Upland ecologist Barbara Jones writes about the mountain plants that can be spotted on UK cliffs and what climbers and walkers can do to help protect these sensitive flora...
How often do you see the media writing about mountain plants in the UK? Woodlands, peat bogs, meadows, heaths, yes, but seldom mountain flora. The reason is obvious. Compared to easily accessible meadows showing a riot of colour in summer, mountain plants need dedication and effort. You usually have to slog uphill for what feels like hours, it's often wet above, underfoot or both and when you arrive, what do you see but few bedraggled looking patches, hanging on high on a cliff face, if you are lucky.
No wonder few people are interested in alpines in the British mountains when you can go to the Alps and see them easily and in abundance, even growing by the side of the road. And usually in much better weather! However, once you know what to look for and where, the pleasure of finding an uncommon, brightly coloured mountain plant on a high craggy outcrop far outweighs the effort in getting to it, particularly as climbers and mountaineers we are there already!
Tall-herb ledge plants
There is one wonderful habitat on mountain cliffs which does give lowland meadows a run for their money, though. Known as tall-herb ledges, they are inaccessible to sheep and provide a refuge to many plants which are sensitive to grazing, particularly tall growing herbs and shrubs, even dwarf mountain willows in some places. The description 'tall-herb ledges', indicates their nature, and in summer they can provide some of the most attractive and spectacular displays of wild plants in the mountains, often with the appearance of hanging gardens.
Some of the shaded sites create conditions suitable for species that would normally be associated with woodland and one of the most characteristic species of this community is Great Wood-rush which can grow luxuriantly on the cool, humid ledges, often in company with other typical woodland species such as Angelica, Goldenrod, Water Avens and Wood Anemone. Some less common herbs can also occur such as the Globeflower - a member of the buttercup family with a wonderful globular, bright yellow head. It also grows in a number of northern montane habitats, in grassland, woodland and widely in the Alps. Another regular is Roseroot which can form luxuriant masses of fleshy, greenish-yellow flowers extending from the ledges onto the surrounding rock faces. The Welsh name for this plant, 'Pren y Ddannoedd' refers to its one-time use as a cure for toothache, although how such knowledge was originally acquired is hard to imagine.
Oxeye Daisy, Lady's-mantle, Mountain Sorrel, Lesser Meadow-rue and the striking pink flowers of Thrift might also be present. Widely distributed in the northern hemisphere, Thrift is usually a coastal plant, but like several other species, it grows well in both maritime and mountain situations, thriving in the exposure and lack of competition from more vigorous plant species. Scurvygrass is another example, notable for the fact that its leaves, rich in vitamin C, were once valued by early seafarers as a protection against scurvy. What is less well known, is that shepherds have been known to use them in the mountains, perhaps for the same purpose. Some of the best examples of tall-herb ledge vegetation can be seen on Ben Lawers, Ben Lui, Helvellyn, Pillar, Ysgolion Duon on the Carneddau and Snowdon.
Despite the glories of the tall-herb ledges, there is little doubt that the 'jewels' of the mountains are the arctic-alpine plants. They are usually found on high mountain crags well out of the reach of grazing animals, and it seems remarkable that such delicate looking plants can survive year after year in some of the most hostile conditions in the UK.
As their name suggests, arctic-alpine plants come from the cold arctic lands or high mountains of the world. They usually form low growing mats or cushions to hold in heat and minimise exposure to the snow and cold biting winds. So how come they are growing in the UK, where we have a mild, damp climate so different to their usual environment?
They are remnants of more widespread vegetation present after the retreat of the ice around 10-12,000 years ago. Imagine the end of the last glaciation in Britain. Ice covered much of the land, but around 12,000 years ago it started to retreat, leaving behind a cold, arctic environment which would have been colonised by these plants as they followed the retreating glaciers northwards. They would have thrived in this landscape until conditions warmed and plants more suited to the changing conditions came to dominate.
