Category Archives: advice

Adders

Adder sightings in HerefordshireThe Adder is Britain’s only venomous snake. It is a small squat species, fairly heavily bodied with a short tail and a well-defined triangular head, the female approx 55cm long and the male 50cm. One of the largest adders recorded in Herefordshire was 72cm, discovered by Dr Leighton in 1900.

The adder always has a ‘V’ or ‘X’ shaped mark behind the head and zigzag patterning down the back. Colouring varies between the sexes, the males having a pronounced black zigzag with a white or pale background coloration. Females are normally red/brown or darker with a brown background colour. This makes them very hard to see in a bank of dead bracken. The young, 15 – 20cm at birth, are generally reddish brown with a yellow tail tip. The eyes of the adder are red or coppery red with a cat-like vertical pupil. The reason for this vertical pupil is unclear as they are a typically diurnal species.

Very occasionally dark or melanistic adders, the ‘black adder’, occur locally in many parts of Britain, but are seen more in colder, mountainous areas of their distribution, especially closer to the Arctic Circle. Obviously a dark body colour will absorb more heat.

Range and distribution +

The Adder is absent from Ireland but present in most of Europe as far as 69’ N in Scandinavia, parts of France, Germany, northern Switzerland, Austria, across Russia and through Asia to northern China. This is the most northerly ranging snake species in the world.

Its ability to hibernate for up to 5 months of the year and its dark melanistic coloration enable it to survive the short warm season in the very north of its range. Giving birth to live young only every 2 – 3 years is another useful adaptation. In Britain the adder is sparsely distributed throughout England, Wales and Scotland. Population numbers in the midlands are especially sparse due to high urbanization and fragmentation of suitable habitat.

Heath land, moors, chalk down land, coastal dunes, rough commons with plenty of scrub, brambles, gorse and bracken are typical habitat. Most habitats are situated on a sloping gradient with a south or south-easterly aspect. On flat heath land or ancient meadowland large grassy tussocks or anthills make good sunning spots for the adders.

The Adder Year +

Males emerge first from hibernation at the end of February or beginning of March, depending on the weather conditions. They shed (or slough) their skins in mid April and disperse toward the breeding areas and favoured basking sites, ready for the arrival of the females a few weeks later.

This is the best time to observe adders as their patterning and coloration is at its peak after this first skin slough. In March/April, the males begin the ‘Dance of the adder’ where the males perform spectacular mating combat rituals. The males entwine and twist against each other with the front of their body and try to wrestle each other to the ground. The larger snake is normally the victor and goes on to mate with the female who has remained in attendance.

Female adders appear to have a particular smell around this time, perhaps a pheromone, which the males can detect. Mating can last up to 2 hours with the male being dragged through the vegetation backwards. After mating is over the male will stay near the female for several days before departing to summer haunts. These are usually a damper site than the winter one and here they will feed.

Adders give birth to between 3 and 10 live young. Having young tends to put great stress upon a female. Good prey years could result in more frequent births. This has only been proved in captive animals so far, but in theory this could happen in the wild. Females do not become sexually mature until 4 or 5 years of age and can live to over 10.

Population densities in the wild are about 1 to 12 individuals per hectare, and occasionally higher in some of the good southern heath lands. Male adders will travel 0.5 – 2 km from hibernacula sites to breed and to reach summer quarters.  So plenty of habitat is essential to this species.

The adder year ends with a return to the hibernation site ready to emerge again in late February/March the following year.

Prey +

Adults’ prey will mainly be voles, mice, frogs, newts and lizards including slow worms. The prey is dispatched with a venomous bite, taking less than a minute to kill a lizard. The injected venom starts to digest the prey from the inside, speeding up the time when the snake may be vulnerable to attack. Adders 25cm in length are capable of swallowing a fully grown common lizard. The adder will eat between 6 and 9 vole sized meals within a year. Good vole years will mean a good adder year.

Young adders tend not to feed until their second year as straight after birth in September they go into hibernation. They feed on small lizards and mice pups.  Captive young snakes have shown no reaction to insects, but have fed on lizards and vole viscera.

Adder bites +

Belonging to the subfamily viperinae, a family ranging from Europe, Asia & Africa and closely related to the rattle snakes subfamily crotalinae, from the USA. The adder possesses 2 sophisticated fangs up to 7mm in length which, when the snake strikes, hinge forward, each fang having a venom gland supplying venom to the hypodermic fang. This is embedded into the victim and venom pumped in. The venom is cytotoxic, attacking the blood system and eventually the heart.

