(first published in the CBO Annual Report for 1982)
The ecology of the island is a subject that is not well understood. There has never been the expertise to interpret the meaning of the peculiarities of the island's vegetation. The plant life is certainly somewhat limited due to the difficulties for plants spreading to the island in the first place and then due to the successive waves of human and then rabbit colonization over the centuries. Originally the plant life would have arrived as air-borne seeds or as seeds carried in or on birds. Later some species may have been lost under the cultivation regime. However many weeds would have been unintentionally introduced with the seeds of the intended crops. Tilling discourages pasture herbs and encourages quick growing annual weeds. During the past 100 years there has been a return to pasture grazed by rabbits which cannot have been introduced much before that time. Even this change has not become stabilised. It has been noticed by long-standing members that there have been progressive changes in the island's plants. These stem from the arrival of myxomatosis in the rabbit population. Though the rabbits are now partially resistant to the disease, the population is at best only a half or a third of formerly, and is subject to great drops lasting for months at a time periodically during repeated epidemics. For instance during last summer's collapse there was not a single rabbit left alive in the north-east quarter of the island. There is concern about the new instability brought about by the lack of consistent heavy grazing because its effect is that close-cropped grassy areas are contracted due both to under grazing and invasion by the island's common, large rampant weeds, most of which are of lesser value to birds. Breeding shearwaters, oystercatchers and terns have been and are likely to be discouraged by lush, rank vegetation. Even though seeds of ragwort and thistles are liked by various open country birds such as pipits, larks and finches, these species will not land amongst dense vegetation to eat them. The numbers of these species recorded actually feeding on the ground have declined markedly over the past 20 years though they are still sen flying overhead.
The purpose of this account is to inspire further interest and encourage the membership to collectively research for information on the significance of the presence of the various species, especially those few which could be regarded as dominant. The following survey of important species is followed by some more general observations.
Bracken (Pteridium aquilinum)
Resistant to grazing except by goats. Has the somewhat unusual habit of forming very dense pure stands (no other plants are able to grow in their shade). This is a habit found only in western parts of the British Isles, especially coastal areas. Generally its growth is more sparse and less repressive on most inland sites. In the north-west the plant rarely tops 18 inches but is regularly 5 – 6 feet in sheltered eastern spots.
Some strips of bracken have been identified over the years as being on the move. Long strips of dense bracken trail across the top of the island and on the dry western grassland west of the garden. The most obvious one is from the pond to the well path. This band is moving slowly north-east. The leading edge is sharply defined but areas behind are left with a light scattering of fronds, reminding one of the growth of a fairy-ring leaving staled ground behind. A total of around eight acres are dominated by bracken.
Hogweed (heracleum sphondylium)
This is a weed of land formerly under cultivation. On Copeland it tends to form very dense stands though not pure and suppressive like bracken. A large area between pond and pub, and cliff to nearly the crow trap is dominated by this species. It is a biennial and so its numbers fluctuate from year to year. Its flowering is early in the summer and its seeds are dropped in July. Other species grow up through it to flower at the end of the summer especially some ragwort. Over the ppast 28 years the hogweed has slowly spread its area outwards to cover nearly 4 acres. There are a few small groups elsewhere around the island. In Bluebell Gully the plant occasionally reaches 8 feet tall.
Ragwort (Senecio jacobea)
This is a variable biennial mostly left untouched by the rabbits. Its fortunes vary tremendously from one year to the next and on the wets of the island it sometimes establishes pure stands for a single season. It is thinly dispersed over most of the island in almost all years even those when it is not present in dense or pure blocks 3 feet high in the west. Its flowers are well liked by many butterflies during August and September. The seeds are enjoyed by finches, pipits and larks in October. The next season's young plants can be seen as small rosette plants by autumn but some of these young plants are eaten back by rabbits during the winter. Ragwort provides a fair percentage of cover over approximately 5 acres in many years, and is widespread over the rest of the island but much more thinly.
Balsam (Impatiens glandulifera)
This unusual plant is obviously introduced, probably by accident. It tends to form pure stands mostly on the eastern side of the island. Its fortunes, like ragwort, are variable. It is an annual and could be exterminated, if we were determined, by cutting to prevent flowering and seeding. A large area of over two acres was wiped out in this way in the early to mid 1970s on the west side. The plant is most sttractive and seems to be favoured by water rails which can run amongst the thick red stalks at great speed. Heights up to 8 feet are normal near the lower heligoland bushes.. much of the occupied ground is quite dry unlike its naturalised habitat in the rest of Ulster which is the banks of rivers like the Lagan and the shores of lakes like Lough Neagh. Flower colour (on the mainland) varies from light pink to deep dull red but on Copeland they are all pale pink.
