Top 5 most Interesting UK Invasive Species

FactFile

Image taken from a BBC article of a Wallaby stood on Inchconnachan

The Species of Wallaby that inhabits isolated pockets of Britain is the Red-necked Wallaby (Macropus rufogriseus). Native to eastern Australia and Tasmania, this nocturnal Marsupial feeds on grasses, roots and leaves. Similar to most marsupials the female bears one offspring at a time and the joey remains in the pouch for around 280 days. Finally, the Red-necked wallaby has a lifespan of roughly 9 years in the wild, though it is unknown as to how accurate this is in UK populations.

History & Where to find them

There have been many sightings in the last 100 years of wallabies up and down the UK. However, there are three islands in particular in the British isles that have thriving populations. These include the uninhabited island Inchconnachan situated in the middle of Loch lomond in Scotland; the Isle of Man and Lombay island located just east of Dublin. Each of these sites are shown in the interactive map below.

Interactive map showing the location of densely populated wallaby habitats

The feral wallabies have roamed Inchconnachan since the 1940s when they were released by Fiona Bryde Colquhoun. An eccentric countess who had an interest in these animals as well as Llamas. She kept these animals in her home near the Loch. However, after WW2 she released them onto the island where they have established a stable population. Many locals call for the marsupials to be culled due to their invasive nature, though they have become a popular tourist destination, and scientists use the island as a special area of conservational investigation.

Ecological Impacts

FactFile

Image taken from saga.co.uk showing a Reeves’s Muntjac

The Muntjac is a species of small deer native to China and Taiwan. There are many species of Muntjac, however the species that has established a large population in the UK is the Reeves’s Muntjac. Muntjacs have an average lifespan of around 10 years and weigh in at roughly 13kg. They breed all year round and are sometimes referred to as barking deer due to the dog-like sounds they make. They show some degree of sexual dimorphism as only the males possess antlers.

History

It is unclear whether the Muntjac was introduced concurrently at different locations or whether all the UK Muntjac come from the same group of released deer. Consistent with most websites and literature is that one population of Muntjac were introduced to Woburn Park in Bedfordshire in the early 1900s.

They are frequently spotted around this area as well as across the the whole of south eastern England. They also have established smaller populations in Northern Ireland and Scotland. Their numbers are still increasing and they are becoming easier and easier to spot. For more information check out the video below.

Ecological Impacts

FactFile

The Egyptian goose is native to south of the Sahara (Africa). Unlike many ducks and geese, the Egyptian Goose has no differences in appearence between males and females. Despite this, males are slightly larger than females. They are more closely related to ducks however their flight style more resembles a goose, hence the name. In addition, their diet includes many plant species and insects. Interestingly they were considered sacred by the Ancient Egyptians and appear in their artwork.

History

Egyptian geese, also known as Nile geese, were one of the first species to be domesticated by humans. They are theorised to be used as guards by the Ancient Egyptians as well as pets. Contrary to the Egyptians, the Romans used these geese as livestock. The following image depicts a famous 4600 year old paining of Extinct Geese that are very closely related to the Egyptian Goose.

The Meidum Geese painting located in the Chapel of Itet at Meidum in Egypt.

The Egyptian Goose was first just confined to a small area in Norfolk. Nowadays the Bird species is abundant across Great Britain and similarly has established populations in other non-native continents such as North America. Over the last 20 years as the globe has suffered from global warming the Egyptian Geese population has vastly increased in the UK. They initially struggled to grow large populations due to their January breeding habits. However, over the last 2 decades the populations have increased as warmer weather has resulted in higher infant survival rates.

Ecological Impacts

FactFile

The American Bullfrog, as the name might suggest, is native to North America. It has an array of habitats including most in-land water bodies such as swamps, ponds, and lakes. It also enjoys other artificial bodies like canals, koi ponds and ditches. Its name derives from its bull-like bellowing it makes during the breeding season. It is this versatility that has enabled this species to overcome challenges in the UK and beyond.

History

They were introduced into the wild from many different sources such as pet-releasing, biological control agents and escaping from pet-breeding establishments. They have a life span of 8-10 years and it takes them from around 3-36 months to metamorphosis, depending on the climate.

Ecological Impacts

FactFile

Photograph of an American Mink taken from a Countryfile article

The American Mink is a semi-aquatic mammal native to North America. This carnivorous species feeds on almost anything including: birds, frogs, rodents and fish. The American Mink were largely used in fur farms due to their long, soft and dense winter fur. They live up to 12 years and assert their dominance by arching their backs and lashing out their tails.

Interestingly, in their non-native habitats, they are known to hybridize with other similar species including European Mink and Polecats.

History

The Mink was first brought to the UK in 1929 to be used in commercial farms that harvested their fur that was popular for fur coats at the time. They managed to escape various farms and were at times deliberately released. This lead to the first recorded wild breeding population in 1956 and since then the mink have spread across the country. Despite this, there are no official present population estimates.

Image from The Humane Society showing mink in small cages in a fur farm.

Ecological Impacts

Tweet from the Scottish Invasive Species Initiative:

This tweet from the Scottish Invasive Species Initiative perfectly summarises the threat of American Mink to UK wildlife. They threaten the extinction of similar water-dwelling mammals like the water vole as well as other types of wildlife such as native birds.