10
The Lowland Fringe

‘To the visitor with an interest in natural history, the first impression
of the Lowlands of Scotland is of a tidy, well farmed scene…In the
broad valleys and foothills the naturalist must be selective, and seek
out those relatively wild places which have been ignored by agriculturists
and foresters, or which, due to the efforts of the old estates, have
been preserved down the ages specially for amenity and sport.
What he will find is a surprising diversity of flora and fauna within a
small compass.’

‘The Lowlands’ (James McCarthy) in
Wildlife of Scotland (Holliday, 1979)

Occupying roughly a quarter of Loch Lomondside’s land surface, most of the area under consideration as Lowland fringe lies below the old head dykes and, with the exception of the low-lying ground between Arden and Luss, south of the Highland Line. Ever since the first Neolithic settlers first cleared the forest and cut into the predominantly sandy soils with their primitive ploughs, the principal use made of the Lowland fringe has been mixed farming, although with the gradual increase in animal husbandry over the last 50 years, little more than five per cent of the cultivatable ground is currently given over to cereals and other crops. The present emphasis in agricultural practice is firmly placed on improved grassland, with a high stocking rate of cattle and sheep.

Despite the long history of farming on southern Loch Lomondside, the familiar patchwork of individual fields dates back no further than the eighteenth century, when the open ground was enclosed by planting thorn hedges and building dry stone dykes (Fig. 10.1), altering the former open landscape beyond recognition. In recent years the practice of enclosure has gone into reverse, with some internal hedges grubbed-up to create the field size required by the larger farm machinery. The remaining hedges and stone dykes are being steadily replaced by more easily maintained fences of posts and wire. Throughout the Lowland fringe, the last few decades have witnessed an accelerated loss of some of the most productive farmland to both housing development and new road construction, this encroachment at its most noticeable in the Vale of Leven.

Plant and animal life of the Lowland agricultural land

Herb-rich pasture on Loch Lomondside was well in retreat even before the outbreak of the Second World War in 1939. With the interruption of essential food imports from abroad due to enemy blockade, County and District Agricultural Committees were formed to enforce the ploughing-up of permanent grassland for cereals and other crops in a drive for national self-sufficiency. Only those pastures with very shallow soils or which were particularly difficult to drain were exempt. Today, the same fields which have also escaped modern selective herbicides and grass fertilizers are just about all that remains of a bygone low input/low output agricultural age. These grasslands’ continuity with the past is evident from the variety of flowering plants found in their undisturbed turf. Typical representatives are bird’s-foot trefoil (Lotus corniculatus), purging flax (Linum catharticum), yellow rattle (Rhinanthus minor), lady’s bedstraw (Galium verum), mouse-ear hawkweed (Pilosella officinarum) and flea sedge (Carex pulicaris). One of the best remaining examples of ancient pasture is to be found beside Dumbrock Loch near Mugdock (Plate 7). Dumbrock Muir’s relict grasslands owe their survival to the underlying basaltic lavas lying so close to the surface that ploughing the land was impracticable. Several uncommon species are to be found growing on the drier and in places moderately alkaline soils, including moonwort (Botrychium lunaria), burnet-sax-ifrage (Pimpinella saxifraga), field gentian (Gentianella campestris), mountain everlasting (Antennaria dioica) and fragrant orchid (Gymnadenia conopsea). A recent decline in the hitherto strong colony of frog orchids (Coeloglossum viride) has been attributed to the cessation of winter cattle grazing, which kept the coarser vegetation under control. Open grassland butterflies such as the common blue (Polyommatus icarus), small copper (Lycaena phlaeas) and small heath (Coenonympha pamphilus), together with the six-spot burnet moth (Zygaena filipendulae), favour the warm, south-facing slopes that lead down to the loch. A contrasting type of old pasture can be found in a drainage-impeded hollow near the southeast corner of Loch Lomond. Known as the Whin Park, this overgrown field is all that remains of the communal grazings of the former farm township of Aber, the soil just too wet and peaty for worthwhile agricultural improvement. Although dominated by purple moor-grass and sharp-flowered rush (Juncus acutiflorus), the sward is considered exceptional for its abundant gypsywort (Lycopus europaeus), bog asphodel (Narthecium ossifragum) and whorled caraway (Carum verticillatum), with occasional tawny sedge (Carex hostiana) in the water seepage areas. Well sheltered from the boisterous westerly winds by the adjoining woodland and heathy scrub, the Whin Park has also been identified as a key site for grassland moths, including the nationally scarce pyralid moth Crambus uliginosellus.

Fig. 10.1 The pattern of field enclosure in the Lowland fringe was not laid out until the eighteenth century.

Fig. 10.2 The Twenty Acres Meadow; a flood meadow once regularly harvested for marsh hay.