Balsam provides partial or total cover over 3 to 5 acres annually.
Elder (Sambucus nigra)
This has been discussed in previous reports but it has been noted by some authorities to be the only woody plant which grows in conditions of heavt rabbit grazing. It is an easily and quickly spread species in droppings of the Thrush family. At least 300, perhaps 400 rootstocks are now actively growing. This is a big increase on 28 years ago, perhaps double.
Bluebell (Endymion non-scriptus)
Enormous numbers of bulbs are dug up by rabbits every year without ill-effects on the blue haze which erupts mostly along the east side each May. Bluebells are notoriously slow spreaders and indicative of undisturbed land, almost always woodland. Their distribution on the island coincides with ground which lacks the evidence of previous cultivation in the form of ridged lazy-beds. Rabbits take an early bite from the new leaves.
Red Campion (Silene dioica)
Red Campion is also thought of as a typical woodland plant. Its behaviour on Copeland is unusual in that the plants have a prolonged flowering season growing to a clambering two feet and again growing more densely than usual, even forming pure stands in places especially where the previous year much scything and consequent suppression of bracken had occurred, or where ragwort had been dense and had left the ground bare after it had died in the course of its normal fife cycle. This is probably the secong most widespread dicot on the island after ragwort.
Lesser Celindine (Ranunulus ficaria)
Also an early season woodland plant, extensively found over the island.
Cuckoo Pint (Arum maculatum)
This is another woodland relic which is early growing and tuberous. Its covers extensive areas with its large deep-green leaves in early spring. Later in August its berries are conspicuous and a favourite with Barred Warblers.
Bracken, Bluebell, Red Campion, Lesser Celindine and cuckoo Pint are thought to indicate that the land was formerly wooded. It would be interesting to know if this was so but how to prove it is the problem. Decay of wood and roots is quick in the rich mineral earth. Perhaps some of the peaty ground near the pond could provide evidence in the form of pollen remains that could be interpreted by experts in this field.
Sea and Bladder Campion (Silene maritime, Silene vulgaris)
Extensive beds of these two low herbs creep over the ground above and below the tallest parts of the cliffs and also occur more sparsely in all the other rocky areas of the island.
The two plants look identical to most observers but the bulbous back part of the Sea Campion flower light greenish-purple from the distance. These flowers contrast with the pale yellow-green colour of the same structure on the Bladder Campion. Since the plants are so prolific at their peak that the leaves are almost obscured, the different tone of the two species is quite conspicuous. Scarcely 20% of the white Silene plants are Bladder Campion. The habitat of the Bladder Campion on Copeland is somewhat differet from the usual upright growth elsewhere. It grows low and creeping just like the closely related Sea Campion. This is probably an adaptation to the strong winds and the heavy grazing by rabbits.
Common Dock (Rumex crispus)
This plant is very common in the northern half of the island. It forms dense and pure stands especially in the NW and NE above the rocky zones. It also is common in the small gullies running between the rocks and in the north 'canyon'. Over long periods of years it has gradually drifted in its distribution, primarily by invading new ground but sometimes retreating. Its seeds are eaten by Twite.
Hemlock (Conium maculatum)
This tall, delicate looking but actually strong umbellifer has dark blotched stems. It is said to be extremely poisonous, even to touch. One wonders how the rabbits avoid it but they seem to. It is common around the buildings tip and in some north and west gullies.
Cuckoo Flower or Lady's Smock (Cardamine pratensis)
This plant was recorded by Margaret Hayman in her original plant list for the island in 1956. however it was not noticed during the sixties or seventies. When the rabbit-proof fence was built around the marsh north of the pond it appeared in force within. The explanation seems to be that it is preferentially grazed by rabbits as a tasty bite and although it was heavily suppressed it neither reproduced nor died out. A similar effect has been noticed with Marsh birds-foot Trefoil which never tops 2 cm outside the fence but reaches 45 cms inside.
There seems to be some dispute in flower books about the reason for the name Cuckoo Flower. The reason is surely that Cuckoos search for this flower because the plant is the food plant of the caterpillar of the Orange-tip Butterfly. The hairy caterpillar, instead of being camouflaged, has an obvious warning colouration of orange and black because it is very poisonous. However the digestion of the Cuckoo is able to cope with the toxin and so Cuckoos can eat the caterpillar with impunity and without competition. Orange-tips have not bred on Copeland but with its food plant now becoming common enough, it may not be long before they do.