Adders very rarely bite humans. If they do it is in defence, possibly as they are frightened of being trodden on or roughly treated. Most bites are to young males picking up adders in a show of bravado. The chances of being killed by an adder bite are very rare. There is a greater chance of being killed by a wasp or bee sting, stray dog or in a horse riding accident. Statistically one person in a decade of bites in Britain has died, and with nearly one hundred bites per year fatality must be one in a thousand bites. 70% of bites are dry bites, all bluff no venom injected. Deaths of pets or domestic animals from adders are also rare.

Adders in Folklore +

Adders are surrounded in superstition even today in the 21st century. One tale I still regularly come across from countrymen who have spent their lives amongst adders is that female adders swallow their young to protect them from danger. I have also seen this in old natural history books. This most likely originated when a gravid female adder was killed with well developed young inside her. If she did attempt to swallow her own young the strong stomach acids would digest them.

Snakes do not hypnotize their intended prey. This story was even related in Rudyard Kipling’s The Jungle Book. Snakes do appear to stare, as they have no eyelids, meaning they even have to sleep with their eyes open.

Adders will not die till sunset if mortally wounded. More fantasy – they will take time to die if wounded, but won’t wait till sunset.

Adders and Game Birds +

Gamekeepers have informed me that if an adder comes across a clutch of pheasant eggs it will eat the whole clutch. While they may occasionally take the odd ground nesting bird I have never heard of or seen an adder take eggs. The biggest threat to egg clutches is from rats, hedgehogs, corvids and foxes.

Adders live mainly on rodents and lizards with also the occasional amphibian. In reality game birds do more damage to them. In the late summer they constitute a lot of reptile mortality, feeding on lizards and small snakes. The large numbers released must have an impact on the ecosystem. Anyone who keeps chicken will know how in a coop they clear the ground of vegetation and insects leaving bare earth.  More game birds appear to die on the roads than go to predators anyway.

Conclusion +

The adder has survived in our country for hundreds of years and should remain for the future. Human persecution and habitat loss are its main threats. Folklore and superstition even today have helped instil a hatred for this shy and retiring reptile, which many people have never even seen. It has a fascinating natural history and is essential to the balance of our ecosystem.

Watch Springwatch on BBC Midlands Today +

References +
  1. British Snakes, Leonard G Appleby, 1975
  2. Collins Field Guide Reptiles and Amphibians of Britain and Europe, E.N. Arnold & Denys Ovenden, 2002
  3. Snakes & Lizards, Tom Langton, 1989
  4. Amphibians & Reptiles, Trevor Beebee & Richard Griffiths, 2000
  5. Habitat Management and conservation of the adder in Britain, Chris Wild & Carole Entwhistle, British Wildlife Volume 8 No. 5, June 1997

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.

Invertebrates in Herefordshire ponds

Apart from dragonflies, in general Herefordshire’s ponds have been poorly studied for invertebrates. For example to date only 156 species of water beetles have been found within Herefordshire (of which about 120 are associated with still water habitats) a relatively low number in comparison with the 250 species of water beetle recorded within Britain and Ireland.

The exception to this rule is Moccas Park National Nature Reserve with its associated water bodies where remarkably over 100 species of water beetles have been recorded over a 30 year period. Notable examples include Graphoderus cinereus which is listed as Red Data Book 3. The Lawn Pool at Moccas Park also supports the nationally scarce Medicinal Leech (Hirudo medicinalis) which is specially protected under the Wildlife & Countryside Act and also listed as Red Data Book 3.

At the Herefordshire Wildlife Trust Sturts reserve at Letton in the Wye Valley, the Mud Snail (Lymaena glabra) a Red Data Book 2 species was recorded in April 2003. It was found within the ditches and shallow ponds and typically was found in associated with the local Moss Bladder Snail (Aplexa hypnorum) and the Button Ram’s-horn (Anisus leucostoma). The latter species is known from 2 other sites within the county.

There are few records for aquatic bugs within Herefordshire, however, it has been interesting to observe how many ponds support all 3 species of the commoner backswimmers: the Common Backswimmer (Notonecta glauca), the Spotted Backswimmer (Notonecta maculate) and the Black Backswimmer (Notonecta obliqua). The latter species is generally found in upland habitats, but turns up frequently in ponds on the Devonian Sandstone.

