Invasive non-native species and wildlife disease

Invasive non-native species (INNS) and wildlife disease can have significant impacts on biodiversity and on human society and its economic interests. INNS are recognised as one of the major causes of global biodiversity loss in the Millennium Ecosystem Assessment.

Invasive Non-Native Species and wildlife disease are growing problems because of:

  • Increasing movement of people and materials around the world including international trade in livestock and wildlife, animal products, food crops, timber, and biologically contaminated wastes such as agricultural commodities, waste/by-products, landfill and ballast water.
  • Increasing trade in exotic pets and horticulture products.
  • Indirect effects of climate change, such as the pressure to use biofuels and the use of non-native species for rapid growing biomass
  • Global biodiversity loss, which increases the opportunity for establishment and spread of non-native species.
Invasive non-native species have a major impact on biodiversity and are costly to eradicate. Japanese knotweed Fallopia japonica and Himalayan balsam Impatiens glandulifera can reduce plant diversity through competition and the formation of dense monospecific stands.
Aquatic plants such as the water fern Azolla filiculoides form dense floating mats which cover on the water surface and obstruct sunlight from entering the water. Many invasive aquatic plants reproduce very quickly and out compete native plants as a result.
The carpet sea squirt Didemnum vexillum reproduces rapidly and overgrows shellfish (e.g. mussels, scallops) and other sessile invertebrates and inhibits settlement of native invertebrates. It is a pest to mussel farmers and must be removed either manually or by innovative engineering.
The Quagga Mussel Dreissena rostriformis bugensis and Zebra Mussel Dreissena polymorpha are highly invasive non-native freshwater mussels from the Ponto-Caspian region. They can significantly alter whole ecosystems by filtering out large quantities of nutrients and are serious biofouling risks blocking pipes, smothering boat hulls and other structures. Also from the same area are Dikerogammarus villosus and Dikerogammarus haemobaphes, sometimes known as 'killer shrimps'. These predators kill a range of native species, including young fish, and can alter ecosystems.
The impact of disease on wildlife populations can be dramatic, particularly when those populations are small or fragmented. For example, in the UK red squirrel populations succumb to the deadly squirrel pox virus (as well as suffering from competition with the non-native grey squirrel). Our native freshwater crayfish are impacted by crayfish plague, harbour and grey seals are impacted by seal distemper virus, bats with Lyssavirus and birds can succumb to avian influenza.
The impact of disease on domesticated animals and humans can also be immense. For example the Foot and Mouth outbreak in 2001 in Britain lead to the death of millions of cattle and sheep and cost vast amounts of money.
Both wild animal disease and invasive species require similar responses: prevention through policy, surveillance and control. JNCC provides advice and comment on non-native species as a long standing member of the programme board of the Non-native Species Secretariat ( 
The EU has recently passed the Invasive Alien Species Regulation which came into force on 1 January 2015 and requires member states to undertake various actions. JNCC is working with the UK governments to advise on non-native species surveillance, identification of priority pathways of entry of invasive species, management measures for invasives and listing species of European Union and member state concern.