An introduction

Contents:

Geography

The Isle of Man lies in the northern part of the northern Irish Sea, roughly equidistant from the coats of Galloway, Cumbria and County Down. Its centre is at latitude 54 degrees 13' N and 4 degrees 35' W. Its maximum length is 51km and breadth 21km. The Island's territorial waters extent to 12 nautical miles in all directions, thus 87% of its territory is sea. The final severance which formed the island occurred when the land connection with northern England was removed by rising relative sea levels around 9,000 years ago. No endemic species have evolved since this isolation began. Many species pass through or past the Island on migration, north-south and east-west.

The highest hill is Snaefell which is 621m above sea level. Of the 120km of coastline the northern coast is sand and shingle with dunes and soft sand clay and gravel cliffs, while the southern coastline has rocky cliffs and beaches with the occasional sandy bay. There are two upland masses divided by the central valley and these make up about a quarter of the land area. The longest river is the Sulby which forms a small saltmarsh and estuary at Ramsey. The largest wetland is the Ballaugh Curragh at the foot of the northern hills on the northern plain. This varied topography accounts for the diversity of habitats and associated species. But as with all islands the terrestrial species diversity is less than on the adjacent land masses mainly because there are some significant habitats that are poorly represented.

To the south is a small seasonally inhabited island, the Calf of Man whose habitat mirrors the mainland and is significant for the passage of migrant birds. It can be visited by boat from Port St Mary, taking in views of the seabird cliff colonies, seals and basking sharks.

Geology

Most of the Island is built up of layers of ancient mudstones and sandstones from the Ordovician/Silurian period, heavily deformed by continental collision of long ago and in many places altered by both intrusive and extrusive volcanic rocks. Carboniferous Limestone occurs along the south coast and off-shore and its 'ledges' form significant marine biological habitats. The Peel Sandstone occurs in a limited area on the west coast where it forms red cliffs with a very varied composition. The northern plain is composed of glacial tills, gravels and outwash sands with the remains of several pro-glacial lakes and a series of small glacial features that now form what are locally called 'dubs'. Large areas of impeded drainage caused the formation of extensive peat-filled wetland areas over the last ten thousand years and although much of the peat land has been exploited for fuel and drained, significant areas of lowland peat remain.

Offshore the sea bed also has a great variety of substrates and although there are strong tidal currents there are areas of biogenic reefs and kelp forests that provide habitats for many varied and colourful species.

Species

Allen (1984) noted that "in every plant and animal order (except the wholly freshwater ones) that has so far been adequately worked, with striking consistency Man proves to have two-thirds of the Irish total and two-fifths of the British". It is a feature of the Island that some plant species are only found at single sites and are therefore highly vulnerable. For this reason, those on three or fewer sites are listed in Schedule 7 (of the Wildlife Act 1990). These include all orchids, agrimony Agrimonia eupatoria, ivy leaved bellflower Wahlenbergia hederacea, Isle of Man cabbage Coincya monensis and spring sandwort Minuatertia verna.

Significant breeding birds include: hen harrier Cyanus cyanus, colonised during the 1970s; chough Pyrocorrax pyrocorrax, in large numbers; corncrake Crex crex, although not heard since 2008; Manx shearwater Puffinus puffinus, small numbers nest on the Calf; and little tern Sterna albifrons, one nesting colony at the Ayres. Our rarest birds are specially protected and listed on Schedule 1 of the Wildlife Act. The Manx Bird Atlas was published after a most detailed survey of the island's breeding and visiting birds.

The island has few terrestrial mammals: no foxes, moles, badgers, otters, voles or weasels. Nine species of bats are found, as well as stoats Mustela ermine, feral polecat ferrets Mustela lutreola x putorius and introduced or reintroduced brown and mountain hares Lepus europaeus and L. timidus and hedgehogs Erinaceus europaeus. Amphibians are limited to one species, common frog Rana temporaria and the reptiles to common lizard Lacerta vivipara.

The marine mammals are significant, with Risso's dolphins Grampus griseus, common and bottlenose dolphins Tursiops trunctus and Delphinus delphis, harbour porpoises Phocoena phocoena and minke whales Balaenoptera acutorostrata being seen regularly. Many other whales are seen regularly.

Salmon Salmo solar, brown trout Salmo trutta, eel Anguilla Anguilla, brook lamprey Lampreta planeri and river lamprey Lampreta fluviatilis occur in the rivers which have a mainly upland character.

Commercial fisheries include scallops Pecten maximus, queen scallops Aequipecten opercularis, lobsters Homarus gammarus and edible crabs Cancer pagarus.

