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Isle of Man

About the territory

The Isle of Man is located in the Irish Sea between Ireland, England, Scotland and Wales, with its centre at latitude 54 degrees 13' N and 4 degrees 35' W. The island covers an area of about 572 km2 and is 52 km long by 22 km wide at its widest point. As well as the main island there are a small number of islets, including the Calf of Man which has an area of 250 hectares. February is the coldest month with an average temperature of 3 °C. The hottest month is July with an average temperature of 17-18 °C. Rainfall ranges from 9.0mm in July to 15.2 mm in November.
Map of Isle of Man

Colonisation of the island by humans took place sometime before 6,500 BC. It was settled by Norse people in the ninth century AD. In 1266 it became part of Scotland and then after a period of alternating rule between England and Scotland it came under the feudal Lordship of the English Crown in 1399. It has never become part of the UK and is now a self-governing Crown Dependency. The island has a population of about 85,000, of whom nearly 30,000 live in the main town of Douglas (Isle of Man Census Report, 2011). Over half of the island is farmed, with pasture predominating. About 25% of the Isle of Man consists of moorland and heathland, while only about 6% is wooded. Read a detailed breakdown of the total coverage of habitat types (external link).  


According to the Manx biodiversity database the flora of the Isle of Man consists of 139 terrestrial plant species, none of which are endemic to the Isle of Man. The official list of birds recorded on the Isle of Man (external link) is maintained by the Manx Ornithological Society (MOS), available at;  In October 2014 Manx Birdlife recorded the total of 170 avian species. In recent times the Hen harrier population on the Isle of Man has declined.

The Isle of Man has three indigenous species of amphibian and reptile (Edgar, 2010);

  • Common Frog Rana temporaria (this is likely to be changed to Laurasiarana temporaria). The Common Frog is widespread in Europe but its status on IoM is unknown.
  • Leatherback Turtle Dermochelys coriacea, listed as Critically Endangered and CITES I, on The Isle of Man it is an itinerant visitor only.
  • Viviparous Lizard Zootoca vivipara (formerly known as Lacerta vivipara), listed as Least Concern but in serious decline on The Isle of Man resulting in it being a priority species for conservation on Isle of Man. Moorland and heathland are important habitats for the common lizard.

The Manx bat group has recorded eight species of bat; Brown long-eared bat, Pipistrelle, Soprano pipistrelle, Natterer’s bat, Daubenton’s bat, Whiskered bat, Leisler’s bat and the Common long-eared bat. Many Cetaceans frequent the Manx waters with the five key species being the Harbour Porpoise, Risso’s dolphin, Bottlenose dolphin, Short beaked common dolphin and Minke whale.

Examples of Internationally important species found on the Isle of Man or in the surrounding waters, as identified in the Manx Biodiversity Plan, are the Critically Endangered European eel, Atlantic cod, Curlew, Balearic shearwater, Basking shark, Grey seal and the Manx shearwater. The only truly native member of the mustelids (weasel) family present on the Island, the Stoat, appears to be declining in numbers. The Isle of Man is the only place in the British Isle where the Lesser mottled grasshopper can be found. Some species, such as agrimony Agrimonia eupatoria, bee orchid Ophrys apifera, and spring sandwort Minuartia verna are only found at single sites and are therefore highly vulnerable.

Read the full species list for the Isle of Man (external link)

Policy/strategy background

The Isle of Mans’ most bio-diverse habitats are its horse mussel (Modiolus modiolus) reefs. Horse mussel reefs are listed as Threatened and/or Declining Species and Habitats under the Oslo-Paris Convention for the Protection of the Marine Environment of the North East Atlantic (OSPAR Convention), to which the Isle of Man is a signatory. Other OSPAR listed habitats are Eel grass, maerl beds, Ross worm reefs, intertidal mudflats and other shoreline habitats. OSPAR listed species are Skates, rays and other sharks, including porbeagle and spurdog. Risso’s dolphin is listed under ASCOBANS, Bern and Bonn Conventions. Two sites are listed as Important Bird Areas; the Isle of Man Sea Cliffs, for species such as red-billed chough and European shag, and Isle of Man Hills for hen harriers. Ballaugh Curragh is designated as a Ramsar site.

