Biodiversity of Clara Bog

Nature & Wildlife


The word biodiversity simply means the variety of life found in a particular place. Peat bogs are home to a unique combination of species, and although they do not have as much biodiversity as a tropical rain forest, they are just as important, and are also under threat. Most plants and animals have specific requirements for their existence. The main building block of bogs, sphagnum moss, is an outstanding example as it will only succeed on waterlogged acid ground. This and many other plants contribute to biodiversity by occupying distinct ecological niches in the bog system. This niche is called a habitat. Human interference with habitats can affect their natural biodiversity by increasing or decreasing the amount of species present. Despite peat cutting in the past, Clara Bog has been much less developed than many other Irish raised bogs and has remained relatively intact. This has resulted in a rich variety of natural habitats and wetland species.

Clara Bog contains the typical components of a raised bog; hummocks, hollows, flushes and lawns. There are also very unique topographical features that are not common to all raised bogs. Soak systems are open areas of water that are more nutrient rich as they are fed with groundwater and can support alkaline plant species thereby increasing the overall biodiversity of the area. Shanley’s Lough is found on the West bank and Lough Roe on the East Bank. Native Bog Woodland consisting mainly of Downy Birch (Betula pubescens) grows in a flushed area near Shanley’s Lough. This is a rare and protected priority habitat under EU legislation.

Plant Life

The raised bog flora is very unique. The waterlogged and acidic peat is contrary to what most plants usually thrive in yet Clara Bog is covered in plants. That is because many of them are specially adapted to growing in adverse conditions.

Sphagnum moss is without doubt the most important plant on the bog. It is also called the bog builder as it is the main peat forming plant of raised bogs. It has amazing absorbency qualities and can hold up to 20 times its own weight in water. This accounts for the high water content of the bog, typically 95% water. It is a curious little plant. It has no roots and lives in acid water with very few nutrients. It grows by absorbing nutrients from the moisture droplets in the air. The top part of the moss is living while the bottom part is dead. The dead part helps the living part by storing water in its cells to help prevent it from drying out during drier spells. There are about 24 species of sphagnum moss in Ireland; 13 of these grow in Clara Bog. They are like living carpet on the bog’s surface and are varied in colour. They occupy different moisture zones on the bog. In the bog pools you will find the bright green Sphagnum cuspidatum, while on the bog’s surface the crimson Sphagnum magellanicum and ochre Sphagnum papillosum can form a wet mosaic carpet. The ginger brown Sphagnum austinii forms tightly packed hummocks raising the water table above the bog’s surface. Besides Sphagnum there are many other moss types present in Clara Bog. A noticeable one, Leucobryum glaucum, forms tightly packed green “pincushions” that can grow as high as 50cm. Ling Heather can often be seen growing on the pincushions. Clara Bog is also the only known Irish site for Narrow Cruet-moss (Tetraplodon angustatus).

Other interesting plants on the bog include the collection of carnivorous plants. Sundews, butterworts and bladderworts all trap and digest their insect prey.

Attracted by the glistening and sweet-smelling “tentacles” of the sundew, a fly lands. The ultra-sensitive stalks bend inwards immediately, trapping the insect with their sticky glue. The creature struggles to free itself, only enmeshing itself further. In less than 15 minutes it is dead from asphyxiation or exhaustion. Then enzymes in the plant get to work, digesting the creature to create a nutrient soup for the plant to devour. Two types of sundew grow on Clara Bog; round-leaved sundew (Drosera rotundifolia) can be found in drier areas where there are pockets of bare peat and the larger Great Sundew (Drosera angelica) can be seen growing in wetter areas such as bog pools and remnant drains.

The purple flower on the slender stem of the Butterwort may look attractive, but its leaves are deadly for insects. They are attracted by the wet appearance of the sticky mucus secreted by the leaves – once they land; there is no escape… the leaf edges can curl over to pour more of this “glue” on to the creature till it quickly expires.

Sphagnum moss

The yellow flowers of Bladderwort can be seen above the bog pools in summer. The feathery submerged leaves have many tiny bladders. These are used to trap insects with a unique trap door and trigger hair mechanism. When the prey touches off the trigger hair, the trap door opens and the insect get sucked into the bladder. The door closes then the unfortunate creature becomes trapped and eventually digested by the plant.

Bog cotton, perhaps the quintessential plant of bogs, can give the distant appearance of a snow covered landscape even on a sunny day. Two types of bog cotton grow on Clara Bog. The first to appear is Hare’s-tail Cottongrass (Eriphorum vaginatum) with its single fluffy head followed by Common Cottongrass (Eriophorum angustifolium) with its multi-cottony flower heads.

Heather, another classical plant of bogs, begins to swathe the drier areas in a deep pink colour from mid-summer onwards. The more dominant and bushier Ling Heather (Calluna vulgaris) can provide food for hungry birds and insects in the form of nectar, leaves and seeds. The more slender Cross-leaved Heath (Erica tetralix) weaves it way amongst the Ling Heather and has beautiful pink to magenta bell-shaped flowers.

