Limestone Country: The Burren


A thick blanket of fog covers the wintery landscape. The path, carved by countless feet into the shallow layer of dirt that covers the limestone, is barely visible. The damp air is swirling around me, at times lifting for the blink of an eye to allow a brief glance on wet limestone slabs and the vague outline of shrubs. Suddenly the lake emerges out of the grey wall of mist, its surface motionless, its extend hidden. I am gathering some clues on where I am from the few visible landmarks and keep on walking, trying to follow the lakeshore or at least keep it in sight. It is winter solstice day and even though it is almost lunch time it still feels like early morning. The fog is the perfect cover for this mysterious landscape that extends around as well as below me. I am on my way to the summit of Mullagh More, the iconic, flat-topped hill that sits in the heart of the Burren National Park, a limestone karst area that has mesmerized visitors and residents for millennia.

I am losing sight of the lake but the stile in a dry-stone wall shows me that I am on the right track; a few steps further a small group of hazel and ash that host a colourful accumulation of Primroses and Bluebells in spring, becomes just about visible to my left, are another waymark. Soon after a number of natural steps in the limestone bring me onto the first plateau of Mullagh More. Landmarks and way markers are now completely hidden in the fog which is thicker than ever. The well-trodden path has disappeared and the now bare limestone at my feet didn’t keep any memories of previous travelers. I am stranded and all I can do is sit and wait. The silence is eerie. After what feels like hours there is a hollow clock-clock, the unmistakable sound of limestone on limestone; feral goats navigating the winter fog maybe? After another couple of hours (?), minutes (?), seconds (?) a raven croaks close-by or at least it sounds close. In this impenetrable fog it is impossible to tell. Time goes by, I am alone with my thoughts in this ancient landscape, the cold and damp slowly making its way through layers of clothing. All of a sudden it seems to be getting brighter. I can see a bit further; the curtain is lifting enough to wander on.

Many steps later and three plateaus higher I am witness to the fog finally falling apart, holes appear in the soft sheet and a soft breeze rips further openings in the wall of droplets. Patches of blue appear in the sky above me and the mountainscape of the Burren is revealing itself all around me. Poulnalour and Slievenaglasha to my left, Slieve Roe and Knockanes ahead of me and the lowlands of County Clare and Galway to my right. Wafts of mist are still lingering but most of the limestone hills are now bathed in warm winter sunshine. The skeletons of the hazel scrubs glow in gentle brown and yellow tones, the wet limestone is glistening in the light and the only sound is the hushing of the wind. This is the Burren.


Most of Ireland’s bedrock is made from limestone but only in a few places this rock has come to the surface to become the landscape. It does so in the counties Fermanagh and Cavan and a few odd spots in the midland counties, but Ireland’s ultimate limestone landscape, the Burren, lies in the northern half of County Clare and spilling over into a small part of southern County Galway. The first impression of this area is one of gloomy desolation. From a distance the first feature that catches the eye are teracced, raggy and seemingly bare hills. A closer look reveals polished rock pavements that are traversed by deep fissures and strewn with rocks known as erratics.

On dry, sunny days the rock presents itself in a bright, in the sunlight almost blinding, grey. After a downpour the landscape changes to a dark grey, almost black, and glimmers with a blueish tint. And on those soft days, that are so typicall for Ireland, when a constant fine drizzle drenches the land, it is almost impossible to tell where the dark, grey landscape of the Burren ends and the sky begins.

The name of this landscape derives from the Irish word Boireann which translates into large rock or rocky district and the English politician and military leader General Edmund Ludlow, while passing through the area on a military campaign in 1659, described the Burren like this:

“It is a country where there is not enough water to drown a man, wood enough to hang one, nor earth enough to bury him.”

In the following centuries the Burren was being given many names. It was described as a moonscape and has been called the fertile rock. Singer & songwriter Luka Bloom sang about the flowering desert and for botanist Charles Nelson the Burren is a limestone wilderness. Whatever you would like to call it, the Burren is a landscape that catches the imagination. The landscape is cherished and respected by its people and known to leave a deep impact on its visitors. The Burren seems to exist on another plane, not quite part of real world, timeless in one way but also laden with the burden of history. There just is no other place like it.


