The Natural History of Alderney

by Brian Bonnard

General Comments

In comparison to its size, (under 2,000 acres), Alderney has a greater number of rare species of both plants and animals, than anywhere else in the British Isles, that being said, the largest of our ten mammals, in the wild, is the rabbit and there are no major carnivorous species at all. Many of the rarest plants and animals, especially the insects, are small and scarcely noticed by the casual observer.

The Flora and Fauna of all the Channel Islands is influenced in it's relationship to that of mainland Britain and France by two principal factors.

Firstly, the period of time since the various islands in the Group became detached from the Continent, which has limited the range of plants and animals present in each island.

Secondly, perhaps more particularly with regard to the flora, the effect of strong, salt-laden winds across small islands and the exposed situation.

During the time between the last ice age and the present day, vast forests, including alder, hazel, lime and elm, with some pine, but with oak predominating, covered the islands and much of present day France. Evidence of this lies in several peat beds around Jersey and Guernsey and in a small area of Alderney, sometimes exposed at freak tides and after storms, which have on occasions revealed tree stumps.

The rising waters from the end of the last Ice Age separated Britain from the Continent and by about 7,500 BC., Alderney was an island. The northward and westward spread of both Flora and Fauna was largely halted once separation occurred and accounts for some of the differences between the Islands.

It is likely that much of the forest was cleared for crop growing during the Bronze Age, or burnt during the Iron Age and the exhaustion of the timber supply, or a freak inundation by blown sand, are possible reasons in Alderney for the apparently sudden cessation of use of the Iron-age site at Les Huguettes. Any large animals which might have roamed the area when it was still attached to mainland Europe would have been eliminated by this time. It may also account for the comparative lack of trees on the smaller Islands, which was sufficiently noticeable to cause John Leland (1506-1552), to note on his sketch map of the Channel Islands; 'Alderney is fairly fertile in corn and cattle, but is notably lacking in trees', a comment echoed by Ansted in his "Channel Islands", (1862), who states that 'Alderney and Sark are very badly provided with trees'.

Compared with 50 years ago very little of the island is regularly cultivated today and where the poorer areas were regularly grazed by sheep 100 years ago, today much is covered by bramble, bracken and gorse. The practise of cutting gorse for fuel, particularly for bread ovens, has also long ceased and much of the gorse is old, leaving the new shoots to gradually surround dead wood.

The Flora

The recorded flora of Alderney now contains about 1,030 species of flowering plants and ferns, about a hundred of which have not been seen and recorded, for at least 50 years and some others only noted on a single occasion. Over 800 species are still to be found today.

Many herbs (formerly used for medicinal or culinary purposes) were introduced in ancient times and now form part of the naturalised flora.

During the Victorian Era, especially due to the movements of Army units, many new species were introduced, from New Zealand, Australia and South Africa, as well as from the Americas. Some of these, notably the Kaffir or Hottentot Fig, Escallonia, the Duke of Argyll's Tea-plant, the Giant Echium and Veronica (or Hebe) species, have thrived in our climate and since that time many have seeded themselves or been spread by birds and small mammals to parts of the Islands far removed from their original sites. Others, notably several tree and shrub species such as the Monterey Pine, the Japanese Spindle-tree and Eleagnus and Griselina species, have continued to grow and take their place in the landscape of the Island, but for various reasons have not spread widely. The last three of these are widely planted as salt-resistant windbreaks.

Agriculture over the centuries has also been an important source of new plants, many imported inadvertently with seed. A majority of these adventives were annuals and, in recent years, better seed cleaning techniques and the use of herbicides has produced a sad decline in these species. Amongst the most noticeable is the decline of cornfield weeds, such as Poppy, Corn Marigold and Corn Sow-thistle.

Today these are more common in Alderney, where more traditional farming methods are still in use, albeit on a very limited scale now and where herbicides and pesticides are little used, than in the other larger islands or in Britain.

Alderney has two plants so rare, that their world-wide official “Common” names include that of the island.

Alderney Sea-lavender, Limonium normannicum, only finally recognised a few years ago as a distinct species, (as opposed to a ‘variety’), is only found here in a single area with perhaps 1-200 plants; in a small part of St. Ouen’s Bay, Jersey; and on the coast of the Cotentin across The Race in France.

The Alderney Geranium, Geranium submolle, is thought to be of South American origin and otherwise only exists in Guernsey. It has recently started to spread in Alderney, from the spot near Battery Quarry, where it was first found in 1938.

Of other species listed in the current British ‘Red Data book’ list of endangered, vulnerable and nationally scarce species, which contains some 547 flowering plants, 147 are currently found in the Channel Islands and 57 of these occur in Alderney. A few of these of particular interest are;

Bastard Toadflax, Thesium humifusum which has two small colonies at opposite ends of the island close to the shore and another large area on Mannez Garenne. In the British Isles this parasitic, lime-loving plant is otherwise now only found in a few places on chalk grassland in England and in Jersey.

