Invasive species

What's going on

Invasive non-native species (INNS) are one of the most significant drivers of global biodiversity loss, contributing to 40% of animal extinctions in the last 400 years. The impacts are greatest within island ecologies, and the UK has amongst the highest presence of invasive species globally and this appears to be increasing [source].

INNS can threaten native biodiversity though the spread of disease, competition for resources, modifying ecosystems, direct consumption, parasitism and hybridisation [source].

Their impacts can be far reaching, potentially affecting the environment’s ability to provide vital services such as regulating water quality. They can also put additional pressure on native species already struggling under climate change and habitat loss, both of which can make conditions more favourable for invasives and exacerbate the problem.  

They can have serious economic impacts, too, costing the UK economy an average £1.8 billion per year, with construction and infrastructure one of the primary sectors impacted [source]. For example, non-native grey squirrels cost woodland owners an estimated £37million in lost timber and damage mitigation measures each year and also threaten native species such as the red squirrel. Deer are a valuable and charismatic part of our natural history, however the range and size of populations of both native species and four exotic species present in England are growing.

High deer densities lead to significant damage to woodland biodiversity, young trees and agricultural crops.

It is far better to prevent INNS in the first place than it is to treat them once they have become established [source].

Steps within design and the early stages of the project lifecycle can mitigate these risks. For example, considering invasive species and biosecurity within procurement decisions or assessing the risk of introduction, and considering mitigation early within the planning stage. Designers should consider future risks and the likelihood of new species being introduced or spread, then take steps to block the pathways for their introduction and spread.

Designers should consider future risks and the likelihood of new species being introduced, then take steps to block the pathways for their introduction.