Traditional floristically-rich hay meadows on the better drained land have completely disappeared, replaced by artificially fertilized monocultures of cultivated grasses intended primarily for the production of silage. A few former bog (marsh) hay meadows enriched by river or stream-borne silt linger on, although the days of harvesting the lush vegetation for animal fodder and bedding is just a distant memory. Only one such meadow is still regularly cut – the Twenty Acres (Fig. 10.2) in the lower flood plain of the River Endrick. Very little of this damp field appears ever to have been ploughed, and its flora is made up of well over a hundred different meadow and marshland plants. An abundance of tufted loosestrife (Plate 8) is one of the meadow’s many delights. The continuing presence of the Loch Lomond dock in the wetter parts of the field calls for explanation, as the field is usually mown at the beginning of August, well before this late-flowering species reaches the stage of ripe seed. Persistent rain followed by flooding will delay the cutting for a month or more in only about one year in ten, but this would appear sufficient to maintain at least small populations of this rare water dock and other late-seeding perennial species. All of the other remaining bog hay meadows on Loch Lomondside are in a derelict and overgrown condition, used now only for rough grazing. Of these, one especially worth preserving is the Bog of Ballat, a high profile site beside the junction of the A81 and the A881 on the extreme eastern edge of the region. Last cut by scythe in the late 1940s, the central compartment of Ballat meadow has a very uncommon sward of brown sedge (Carex disticha), with globeflower in the adjoining compartment to the south.

The population of breeding birds found on Loch Lomondside’s lowland farmland can fluctuate year by year through weather-related causes alone, but more permanent decreases in numbers of some species have been attributed to recent changes in agricultural management practices. With the trend towards improved grassland and a reduction in cereal growing, the virtual elimination of many arable weeds and the unavailability of autumn stubble has been matched by significant population declines in the small seed-eating birds. One species, the corn bunting (Miliaria calandra), has vanished from the area altogether. Gone too is the corncrake (Crex crex), its eggs and small young all too readily destroyed by the early cropping of grass for silage, which has replaced the cutting of hay in late summer. Other farmland birds have been affected by the gradual loss or deterioration of the once substantial stock-proof hedges and accompanying hedgerow trees. No longer carefully maintained by hand, farm hedges today are mechanically trimmed with cutter-bars or flails, in the process decapitating the young saplings which would have become the next generation of hedgerow trees. These skimpy hedgerows can also be subjected to pesticides, either indirectly by wind-drift or, on occasions, deliberately targeted for harbouring agricultural weeds and invertebrate pests. The end result is that most hedgerows on Loch Lomondside provide little in the way of protective cover, nest sites or food for small birds.

A breeding bird survey carried out on a 133.5 ha mixed agricultural plot in mid Strathendrick for ten nesting seasons from 1975 showed that the overall population (less uncensused wood pigeons, starlings and carrion crows) averaged almost 300 pairs per km², between three to four times the density of birds occupying the most intensively farmed arable land on the east side of Scotland. The top ten passerine species (in descending order) were chaffinch (Fringilla coelebs), willow warbler, skylark (Alauda arvensis), blackbird (Turdus merula), yellowhammer (Emberiza citrinella), blue tit (Parus caeruleus), wren, robin (Erithacus rubecula), great tit (P. major) and song thrush (T. philomelos), the high percentage of woodland birds represented being a reflection on the large number of small woods and plantations scattered throughout the Lowland agricultural zone (Fig. 10.3). Changes noted during and immediately after the survey period included a significant reduction in the populations of skylarks, yellowhammers, grey partridges (Perdix perdix) and lapwings. The sharp fall in skylark numbers was attributed to an increase in silage making, as the early cut destroys their nests. Yellowhammers were affected not only by the severe pruning of hedges, but the clearing away of patches of gorse as part of a general ‘tidying-up’ which took place in the study area. The virtual disappearance of the grey partridge from the area appeared connected to the practice of ploughing right up to the hedgerows for increased yield, in the process removing the field margins where formerly the partridges and their young found much of their invertebrate food. As a breeding species the lapwing was well established (up to 29 pairs) in the Strathendrick study plot, but has since fared badly not only there, but throughout southern Loch Lomondside. Until recently, two of the largest concentrations of lapwing were to be found along the flatlands of Strathblane and Glen Fruin; both originally the beds of pro-glacial lakes as described in Chapter 3. Several factors involved in the lapwing’s decline have been identified, not least land drainage which makes possible the conversion of rush-infested grazings to improved grassland. Following draining and re-seeding, much higher numbers of cattle and sheep can be kept, increasing the risk of ground nests being trampled underfoot. Incubating lapwings are also more conspicuous on grasslands that are closely cropped, adding to the chances of nest predation by crows. The local populations of redshank and common snipe have been similarly affected by the upgrading of damp pasture into improved grassland.

Fig. 10.3 Small woods and plantations are a feature of the agricultural land in mid-Strathendrick.

It has not been all doom and gloom for the region’s farmland birds. At one point it seemed likely that the barn owl might be lost, but the timely provision of specially constructed nest boxes to replace the rapidly disappearing lofted outbuildings to farms formerly used as breeding sites, has initiated a promising recovery in barn owl numbers; this despite an overall reduction in the availability of small animal prey on the best land due to the attrition of hedges and field margins. Most barn owls in the area are very dependent on the short-tailed voles (Microtus agrestis) they can still find in the longer grass of the peripheral rough grazings and newly established forestry plantations. When vole numbers are high, as in 1997, the eight pairs of barn owls monitored that year successfully reared an average of over three young each. Another species that has made a comeback on the lowland agricultural ground is the common buzzard (Buteo buteo). Once banished from the Lowland fringe by game preservers, it is now the most widespread bird of prey. Farmland interspersed with numerous small woods is the species’ favoured habitat, with densities of up to 25 occupied territories per 10-kilometre square where there is a healthy population of rabbits (Oryctolagus cuniculus) and persecution in defiance of the law has completely ceased. The buzzard is very much an opportunist hunter and scavenger; mole, salmon, powan, slow-worm (Anguis fragilis) and even common frog (Rana temporaria) are among the less usual items that have been identified at local nests. Raptor enthusiasts look forward to the day not too distant when the soaring buzzard in the Lomondside sky is joined by the red kite, following a successful release programme of young kites in central Scotland. Before the species was ruthlessly extirpated by nineteenth-century game preservers, the resident minister for Campsie observed ‘so common is the glade [red kite] with us that its various modes of flight are considered an almanac for the weather’.

