How and why are hedgehogs declining?
It’s thought that hedgehog numbers declined by up to a half in rural areas and a third in urban areas between 2000 and 2015. The availability of habitat and food may be two of the main factors affecting them, along with them being killed on roads. The use of pesticides reduces the numbers of invertebrates that they feed on.
Do predators have an impact?
Badgers and foxes can both attack hedgehogs, but we don’t know how common it is or how often a hedgehog is killed. It’s also complex because all three species eat invertebrates and are therefore competing for the same food sources.
We have found you’re less likely to find hedgehogs where badgers and foxes are present, but simple correlation does not imply causation. In short, it’s not clear how predators contribute to the long-term hedgehog decline.
Given good habitat, hedgehogs can probably live alongside badgers © Harald Lange / Getty
Has the badger cull helped hedgehogs?
One study found that hedgehog numbers increased during the Randomised Badger Culling Trial (RBCT). We’d expect any prey species to increase in an area where one of its main predators is removed.
But hedgehogs are declining all over the UK, including areas with lower numbers of badgers than in the cull areas. Further study is needed to look into the exact causes of the hedgehog decline. When invertebrate food availability is low, for example, does that increase badger predation on hedgehogs?
So should we control badgers for the sake of hedgehogs?
As it stands, there’s not enough evidence that reducing the numbers of badgers would work. And even if there was, is it morally right to cull one native species to save another? Badgers and hedgehogs have co-existed for thousands of years and hopefully they can continue to do so, given the right environmental conditions.
Dr Carly Pettett's hedgehog research was carried out at the University of Oxford's Wildlife Conservation Research Unit.
This article originally appeared in BBC Wildlife. Take a look inside the current issue and find out how to subscribe.
Main image: Badgers and foxes both attack hedgehogs © Arterra/UIG /Getty