This meant that, especially in more southerly areas such as Wales and the Lake District, the true 'mountain' vegetation was forced to retreat to the higher, colder mountains where they were free from competition, where particular rock types provided them with the nutrients they needed and where the climate suited them. They can still be found there now on just a few sites on steep, ungrazed, north-facing cliffs, where the cool temperatures and lack of competition from more vigorous plants allows them to maintain a foothold well outside of their alpine or arctic home. There is also the possibility that some of these arctic-alpine species may have survived the last advance of ice in the UK on rock outcrops jutting out above the ice known as nunataks.
Mountain cliffs also provide an important refuge from the attentions of sheep and goats, which manage to graze vegetation in most places in the British uplands, except steep rock faces and fenced exclosures. It is no accident that some of the best sites to botanise in the uplands are often on rock faces and very steep ground which are effectively mountain 'islands', with little surviving woodland or scrub and surrounded by agricultural and urbanised lowlands. England and Wales are not as richly endowed with these native mountain species as the Alps, the mountains of Scandinavia, or even the Scottish Highlands, but the fact that they are on the edge of their European distribution gives them special significance in conservation and in our understanding of the post-glacial history of the British Isles.
You won't find these plants everywhere in our mountains, though. They tend to favour sites with lime-rich soil or with mineral-rich water flushing through them to provide the nutrients they need. Places such as Cwm Idwal in North Wales, Helvellyn in the Lake District or Ben Nevis in Scotland are all good places to look, but where to start and what species are we talking about?
Few groups of plants are more at home in mountains than the saxifrages. The name literally means 'rock breaker' but this belies the delicacy and beauty of many of the species. Few summer visitors see the magnificent Purple Saxifrage in bloom as it is an early flowerer, sometimes as early as February and it will even flower in snow. It is reputed in fact, to grow further north than any other flowering plant, having been recorded at Cape Morris Jessup on the north coast of Greenland. It also has the unusual ability to secrete excess lime from glands on its leaves, so that it appears to be encrusted with lime.
True to its name, the flowers are normally purple, but white varieties also occur. It can be confused with wild thyme, which grows in similar places, but thyme flowers later and doesn't have the opposite rows of leaves that purple saxifrage does. The two most common saxifrages are Mossy Saxifrage and Starry Saxifrage, both of which occur at relatively low altitudes in the mountains. Starry Saxifrage is one of the few arctic-alpines able to grow on acid rocks and is arguably one of the most beautiful of alpine flowers. Look at it closely through a hand lens when it's fully open and see if you agree! The Alpine Saxifrage is restricted to damp crevices where competition is low, and consequently can be very scarce.
One thing most arctic-alpine plants have in common is that they keep their heads down and are low growing, either hugging the ground or growing as a cushion form. The cushion habit of growth is rather common, probably because it lowers wind resistance, and improves the plant's retention of metabolic heat. One cushion plant which graces many rock faces with bright pink cushions of flowers in spring and early summer is Moss Campion.
As with many arctic-alpine plant species, the harsh environment means that it grows very slowly and it has been used experimentally in Canada to date recent glacial deposits by relating cushion sizes on moraines left by melting ice to known growth rates. The fact that it grows very slowly in this environment means that dating is possible over a surprisingly long time scale. Similar protection to the cushion habit is given by a covering of hairs, which helps to reduce heat loss, reflects damaging radiation and helps to retain moisture in arctic-alpine species such as the Alpine Mouse-ear, Arctic Mouse-ear and Mountain Everlasting.
There are rarities, such as the Tufted saxifrage or the Snowdon Lily, which you are unlikely to see unless you are very lucky. Both are very restricted in the areas in which they grow and the numbers of plants left, particularly the Tufted Saxifrage, which is limited in Britain to a few small colonies, mainly in Scotland, and to altitudes above 600m. One single remnant population in Snowdonia, is one of the most southerly in Europe. By 1977 the population had declined to four small plants, bringing it to the brink of extinction in the area, so there was an attempt to boost plant numbers artificially using seed collected from the remaining wild plants. Their fate is still being monitored today and although the experiment was partially successful, numbers remain low and very few seeds seem to germinate naturally. One possible conclusion is that the climate and environment of Snowdonia is no longer ideal for the species, although genetic factors could also be an issue.