The Isle of Man is signatory to the Wildlife Act 1990. This Act protects birds, other animals and plants, controls introductions to the wild, enables marine and terrestrial site protection and controls the keeping of certain birds. Read the wildlife act schedule (external link), including the list of protected species (external link)

Read a comprehensive list of the regulations or agreements that the Island is signatory to (external link).

Read the Isle of Mans’ Biodiversity strategy (external link).

Invasive species data & legislation

There are 18 invasive species listed on the Global Invasive Species Database (GISD), of which 12 are categorised as alien-invasive species. These are the perennial freshwater herb parrot’s feather milfoil Myriophyllum aquaticum , three shrubs; Buddleja davidi, Japanese Knotweed Fallopia japonica, and Rhododendron ponticum. One herb; Himalayan balsam Impatiens glandulifera and two alien invasive fish; northern pike Esox Lucius and the gregarious, freshwater fish Phoxinus phoxinus. Six alien invasive mammals; the European hedgehog Erinaceus europaeus, House mouse Mus musculus, ferret Mustela furo, the Norway rat Rattus norvegicus and the European red fox Vulpes vulpes. There are no known introduced amphibians or reptiles.

The only avian invasive species listed on GISD is the native domestic pigeon Columba livia, however, the Rose-ringed Parakeet Psittacula krameri is a vagrant, and the Ruddy Duck Oxyura jamaicensis has visited the island from an introduced population in Great Britain.

Other native invasive species listed are the common red algae Polysiphonia brodiei, the stoat Mustela ermine and three species of fish; Roack Rutilus rutilus, Atlantic salmon Salmo salar and Brown trout Salmo trutta. Two marine invasives mentioned in the government’s 2014 newsletter are Sargassum seaweed, also known as wireweed, and the carpet sea squirt Didemnum vexillum.

Schedule 8 of the Wildlife Act lists non-native species that are established in the wild and continue to pose a conservation threat to native biodiversity and habitats, such that further releases should be regulated. Eleven non-native terrestrial animals and 31 plants species are recorded to be established in the wild on the Isle of Man, read a complete list (external link). National wildlife legislation includes the Destructive Imported Animals Act 1963 and Wild Animals (Restriction on Importation) Act 1980. Incentives for control of invasive weeds were included in the pilot Agri-environment Scheme. Invasive weed control is a condition of the Countryside.

Problems with invasive non-native species

Japanese knotweed is the most invasive plant in Britain and is very difficult to control. It spreads rapidly, especially on waste ground and next to streams and rivers. It shades out native plants, posing a threat to biodiversity, its roots and stems also cause structural damage to buildings. Himalayan balsam also competes with and displaces native plant species. Rhododendron can form dense stands which can inhibit the regeneration of native species and alter plant and animal communities. Sargassum (wireweed) is widely colonised in the south of the Island, manual weed removal has proved ineffective.

The ‘New Zealand’ flatworm, Arthurdendyus triangularus and ‘Australian’ flatworm, Australoplana sanguinea, are non-indigenous flatworms predominantly found in gardens where they pose a potential threat to native earthworm populations. They could also, given time, have an impact on wildlife species dependant on earthworms and have a deleterious effect locally on soil structure.

Hedgehogs threaten native invertebrates, reptiles, amphibians and ground-nesting bird nests (such as the little tern) through predation; they also compete with native insectivores. Brown rats have been monitored recording the eggs of Arctic terns. The ferret is a threat to native prey species, particularly ground nesting birds.

Priority invasive non-native species and actions

There is ongoing herbicide control of Japanese knotweed along water courses. Read the Government pages for Japanese knotweed (external link) are at;

Information and advice on the control of injurious weeds (external link) 

Parrot’s feather milfoil Myriophyllum aquaticum has been successfully controlled by the Société Guernesiaise at one of their nature reserves and control efforts are ongoing elsewhere on the island.