The Burren is a limestone karst landscape. Its foundations were laid down during the lower carboniferous period some 350 Million years ago far away from its current location on the west coast of Ireland. Imagine a shallow ocean in a tropic climate just south of the equator. Some of the inhabitants of this ocean were the ancestors of our snails, mussels and corrals, all of which shared one feature, a shell made of the minerals calcite and aragonite. After the inhabitants of these shells had met their end, the shells sank to the seafloor. There they accumulated, layer after layer, and over a period of some 20 Million years hardened into limestone which eventually reached a thickness of up to 800 meters. Periodic outwashes of mud, sand and clay from adjacent river estuaries added bands of shale and other deposits that in places separated the limestone beds. During the upper carboniferous period these fluvial outwashes became more dominant and as a result shales and sandstones built up over the limestone and in time completely covered the older rock.

Time passed, continents moved and Ireland took its current place on the map. The earth’s climate oscillated, cooling and warming in cycles. The colder periods saw vast glaciers advancing from the poles covering much of Europe including Ireland including the area of the future Burren. Once the temperatures started to rise the ice would retreat northward for a while, releasing the land from its icy grip. This process went on for thousands of years and the back and forth and back again movement of these immense masses of ice, several hundred meters thick and weighing many tons, was sculpting the landscape. In some places the glaciers cut deep valleys in the rock. In the Burren they completely removed the top layers of shale and sandstone, exposing some 250 square kilometers of the underlaying limestone. The best place to see the transition from limestone to shale and sandstone is to the south-east of Doolin Harbour. Here the limestone disappears under the sandstone cliffs that a bit further south rises to form the Cliffs of Moher.

The glaciers carried vast amounts of rocks, gravel, sand and silt with them. Once the temperatures rose and the ice begun to melt this luggage was dropped on the landscape. Drumlins, small elongated hills made of silt, gravel and rocks, are a common sight all over Ireland. In the Burren the drumlins mainly appear along the southern and eastern borders of the area. Erratics however, from the Latin errare, to wander, are very obvious all over the Burren from the coast to the mountaintops. Most of the wandering rocks are made of limestone but sandstone and granite erratics that had originated further north in Connemara and were transported by the glaciers to their current resting place can also be found.


Today’s bleak landscape of the Burren is not an entirely natural phenomenon. The late cartographer and author Tim Robinson wrote in one of his books: “The Burren’s austere beauty is due to millennia of abuse.”

After the end of the last glaciation, about 10.000 years ago, the Burren didn’t look very much different than the rest of Ireland at the time. After the ice had disappeared a tundra-like landscape developed, with a warming climate shrubs and trees established themselves and over time vast pine and oak forests took over the land. In the area known as Rock Forest, in the eastern corner of the Burren National Park, stand a few gnarled and stunted trees in the shelter of a stone wall. Their size and shape bears little resemblance to the mighty scot’s pines that once stood in Ireland’s forests but nevertheless pollen analysis has shown that these trees are the direct descendants of the old forest trees that once covered the Burren.

It is possible that the limestone of the Burren area never had a very deep soil cover and was more susceptible to erosion than other areas. It is however clear that the first Burren farmers and the following generations sped the erosion process along by clearing land for crops and livestock. The early settlers also left their mark on the landscape in other ways. The Burren has one of the highest concentrations of ancient monuments in Ireland, many dating back as far as the stone age. Cooking places known as fulachta fiadh, portal and wedge tombs, cairns, ring barrows and stone forts, early Christian monasteries, medieval tower-houses and the ubiquitous dry stone walls are by no means natural but have all become an integral part of the Burren landscape.

Another factor that had significant influence on the juvenile Burren, even before the arrival of men, was water. Limestone has one very prominent feature: It dissolves when it comes in contact with water. Rain water contains liquified carbon dioxide which makes it slightly acidic and this acidic solution converts the calcite in the limestone into calcium bicarbonate which is soluble and subsequently dissolves in the water and gets washed away.

It is this process that shaped and sculpted the Burren to its unique appearance: Smooth limestone blocks, known as clints, that are separated by deep fissures, known in Ireland as scailps (from the Irish word for fissure or cleft) and everywhere else as grykes, runnels and flutes, terraced hills, sinkholes and vast cave systems. To date some 60 kilometres of cave passages have been explored but the real extend of the Burren cave systems is believed to be a multitude of that.

