eggs into the stems of marginal vegetation, others into floating or submerged plants. Red-eyed damselflies spend long periods perched on the leaves of water-lilies.

▸ Follow the link for more information about dragonflies and damselflies.

Moorhens and coots build their nests within the protection of tall rushes and reeds, which also shelter the chicks from predators like foxes.

There are even moths, the Chinamark moths, whose caterpillars live under water, feeding on pondweeds and duckweeds.

So it is the variety and balance of plant species which is so important.

Dragonflies & Damselflies

Herefordshire supports 25 of the 40 or so species of dragonfly recorded in the UK. There are 5 species which are very rare and 10 which are very common within the county. Some species lives by running water and other besides ponds. Features of good dragonfly habitat include unpolluted water, sun, shelter, emergent and floating vegetation and muddy edges.

The following species account was prepared by Mike Williams of the Farming & Wildlife Advisory Group following a talk by Peter Garner, former dragonfly recorder for the county.

 

Dragonfly Species found in Herefordshire

Broad-Bodied Chaser

 

Flies from mid-May onwards. Very common in all types of ponds, even very small ones. Male gunmetal blue, female yellow/bronze.

Four-Spotted Chaser

Can be confused with female Broad-Bodied Chaser but it is smaller. Four spots on wings. Only seen on 12 ponds in Herefordshire and only known to breed on 3.

Club-Tailed Dragonfly

Breeds by large rivers, never in ponds. Only found on about 12 rivers in the UK, the Wye, Severn and Avon are its stronghold. It has also been recorded on the Lower Teme and the River Lugg near Hereford. It is common on the Wye south of Hereford. Flies May – June. Sits on vegetation and easy to see when vegetation is disturbed. After emergence commonly disperses several miles from the river.

Emperor Dragonfly

 

The largest dragonfly in the UK. Common on big garden ponds, it is blue with a black line down its back. Patrols a pond incessantly, flying 1 to 1½ metres above the water. Found in about 60% of all ponds. Climate change has led it to spread its range to include Herefordshire in recent years.

Black-Tailed Skimmer

 

Flies 5cm above the water. Needs a pond with a bare bank, gravel pits or mud at the edge of the pond. Recent colonist. Male/female coloured similarly to the Broad-Bodied Chaser.

Golden-Ringed Dragonfly

Common in Cornwall and Pembrokeshire. Likes stony streams. Only common in Herefordshire in the Olchon Valley, also occasionally seen in Brilley and Cusop, and near the Forest of Dean.

Southern Hawker

 

Flies from late July to October. Uses ponds as small as a metre across. Patrols less than an Emperor and does not have the black line of the Emperor down its back. Emperors are gone by the end of August. Wanders away from ponds more than the Emperor. Curious of humans, will come up to you and hover, then fly off. It may repeat this behaviour. Clear end blue segments on the tail are the defining feature of the male. It has a perch that it returns to regularly to eat its food.

Migrant Hawker

Flies from mid-August onwards. There are about 25 known breeding sites in Herefordshire. Until recently it was only a migrant in the county. Almost a centimetre shorter than the Southern Hawker and more than a centimetre shorter than the Emperor, and with more black on it. The tail is not pure blue.

Common Hawker

Very rare in Herefordshire. Found only on 2 sites. Probably breeding near High Vinnals. Similar in size to the Southern Hawker.

Brown Hawker

Cannot be confused with any other species. Only found in the east of Herefordshire, particularly around Upper Sapey, Mathon and Whitboume. Large and brown, brown wings, it is slightly smaller than the Emperor.

Common Darter

Flies from the end of July onwards. Commonest dragonfly in the county. It is possible to see 100 at once on a good-sized pond.

Ruddy Darter

First seen in Herefordshire in 1987. It is different from the Common Darter, being a brighter red and having black legs.

Banded Agrion

Found commonly in good numbers on slower flowing rivers, e.g. the Arrow below Pembridge, the lower Lugg and the Wye.

Beautiful Demoiselle

Found on faster flowing rivers and small streams, e.g. the Arrow above Pembridge. The wings of the male appear brown or blue depending on which way the light falls on them.

Large Red Damselfly

First damselfly to appear, usually in late April early May. Hides in vegetation, especially nettles, Appears in smaller numbers than the blue damselflies.

Emerald Damselfly

Very common in west Herefordshire, rarer in the east of the county. It is not very conspicuous and the male has a blue tail. The female hides like a stalk in vegetation near the river.