No resident bird on Loch Lomondside’s lowland farms has attracted ornithologists’ attention more than the rook (Corvus frugilegus), with periodic nest counts at breeding colonies dating back to 1945–46. In the immediate post-war years almost all the rookeries were to be found in the grounds of country houses, one long-established colony totalling over 600 nests. With the gradual fragmentation of many of the larger estates and felling of mature trees, the larger rookeries dispersed, in the process trebling the number of separate but smaller colonies. Oak and Scots pine share equal first place in the rooks’ choice of nesting tree. Recent census figures have showed that, under a predominantly grassland regime, the overall number of nesting pairs increases or decreases with the rise or fall in the comparatively small amount of land under cultivation. The present population of rooks on the 16,835 ha of Loch Lomondside’s improved low ground is around 2,700 nesting pairs, a high density for northwestern Britain and one reflecting the wide range of feeding opportunities available to the birds. One potentially lean period for rooks is the occasional sustained dry spell in late spring, when the birds desert the hard-crusted fields to feed on the superabundance of defoliating caterpillars in the neighbouring oak woods. If the drought persists, they move on to the still damp high ground of the surrounding hills. Winter too can be a difficult time for rooks, especially after a heavy fall of snow. At such times they concentrate where cattle and sheep are feeding in the fields. Not only do the foraging beasts scrape through the snow to expose potential food sources for the rooks in the ground below, the birds are quick to take advantage of anything they can find edible amongst the supplementary fodder put out for the stock. A welcome bonanza of invertebrates is also provided with the winter spreading of byre manure over the frost-stiffened fields.

Best known of all the mammals that inhabit the lowland agricultural ground are the mole, rabbit and brown hare (Lepus capensis). Although the mole is seldom seen above ground, its conspicuous strings of mounds in the cultivated grasslands attract both the casual observer’s attention and the farmer’s wrath (Fig. 10.4). A recent upsurge in their damaging activities has been attributed to the virtual disappearance of the professional mole-catcher. Rabbits were unknown on Loch Lomondside until the 1820s, when the newly improved agricultural land proved so congenial to the early colonists that they rapidly increased to pest proportions. By the end of the nineteenth century the Montrose Estate gamekeepers alone were killing nearly 5,000 rabbits each year in an effort to limit damage to pasture and crops. The first real check on the rabbit population came with an outbreak of the virus disease myxomatosis in 1955, followed by a more severe reoccurrence two years later. One of the consequences of the rabbit coming close to local extinction was a dramatic reduction in the numbers of the animal’s predators, such as the stoat (Mustela erminea) and weasel (M. nivalis). From an agricultural point of view it was an opportunity missed not to have mopped up the last few rabbits, for the survivors’ descendants have developed a partial immunity to the disease, leading to the population increasing again year by year, together with reports once again of damage to crops. Estimated losses to agriculture throughout Scotland have once again risen to several million pounds per annum. Like the rabbit, the brown hare population on Loch Lomondside has had its ups and downs. Numbers rose in line with agricultural development, but then decreased significantly following a change in the law in 1880 which gave tenants equal rights with landowners to kill and take ground game. This in turn led to the Hares Preservation Act 1892, which afforded the hares a measure of protection during their breeding season, March–July. Although relatively common throughout the southern agricultural zone, the brown hare’s presence is not always easy to detect because of its habit of lying up in its concealed ‘form’ during the day and feeding by night.

Fig. 10.4 Fresh molehills thrown up through the snow show that the animal is active all year round.

The older faunal works covering the Loch Lomond area distinguish only three species of bat – pipistrelle (Pipistrellus pipistrellus), brown long-eared (Plecotus auritus) and Daubenton’s (Myotis daubentonii). Thanks to an upsurge in interest in these small nocturnal mammals, breeding colonies of natterer’s (M. nattereri), whiskered (M. mystacinus) and the recently described soprano bat (Pipistrellus pygmaeus) – the last so named because it echolocates using a higher frequency than the closely related pipistrelle – have all been found in the district. This extended list is probably still incomplete, as improved identification techniques have shown Nathusius’ pipistrelle (P. nathusii) to be present in the neighbouring Forth Valley.

Roadside verges

At the end of the eighteenth century, the naturalist Thomas Garnett, touring Scotland, wrote in his journal:

‘Both sides of the road from Dumbarton to Luss are interesting to the botanist. The Digitalis purpurea, or foxglove, enlivens the hedgerows the whole way with its purple spikes: opposite Cameron, are amazing quantities of the Spiraea ulmaria, or meadow-sweet, and Valeriana officinalis, or great wild valerian, the largest I ever saw. Near Ross Lodge, on the opposite side of the road, the Narthecium officinalis, or bog asphodel, grows in abundance. In many parts of the road between Rossdhu and Luss, the Erica tetralix, or cross-leaved heath, beautifies the banks with its elegant purple flowers.’

