Bad dog? The environmental effects of owned dogs

Dogs as owned pet animals are globally ubiquitous and numerous. While the impact of cats, both feral and owned, on biodiversity has been relatively well-studied, by contrast, the comparative effect of owned dogs has been poorly acknowledged. As the commonest large carnivore in the world, the environmental impacts of owned dogs are extensive and multifarious: they are implicated in direct killing and disturbance of multiple species, particularly shore birds, but also their mere presence, even when leashed, can disturb birds and mammals, causing them to leave areas where dogs are exercised. Furthermore, scent traces and urine and faeces left by dogs can continue to have this effect even when dogs are not present. Faeces and urine can transfer zoonoses to wildlife and, when accumulated, can pollute waterways and impact plant growth. Owned dogs that enter waterways contribute to toxic pollution through wash-off of chemical ectoparasite treatment applications. Finally, the sheer number of dogs contributes to global carbon emissions and land and fresh water use via the pet food industry. We argue that the environmental impact of owned dogs is far greater, more insidious, and more concerning than is generally recognised.