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.

Pond creation & management

Creating and Managing Ponds for Amphibians

by Will Watson (November 2003)

There is a direct correlation between the decline in amphibian populations with pond loss and habitat deterioration in Herefordshire as elsewhere in the UK. Smooth, palmate and great crested newts have all declined in the countryside. However, the growth in the popularity of garden ponds and demand for fishing pools has helped to compensate for these deficiencies, allowing for a small increase in the frog population, whilst smooth newt numbers have remained at a stable level.

This guide outlines the methods by which both keen amateur and professional managers of the countryside can help to increase local amphibian populations by creating new ponds and modifying and maintaining existing ponds and their associated habitats. The methods are mainly directed towards encouraging amphibians. However they are also complementary towards other aquatic flora and fauna.

POND DESIGN +

Pond shape and dimensions

An amphibian pond should have the following basic characteristics.

  • They should have shallow sloping sides for the growth of marginal vegetation. Preferably at least two different depths of shelving should be created to cater for the varying requirements of emergent aquatic vegetation and to allow for variations in rainfall patterns (see photo above).
  • There should be a deeper area in the centre of the pond which will retain water during periods of drought. The ideal depth for an amphibian pond is about 2 metres. However, a pond depth of a metre may be sufficient to retain water throughout an average year. If you want to create a smaller shallower pond, bear in mind that evaporation will occur more rapidly. If a pond dries up in the breeding season any remaining tadpoles that have failed to develop into metamorphs will die. You can compensate for this by filling up the pond with tap water or by providing some form of regular inflow. There is no great benefit in constructing very deep ponds because amphibians, with the exception of our common toad Bufo bufo, tend to confine themselves to the vegetated margins.
  • Studies have revealed that the optimum breeding site size for palmate and smooth newts is 100 m2, great crested newt frequently thrive in ponds between 250 m2 and 400 m2 but may found in larger ponds.

You must decide on what size the pond should be, whether the pond should be lined and if so what material should be used. If you can rely upon the natural geology to hold water then that will be the preferable option, both from the cost point of view and for the amphibians. Natural clay is common in many regions of the UK, but make sure you get down to natural levels. Digging a pond by hand is very laborious work and serious consideration should be given to hiring a small mechanical excavator. Always bear in mind your water source and how you are going to conserve water.

Pond restoration

A biological survey should be conducted before you undertake any restoration work to find out what amphibians are present and in what numbers. The survey work should be carried out by a suitably qualified person. HART members can undertake amphibians surveys on your behalf, but they will usually request travel expenses or Additional expenses may be charged when giving advice on pond management or creation.

It may be necessary to modify your management practices according to what is found in your pond. For example, ponds containing the specially protected great crested newt which are silted should have management priority over ponds where no amphibians were recorded. If protected species are present do seek further advice (see Protected Species Advice section below). Restoration work should be carried out in amphibian dormant season although work can commence in summer if the pond is totally dry. It is also important to establish whether any other key aquatic species are present and adapt the management to benefit rare or protected species. It is normally advisable to de-silt half the pond one year and complete the task the following year as this assists natural re-colonization by existing pond flora and fauna. In poorly vegetated ephemeral ponds this practice may not be necessary.

Planning Permission

Ponds excavated for agricultural purposes do not require planning permission. However ponds excavated for other purposes, such as wildlife conservation, may require permission, even if they are to be located on agricultural land. Local planning offices will be able to advice, and should always be contacted prior to pond construction. It may also be necessary to consult planning offices regarding disposal of spoil.

Before undertaking construction or restoration you are advised to consult some of the pond literature. There are some free leaflets and information is also given on how to obtain these publications (see Book List below)..

CREATING THE RIGHT CONDITIONS +

Plants

A healthy zonation of plants in and around a pond is important for amphibians as plants provide the right habitat for invertebrate prey, cater for oviposition and provide the necessary cover for protection and the means to ambush prey. The choice of plants is partly dependent upon the size of the pond.

In the submerged zone you should establish native plants such as hornwort Ceratophyllum demersum, water crowfoot (Ranunculus aquatilis) and water-starwort Callitriche stagnalis. In semi-natural ponds these plants always seem to provide niches for a myriad of invertebrates and should be selected in preference to curly water-weed (Lagarosiphon major) or Canadian pondweed (Elodea canadensis) because these latter species quickly produce dense growths of vegetation that will require frequent thinning out.