The Spotted Rock-rose, Tuberaria guttata is otherwise only to be found near the sea in W & SW Ireland, NW Wales and Jersey. In Alderney there is a fine area along the South Cliffs. This small annual drops its petals before noon, so must be looked for in the morning.

Our most common Fumitory, Fumaria muralis, ssp boraei, is rarely found in Britain.

Flax-leaved St. John's-wort, Hypericum linariifolium, rare in England exists as a single small colony on a bare rock face.

Four-leaved Allseed, Polycarpon tetraphyllum is common in the Channel Islands, but usually only seen otherwise, in Cornwall and the Scilly Isles. Small Hare's-ear, Bupleurum baldense grows in some quantity at one spot on the east coast and on Longis Common.

Of the leguminous plants, the Orange Bird's-foot, Ornithopus perpusillus frequent in Mannez Quarry and on Tête de Judemarre, grows only in the Channel and Scilly Islands, the Bithynian Vetch, Vicia bithynica rare and decreasing by the coast in Britain, may be found in one large patch at Crabby Bay. Small Restharrow, Ononis reclinata rare in England and Guernsey, absent from Jersey, still has a tenuous hold in one small patch on the east coast of Alderney. Atlantic or Western Clover, Trifolium occidentale, is frequent round cliff edges and in short turf near the sea.

The parasitic Broomrapes are declining in the UK through the use of herbicides. Alderney is still blessed with a variety. The Purple Broomrape growing on Yarrow is found frequently, even in lawns. It is very uncommon in UK and virtually unknown in Guernsey. The Greater Broomrape makes a distinctive sight on the Prostrate Broom on the South cliffs, whilst the reddish, Carrot Broomrape is frequent along the margins of the sand dunes. Common Broomrape is just that, but Ivy Broomrape, extremely common in Guernsey can only be found along a single valley here, despite vast quantities of Ivy everywhere.

Cape Cudweed, Gnaphalium undulatum is naturalised and frequent in all the Channel Islands but absent from Britain, whilst Jersey Cudweed, G. luteoalbum is found very locally in Jersey, Guernsey, Alderney and W. Norfolk.

The Dwarf Rush, Jucus capitatus may be found on the cliffs around the Giffoine. It is very rare in W Cornwall and was formerly found in Anglesey. It occurs in several places in Guernsey and Jersey.

The Sand Crocus, Romulea columnae thrives on the East coast and along the cliffs, especially near Essex. It is also found in the other islands and very locally in Devon.

Another member of the lily family, the New Zealand Cabbage Palm, Cordyline australis will be noted frequently, in and out of gardens. Originally planted in the 1930s, many of these were about 12-15 feet tall until the 1987 hurricane almost killed them, but most have grown up again from the base. It now seeds quite frequently, but the seedlings are usually mown off before they reach any size.

Some strange grasses may be noticed, including Bermuda Grass at Longis, Canary Grasses scattered in the sandy areas, Sorghum and Millet at Saye and Braye.

Of the ferns, the Royal Fern, Osmunda regalis flourishes in a single patch in an old quarry on the south cliffs and a single specimen of the House Holly-fern, Cyrtomium falcatum in Bonne Terre have both were probably planted originally but have survived for at least 40 years and possibly a lot longer and have multiplied a little in their original spots but not spread further. Lanceolate Spleenwort, Asplenium billotii and Rusty-back Fern, A. ceterach are rare in the island, the latter only existing at five small spots, on walls in Town. The Great Horsetail Equisetum telmateia is not particularly rare in Britain, but Alderney possesses the only natural Channel Island colony, either side of the road, not far from the airport.

FUNGI. As Alderney is poorly supplied with large woodland areas, the species of larger gill, pore and bracket, fungus normally found in this habitat are in short supply.

Lichens are formed by a symbiotic association of a fungus and an alga and are very susceptible to atmospheric pollution. Alderney's unpolluted atmosphere has helped to retain a number of species in this group which are generally declining in the U.K.

30 species of Liverworts and 145 Mosses have been found in the island.

The Fauna  

Land Mammals

Rabbits

The most common wild animal. Possibly introduced by the Romans or the Monks of the 8-9th centuries. It became so common by Elizabethan times that on Leland’s map already referred to, Burhou is noted as; ‘the island of much fern and many conies’. The inhabitants also fell into conflict with the Seigneur over the damage done by rabbits spreading from his warren the ‘Mannez Garenne’, still marked on maps today, and were given permission by the Crown to take or kill any found outside its boundaries and remove their droppings. Numbers now fluctuate from year to year with myxomatosis.

A number of black rabbits will be seen, the lack of natural predators ensuring their survival despite being more conspicuous.