A contemporary travel guide writer on the same highway where it passed through the Vale of Leven added: ‘beautiful hedges bound the road, which in the season of summer, are finely interwoven with the wild rose, honeysuckle and other sweet smelling plants’. One thing is certain – neither would recognise this much changed main thoroughfare today.

Left undisturbed, grassy verges fringing the sides of the country roads can offer a refuge for flowering plants and ferns that have been unable to withstand modern farming practices on the other side of the fence. Roadside verges also act as a means of plant and animal dispersal through areas of intensive farming, the recent east to west spread of the ringlet butterfly (Aphantopus hyperantus) in southern Loch Lomondside being a case in point. Yet it is a wildlife habitat that is all too often taken for granted; one that is all to easily destroyed under the current programme of road widening and straightening necessitated by the continuing increase in vehicular traffic. One individual casualty already has been spignel (Meum athamanticum), this locally rare umbellifer now lost from its only known roadside site. Less obvious, but affecting the botanical quality of the verges none the less, is the disappearance of the old-style parish roadman or ‘lengthsman’, his often selective scything around the more herbaceous stretches replaced with a uniform trim by machine and (thankfully not a regular occurrence) spraying the verges with a chemical herbicide.

Although most of the local verges have very limited floras, a few stretches can produce a pleasing diversity of species before the tall grasses take over in mid summer and the local authority mechanised cutters appear on the scene. Usually the earliest spring flower of the wayside to be noticed, even from a moving car, is the appropriately named jack-by-the-hedge (Alliaria petiolata), immediately followed by cow parsley (Anthriscus sylvestris), occasionally in such profusion as to turn entire roadsides snow-white. The observant pedestrian will quickly discover that the most productive spots for wayside flowers and ferns are to be found where the older, scarcely modernised back roads wend their way through undulating glacial topography, giving the verges to these partially sunken byways a three-dimensional profile, the upper half of the bank out of reach of the damaging effects of combustion engine fumes and road de-icing salt. A good example can be seen near the Park of Drumquhassle on the brow of the Gartness road, where in May its seasonal splash of colour includes a patriotic display of red campion (Silene dioica), the white flowers of earthnut (Conopodium majus) and bluebell (Hyacinthoides non-scripta) (Fig. 10.5). The richness of the verge flora there is not by chance, for this part of the road is the last surviving stretch of a very old and long-since abandoned direct route from Drymen to Killearn. By way of contrast to Drumquhassle, a heathy flora can be found on the south-facing raised verge close by the Loup of Fintry on the Carron Valley road. Amongst the plant assemblage on these less fertile hill soils are ling heather, blaeberry or bilberry (Vaccinium myrtillus), mountain pansy (Viola lutea) and bitter-vetch (Lathyrus linifolius var. montanus), along with the shuttle-cock shaped tufts of the golden-scaled male fern (Dryopteris affinis). Different again are the verges near the radio mast at the summit of the Muirpark, where the soft peaty ground regularly catches out unwary motorists as they attempt to pass one another on this single track road. Characteristic of these rather wet acidic soils are bog asphodel, heath spotted orchid (Dactylorhiza maculata ssp. ericeto-rum), common butterwort (Pinguicula vulgaris) and an eyebright with a northwesterly distribution, Euphrasia arctica ssp. borealis.

Fig. 10.5 Ancient roadside verges can be rich in wild flowers and ferns.

Apart from spignel already mentioned, a few other locally uncommon plant species have been reported from the Lomondside roadside verges. The broadleaved helleborine (Epipactis helleborine) grows alongside a now bypassed wooded section of the Strathblane road immediately south of Blane Smithy. Another – the great horsetail (Equisetum telmateia) – has conspicuously colonised a verge in Glen Fruin, just a short distance east of the dismantled old bridge at Dumfin. A single patch of melancholy thistle (Cirsium heterophyllum) manages to survive beside the northern approach to the Queen’s View, despite the almost annual decapitation of the flowers by the grass cutter before they have a chance to set seed. A few stretches of roadside hedgerow contain species that are virtually unknown elsewhere in the area, such as hop (Humulus lupulus) and field rose (Rosa arvensis), both either deliberate or accidental introductions. Also worth looking for are some fine clumps of the extremely local rustyback fern (Ceterach officinarum) growing on a roadside wall bordering the Edenkiln road from Mugdock to Strathblane.

Non-indigenous plants springing from thoughtlessly discarded garden refuse are a fairly frequent sight in the roadside verge, although few species can survive the competition from the vigorously growing grasses for more than a season or two. One that has proved persistent is Pilosella aurantiaca from Central Europe, this vivid orange coloured hawkweed going under several English names, the devil’s paint brush being one which describes the flower particularly well. There are also several instances of native species taken into cultivation for use as ornamental garden plants, only to make their escape back into the wild by spilling out on to the adjoining roadside verge; lords and ladies (Arum maculatum), orpine (Sedum telephium) and pendulous sedge (Carex pendula) are three Loch Lomondside examples that come to mind.

An unusual mix of plants has been recorded springing up on the landscaped verges to the region’s new roadworks. Unlikely bedfellows such as cowslip (Primula veris) and northern marsh orchid (Dactylorhiza purpurella) grow almost side by side. Apart from the seeded grasses, most of the introduced species decline and often disappear after only a few seasons. One of the exceptions is the oxeye daisy (Leucanthemum vulgare), which occurs in some abundance alongside the upper route through Glen Fruin. Another survivor is likely to be the dwarf gorse (Ulex minor), planted as a soil stabiliser beside the same road. Hybrid lupins (Lupinus x regalis) and massed daffodils (Narcissus spp.) have been used to create seasonal swathes of colour along the bypass to the Vale of Leven.

