Limestone: ‘pavement’ plants

This blogpost is part of my ‘limestone lockdown’ project. For an Introduction to the project, and a guide to the growing list of related posts, see Limestone in the Lake District: an Introduction – and the ‘categories’ list in the right-hand bar.

Great Asby Scar, in the Orton Fells on the east side of Cumbria, is one of the best limestone pavements in Britain. From Victorian times until fairly recently, areas of the pavement were plundered and damaged due to the fashion for garden rockeries: indeed, the garden of my own Victorian house has a pile of artistically-arranged limestone boulders, apparently installed as recently as the 1960s and now home to an assortment of ferns and ‘alpine’ plants. Thankfully, the Scar is now protected by several conservation designations – SSSI, SAC and NNR – and monitored and managed by Natural England.

A natural ‘rock-garden’

One route to Great Asby Scar is to leave the motorway at Tebay just before it sweeps up and through the enticingly smooth hills of the Howgill Fells, and head through Orton and up the Orton Scar – into a landscape that is more manageably uniform to the eye and mind than the lumpy, mismatched skyline of the Lakeland fells to the North-West. The countryside opens out each side of the road; sheep, mainly black-faced, white-spectacled Swaledales, wander amongst heather and rough moorland grasses, cattle-grids rattle under the wheels, and occasional patches of woodlands are incongruously dark.

It is a warm day in mid-June, and I’ve arranged to meet Trevor Lowis who, I’ve been assured, ‘knows all about the plants’. We have not met before, and his email tells me he has a pale blue campervan. As I turn into the small carpark I see an old and slightly battered blue campervan already parked, with curtains drawn. I wander across and call “Hello? Hi, Trevor …” A young woman in her thirties, with rich red hair in dreadlocks, pulls back a flowery curtain and leans out of the sliding door, smiling. “Hi, I’m not Trevor. How are you?” It turns out she is on her way from visiting friends in Aberdeen to Bristol, where she hopes to find work. I explain that I’m waiting for someone who is going to show me the flowers on the Scar. “Haven’t you met him before?” she asks. “Are you going on a first date?” I’m still laughing when the real Trevor, driving a pale-blue and immaculate VW campervan arrives.

Trevor – slight, tanned, with brown hair – has the build of a fell-runner and we set off across the moor towards the Beacon at a good pace, stopping to look at various plants along the way. Since he retired from the low-energy construction industry, he tells me he has had more time to concentrate on botanizing, and is now a recorder for the Botanical Society of Britain and Ireland (the BSBI); he has his own hectads (10km x 10km squares) around the Great Asby Scar to survey, recording his finds on the BSBI distribution map. The resulting online Plant Atlas is an extraordinary, free, resource where you can look up the distribution of each species, with photos, maps, and other information.

From the Beacon we head to the Scar reserve, which is enclosed in tall and perfectly-constructed drystone walls, and spend a couple of hours walking, talking and investigating the topography and the botany of the limestone pavements. It’s a glorious day, and a delight to be in such empty, open country, clambering across pale stone under a blue sky.

There are so many different species of grass, of fern, of flowering plants, all with their different preferences, different times of appearance; a plethora of names – Trevor has recorded more than 200 species in his survey area. We point out plants to each other, and he tells me the name and why the plant is interesting. I ask how he has come to know so much and he says he is self-taught, but is quick to point out that he has had “huge and generous support from several very experienced County recorders.” Recording is “just a matter of patience,” he says, of observation, and of checking the visual details with identification keys and photographs. A quick photo taken using the MapMate app on his phone, and the grid reference is automatically recorded, ready to be transferred to the BSBI database.

And so we look at the delicate shivering heads of quaking grass, Briza media, the languidly drooping glaucous sedge, Carex flacca, and the purple moorgrass, Molinia. The forms of the pavement vary from place to place; sometimes they are shallow plates of smooth-topped clints, well-spaced amongst the varied grasses; in other places there are deep bands of rock, sculpted by karren and kamenitsas (see ‘The language of pavements’), the intersecting grikes deep and narrow. There are areas where the lines of grikes are made visible by rows of the pale green, shining and pointed fronds of Harts-tongue Ferns, Asplenium scolopendrium; scattered stunted hawthorns and birches bristle amongst the flat plates. (This is in marked contrast to pavement outside the reserve’s wall, where the wandering sheep have grazed down any saplings that stick their heads above the parapet.)

Trevor knows about ferns, and soon we have a collection of ‘limestone specialists’, large and small, including the greyish-green Rigid Buckle-Fern, Dryopteris submontana, (‘Very rare, on Carboniferous limestones of N England’, according to the Collins Wildflower Guide), and the ‘dull green’ Limestone Fern, Gymnocarpum robertianum. We find tiny Wall Rue, Asplenium ruta-muraria, with fan-shaped leaves, common, and often found growing from the lime mortar of old buildings; and the related but longer Green Spleenwort. There are others with names like Brittle Bladder Fern, Scaly Male-Fern and Hardshield Fern. It’s like a game, what sort of fern can we find next, hiding within or bursting from the grikes. The scientific names taunt me to remember or guess at the Graeco-Latin meanings: aculeatum – prickly, barbed; scolopendrium, Latin version of the Greek for centipede; ornithopoda – bird + foot; pilosella – from ‘hairy’.

(L to R) Dryopteris filix-mas (Common male-fern), Asplenium scolopendrium (Hart’s Tongue), Dryopteris affinis aggregate (Scaly male-fern), Polystichum aculeatum (Hard shield fern ) and probably Dryopteris submontana ( Northern buckler fern ) or Rigid buckler fern

Pink and deep purple spikes of orchids, Early Purple, Common Spotted and the much less common Northern Marsh Orchid are dotted among the grassy areas between the pavements, and here too is a small patch of furry white balls of flowers, Mountain Everlasting, Antennaria dioica. Something new: Trevor photographs and records it. There are too many names for me to remember or note as we work our way through the maze-like pavement and later we sit on a bank in the car-park and Trevor shows me illustrations and reads out names from the Guide. Plants that are thought to resemble the parts of animals – Cat’s Foot, Birds-foot Sedge (Carex ornithopoda), and bright-yellow Mouse-ear Hawkweed, Pilosella officinarum. There was a patch of Hairy Rockcress (Arabis hirsuta,‘erect unbranched, pubescent’), and mats of white-flowered Limestone Bedstraw. Some were common, others restricted to limestone country. It’s always thrilling to find rare species, whether plant or animal, and tempting to tick boxes, but it has been even more thrilling this morning to see such richness and variety in what, at first glance, might seem like an uninhabited rock-scape; a difficult terrain.

Wall Rue

We had walked up onto a slightly raised area which has been identified as a Romano-British settlement of stone hut circles, Castle Folds. A large-diameter circle of tumbled stones hints at the wall that circumscribed the camp, now all that remains of a barrier that was apparently about three metres high. It is a good vantage point, from where you can look down into the valley and with clear views on all sides. But where is the water? We puzzle where the inhabitants could have obtained water for themselves and their animals.

Remains of the wall at Castle Fold

And so it is with the plants that live within the cracks and deformities of the limestone pavement; the micro-climate in the grikes is humid and protected from excesses of temperature and dehydrating winds, but there are other plants, like ferns and herbs, rooted in tiny crevices or in sparse soil at the edges of hollows and grooves where water infrequently collects. They are indeed specialists, adapted to live in a unique landscape.

This entry was posted in LIMESTONE, limestone pavements and tagged , , , , . Bookmark the permalink.