Biological invasions occur when organisms such as animals and plants are introduced by people to regions of the world where they do not naturally occur. In these new locations, these organisms are referred to as “alien species”.

Biodiversity is the variety of all living organisms on earth. It is the interconnected web of life that is a wonder to behold – it is also vital for people, providing the foundation for happy, healthy lives.

Biological invasions can be severely damaging to biodiversity. Alien species interact with native species in many different ways. For example, they often compete with native species for resources such as food.

This can cause declines in the abundance of native wildlife and, in some cases, the permanent loss of native species (their global extinction).

The number of alien species being introduced to new regions continues to rise. Hence, identifying and managing their impacts on native biodiversity is a global conservation priority. A great deal of research has been published on this topic.

However, biological invasions can cause another type of impact that is far less comprehensively studied and managed. These are impacts that cause the suffering of animals.

Animal welfare and sentience

Animal welfare is defined by the World Organisation for Animal Health as

“the physical and mental state of an animal in relation to the conditions in which it lives and dies”.

“the physical and mental state of an animal in relation to the conditions in which it lives and dies”.

Sentience is the ability to experience feelings and sensations, such as pain, fear and anxiety. It is now widely recognised that many different types of animals are sentient. In the United Kingdom, the welfare of these sentient animals is protected under the Animal Welfare (Sentience) Act 2022.

Biological invasions affect the welfare of sentient animals

Biological invasions result in interactions between organisms (including plants and animals) that can severely harm the welfare of the animals involved. For example, the avian vampire fly (Philornis downsi) was accidentally introduced to the Galápagos Islands from South America several decades ago.

It lays its eggs in the eyes of fledgling native birds. When........

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