Few counties can have a small bog plant on their coat of arms, but County Offaly is proud of the Bog Rosemary. It is easily distinguished by its leathery rolled leaf edges and its delicate pink flowers and usually grows with Sphagnum and sometimes Cranberry. Bog Rosemary features as the emblem for the Irish Peat Society (IPS). Due to the destruction of lowland raised bogs to which it is restricted, this small member of the heather family is relatively local in its distribution in Ireland.

Heath-spotted orchid (Dactylorhiza maculata) and Common-spotted Orchid (Dactylorhiza fuchsii) are plentiful in the drier areas and they often hybridize. The Lesser-butterfly Orchid (Platanthera bifolia) with its almost luminous flower spike colonise similar areas. Marsh Helleborine (Epicactus palustris) and Common Twayblade (Listera ovata) are found on either side of the boardwalk before it ascends onto high bog.

Several bog-loving berry plants thrive on top of the Sphagnum mosses. Cranberry stems wind their way along the top of wet Sphagnum producing red berries that are edible. These can be seen from the board walk. Bilberries (Vaccinium myrtillus) are plentiful in the Bog woodland and provide food for passing mammals such as Fallow Deer. The Bog Woodland is visible from the board walk on the high bank looking in south westerly direction. Crowberry (Empetrum nigrum) also occurs close to this wooded area.

Other plants that can be seen on Clara Bog include Deergrass (Trichophorum germanicum), White Beak-Sedge (Rhynchospora alba), Bogbean (Menyanthes trifoliata), Bog Asphodel (Narthecium ossifragum), Bog-myrtle (Myrica gale), Meadow or Bog Thistle (Cirsium dissectum), Purple Moor-grass (Molinia caerulea), Carnation Sedge (Carex panicea), and Heath Milkwort (Polygala serpyllifolia).

The laying of limestone gravel beneath the boardwalk on the low bog near the roadside has buffered the acidity of the peat and allowed a community of more alkaline loving plants to flourish. Bird’s-foot Trefoil (Lotus corniculatus), Lady’s Bedstraw (Galium verum), Yarrow (Achillea millefolium), Burnet-saxifrage (Pimpinella saxifraga), Wild Carrot (Daucus carota), Quaking Grass (Briza media) and Columbine (Aquilegia spp.) are some of the plants to be seen. They attract many insects such as moths, butterflies, bees, hoverflies and beetles especially when they are in flower. Their presence enriches the overall biodiversity of the area.


Lichens and fungi belong to their own kingdoms separate from the plant kingdom. Few fungi are found but the brown toadstool is often seen growing on top of Sphagnum moss. Noteworthy are the lichen community. Lichens are unusual living organisms. They are an assemblage of two or three living organisms that have a symbiotic relationship. The dominant partner is a fungus and it can co-exist with either or both an algae and a cyanobacteria. The latter two provide the photosynthetic part for the lichen. Cladonia lichens are the main types that grow on the bog surface. They have a grey appearance. The most obvious ones are the matchstick lichen (Cladonia floerkeana) with its bright red tips. It is found on drier more disturbed areas and the reindeer or antler lichen (Cladonia portentosa) which can grow in large sponge-like clumps in both wetter and drier areas. Viewing this lichen using a hand lens, the “antler” look becomes apparent. When wet, the antler lichen has a soft spongy texture but is brittle and rough when dried out. Lichens are amongst the oldest living things on earth and in the past they had many uses ranging from dyes to antibiotics and some were even used as packing material for ancient Egyptian mummies.

Animal Life

Clara Bog is a haven for invertebrates. On a fine summer’s day many dragonflies can be seen darting and gliding over the bog pools. Their transparent wings and colourful bodies may look pretty, but they are fearsome ambush attackers. They spot their prey using their 30,000 eye lenses and can fly at speeds of up to 30 miles an hour. They are formidable aerial acrobats, able to fly in every direction as well as hover – better than helicopters! Four-spotted chasers (Libellula quadrimaculata), Common Hawkers (Aeshna juncea) and Common Darters (Sympetrum striolatum) are often seen. The Keeled Skimmer (Orthetrum coerulescens), a powder-blue dragonfly has been recorded from a soak area. Damselflies are also commonly seen and the Scarce Blue-tailed Damselfy (Ischnura pumilio) has been recorded on Clara Bog.

Many spiders weave their intricate webs amongst the heathers and surrounding vegetation ready to pounce on their prey. The Raft spider (Dolomedes fimbriatus) is Ireland’s largest spider. It is only found in bogs and it does not spin a web. Instead, it waits at the edge of a pool; it can sense any vibration on the water surface from a potential prey through his sensitive forelegs. The unlucky prey may be met by the Raft spider as it quickly runs across the water’s surface in hot pursuit. Raft spiders are also known as the Jesus Christ spider for their ability to walk on water.