The story of these rare species highlights a threat many arctic-alpines are facing in our mountains. They were quite happy growing on their mountain cliffs until recent years when they have had to face a number of challenges:
- They cannot tolerate grazing and so with the increase in sheep grazing in the UK hills in the 20th century, they have been forced to retreat even further to the most inaccessible cliffs, reducing their numbers to small, isolated groups of plants.
- Victorian plant collectors were insatiable and collected many rarities, particularly ferns. Collecting is seldom undertaken now but its legacy remains.
- Climate change in the present day may have a severe impact on these plants which are right on the edge of their range and so may not be able to cope with higher temperatures, increased rainfall or competition from more vigorous plants moving into their habitats.
These factors have resulted in one of the main problems for arctic-alpine plants in the UK today. The numbers of individual plants in each species are so small and their populations so isolated from each other, that they are in danger of being lost completely. Consider the tufted saxifrage, mentioned above, which has declined to just a few plants on a couple of boulders in North Wales. It grows nowhere else in Wales or England and a misplaced foot or wandering sheep could result in its extinction in Wales!
These small populations are also in danger of losing the genetic diversity they need to survive in a changing world. They need bigger populations to cross fertilise with each other and increase their diversity and potential adaptability. To help them do this, we need to keep the plants as healthy as possible and provide opportunities for them to increase in number. Through this they can develop a wider genetic base to hopefully allow them to cope with changing conditions brought on by climate change. On Helvellyn, the John Muir Trust and Natural England together with the local community are reinforcing the populations of rare mountain willows and other upland species on the mountain ledges to try and boost population sizes and introduce some genetic diversity.
So, what can we do to help them to survive into the future so they can brighten up our mountains for centuries to come? Well in many cases, all we need to do is to give them room. They won't generally grow on gentle grassy slopes as they can't compete with the grasses and heaths already there and conditions would be too wet for them. But they can grow on broken rocky ground and in scree slopes below their cliff sites if they are protected. Let them spread and they will do the rest and hopefully build up enough diversity to be able to cope with a changing climate.
As for grazing, you would think that the obvious solution here would be to reduce or remove grazing animals, but that is not an easy option. Apart from the political, social and cultural pressures to retain sheep farming as an upland enterprise, most mountain land is unfenced and so a reduction of animal numbers in one place can often just draw in sheep from adjoining land. Fencing is expensive and most people don't like extra fencing in the mountains. However, we aren't asking for sheep to be removed from all the mountains. These plants only grow in certain climatic conditions and on certain rock types. We know where these are and with a little planning could protect just these sites from too much grazing – which would be a large win for relatively little grazing loss.
This has already been done in one of the most important sites for arctic-alpines in Wales. Cwm Idwal National Nature Reserve supports many of these species on its cliffs but was heavily grazed until around 20 years ago when grazing was removed from this one small site to give the flora a chance to move off the cliffs and onto the surrounding rocky ground. Change is slow in the UK uplands and we can't expect the flora to recover overnight, but we are already getting spectacular results with drifts of mossy saxifrage along the back of the cwm in summer. Other species which reproduce and spread in a less flamboyant manner will take longer to benefit from the relaxation of grazing, but there are already positive signs of recovery and as an added benefit of this change in management, the heather is regenerating and the bog asphodel looks wonderful in July.