The exploration of this underworld brought some unexpected glimpses into the Burren’s past. At Ailwee Cave, one of the two show caves of the Burren, the skeleton of a brown bear was found and dated to be 10.400 years old. A bear patella, discovered in another cave, shows parallel cut marks that were most likely caused by a stone knife some 12.500 years ago. The presence of a top predator like the brown bear and signs of it being hunted by men suggests that a diversified flora and fauna already existed in the Burren towards the end of the last glaciation, before the complete disappearance of the ice. The second show cave of the Burren, Poll-an-Ionain,  today better known as the Doolin Cave, features the Great Stalactite. With a length of 7.3 metres this is the biggest free hanging stalactite in Europe.

Most of the Burren’s cave systems have been formed by streams and rivers. The majority of those water courses stay underground which is the reason for the lack of rivers above ground. The only stream that runs its complete course on the surface is the Caher River which has its source beneath Slieve Elva and enters the sea at the Fanore beach after a rather short run of only 7 kilometres. The upper part of the Caher is a gentle flow through hazel scrub and meadows, one of the most secluded and beautiful spots in the Burren. In the early 1990s local man John MacNamara turned this area into a nature reserve. His goal was to let nature run its course and leave the plants and animals in this little kingdom undisturbed. I had the pleasure to know and work with John for a brief time but unfortunately our plans to put together a photographic record of the plants and animals at the Caher Valley Nature Reserve were cut short. John passed away after a short illness in 2004. His hopes for the reserve however came true. After his death the gates to the valley were closed and the plants and animals were left in peace.

After leaving the Caher Valley Nature Reserve the river turns west and starts to descend. Trout can often be seen swimming in the clear water and it is not unusual to come across a dipper, otter or grey heron. On its last 2 kilometres before reaching the Atlantic Ocean the Caher drops 60 meters and completely changes its attitude. The gentle river  becomes a mountain stream and after heavy rain turns into a raging torrent rushing around boulders and tumbling over cascades. Why the Caher River never wanders underground is not entirely clear but it is known that in parts of the Burren impervious layers of clay, chert and sandstone exist between the limestone. The most likely explanation for the Caher River’s unique behaviour is therefor that it runs above one or more of these layers that prevent the water from going underground. Some rivers make a sporadic appearance on the surface. The Rathborney River emerges from under Gleninagh Mountain, runs down the Feenagh Valley only to disappear under the limestone once it has reached Ballyvaughan Valley and Castletown River appears in the Carron basin where it is the main source for the Carron Turlough, the largest of the Burren turloughs.

Turloughs are a special form of water body unique to the Burren and other karst areas and are often being described as seasonal lakes. Their existence is very much dependent on the prevalent precipitation. Unlike proper lakes turloughs are not fed by a constant water supply like a river or groundwater. They are however connected to the cave systems of the Burren. During times of consistent or high rainfall these underground passages flood and eventually overflow, filling the turloughs in the process. During dryer periods, mostly during spring and early summer, water levels fall and the turlough disappears.

All standing water bodies are restricted to the eastern Burren, an area known as the Burren wetlands. In addition to the turloughs there are fens and lakes. Some of these lakes are a combination of lake and turlough. This means they never disappear completely but will easily triple in size during times of high rainfall. The most interesting of those is Lough Gealain. This lake is fed through springs under the limestone but also features a number of swallow holes that connect to the underground cave system. During dry periods these swallow holes can easily be observed to the south of lake proper. In autumn and winter, when rainfall amounts are usually higher, Lough Gealain expands considerably and at times floods the nearby road. Lough Gealain is also special in other ways. The spring water that feeds the lake is rich in dissolved carbonate which makes the lake alkaline and so impossible for the water to dissolve the limestone. The carbonate is also present in the mud layer that forms the bottom of the lake. This mud, scientifically known as marl, does not only acts as a protective layer but also gives the lake its distinctive cerulean colour.

Lough Gealain sits in the heart of the Burren National Park, an area that hosts all of the major Burren habitats. In addition to the fens, lakes and turloughs there are vast stretches of limestone pavement interspersed with patches of fertile soil, small woodlands and wildflower meadows. It is in these habitats where the flora, for which the Burren has acquired world-wide fame, can be found. This wonderworld of wildflowers is rather unexpected in a place that on first sight appears to be made of barren and desolate rock. The Burren however hosts 600 species of wildflowers and other plants which is 70% of all species known in Ireland. But it is not only the abundance of plant life that makes the Burren unique, it is especially the distribution of individual species and the composition of plant communities that makes the Burren stand out.