Kirkyards and castles

Botanists delight in old edifices that are in a picturesque state of decay, for the nooks and crannies where the crumbling mortar has fallen away offer sanctuary to rock plants, some of which appear to flourish better on this artificial substrate than in their natural habitat; that is until the decision is taken to tidy the buildings up. Local historian John Guthrie Smith wrote that the walls of Duntreath Castle in Strathblane were covered in wild flowers and ferns before renovation work was carried out in the mid-nineteenth century.

Today, grass cutting in kirkyards throughout the Loch Lomond area is undertaken with such Calvinistic zeal that even those wild flowers that formerly escaped the scythe or mower by growing close to a memorial stone or wall, are now efficiently dispatched with the ubiquitous strimmer. It would not be too far from the truth to say that the botanical interest of most of these kirkyards is now confined to the lichen-covered gravestones and the occasional unpointed boundary wall. The early headstones are of local sandstone and usually very plain in design, so that their appearance can be enhanced by an encrustation of lichens (Fig. 10.6). But as one visitor to the island burial ground on Inchcailloch observed, they render their engraved wording increasingly difficult to read:

Fig. 10.6 An early nineteenth-century gravestone in Drymen kirkyard with a well-developed lichen flora.

‘I trace the old inscriptions dear,
Fast fading now from mortal ken,
And through the silvered lichens peer,
To read MacAlpine’s [MacGregor’s] name again’.

Those with a special interest in this group of small flowerless plants will almost certainly wish to visit Luss kirkyard to see the memorial stone to the Reverend John Stuart D.D. (1743–1821), amongst other things an early liche-nologist of note. Apart from lichens, there is not a great deal growing on the well-maintained churches themselves. An exception is the now roofless Old Kirk of Killearn, its time-worn stonework adorned with a variety of species including the rustyback fern. Flowering plants and ferns most likely to be found on the kirkyard perimeter walls are ivy-leaved toadflax (Cymbalaria muralis), wall-rue (A. ruta-muraria), maidenhair spleenwort (A. trichomanes), hart’s-tongue (Phyllitis scolopendrium) and the common polypody (Polypodium vulgare). In late spring, the internal face of the east wall to Strathblane kirkyard is enlivened by an impressive show of the naturalised fairy foxglove (Erinus alpinus). Almost every Loch Lomondside kirkyard has its evergreen symbol of immortality – the yew tree – usually the cultivated Irish variety which is readily distinguished from the common form by its upswept limbs.

Turning to four ruinous old castles in the district, Rossdhu Castle is Loch Lomondside’s only known site for pellitory-of-the-wall (Parietaria judaica), a herbal remedy once prescribed for a variety of common complaints. Crevices in the walls of Kilmaronock Castle have been colonised by the naturalised mossy sandwort (Arenaria balearica) and Siberian wallflower (Erysimum x marshallii), while Bannachra Castle in Glen Fruin is covered with garden flowers in profusion. In the late eighteenth and early nineteenth centuries, a sightseeing visit to the pair of ospreys nesting on top of Inchgalbraith Castle in the loch formed part of the Scottish ‘grand tour’. Amongst those who took a boat out to this island castle to see the nest was the celebrated Dr Johnson and his companion James Boswell in 1773. Today, it is common gulls that find sanctuary on the castle ruins.

For all-round natural history interest, Dumbarton Castle, perched on its twin-topped volcanic plug, is in a class on its own. Formerly surrounded by the sea at high tide, Dumbarton Rock’s ‘island’ character was lost during the late eighteenth century when the extent of the intertidal area was reduced through the dredging of a deep navigation channel in the estuary of the River Clyde. This allowed the saltmarshes on the north side of the castle to be reclaimed and developed for industrial use. The Rock itself, with its cloak of spring flowers, has for many years been a special favourite with botanical excursionists, not least to search for the naturalised culinary and medicinal herbs formerly grown in the castle’s kitchen and physic gardens. Heading the list of both native and introduced species that are eagerly sought after because of their very restricted distributions in the west of Scotland are greater celandine (Chelidonium majus), musk mallow (Malva moschata), common mallow (Malva sylvestris), wallflower (Erysimum cheiri), spring vetch (Vicia lathyroides), Alexanders (Smyrnium olusatrum) (Fig. 10.7) and hemlock (Conium maculatum). The early botanists also recorded Our Lady’s thistle (Silybum marianum) – a plant with early religious connections and one of the contenders for the title of the true Scottish thistle – woolly thistle (Cirsium eriophorum) and that malodorous flower, the henbane (Hyoscyamus niger). All three now seem to have disappeared. In times past, Dumbarton Rock was justly famous for two associated birds. The first – the peregrine (Falco peregrinus) – had from time immemorial nested on one of the more precipitous cliffs. King Robert I employed three professional falconers at his Levenside manor house just a short distance away, so that it is conceivable that Dumbarton Rock was one of their sources of young peregrines selected for training. They were almost certainly taken by falconers in the service of the sporting 11th Earl of Eglinton, who was governor of the castle from1764–82. The occupied peregrine eyrie on the Rock was examined on one occasion by the late eighteenth–early nineteenth-century ornithologist Colonel George Montagu, who noted that both red and black grouse (Tetrao tetrix) were brought to the nest as food for the young. If peregrines ever return to this once favoured site, it is unlikely they will get the opportunity to dine very often on such rich fare again. The second bird of historical interest is the barnacle goose (Branta leucopsis); as early as 1597 annual wintering flocks were described as feeding on the mud flats and salt marshes around the Rock. Loss of estuarine habitat and continual disturbance by boatloads of shooters eventually caused the geese to move elsewhere. Ravens looking for an opportunist meal still occasionally haunt the castle walls, just as their ancestors must have done from man’s earliest occupation of the site.