And this brings us to recreation. What about the climbers, I hear people say? Don't they tear out the plants and trample all over their habitat and cause more damage than anything else? Well hopefully not these days, although there will have been gardening in the past. There is one saving factor in the climbing vs conservation debate. As a general rule in the mountains, cliffs which are popular for summer climbing are not usually good for plants, and vice versa. Arctic-alpine plants survive in the UK mountains mainly on cold, north-facing, damp, nutrient rich, friable rocks with plenty of loose flakes and pockets, such as the rocks on the eastern cliffs of Helvellyn and the back of the Devil's Kitchen in Cwm Idwal. Most traditional summer climbing cliffs (with some notable exceptions) are not north facing or friable and aren't usually wet or botanically rich, but where there is a conflict between climbing and conservation interests, agreements are generally worked out to ensure the plants aren't damaged by gardening either deliberately or inadvertently.
But, and there is always a but: these arctic-alpine species may not generally grow on the cliffs we use for summer climbing, but they do like the same north facing, damp cliffs favoured for winter climbing. Here there is potential to damage these rare plants, either through overenthusiastic ice axe placements on poorly frozen turf or clearing plants out of cracks for runners. This is worse in lean winter conditions with little snow or ice cover and each year, whenever there are marginal winter conditions, I fret when I know climbers are out and about, desperate to get a winter fix and unaware of the treasures growing under the ice and snow they are climbing up.
This concerned me so much that a few years ago, I worked with the BMC, staff from the Countryside Council for Wales (now Natural Resources Wales) and Ground Up to produce a booklet to give winter climbers in North Wales information about these plants, where they grow and what to do to avoid damage and cliffs being closed to climbing because of damage. A similar guide was produced for the Lake District. The BMC winter conditions project provides information on temperatures and conditions at key winter climbing cliffs in North Wales and the Lake District, and the UKC winter conditions page provides nationwide information on forecasts and recent ascents, which allow climbers to make informed decisions about whether it is worth travelling hundreds of miles to climb. The aim is to avoid the situation where people turn up at a cliff to find unfrozen turf and minimal ice/snow, but climb anyway because they have travelled so far.
I do get some grief from climbers complaining that they are being unfairly targeted for conservation measures on cliffs, whether it's to protect plants or nesting birds. Our countryside has been affected for many years by far more damaging activities than climbing - such as agriculture, forestry, drainage, construction and pollution - I hear them say, so why target us? The reason is that cliffs and crags are some of the few places in the UK where natural habitats have managed to survive and are often the refuge for plants and animals displaced from their more natural distribution by these widespread operations. The consequences of climbing activities may appear insignificant in relation to the numerous and more substantial pressures on the countryside, but the fact that we undertake our sport in these special areas can dramatically magnify any impact we have.
Hopefully measures like those described above will help protect rare plant species, but some might ask, why worry about plants like the Snowdon Lily? If it grows more widely in other parts of the world, that's fine, look after it there. There is some sense in this and we should focus on species in the UK which are important in a world context, but the flip side to this argument is that populations at the edge of their range (like the Snowdon Lily and Tufted Saxifrage) are often slightly different to those at the centre of their distribution and it is these differences on which evolution works to produce new forms with new potential. If we lose these edge-of-range populations, then we lose this evolutionary potential and then we are into the arena of death by a thousand cuts. Lose a bit here, a bit there and before you know it there is only the central portion left. Also, these species are so important culturally for us all to appreciate locally. It would be a sad situation if the Snowdon Lilies of the world could only be seen in the Himalaya or the Rocky Mountains.
Beyond the Snowdon Lilies, there are lots of other plant species hanging on in small numbers on our UK cliffs, waiting for the chance to spread out onto more accessible rocky places, when (if?) grazing levels are ever reduced enough for them to do so. In the meantime, they need all the help we can give them, but to protect these plants would you be prepared to avoid a particular climb or part of a cliff, or to accept that the snow and ice conditions are poor after you have slogged all the way up to a cliff and go somewhere else? I surely hope so, because if, as cliff users, we can't protect these plants, who can?
The UK plant conservation body Plantlife recently commissioned and produced six short films highlighting the wonderful flora in Wales. Arctic-alpine conservation was covered in one episode. Watch it below: