Manx Wildlife Trust is the Island’s leading Nature Conservation charity, we are a major force in promoting wildlife and wild places in the Isle of Man. We keep a close eye on what is happening in wildlife populations to enable us to help, protect and understand the impacts on species. One of those biggest impacts are invasive species which sounds very like an alien invasion. What is an invasive species?  It is an animal or plant that harms an environment after being introduced to it by humans. This might be accidental, or as a result of garden escapees or even introduced on purpose. Invasive species are harmful to our natural wildlife and overall ecosystem health, they can harm native species because they are suddenly competing with a new species for the same resources (eg food, water, shelter, etc.). Invasive species often outcompete the native species for these resources leaving an ecosystem which is much less diverse. sometimes even driving native species to extinction.

However, it is not all bad news, for example Manx Wildlife Trust has been monitoring the invasive pacific oysters which appeared in numbers on Ramsey Harbour walls. Monitoring of the numbers of these oysters showed a decrease, but the decision was also taken for complete removal of this species from here.  The pacific oyster is native to Japan and was deliberately introduced for oyster farming in the UK in the 1950’s. This introduction was planned in part to compensate for the near eradication of our native Oyster, the European Oyster which are slower growing by comparison and were also over harvested.

Why are we concerned for our wildlife?  It is important to know if there are large amounts of the invasive pacific oysters present as they can form large reef beds on the sea floor, disrupting the native marine life of the area, which is particularly significant as Ramsey Bay is a marine nature reserve. It has also been observed that birds such as Oystercatchers find it harder to break open these oysters to eat, mainly due to the pacific oysters growing tightly compacted together. This monitoring work of the numbers of pacific oysters was undertaken by volunteers which shows how together we can redress problems and remedy them, we are so grateful for all our volunteers. If you would like a free booklet showing marine invasive species to watch out for around our coasts pop into the Information Centre in our shop in Peel.

Most people have heard about Japanese Knotweed also known as donkey's rhubarb, which was introduced to Britain from the Far East in 1825 as an ornamental plant. It spreads very quickly and is commonly found next to streams and rivers, creating dense patches that shade out our native plants and damage wildlife habitats. Japanese Knotweed can cause structural damage to buildings from its roots and stems, and any tiny fragments of these can easily propagate new plants. For identification and to report this species please contact DEFA. Another easily spread plant is Himalayan balsam, which was introduced as a garden plant in 1839, but soon escaped and became widely naturalised along riverbanks and ditches, especially close to towns. It is fast-growing and spreads quickly, invading wet habitat at the expense of other, native flowers. Its explosive seed pods aid its spread by sending the seeds into the river, causing further dispersal downstream. The volunteer group “the Friends of the Neb” often run work parties to try and eradicate this plant and have helped to clear large areas in the Raggatt, keep an eye out on Facebook for their work parties.

For further information about invasive species look on the DEFA website, you can also report any sightings of invasive species either to DEFA or Manx Wildlife Trust enquiries@mwt.im