The most famous of the Burren flowers and something of an emblem for the area is the spring gentian. This species with its deep blue flowers is an alpine species that usually flourishes in the high mountains. In the Burren it bursts into bloom around April and can be found not only at sea level but even right beside the sea. The coastal area of Ballyryan north of Doolin is, together with the Burren National Park, one of the strongholds of this enigmatic plant. Each plant produces several hundred seeds which are shed in summer for germination in the following spring. There is however one problem. In order to germinate, spring gentian seeds have to experience frost. Experiments have shown that seeds kept in warm soil will not germinate and will keep lying dormant, only seeds that have been exposed to sub-zero temperatures will produce a new gentian plant. Although frost is not unknown in the Burren it is very rare and years can go by between one frost event and the next. In order to survive, the Burren gentian came up with another solution. Mature plants produce underground stolon and these grow new rosettes and subsequently produce new gentian flowers. In its 8000 years of isolation the Burren gentian has not only developed an alternative reproduction method, it is also visually slightly different from the populations on the continent. For now these differences are minutiae and are only of interest for the keen botanist. But give it another few thousand years and gentiana verna might develop into a completely new species. 

Often found in the vicinity of this alpine beauty is the early purple orchid, a species more commonly at home in the Mediterranean. A little bit later in the year the mountain avens, an arctic species, joins the mix and bursts into bloom beside other orchids like the fragrant orchid, the pyramidal orchid, the red helleborine or the twayblade to name just a few of the 24 species of orchid that call the Burren their home. The orchids are without a doubt the stars of the Burren flora. Today it is the striking colours and intricate shapes that make these flowers attractive, until not so long ago however it was another alleged ability that made orchids very appealing to certain people. The word orchid comes from the Greek word όρχεις (“orcheis”) which means testicles. Orchids spend most of their life underground in the form of tubers and these tubers very much resemble a particular male body part. It is likely that this very distinctive shape led to the belief that orchids have aphrodisiac properties which led to their name.

Orchids lead a fascinating and somewhat complicated life. Each orchid tuber lives in a symbiotic relationship with a particular fungus and this fungus has to be present from the very start, without the fungus the orchid’s seed won’t be able to germinate. Over recent years it became clear that most plants live in a symbiosis with mycorrhizal fungi, so this is nothing too unusual. Orchids however belong to a group of plants where this relationship is rather one sided. The orchid seems to be the sole beneficiary in this pairing, receiving all nutrients necessary to survive and reproduce from the fungi. The orchids’ unusual lifestyle continuous also above ground. For starters orchids produce flowers in rather irregular intervals. Years can go by without any flowers showing. Once they do the various orchid species have each specialized for one very particular pollinator which is reflected in either the shape of the individual flower or their scent. Fly orchid and bee orchid are some of the most obvious examples. Should this pollinator for one reason or another not appear the orchid won’t be pollinated and not produce seeds. In a worst case scenario, many years can go by for an individual plant without producing any offspring. The perfect example for the orchids’ unpredictability is the story of the narrow leaved helleborine. One lonely specimen of this woodland plant was discovered in 1980, halfway up a mountain on open limestone. Over the following years the plant produced flowers every spring like clockwork. In the year 2000 it refused to appear above ground for the first time and despite repeated searches the narrow leaved helleborine hasn’t been seen since.

Another piece in the floral puzzle of the Burren is the presence of lime-loving (calcicoles) and lime-hating (calcifuges) plants which are often growing in close proximity. Giving the ubiquitous presence of limestone it would be logic to conclude that the soil cover would consist of weathered limestone rock and the remains of glacial drift, a soil type known as rendzina. Calcifuges however wouldn’t thrive on such a soil and the existence of other soil types in the Burren has been a bit of a mystery until microscopic examinations revealed the prevalence of an aeolian (wind deposited) soil known as loess. This loess most likely came from east Galway and Connemara and was deposited in various places all over the Burren during the Tundra period shortly after the last glaciation. Another theory is that sandstone and granite erratics that originated further north disintegrated over time to form loess.

In addition to its strange plant communities the Burren also hosts a few unusual flowers and strange rarities. The O’Kelly’s spotted orchid is a rare white subspecies of the common spotted orchid which was named after Patrick O’Kelly from Ballyvaughan who first described the plant. A bit of an oddity is the pyramidal bugle, something of a stumped version of the common bugle. This is one of Ireland’s rarest plants and only flourishes in a few localities along the Burren coast, the Aran Islands (which are geologically a part of the Burren) and it has also been reported in Connemara and on Rathlin Island off the Northern Ireland coast.

The question why the Burren hosts these unusual and rare plants and plant communities has never really been answered. It is thought that the alpine and artic species arrived during or shortly after the last glaciation and were a feature of the early tundra-like landscape. After the climate had warmed enough other plants, including the beloved orchids, followed from the south and settled in the Burren right beside the existing flora that for whatever reason feels very comfortable in the mild climate of Ireland’s west coast to this very day.

How much human activity and the Burren flora are connected and why the Burren is essentially men-made came to light in the final decades of the last century. Back then, in order to protect the delicate wildflowers, it was decided to restrict farming activities in the Burren and reduce the number of grazing animals considerably. Surprisingly this conservation effort had the exact opposite effect of what it was supposed to have. Because the fast growing grasses and shrubs, mainly hazel, blackthorn and hawthorn, were no longer kept in check by grazers many of the delicate wildflowers were pushed out of their habitat.

Then, in the year 2010, the Burren Life project was founded. Goal of this project was not only to find a balance between farming and conservation but to actually use farming as a conservation tool. The farmers who signed up for this project took on a number of tasks to preserve the natural as well as the built heritage of the Burren. Among the actions taken was the re-building of dry stone walls, shrub removal and the re-introduction of the Winterage and other traditional farming methods like herding and goat husbandry. The century old tradition of Winterage sees livestock being brought to pastures in the uplands of the Burren in autumn in order to spend the winter there. The generally mild climate and the heat-storage capacity of the limestone make sure that grasses are growing almost all year round. This provides free, natural food for the animals and in turn keeps the grasses down which benefits the wildflowers in the following spring. Over time the Winterage became a yearly community event and now every October the cattle are being accompanied by crowds of people on the way to their winter pastures.


Today the Burren Life project is one of the most important factors in the conservation of the Burren. Without grazing animals the diversity of the flora would be greatly diminished which would eventually effect the overall biodiversity of the area. In the wake of the loss of flowering plants the insect population would suffer which would subsequently impact birds and mammals.

The Burren is a haven for insects. In addition to bees and bumblebees, dragonflies and damselflies, there are 27 species of resident butterfly and well over 200 moth species. One of the latter and a true Burren speciality is the Burren Green. This moth had first been recorded in 1949 and put the Burren on the map for Lepidoptera fans. The Burren is the only place in Ireland and Great Britain where this emerald green beauty has ever been seen.

One of the animals for which insects are a major food source are the bats. The Burren is an important stronghold for these flying mammals and all seven bat species known in Ireland have been reported in the Burren including the lesser horseshoe bat which is already extinct in many parts of Europe.

Other insectivores are the viviparous lizard, which can often be found sunbathing on the warm limestone, the slow worm, which was introduced to the Burren in the 1970s, and the common frog, who can look slightly out of place hoping across the limestone pavement. The pine marten, who has a very varied diet which includes birds, small mammals, insects, fruit and nuts, and its relative the stoat are the Burren’s top predators while the feral goat is the largest of the Burren’s wild animals. These descendants of once domesticated goats roam the Burren and are not only very pretty to look at in their rugged and colourful appearance but they are also the only animal that munches on the ever spreading shrubs and so play their part in the conservation of the Burren.

Unlike other landscapes and habitats in Ireland the future of the Burren karst and its famous flora is safe, for the moment at least. The combined efforts of farmers, communities and environmental groups make sure of this. The special case of the Burren however raises the more fundamental question of what conservation really means. Is it right to protect an admittedly unique but ultimately men-made piece of landscape or would it be proper to let nature reign which would transform the Burren into a very different landscape. Ungrazed the Burren would quickly develop a hazel and ash woodland, a process that can already be observed at the foot of Mullagh More and around Eagle’s Rock, and in time other trees, most likely oak and scots pine, would take over, soil would built up and revert the Burren to its origins of a mixed woodland. Parts of the current Burren flora would survive in this new habitat, others, first and foremost the arctic and alpine species, would probably disappear.

Ultimately the Burren as it is today will only exist for a glimpse in the vast reign of time. In another few thousand years all the limestone will be gone, washed away into the ocean, or the Burren will have been decimated to a few small limestone islands by rising sea levels. Whichever way it may turn out another of nature’s circles will have been completed.

Carsten Krieger, September 2021