Fig. 10.7 Alexanders was probably introduced as a potherb to Dumbarton Castle’s kitchen gardens.

Parkland

Many of the private parklands that once provided the picturesque settings to Loch Lomondside’s oldest country mansions have been put to other uses, such as golf courses, housing and industrial estates. For a number of years the one surrounding Cameron House was run as a safari-style wildlife park, leading to a string of exotic escapes from skunks to brown bears. Other proprietors of parks have been responsible for the introduction of ornamental wildfowl, the most successful being the Canada goose (Branta canadensis). From the first escaped pair discovered nesting on Loch Lomondside in 1968, feral flocks established in the area together exceed 250 birds.

The largest of the remaining parks is the 81 ha Balloch Castle Park situated beside the loch’s southwestern shore. Although it has a history dating back to the motte and bailey castle of the early Earls of Lennox, the planted woodlands and great sweeps of open grassland around the present castellated building were not laid out until the nineteenth century. Subsequently purchased by the far-sighted Corporation of Glasgow as an open air ‘lung’ for its smoke-weary citizens, the estate was formally designated as a country park in 1980. Despite the popularity of Balloch Country Park with recreation seekers, the grounds are by no means devoid of wildlife interest, the combination of land and waterside habitats ensuring a wide range of breeding birds. Woodland species predominate, with the novice ornithologist given ample opportunity in spring to learn to distinguish between the similar songs of the garden warbler (Sylvia borin) and the closely related blackcap (S. atricapilla) coming from the well-established clumps of rhododendron. A favourite pastime amongst visitors to the park is feeding the remarkably tame squirrels. Originally these were all red squirrels (Sciurus vulgaris), but today this native animal has been entirely usurped by the North American grey (Neosciurus carolinensis). First introduced into the west of Scotland in 1892, the grey squirrel had spread to Loch Lomondside by 1903, colonising the entire area within 40 years. Other midsummer attractions of Balloch Country Park to the naturalist include a variety of the more common butterflies drawn to the sun-lit flowering shrubs in the vicinity of the visitor centre, the many hundreds of greater butterfly orchids (Plantanthera chlorantha) that appear in the uncut grassland, and bats flitting around the castle turrets at dusk.

Parkland elms throughout southern Loch Lomondside are very much at risk of Dutch elm disease which has swept much of Britain, having apparently been introduced into the country with imported timber. The unwitting carrier of the deadly fungus Ophiostoma nova-ulmi is the elm bark beetle (Scolytus scolytus). Since diseased trees were first reported in the west of Scotland in 1975, elms within the grounds of Culcreuch and Balloch Castles have been particularly badly affected.

The legacy of mineral exploitation

Opening up the ground for minerals can permanently disfigure the landscape, so it is fortunate that the majority of Loch Lomondside’s quarries and pits in the Lowland fringe and southern foothills have been on a relatively small scale. The most prominent eyesore of the nineteenth century was the Camstradden slate quarry near Luss, but even there woodland regeneration is well on its way to healing over the scar. Despite their initial unsightly appearance, there is no question that old mineral workings can provide a refuge for certain plants and animals whose natural habitats the quarry resembles. All too frequently, however, large holes in the ground are seized upon as convenient places for the dumping of domestic refuse and other waste material, euphemistically described as land-fill or land-restoration sites.

The worked faces of disused red sandstone quarries, particularly those in some dark and damp recess, are eminently suited to a luxuriant growth of ferns. Although most of these are ubiquitous species, Dalreoch and Bonhill sandstone quarries can both lay claim to the royal fern, although it is possible the first colonists originated from garden stock rather than from the wild.

Associated exclusively with Upper Old Red Sandstone are beds of calcium carbonate rich rocks known as cornstones. Valued as an agricultural fertilizer up to the mid-nineteenth century, former cornstone workings can be traced in the district from Carman Muir in the west to Kippen Muir in the east. The heaps of discarded spoil are almost always closely grazed by sheep, but the wet flushes that drain from them can be rich in calcicole (lime-loving) plants, such as the lesser clubmoss (Selaginella selaginoides), broad-leaved cottongrass (Eriophorum latifolium), few-flowered spike-rush (Eleocharis quinqueflora), dioecious sedge (Carex dioica) and long-stalked yellow sedge (C. viridula ssp. brachyrrhyncha). On Loch Lomondside, the delicate bog pimpernel (Anagallis tenella) appears confined to the cornstone flush habitat.