White-Legged Damselfly

Found by rivers including the Wye, Lugg, Arrow and Monnow, Can be very common beside the Wye, which is one of the best sites in the UK. Has very blue eyes.

Blue-Tailed Damselfly

Will tolerate mildly polluted ponds, Thorax varies greatly in colour between blue, pink, bronze and violet, but all have a blue tail on the penultimate segment of an otherwise black abdomen.

Scarce Blue-Tailed Damselfly

A nationally rare species, its only site in Herefordshire is a gravel pit. It is Britain’s smallest damselfly. Needs shallow water that does not freeze. Less blue on the end of the tail, marking it as different from the blue-tailed damsel fly.

Red-eyed Damselfly

About 10 ponds host this blue damselfly with conspicuously red eyes – likes floating vegetation to bask on especially water-lilies.

Azure Damselfly

Very common and many found in most ponds. Very similar to the Common Blue Damselfly.

Common Blue Damselfly

Very common and many found in most ponds. Very similar to the Azure Damselfly.

 

Further Reading:

  • The Dragonflies of Herefordshire” by Peter Garner. View on Amazon.
  • An excellent book for dragonfly identification is “The Field Guide to the Dragonflies and Damselflies of Great Britain and Ireland” by Brooks and Lewington. View on Amazon.

Pond creatures

Ponds support an incredible diversity of animal life. Some, like the microscopic protozoa and tiny water fleas, freshwater shrimps, fish and snails, spend their whole lives in the water. Others, including of course frogs, toads and newts, numerous bugs and beetles and the spectacular dragonflies, come to ponds to breed and are dependent on water for the early part of their lives. Even a few moths have caterpillars which live under water. As well as these which depend on ponds, many birds, mammals, insects and the grass snake come to find food and water. All these creatures, together with the plants, make up an interdependent community which has had millions of years to adapt to ponds.

Here are just a few samples from the great variety of pond animals.

 

At the bottom of the food chain:

Water fleas up to 1.5mm long, swim freely in the water and are very common. They have a transparent shell covering thorax and abdomen through which the heart can be seen beating. Most species feed on minute plant life, and form a very important source of food for many predators.

Freshwater shrimps  are an important source of food and are often found in shallow water among plants and under stones where they feed on decomposing animals and plants.

 

Some of the larger creatures:

 

Pond skater

Pond skaters skim across the surface feeding on insects which have fallen into the water. They are some of the first colonisers of new ponds.

 

 

 

 

Backswimmer

Backswimmers are often seen swimming upside down as they hunt just below the water surface, propelling themselves along with their powerful back legs. Their piercing mouthparts can inflict a painful bite. See drawing on right (courtesy of English Nature).

 

Whirligig beetles are the small beetles frequently seen swimming in rapid circles on the surface of ponds. Their eyes are in two parts so that they can see both above and below the surface.

Diving beetles are carnivorous and swim swiftly through the water hunting for food. They have strong wings and can fly from pond to pond, usually at night. Most can live for several years and lay eggs every year, which develop into larvae which are voracious predators. The larvae inject poison into their prey which partially dissolves the internal organs.

Dragonflies and damselflies are brilliantly coloured and incredibly skilful fliers. They are one of the oldest orders of life, their ancestors having been around 300 million years ago, long before the dinosaurs emerged. Eggs are laid among pond plants where they develop into nymphs which live under water hunting for small insects and tadpoles. After one or two years the nymphs crawl out of the water, split their skin and emerge as adults.

Moorhens frequently nest on even the smallest of ponds, building a nest amongst marginal vegetation.

 

 

Some useful aids for identification:

  • Small Freshwater Creatures, Lars-Henrik Olsen, Jakob Sunesen, Bente Vita Pederson. Oxford Natural History Pocket Guides 2001 ISBN 0 1985079 8 4  www.oup.com
  • A Field Guide to the Dragonflies and Damselflies of Great Britain & Ireland, Steve Brooks, Richard Lewington. British Wildlife Publishing, 2002, ISBN 0 9531399 0 5
  • Fold-out charts published by the Field Studies Council  www.field-studies-council.org, include Reptiles and Amphibians of Britain and Ireland, The Freshwater Name Trail, Commoner Water Plants, Dragonflies and Damselflies of Britain, and are on sale at HART meetings.

Ponds in Herefordshire

Ponds within the County of Herefordshire are many and varied. This article by Will Watson explores their origins, formation and history.