On the shallow shelves you should establish plants for oviposition by newts. Newts will select specific species of plants in preference to others; the most popular plants used by great crested newts are float-grass (Glyceria fluitans) and water forget-me-not Myosotis scorpioides. Watercress Nasturium officinale, Water Mint (Mentha aquatica) and great hairy willow-herb Epilobium hirsutum are also commonly selected. In small ponds (less than 10m x 15m) avoid using aggressive colonizers such as reedmace Typha latifolia, reed sweet-grass Glyceria maxima and common reed Phragmites australis, as they are easy to establish but hard to control. If you want create a floral screen to your pond it is recommended that you plant Yellow Flag (Iris pseudacorus) which is less aggressive and also provides welcome colour.

Predation

Fish predation has a great impact upon amphibian populations. Under most circumstances, introduction of fish into a newt pond will eventually lead to the elimination of the newts. It is the newt tadpoles that fall easy victim to fish. The presence of fish imposes a critical limitation on the ability of newts to exploit larger water bodies and restricts newts to smaller water bodies. So, if you want to establish a thriving population of amphibians make sure that there are no fish present! On the other hand, toads are not particularly affected by fish predation because their skin contains distasteful toxins and as a consequence large populations can coexist with fish. Fish management and control is complicated and governed by several laws. For further advice please refer to the Countryside Council for Wales contract services report 476.

Herons feed on amphibians usually in an opportunistic manner, some birds may develop a preference for newt tadpoles; includes those of great crested newts. Ducks directly affect amphibian populations by preying on eggs and tadpoles. They also have an indirect effect; their dabbling uproots plants on which eggs are laid, prevents plant re-growth and disturbs water sediments. On small ponds you would be advised not to encourage ducks; on larger ponds numbers should monitored and, if necessary, regulated. It is possible to discourage herons and ducks by erecting cane and strands of string around the edge of the pond. See the RSPB guide to discouraging herons.

Adult great crested newts frequently prey upon tadpoles and will readily make a meal out of their own tadpoles. Invertebrate predation is also common although it is not normally at the level which would cause a serious decline in a population. Great diving beetles and dragonfly nymphs are the most significant in this respect.

Food Availability

Most aquatic invertebrates are good colonizers of new sites, so if you have created a well-balanced pond with a good range of aquatic flora they’ll find it. It does take time, though, for new ponds to settle. It may take two years or more before invertebrate levels approach a similar density to those in established ponds. However, there are various ways in which invertebrate populations may be encouraged to establish more rapidly. Inoculation of pond silt, containing invertebrate eggs and larvae will help provide the right micro-environmental conditions for invertebrate development. Removal of silt should occur in the dormant season (from September to January). Ideally silt should be taken from an existing amphibian site. Make sure that the pond that you take the silt from does not contain fish. Even if you ensure no adult fish are present you may inadvertently be introducing fish eggs. Dragonfly nymphs over-winter in silty mud, if they are known to be present in the donor pond extra care will have to be taken as odonata populations can be damaged during this type of operation.

After hatching newt tadpoles are thought to feed on protozoa (single celled animals) whilst frog and toad tadpoles in their early stages of development show a greater preference for algae. Daphnia and Cyclops are important dietary constituents for tadpoles of all species in their mid-stages of development. Adult frogs and toads are relatively catholic in their diet. All three species of newt show similar dietary requirements with certain populations developing preferences for selected invertebrate prey. The following invertebrates regularly fall victim to newts; water snail, water hoglouse, and various aquatic fly larvae; blood worm and the like.

Whilst on land newts forage for worms, slugs, snails and other invertebrates. Smooth and palmate newt will take relative small prey items whilst great crested newts will tackle larger items. Many of the larger invertebrate prey items can be specifically selected for translocation. Water snails are easy to establish in new ponds and will not only benefit newts as a food source but also keep the water in good conditions by removing surface algae and unwanted plant remains.