Carbonated serpentinite, which outcrops in the Highland Boundary Fault zone, was also used as an agricultural fertilizer. It is to be regretted that most of the calcium-rich serpentinite exposures and flushes on Ben Bowie overlooking the west side of the loch have been largely covered over by a recently established conifer plantation, but at Creag Mhor on the opposite side of the loch, the dry spoil heaps from the quarry have abundant stone bramble (Rubus saxatilis) and false brome grass (Brachypodium sylvaticum). The plant assemblage in the seepage zone below the worked serpentinite on Conic Hill is very similar to that found in the cornstone flushes, but with the addition of the black bog-rush (Schoenus nigricans), a species generally confined to the coast in the west of Scotland. Of interest to the fern specialist is a serpentinite form of the black spleenwort (Asplenium adiantum-nigrum). Distinguished by its less rigid and more broadly triangulate fronds (Fig. 10.8), it is now recognised as an ecotype rather than a distinct species. Higher up the hillside, serpentinite-influenced boggy vegetation with marsh violet (Viola palustris) and marsh thistle (Cirsium palustre) is a favoured habitat of the dark green fritillary (Argynnis aglaja), this fast-flying butterfly on the wing from mid-July.

Fig. 10.8 The serpentinite form of the black spleenwort fern.

Glacial sands and gravels have been extensively worked in southern Loch Lomondside. When freshly excavated the disturbed ground temporarily acts as a refuge for once common arable weeds, which have become very restricted in their distribution with so few fields now under the plough. Amongst several locally uncommon species that occur in these abandoned pits are yellow bartsia (Parentucellia viscosa), great mullein (Verbascum thapsus) and weld (Reseda luteola), the latter formerly cultivated as a yellow colouring agent used by the then thriving textile industries in the Vale of Leven. Infill material of unknown origin dumped in the worked-out sand and gravel pits in the Vale is probably responsible for the unexpected appearance of several species of mainly southern distribution in Britain; the smooth tare (Vicia tetrasperma) and spiked sedge (Carex spicata) at Dillichip and the grass vetchling (Lathyrus nissolia) at Dalmonach are three which have attracted the botanical recorder’s eye. Such casuals usually disappear when the workings become overgrown or the site is redeveloped. Now nearing the end of its working life, Drumbeg pit near Drymen has for many years boasted the largest sand martin colony in the Glasgow area, at peak over 600 pairs strong. On the west side of the loch, the Midross quarry is sited beside the lower reaches of the Fruin, an area of old river meanders noted for its wetland birds even before sand and gravel extraction created the first artificial lagoons. Excavations began in 1947, each worked-out and then water-filled pit being left to the natural process of ecological succession. Shingle-nesting species such as the ringed plover, oyster-catcher and common tern (Sterna hirundo) have now all but given way before the encroachment of willow, alder, birch and broom (Cytisus scoparious), their place taken by a community of scrubland birds, with sedge warbler, garden warbler and lesser redpoll (Carduelis flammea) amongst the earliest colonists. Shelduck prospecting for nesting holes have on occasions been attracted by rabbit burrows in the sandy banks. Elsewhere, the partially water-filled Muirhouse Muir quarry near Blanefield attracted over 300 nesting pairs of black-headed gulls (Larus ridibundus) within a few years of gravel extraction coming to an end. The totally flooded workings adjoining Drumkinnon Bay were much frequented by coarse anglers before work began on the site for a major tourist development, with crucian carp and tench known to have been introduced. Even the smallest area of standing water in the sand and gravel pits can quickly attract several species of dragonflies and damselflies, including the common and Highland darters (Sympetrum striolatum and S. nigrescens), both recent additions to Loch Lomondside’s invertebrate fauna.

The zoological interest of other abandoned mineral workings has attracted little attention. Until a rock fall destroyed the chosen ledge, a pair of peregrines nested on a worked face of Camstradden slate quarry; and before the quarry was infilled, the mounds of discarded slate dross formed a shady hideaway for the slow-worm. A curious find was a small population of almost colourless common frogs living in the semi-darkness of a partially flooded barytes mine near Kilmannan Reservoir. The only obvious sources of food for these underground mine-living frogs are hibernating herald moths (Scoliopteryx libatrix) and flies (Diptera) on the passage walls.

Lochs and reservoirs

Standing waters of natural origin are not a prominent feature of the lowland agricultural zone. Of the two largest, Loch Ardinning south of Blanefield is a glacially excavated rock basin lochan, whereas Caldarvan Loch in Kilmaronock nestles amongst mounds of glacially deposited material. Both have a long history of maturation and are rich in wildlife interest.

Fig. 10.9 Caldarvan Loch is affected by water enrichment through its close proximity to agricultural land.

Loch Ardinning, whose size has been increased by damming, is one of a number of natural and artificial water bodies which once served the former corn mill and textile industries in Strathblane. Protected from the prevailing wind by a wood along the loch’s western perimeter, Ardinning’s emergent aquatic vegetation is well developed, including a fair-sized stand of common reed. The little grebe (Tachybaptus ruficollis) is very much at home in this reed bed habitat. What is fairly unusual for a lowland loch is the well-established presence of water lobelia, which flowers profusely if the surface level is drawn down in summer. Loch Ardinning drains into the Mill Dam just a short distance away, a small but attractive water body noted for greater spearwort (Ranunculus lingua) and round-leaved crowfoot (R. omiophyllus), both uncommon plants in the region.

