Environmental Impacts

Invasive species are one of the main drivers of biodiversity loss across the globe.

Ecosystems provide a variety of services to us for free and these bring many benefits to society and the economy. There are four main categories: provisioning, such as the production of food and water; regulating, which includes the control of climate and disease; supporting, for example, nutrient cycling and crop pollination; and cultural, such as spiritual and recreational benefits.  Invasive species can impact on the ability of nature to provide these services resulting in increased economic costs and environmental damage.

The impacts of invasive species on biodiversity are widely demonstrated and can occur in all habitats. For example:

• Outcompeting native species for resources (grey squirrels)
• Reducing native biodiversity by grazing on native flora (muntjac deer)
• Predation on native species and their young (Feral ferret)
• Altering habitats which can lead to flooding (Aquatic plants blocking rivers, canals and drainage channels)
• Introduction of parasites (eel swimbladder nematode) and pathogens (squirrel poxvirus) which were not previously found here and against which our native species are not adapted to cope.
• Dilution of native gene pools by interbreeding with native species (ruddy duck).

A summary of the impacts of invasive species in Ireland can be found in the Invasive Species in Ireland report. A summary of economic impacts can be found in the economics section of the website.