It would seem to be a reasonable deduction that most of the plants on the island which do well are distasteful to rabbits or resistant in some way to grazing and that those plants which are surprisingly scarce or absent may well be types which rabbits like to eat.
Other farmland weeds
There are several other weeds very abundant on the island which are clearly left-overs from the former cultivation up to 100 years ago. Nettles (Urtica dioica), thistles of three main types, and sow-thistles are typical of derelict farmland, the nettles especially denoting a rich soil. Corn Marigold (Chrysanthemum segetum) grows on the slaty shingle just west of the south landing. This species is presumably a left-over from the time that cereal crops were grown. It is now very much out of its typical habitat.
Other species indicative of the main habitat zones
There are various habitats on the island denoted by distinctive vegetation types. Some are very small such as the salt marsh patch below the cliff steps. There is a shore shingle strip along the south shore and in little patches in the slaty gullies around the west. These habitats are not rich in species because of their restricted size. However at least some of the expected plants are represented.
There are also several marshy zones containing a fair range of typical species though with a number of notable exceptions. The marshes are the area around the pond, the crow trap, in various patches among the rocks around the west shore, as well as a few scattered flushes elsewhere. Typical plants of Copeland marshes are the large rushes at the front of the house, Marsh birds-foot-trefoil, Lady's Smock, Lesser Spearwort, Cudweed, and Yellow Iris. Marsh pennywort is common in the west and watercress is found abundantly in one northern gully. The main underwater plant in the pond is starwort. Apart from the extensive bracken dominated thickets the rest of the island is basically grassland, most of which is threatened by invasion by taller growing herbs, such as ragwort, balsam and hogweed. While most of the grasses never flower and therefore identification is difficult, fescues and bents are present but the most common type is Yorkshire Fog which in a few years grows to dominate much of the western half and goes to seed. It eventually leaves a self-suppressing mat which takes a few years to rot, allowing beds of other invasive species to develop and dominate temporarily before rabbit grazing eventually allows the grass to recover. Rabbits eat Yorkshire Fog when it is young but not after the end of May as it toughens. Anyway, its growth is too fast for the rabbits to keep down by June. Yorkshire Fog is now much more extensive than formerly presumably due to the lower rabbit population since myximatosis. This is also true for many of the islands main species now occupying large stands over the island. Interestingly Yorkshire Fog is also known as an open woodland grass.
The soil type as indicated by the vegetation is a neutral loam. The marsh seem to be slightly acid. The ground is very variable in its soil moisture content. In winter it is all wet. In summer it often dries out considerably. Drought has caused plant deathon all higher parts and ridges in 1975 – 78 and in 1982. the pond has dried out every summer so this shows that even the soil in the main marsh becomes very dry in summer. This is why the marsh is a peculiar mixture of dry and wet ground plants and some compromise species like Creeping Buttercup (Ranunculus repens) and Marsh Birds-foot Trefoil (Lotus uliginosus).
There are a large number of less common species which cannot be mentioned because of space but perhaps mention of a very few special species which have affinity for certain habitats. Brookweed (Salomus valerandi), a weed of damp brackish ground, is very common in normally damp patches especially near the ditch in the south garden. Silverweed is typical of damper patches on all offshore islands. It grows in damp flat gullies near the shore and in the north garden sward below the tip, though it is less common there since the dry years. Growing just a few yards up the slope nearer the tip are some squat Centaury (Centaurium erythraea) plants, typical of the form found on dry chalky dunes. Perhaps limey rubble at the tip is seeping the appropriate juice over this patch of shallow poor soil. With it and in the sward of the south garden is some Eyebright (Euphrasia namorosa) which is a typical turf plant especially behind dunes. Orchids have been deliberately not discussed because we do not have a clear idea of their ecology on Copeland or even their identification. Help would be appreciated.
Finally mention should be made of the Comfrey. This plant is probably the only surviving species to have been cultivated during previous settlements. It was formerly highly regarded as a medicinal herb and as a vegetable both raw and cooked. Eating the coarse hairy leaves is a sensation to be experienced. The plant grows solidly inside and to the east of the Heligoland trap in soil that is the driest on the island. This is unusual since the species is regarded as preferring damp ground.
There is little doubt that the island's vegetation is of a disparate mixture of natives and introduced plants. The sources of even the ten most common species are varied. This, and the year to year variability of the vegetation would suggest that there is considerable instability and that a succession is in progress. The only question is about what the eventual stable result will be. How it will affect the island's wildlife and can or should we do to help or hinder the progression?