Herefordshire’s Ponds

Most of the county’s undulating landscape is on the Lower Devonian Sandstone. The central plain is on the Raglan Mudstone Formation consisting of mudstones with smaller amounts of sandstone and limestone. The weathered rock breaks down into sandy silts shales and clay. Clay tends to concentrate in the river valleys and lower ground and this maybe augmented by alluvium clays on the river floodplains. The lower-lying parishes in the county support higher densities of ponds because clay is more predominant and the water table is higher. For example Pembridge, Letton and Madley have relatively large numbers of ponds, reaching in access of 5 ponds per Kilometre Square. Such ponds are typically between 100 to 2500 metres in area. Most of the smaller ponds were dug for the watering of stock and/or horses. In some areas ponds were formed after the digging of pits for clay which was used for daub, cooking pots, tiles and latterly for brick making. The smaller ponds which periodically dry up provide good habitat for amphibians; particularly for newts. Other ponds have been constructed around farmsteads as duck/fish pools and or cart ponds/horse ponds. Where the ponds were located close to the buildings they would serve in emergencies as fire ponds.

The St. Maughans Formation is located on the higher ground in the northeast and south of the county; these formations also comprise of sandstones, mudstones and calcretes but have a greater concentration of the harder sandstones. The ponds on the higher, steeper ground are often of larger construction because water may only hold once the water table is reached requiring more extensive excavation. For example on the freer draining ground on Bromyard Plateau in Hatfield, Grendon Bishop and Bredenbury the majority of ponds are between 2500 to 5000 metres in area, many are stream of spring-fed and typically support fish and are hence of limited value for newts. The average pond density on this formation is between 1 and 1.5 ponds per square kilometre – less than the English average of 1.7 ponds per square kilometre. Despite the fact that there are low numbers of ponds many of the semi-permanent ponds over sandstone support all three species of newt.

Hard Silurian Limestone is to be found in several parts of the county. The three largest areas for this stratum are the northwest Herefordshire Hills, the Woolhope Dome and the west flank of the Malvern Hills. These landscapes typically have low pond densities.

On the river terraces beside the River Wye kettle holes were formed after the last glaciation. As the ice retreated the hollows were filled with water creating a series of natural lakes and pools. Many still exist to the south of Wye between Hay and Hereford, although often modified by ‘restoration’. The Lawn Pool at Moccas Park is one of the best known of these natural landscape features. Natural ponds and pools are particularly special because, apart from supporting rare or unusual freshwater life, they contain uninterrupted sequences of sediment with preserved pollen and wood deposits which can inform us about past climatic conditions and vegetation communities. They are also nationally scarce; it has been estimated that only 2% of ponds are of natural origin.

The county also has its fair share of moats with 120 confirmed sites. These were usually constructed for ornament rather than defensive purposes. Lower Brockhampton, near Bromyard is one of the finest examples of a moated medieval manor house in England. However, the moat at Bronsil Castle (privately owned) is clearly a defensive feature (see photo above). Herefordshire is also renowned for its large country estates. Medieval moats, such as the one at the Court of Noke were transformed into water features in the 17th century. The great period of the country house was in the 18th and 19th centuries. On many of the larger estates at this period many ornamental lakes and pools were constructed. For example at Croft Castle (National Trust) a series of fish pools were constructed in what is now known as Fishpool Valley (SSSI), at Berrington Hall (National Trust), a pool with an island fed by a tributary of the River Lugg was created by Capability Brown and at Eastnor Castle (a private visitor attraction) a lake was constructed as backdrop to the castle in the 19th Century. (See photo below)

In the mid 20th Century we began to lose ponds in Herefordshire. Some were filled in as pasture was converted into arable and others were destroyed because ponds no longer had an economic function within the modern farm landscape or were lost simply through neglect. It has been estimated that there was an overall loss of 30% of ponds within the county from the 1920s to the 1980s (A Survey of Herefordshire Ponds and their value for Wildlife 1987 – 1991). Most of these losses occurred in the fertile arable farmland of the central plain and mainly the smaller field ponds were affected.

In the latter half of the 20th Century new fishing pools were constructed across the county for both commercial and private amenity use. Many of these sites support good breeding common frog and common toad populations, but they have very limited value for newts. At the beginning of 21st century HART along with other organisations such as FWAG (the Farming and Wildlife Advisory Group) are seeking to redress the balance by encouraging the restoration and creation of small ponds in the countryside through the Herefordshire Ponds and Newts Project.