Hibernation sites

Most species of amphibian spend the majority of their lives on land. This is certainly the case with our native amphibians. However the palmate newt is more aquatic, and may spend much of the spring and summer in water. In the case of the great crested newt its dormancy may start from June and last until March; strictly speaking they aestivate from June to October. All amphibians in the United Kingdom hibernate during the winter. They normally seek frost-free conditions. Ease of access to suitable conditions is an important factor. Newts are known to select holes by the bases of live and dead trees, light loamy soil, and rubble and rocks with plenty of voids . It is also normal for newts to move around within hibernacula in response to changes in temperature. The lack of availability of adequate hibernacula may restrict the expansion of amphibian populations. On sites which have poor terrestrial habitat structure, it is therefore well worth providing artificial hibernacula. The specifications below have been devised to replicate these semi-natural conditions.

Hibernacula specifications

Sunken hibernacula are more likely to protect newts from frost penetration. Ideally you should aim to contract a trench about 40cm in depth by 1 metre wide; the length depends on the size of your pond. It is recommended that the hibernacula are situated parallel to the pond to intercept amphibians when leaving the water. (In particularly boggy conditions with a high water table it will be necessary to construct a raised hibernacula).

The hibernacula trench should be filled with 10 sheets of correx fluted board (plastic estate agent board) approximately 0.75m². Old slates or large tiles of similar dimensions could also be used. Pea gravel should be liberally distributed one layer thick, between each of the sheets to provide a consistent depth of 3 to 4mm. Additional infill should consist of loose loam, soil conditioner and sand, whose proportions should vary between the different layers. Stacks of 10 correx sheets 0.75m² can be placed in line. However it is important that a gap is left between the stacks to create the access voids. The gap should be 10cm wide between the correx sheets and also the vertical cut of the excavation. The gaps should be filled with a combination of clean hard-core, wood and soil, which will provide voids to enable the newts to reach the layers. The presence of such layers provides the newts with protection from predators whilst enabling them to move within the hibernacula and locate the right micro-environmental conditions. Finally the hibernacula should be capped with stone. Large stones can be used for maximum visual attraction. A minimum stone diameter of about 100 mm should provide adequate voids for access.

Other Terrestrial Requirements

Frogs and toads regularly forage on land. Newts make periodic sorties on land, foraging for worms and other invertebrates. Great crested newts regularly wander 250 metres away from the water in search of food. Frogs and toads wander considerably further. Ideally a buffer zone should be created around the pond to provide for the amphibians terrestrial requirements. On leaving the water adult newts and emerging metamorphs readily seek out any available flat refuges around the pond as these provide protection and contain prey. You can provide these sites by strategically placing items such as planks of wood, old carpet, brick and rocks around the edge of the pond, for greatest effectiveness they should be placed close to water’s edge where ground level conditions are permanently moist. It may be possible to utilize discarded rubbish scattered for this purpose. Strategically placed wood piles are a useful addition to pond habitat. Wood piles attract many invertebrates and amphibians will readily exploit these situations. They also provide opportunities for amphibians to aestivate. Ideally these should be situated in damp locations but above draw-down zone. Amphibians are prone to getting trampled underfoot around the pond edge. If visitor pressure or human interference is posing problems then it is worth establishing areas of non-intervention. It may be necessary to erect a fence to deter access from sensitive areas. You can also anchor flat refuges such as planks of wood with a metal brace attached to plank and driven into ground, but ensure that there are still gaps underneath. The best terrestrial habitats have been shown to contain some long grass, bushes and shrubs and plenty of damp areas, so aim to maintain the site in an informal method.

Water quality

Great crested newts and smooth newts prefer ponds to be slightly eutrophic (rich in nutrients) and slightly basic. Frogs and toads also show preference for slightly eutrophic water, although the frog is tolerant of a wide range of conditions and, like the palmate newt, are quite at home within oligiotrophic water bodies that are low in nutrients. However, since these conditions support fewer invertebrates population densities are lower. Small amounts of tap water can be used to top up ponds with no adverse effect upon amphibians. Undiluted chlorinated tap water irritates amphibians, therefore it is wise to leave chlorinated water to stand for 24 hours which allows the majority of chlorine to evaporate. Ponds that are regularly disturbed by ducks or other wildfowl or people and dogs will be cloudy with sediment. Such activity will restrict feeding and courtship during daylight hours. As prey items are also disadvantaged by the turbidity it is not normally a serious problem provided water remains opaque. However, if water is constantly very cloudy this will restrict amphibian ability to catch prey, limit courtship behaviour and restrict or eliminate submerged aquatics plants. Ideally ponds should be left settle after disturbance.