Caldarvan Loch (Fig. 10.9), on the Blaeu map of the Province of Lennox (1654) shown as Loch Breac – the loch of the trout – suffers from the problem of over-enrichment as a consequence of fertilizers finding their way in to the loch from the surrounding agricultural land. During warm weather in summer, a thick algal growth covers large areas of the water surface, stifling underwater plant and animal life alike. The coot (Fulica atra), which is one water bird that can thrive in such a nutrient-rich environment, occurs in good numbers. Caldarvan’s botanical interest lies in the lush plant growth that has spread over the water surface at its western end. Common aquatics such as bogbean and water horsetail (Equisetum fluviatile) make up the bulk of the floating mat of vegetation, but more localised species such as tufted loosestrife and lesser tussock sedge (Carex diandra) are also well represented. Set within this quaking greenery are several tree-covered islets, which rise sufficiently above the influence of the loch’s eutrophic waters for the woodland floor to be dominated by bog mosses, here and there carpeted with cranberry and accompanied by occasional spikes of lesser twayblade (Listera cordata).

In contrast to the natural water bodies described above, the 3.9 km² Carron Reservoir is not only entirely man-made, its construction is comparatively recent. Nevertheless, when the Carron Valley was gradually flooded in the late 1930s it still possessed one of the last worked water meadows in Scotland, so there was already some diversity of marshland plants in place to adapt as a marginal community at the water’s edge wherever conditions proved suitable. The reservoir’s wildlife potential underwent a significant change from the late 1980s, when the water level was raised to a new height. In the summer months what was formerly a sandy delta around the mouth of the incoming River Carron has become a mosaic of reed canary-grass and northern water sedge, with scattered ‘rafts’ of amphibious bistort. The ringed plover’s loss of habitat has proved to be a gain for the great crested grebe, for up to five pairs now nest in this sheltered spot. Concealed in the reeds little grebes make themselves heard and even the rare Slavonian grebe (Podiceps auritus) is not unknown. With the reservoir well stocked with fish, the osprey is a frequent summer visitor. The Carron Reservoir is also one of the few places in Scotland where a flock of bean geese still occasionally appears in winter.

Raised bogs

The fragments of low level peat bog that still survive in the parish of Kilmaronock to the south of Loch Lomond are the Lowland fringe’s last remnants of the ancient landscape that existed before the beginnings of agricultural improvement and reclamation of the ‘wastes’. Unlike the valley bogs of Glen Falloch and the fens of the Aber Bogs mentioned in the previous chapter, both of which are enriched to varying degrees by minerals carried by water draining from higher ground, the only source of nutrients for these isolated bogs are the meagre dissolved salts deposited by rain. In such a mineral-deficient environment the bog mosses flourish, even though the rainfall is less and evaporation greater in Kilmaronock than in the mountainous Highlands to the north. Providing a hydrological balance is maintained, bog moss growth will exceed decay in the anaerobic waterlogged conditions, so that over the course of centuries the gradual accumulation of plant material is such that the increasingly dome-shaped profile of the bog surface stands well above the surrounding land. These are known as raised bogs. In an actively growing raised bog, the surface is a mosaic of bog moss hummocks, the hollows between them saturated with water. The most common higher plants are ling heather, cross-leaved heath and hare’s-tail cottongrass (Eriophorum vaginatum), with locally frequent bog asphodel, round-leaved sundew (Drosera rotundifolia) and occasional white-beaked sedge.

As a result of peat cutting for domestic fuel in the past, none of the Kilmaronock raised bogs are still intact, the least modified example being the birch-fringed Blairbeich Moss (Fig. 10.10), whose development probably began as a marsh in a glacial morainic hollow. The site is best known as a locality where the bog-rosemary (Andromeda polifolia) can still be found, a species generally declining in Britain with loss of suitable habitat through drainage, peat extraction and afforestation. The zoological interest of Blairbeich and other raised bogs in the immediate area centres on their invertebrate fauna normally associated with moorland at higher altitude. Day-flying moths found on these lowland raised bogs, and whose larvae feed on heather, include the common heath (Ematurga atomaria), northern eggar (Lasiocampa quercus ssp. callunae) and the eye-catching emperor moth (Pavonia pavonia). Periodically, the larvae of the fox moth (Macrothylacia rubi) occur in such huge numbers as to severely defoliate the heather. Especially noteworthy at Blairbeich is an isolated colony of the large heath butterfly (Coenonympha tullia), its larvae feeding on cottongrass and the adults turning to cross-leaved heath as a favourite source of nectar. The Paisley lepidopterist A.M. Stewart in a little book entitled British Butterflies (1912) recommended to his readers that the most comfortable way he found to pursue the large heath over such squelchy ground was ‘with bare feet and legs, and the trousers well tucked up’, advice that is best disregarded in what is adder (Vipera berus) country. The open and sunlit birchwood on the moss’s southern flank is ideal for the green hairstreak butterfly (Callophrys rubi), the food plant of its larvae confined to blaeberry in raised bog vegetation.

Fig. 10.10 Blairbeich Moss is the most intact of Loch Lomondside’s raised bogs.

A keenly anticipated excursion amongst west of Scotland naturalists of yesteryear was a boat trip to the raised bog on Inchmoan, but today this Loch Lomond island is largely tree-covered (see Chapter 11) and its character totally changed. The Peat Isle, as it was alternatively named, formerly held both red and black grouse. Lapwing, curlew and common snipe also once regularly bred. What particularly intrigued visiting botanists was the presence of cloudberry (Rubus chamaemorus), an upland plant growing on Inchmoan’s bog surface at little above sea level.