For years there has been a battle raging in our rivers, seas and on land by aliens intent on domination. Called Invasive Non-native species (INNS) they are not interplanetary travelers but plants and animals that have arrived from other parts of the globe, and found our countryside to there liking. Unfortunately few if any of them are welcomed and in some instances they have wrecked havoc with our native fauna and flora. Some have traveled by well meaning environmentalists such as botanists importing plants from around the globe, farmers intent on diversifying their business and others hitched a ride in the ballast water and cargo of ships or even on the sole of your boot .
As ecologists we are often asked for advice on the proper control and management of INNS when encountered on site. In the north plant species such as Japanese Knotweed, Giant Hogweed and Himalayan Balsaam present particular problems of control and removal and are the INNS most often encountered. Anyone who has found these species on a development will know that they require careful handling and can be costly to manage and remove. Whether its removal through dig and dump to a licensed facility or chemical control it is important to ensure good bio-security in the movement of plant within the site. There is often a need to establish areas of quarantine to prevent root material and seed from being spread ‘unwittingly’. http://www.sepa.org.uk/environment/biodiversity/invasive-non-native-species/invasive-non-native-species-faqs/
Its not all doom and gloom and a number of non-native species have been credited with helping our native fauna to survive including non-native conifers providing foraging for red squirrels, rabbits providing food for the Scottish Wildcat (on the edge of extinction) and many species of raptors such as Golden eagle. http://www.bbc.co.uk/nature/22173289. So the next your in your garden keep your eyes peeled you may just be looking at the next alien species preparing to make a break for freedom over the garden fence.