Shading & Leaf litter

Shading by trees casts shadows which restricts the growth of aquatic plants. Most aquatic plants require a lot of light and even moderate shading will frequently result in partial elimination of aquatic flora. Leaves contribute to the silting-up of ponds and as they decompose they release substances that are maybe toxic to amphibians. Oak and willow leaves are more detrimental in this respect. You can reduce the effects leaf deposition by systematically removing leaves and silt each winter. On small garden ponds the placement of netting; obtainable from garden centres can be quite effective at catching leaves. Shading has a greater effect on smaller ponds even ponds up to 400 square metres can almost completely be cast in shade. Plants are particularly vulnerable from shading from the south.

On the plus side in large ponds a certain amount of shading can be useful as a means of controlling excessive vegetation and thereby maintaining some areas of open-water for amphibians. On large water bodies surrounding trees act as windbreaks limiting the effects of temperature loss. However, in smaller ponds such shading causes a reduction in temperature due to the lack of sunlight penetration. As a general rule the level of shading around a pond should not be allowed to increase to 50%, anything less than that is fine.

PROTECTED SPECIES ADVICE - AMPHIBIANS & THE LAW +

All UK native amphibians are listed under schedule V of the 1981 Wildlife & Countryside Act. The great crested newt and the natterjack toad Bufo calamita are given greater protection under Section 9 (1) such that it is an offence intentionally kill, injure, catch, possess or handle these species. The smooth newt, palmate newt, frog and common toad are only protected with respect to their sale.

It is necessary to obtain a licence from Natural England if you intend to handle or disturb great crested newts. If you want to carry out management work to an existing great crested newt pond you should refer to the advice given by Natural England on conservation licences for pond management (see link).

For any other guidance about the law please check out the Natural England website or contact the Herefordshire, Warwickshire & Worcestershire Team on 01905 763355.

BOOK LIST and REFERENCES +

  • Anon (1981). The Wildlife & Countryside Act 1981. The Stationery Office.
  • Anon (1992) Dig a Pond for Dragonflies. British Dragonfly Society.
  • Arnold, E.N. & Ovenden, D.W. (2002) Reptiles & Amphibians of Britain & Europe. Collins Field Guide. ISBN 0-00-2199645
  • Arnold, H. R. Atlas of amphibians and reptiles in Britain (1995). ITE research publication no. 10. HMSO Publications ISBN 0 11 70182 4.
  • Bardsley, L (2003), The Wildlife Pond Handbook. New Holland ISBN 1 84330 11 3
  • Beebee, T.J.C. (1985). Frogs and Toads. Whittett Books, Oxford. ISBN 0 905483 38 3
  • Boothby, J. (ed.) (1997). British pond Landscapes. Action for protection and enhancement. Proceedings of the UK conference of the Pond Life Project, Chester, Liverpool John Moores University.
  • Bray, R. & Gent, T. (1997) Opportunities for amphibians and reptiles in the designed landscape. English Nature Science Series No. 30. English Nature. ISBN 1 85716 265 X.
  • Brian, A. & Harding, B. (1996). A Survey of the Herefordshire Ponds and their value for Wildlife 1987-1991. Transactions of the Woolhope Naturalists Club. Vol. XLVIII, Part 3.
  • Brooks, A. Agate, E. (1981) Waterways and Wetlands. British Trust for Conservation Volunteers. Oxford.
  • Drake, M. et al. (1998) Managing ponds for wildlife. English Nature. ISBN 1 85716 25 3. Available free from English Nature at Peterborough
  • Fitter, R. Manuel, R. (1986) Collins Guide to Freshwater Life. Collins. ISBN 0 00 219143 1
  • Gent, A.H., & Gibson, S.D., editors (1998). Herpetofauna workers’ manual. Joint Nature Conservation Committee. Peterborough.
  • Great Crested Newt Species Action Plan Steering Group (1998). Great Crested Newt Biodiversity Action Plan Work Programme (1998-2002) Version 1.1 Froglife, Halesworth.
  • Hilton-Brown, D. & Oldham, R.S. (1991) The Status of the widespread Amphibians and Reptiles in Britain, 1990, and changes during the 1990’s. Nature Conservancy Council. Available from English Nature, Northminster House, Peterborough.
  • Hine, A. (Ed.) (1994). Woodland Pond Management. The Corporation of London. ISBN 0 95016438 0
  • Kabisch, K. & Hemmerling, J. (1984) Ponds and Pools. Croom Helm.
  • Langton, T.E.S., Beckett, C.L., and Foster, J.P. (2001), Great Crested Newt Conservation Handbook. Froglife, Halesworth. Available free from Froglife – but usually given out to great crested newt pond owners or those people recording the species.
  • Olsen, L.H., Sunesen, J. & Pederson, B.V. (2001) Small Freshwater Creatures. Oxford University Press. ISBN 0 19 850798 4
  • Probert, C. (1989) Pearls in the Landscape The Conservation and Management of Ponds. Farming Press. Ipswich. ISBN 0 85236 198 X
  • Sansom, A. (1997). Ponds and Conservation, a guide to pond restoration, creation and management. Environment Agency.
  • Slater, F. (1992) The Common Toad. Shire Natural History. ISBN 0 7478 0161 4
  • Thompson, Bernard & Coldry. (1985) The Pond. Collins
  • Watson, W., Datlen, R., & Hollis D. (2000) Aqua Vitae 21. A Best Practice guide for Pond Restoration. Worcestershire County Council, Countryside Service, Worcester.
  • Watson, W.R.C. (2002). Review of Fish Control Methods for the Great Crested Newt species action plan. CCW contract Science Report 476. On the CCW website as a pdf file
  • Whitehurst, J. Great Crested Newt mitigation guidelines. (2001). English Nature. ISBN 1 85716 568 3.
  • Williams et al. (2000). The Pond Book. A guide to the management and creation of ponds. The Ponds Conservation Trust, Oxford.
  • Wisniewski, P.J. (1989) Newts of the British Isles. Shire Natural History. ISBN 0 7478 0029 4

