Invasive species, as identified under Schedule 9 of the Wildlife and Countryside Act (1981 as amended) are a growing threat to biodiversity in the UK. These species upset the balance of the ecosystem as they may be faster growing or more aggressive than the native species. They may also have fewer natural predators to control their spread. Native species are often unable to compete and the invasive species take over.
Invasive species, such as Japanese knotweed Fallopia japonica can be costly and time consuming to remove and cause significant delays if discovered during works. However, with a pre-construction survey, the implications can be assessed early. Contaminated areas can be avoided or an eradication scheme was undertaken at a known cost and timescale which can be incorporated into the project plan.