There are several important invertebrates. The only site for lesser mottled grasshopper Stenobothrus stigmaticus in the British Isle is on Langness. Scare crimson and gold moth Pyrauster sanguinalis and lesser beefly Bombylius minor occur on the Ayres. There are several species of butterfly that have recently colonised, including, significantly the speckled wood Pararge aegeria, perhaps encouraged by the increase in woodland on the Island in the last 50 years.

Invasive species

There are a number of non-native plant and animal species which are considered to be invasive although some may not yet have shown indications of being invasive on the Isle of Man. Montbretia (Crocosmia) clothes some of the coastal slopes. Winter heliotrope Petasites fragrans is found by roads and rivers. Himalayan balsam Impatiens glandulifera and giant hogweed Heracleum mantegazzianum occur by rivers. Coarse fish are moving between ponds with the help of man, while some species such as Japanese Knotweed Fallopia japonica and Sargassum muticum seaweed are spreading of their own accord.

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Habitats

The island is notable for its variety of habitats in a small area. In the 1990s the terrestrial habitats and land use were mapped. In 2008 an extensive marine biotope survey was undertaken.

Sheep-grazed areas of upland moorland heath are managed for grouse shooting and are surrounded by large areas of upland grassland with increasing areas of marginal natural regeneration in abandoned fields. Areas of flush amongst wet and dry heath and blanket peat support a varied flora. Deep glens, such as Dhoon Glen, Ballaglass Glen and Glen Maye, usually wooded with plantations with some semi-natural areas, extend from the upland edge, rich in ferns and bluebells. The woodland is plantation or secondary regeneration on cleared plantation, with some tiny pockets of native trees with a rich woodland ground flora. Ancient woodland indicator species include wood anemone Anemone nemorosa and wood sanicle Sanicula europea.

Unimproved lowland grasslands occur, especially in the north, with abundant orchids, including greater butterfly orchid Platanthera chlorata and scarce species such as whorled caraway Carum verticillatum. Dry grasslands with hay rattle Rhinanthus minor or bee orchids Ophrys apifera are found on the northern and southern airfields.

The coastal strip in the north is a mix of dunes, shingle, coastal heath land and grassland, all rich in plant species, including pyramidal orchid Anacamptis pyramidalis and early purple orchid Orchis mascula, sea bindweed Calystegia soldanella, sea holly Eryngium maritimum and Isle of Man cabbage Coincya monesis ssp. monesis.

The intertidal habitats cover a wide variety from rocky shores, sand and shingle to boulder clay and mud. The limestone ledges on the south coast are particularly biodiverse. Special marine habitats, such as maerl beds, eelgrass meadows of Zostera marina and horse mussel reefs of Modeolus modeolus provide a home for a great diversity of species.

Statutory protection

Under the Manx Wildlife Act 1990 the Ayres is a designated National Nature Reserve, the Ballaugh Curragh is an Area of Special Scientific Interest (ASSI) and a Ramsar site and there are 19 other ASSI's. Many of the National Glens are managed by the Island's government Forestry department.

The Calf of Man, which has been a bird observatory since the 1950s, is protected through ownership, as National Trust land, by Manx National Heritage. A rat eradication program has been carried out to protect the significant Manx Shearwater nesting population (see news item). Other large areas of National Trust land managed by Manx National Heritage: are Ballaugh Curragh, Cregneash, Eary Cushlin and Maughold Brooghs.

In 2011, a new Marine Nature Reserve was established in Ramsey Bay, covering nearly 95 square kilometres and protecting areas of biogenic reefs, eelgrass beds and a diversity of substrates with full support from local fishermen as this reserve will also help with the conservation of fisheries stocks.

Non-statutory protection

The Manx Wildlife Trust has 19 nature reserves which cover a wide range of Manx habitats, most notably: Close Sartfield with its curragh edge species-rich orchid hay meadows; Dalby Mountain heathland bog and flush; Glen Dhoo meadow grassland and a developing wooded valley; and Cronk y Bing dune and coastal grassland. It also has two visitor centres at either end of the island, Ayres and Scarlett, with its headquarters in Market Place, Peel. The Trust runs a Wildlife Sites System which provides nominal notification protection for important sites not large enough to be scheduled as ASSI's.

Manx BirdLife, which published a detailed breeding and visiting Bird Atlas (Manx Bird Atlas) and produced a wildlife film, has been working with the RSPB to develop conservation on the Island, and further information about their new project at the Ayres Gravel Pits is expected soon.