The bog vegetation provides much needed food and shelter for moths. The bright green caterpillar of the Emperor moth (Saturina pavonia) has many black bristles that help it go along un-noticed. The adult Emperor moth has a trick to avoid being eaten. It rests with its wings open flat to display its four intimidating eye-spots and it can vibrate them to really frighten a predator! A rare moth, the Dark Tussock (Dicallomera fascelina) has been recorded from Clara bog, as has the Large Heath Butterfly (Coenonympha tullia), another moorland specialist. Ireland’s only protected insect, the Marsh Fritillary butterfly (Euphydryas aurinia), can also be found. Its specific food-plant, Devil’s-bit Scabious (Succisa pratensis) grows here. There are many other insects including hoverflies, beetles and grasshoppers. Clara Bog is the only known site in Ireland for two rare midge species, and a click beetle.

Two amphibious creatures; the Common Frog (Rana temporaria) and the Smooth Newt (Lissotriton vulgaris) complete their life-cycles both in the bog pools and on the bog’s surface. Both are protected species.

Another interesting species that is often spotted basking on the boardwalk on a warm sunny day is the Common Lizard (Lacerta vivipara), Ireland’s only native reptile. Atypical of reptiles the Common Lizard gives birth to live young rather than laying eggs. They are about 10 cm to 16 cm in length. When startled they have the uncanny ability to drop their tail, this gives them the chance to escape from a predator who may be distracted by the tail especially as it can twitch after being dropped. The lizard will eventually grow a new one. Besides peat lands they also live in coastal and woodland habitats.

Some of the bird life found on bogs is unique. Wading birds such as Curlew (Numenius arquata) and Snipe (Gallinago gallinago) have long legs and so are specially adapted to living in wetlands such as Clara Bog. Resident Curlews have a red-listed status in Ireland; they are of the highest conservation concern due to a rapid decline in their numbers in recent decades. Thankfully the conservation of Clara Bog has provided a habitat for breeding curlew. During the month of May and June they are most vocal and their distinctive “cur lee” “cur lee” call is heard ascending from the bog. The Snipe produces a most distinctive drumming sound when performing display flights. The sound is actually a vibration from the breeze passing through its stiff tail feathers. The relatively rare Merlin (Falco columbarius), Ireland’s smallest bird of prey, has bred on Clara Bog. It used to nest on the ground but now it usually takes up residence in trees. It is a master of the surprise attack, coming in low and snatching its prey, before plucking and decapitating it on a boulder or fence post. Able to catch birds four times its own weight, it could easily deal with the Snipe. Skylarks (Alauda arvensis) rise up from the ground high into the sky (a staggering 50 to 100 metres!) and continuously warble until they descend with paratrooper-like precision back down to the ground. They can sing their song for extended periods of time and have been known to sing for up to half an hour non-stop.

Other birds to be seen and heard on the bog include Woodcock (Scolopax rusticola), Mallard duck (Anas platyrhynchos), Meadow pipit (Anthus pratensis), Stonechat (Saxicola torquata), Kestrel (Falco tinnunculus) and during the summer months Swallow (Hirundo rustica) and Swift (Apus apus) can be seen flying over the bog feeding on aerial insects. Winter migrant visitors include Hen Harrier (Circus cyaneus) and Short eared owl (Asio flammeus). Along with the Peregrine Falcon (Falco peregrinus) they are known to hunt over the bog. Red grouse (Lagopus lagopus) and Greenland white-fronted Goose (Anser albifrons flavirostris) used to occur on the site but have become locally extinct.

Larger mammals tend to use the bog more as hunting or feeding ground but the Irish Hare (Lepus timidus hibernicus) makes its home called a form, a hollowed out area amongst the bog vegetation. The Irish hare is a distinct sub species of mountain hare endemic to Ireland. It is thought to have been here since before the last Ice Age, and may be the country’s oldest surviving mammal. Unlike its relative in Scotland and elsewhere, its coat remains brown throughout the year. It now appears to be under threat as its usual habitat range is being affected by changes in land use, and its numbers have declined dramatically in the last 30 years. In the wooded areas immediately surrounding the bog there are Fox (Vulpes vulpes), Badger (Meles meles) and Pine Marten (Martes martes). The Pine Marten or Tree Cat as it is also known is an excellent climber. It belongs to the family Mustelidae, which also includes otter, stoat, mink and badger. It has a cat-like appearance with a flatter more pointed head. It has long legs and its tail is long and fluffy, in fact much fluffier than the tail of a red squirrel. The coat is a rich chocolate brown colour with a creamy coloured chin and chest. They are carnivores and mostly hunt small animals and birds. If hungry they supplement their diet with fruit and invertebrates.

Fallow deer (Dama dama) also visit the bog as is evident from droppings often seen near bilberry shrubs. Otter tracks and are sometimes seen near old drains. It is thought they are looking for eels that sometimes end up in the drains by accident.