Habitat management for reptiles

Good reptile habitat consists of a varied vegetation structure and south or south-easterly aspect. Preferred sites include hillsides, banks, slopes and wet areas or semi permanent ponds with tussocky grassland, bramble, bracken, gorse or, occasionally in Herefordshire, heather. Small groups of young trees such as silver birch, elder, or juniper reduce wind chill and create a microclimate.

Early in the spring collapsed dead bracken stands and bramble provide cover and thermo regulation sites for newly emerged species such as adder and viviparous lizard. Without a good height of sward reptiles are vulnerable to predation from birds and mammals. Hibernacula on hills or slopes will be situated out of the damp and frost, under thick bramble, in mammal burrows, root systems, or earthworks.  These are essential to the wellbeing of a reptile population; especially the grass snake and adder who tend to use the same hibernacula each year.  Their loss, either intentionally or accidentally, will result in population decline.  Therefore, before any management for reptiles is planned, it is of the utmost importance to locate the hibernacula or aggregation areas.

Reptiles, and in particular adders, can be found in aggregations in spring on emergence, and in late summer/early autumn when preparing for winter hibernation. At these times any slopes and hillsides with a south facing aspect should not be cut with machinery. Work parties or the rotational cutting of small areas are preferable to the complete eradication of bracken, but some cutting is needed to prevent the bracken from taking over and shading a site in the late summer months.  Thick secondary tree growth and neglect on site also leads to shading out and results in diminishing reptile populations.  During winter the scrub can be cut and the brash turned into refugia piles. Placed in sunny areas these provide attractive refuge and basking areas for reptiles.  Also grass and vegetation cuttings can be turned into attractive heaps for grass snakes and slow-worms.

Grazing by horses, cattle or sheep is good for reptile sites, breaking up bracken, and opening areas to the sun, but high stock density is detrimental. Overgrazing will strip an area of reptile cover and the disturbance caused by large numbers of stock can lead to a rapid decline in reptile numbers.  The use of  “flying flocks” of sheep, which are brought on to a site to graze only when required,  prevents overgrazing.  Temporary exclusion fencing is another way of stopping damage to sensitive areas.

A recent publication, Status of the Adder Vipera berus, and the slow-worm Anguis fragilis, in England (English Nature 2004 publication No. 546 John Baker, James Suckling & Ruth Carey), states that habitat management is the factor most frequently impacting on adder and slow-worm populations. In spite of reports of individual sites being harmed, habitat management or creation was regarded as a positive factor at more than 40% of adder, and 50% of slow-worm sites. Most adder populations in the Midlands are relatively low. A third of adder and a quarter of slow-worm populations consist of fewer than ten adults, so any drastic habitat management could result in the loss or decline of fragile populations.