Invasive Species

There’s a long history of species being introduced to the UK both deliberately and accidentally. These species are generally termed ‘non-native’, by which it is meant that the species is outside of its natural geographical range and has typically been introduced through human activity.

In many instances, these species do not cause any problems for habitats or other species, but there are a number of introduced species that are considered to be invasive or damaging to native flora and fauna. Indeed, the presence of invasive species is a problem globally and has been cited as being one of the biggest threats to biodiversity. Consequently, many of the more problematic species are legislated against and if they are found to be present on a development site, need to be factored in appropriately in relation to projects.

Currently, the Wildlife and Countryside Act (WCA) 1981 (as amended) is the primary legislation in relation to invasive non-native species. It is an offence under Section 14(1) of the Act, to release, or allow to escape into the wild, any animal which is not ordinarily resident in Great Britain and is not a regular visitor in a wild state, or any animal listed on Schedule 9 of the Act. Schedule 9 also lists species that are illegal to plant, or otherwise cause to grow in the wild. The penalties for contravening legislation comprise a maximum fine of £5,000 and/or 6-months imprisonment.

The presence of these species is taken seriously due to the environmental effects that can occur when they are found in habitats outside of their natural range. As they often do not have any natural means of control, invasive non-native species can out-compete native fauna for food and territory. They can lead to population declines in native species due to predation, and they can in some instances spread disease; in addition, hybridisation can lead to declines in genetic diversity of a species, which can in the worst case scenario, lead to extinction. Non-native species can also result in significant adverse changes to the functionality of habitats.

Water fern for example, can achieve 100% cover of a water body, creating a dense carpet of plant material that easily outcompetes native vegetation. It significantly reduces light penetration into the water body, which leads to anaerobic conditions and prevents aquatic plants from photosynthesising. It can also prevent amphibians and invertebrates from reaching the surface of the water body.

Invasive non-native species, therefore, can have significant economic implications in terms of their effects and management.

Control measures vary from no requirements through to total eradication being necessary.

Your project
It is clear then that early identification of invasive species is advisable in relation to a development project, in order to ensure that the species is factored into the preliminary work and scheme design, and dealt with appropriately.

Our ecologists routinely look to identify the presence of invasive species as part of our site surveys and are able to assist in advising on the appropriate course of action if any are found on site, such as altering the design of the scheme through to bringing on board specialist contractors.