Hedgehogs

Next in size and frequency of sighting is the hedgehog. They are almost certainly introduced, probably since the 1939-45 war, probably in the early 1960s. They have thrived, with no natural predators and amongst them are considerable numbers of a pale blond species, with dark eyes and light brown nose and feet, uncommon elsewhere and in almost equal numbers to the more usual brown variety. Rarely, albino specimens are seen with pink eyes, nose and feet. There is also an interesting Alderney story, that the apparent freedom of Alderney hedgehogs from the fleas which so heavily infest most English specimens, is because the first imported pair came from Harrod's. The lack of fleas was confirmed in the 1990s by a widespread investigation by Dr. Pat Morris

Moles

Common in Alderney, but apparently somewhat less so in the very sandy eastern and northern parts, the mole is not found in Guernsey, that island having become detached from the continent before the mole migrated so far west.

The White-toothed Shrew

Completely absent from the English mainland, this little native insectivore Crocidura russula is also found in Guernsey and Herm.

Bats

The only Bat species commonly present in the island is the Pipistrelle

Rats and Mice 

Alderney is one of the few places in the British Isles where the Black Rat still survives, whilst the Brown Rat, Field Mouse and House Mouse, are all present in some considerable numbers, whilst there is some dissent amongst naturalists about the presence (or absence) of the Bank Vole.

Marine Animals 

A range of sponges, ascidians, sea squirts, hydroids, sea anemones and jellyfish etc. will be found on, or under, rocks; as epiphytes on various algae, especially the laminarians; or occasionally free-floating. The reader is referred to the specialist guide books on this subject to identify these.

Of the free-floating or swimming jellyfish, all of which can sting, the Portuguese Man-of-War, Lion's Mane, Octopus jellyfish and Compass jellyfish are sometimes found washed up.

Of the many types of Sea anemone to be found, those most commonly seen are, the Beadlet, in red, strawberry and green forms and Snakelocks in both green and grey forms.

Sea mats, of various species are frequently found encrusting the larger algae.

A wide range of molluscs will be encountered at various levels on the shore.

Amphibians and Reptiles 

Alderney was separated from the continent, before the majority of animals in these groups had reached the area. The only indigenous reptile found here is the Slow-worm, (a legless lizard seen regularly, if infrequently, along the south cliffs, especially near Quatre Vents).

Common Frogs are frequently reported from gardens with ponds, sometimes found hibernating in the mud at the bottom when they are cleaned and spawn is regularly noticed in the spring. Toads are occasionally found, mainly in old walled gardens in Town. Both have been introduced.

Butterflies

Alderney, in spite of a recent increase in the use of herbicides and insecticides, increased clearance of scrubland, and mowing of verges, as well as the recent drought years, is still rich in butterfly life, and during the summer months there are a number of species to be seen in a wide variety of habitats.

These include;

Speckled Wood, Wall Brown, Meadow Brown, Small Heath, Grayling, Glanville Fritillary, Small Tortoiseshell, Red Admiral, Painted Lady, Peacock, Large White, Small White,

Green-veined White, Clouded Yellow, Green Hairstreak, Small Copper, Brown Argus, Common Blue, Holly Blue, Brimstone and Silver-Studded Blue.

Moths

The casual observer will probably only encounter the small number of day-flying moths and micro-moths, or notice the occasional large species in their resting state.

Amongst the more commonly seen, and more easily recognisable, will be;

The Jersey Tiger in both red and yellow under-winged forms, common here, but unusual in Britain, the Garden Tiger, Six-spot Burnet, Cinnabar, the Silver Y, a common migrant often seen in large numbers on the heathland in August, Humming-bird Hawk usually noted around Honeysuckle, Gypsy, Magpie, and the Brown-tailed, whose caterpillars live communally in web-like tents, and completely defoliate the Blackthorn around the cliffs in many years.

The large-sized moths seen may include;

The Emperor, Privet Hawk, and the Convolvulus Hawk, the female of which is nearly twice the size of the male.

Dragonflies

Of which nine species have been recorded in Alderney, the largest and most frequently seen being the Emperor.

Other Insects

The most interesting is possibly the Great Green Bush-Cricket, a spectacular brilliant green insect, the female up to 4 inches long, with feelers as long again.

Alderney has at least eight species of Bumble Bee most of which make their own burrows below ground

Birds

Records of birds in Alderney have been kept for more than a century. About 50 species of sea birds and waders are resident or regular visitors.

Land birds include about 220 species recorded. The speciality of Alderney was the Dartford Warbler which regularly bred in small numbers (15-20 pairs) until the severe winter of 1984/5. Since then and later, following the Hurricane of October 1987, which reduced its numbers further, it probably did not breed again until about 1994 or 95, although individuals were sometimes seen. It has slowly begun to recover and several breeding pairs have been seen since 1997/8.

Brian Bonnard - March 2001

Useful Link

www.flora.org.gg