Be­yond the head­lines

Are bad­gers re­spon­si­ble for hedge­hog de­cline?

BBC Wildlife Magazine - - Contents - DR CARLY PETTETT’S

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.

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.

BAD­GERS MAY AT­TACK AND KILL HEDGE­HOGS, BUT THAT DOESN'T MEAN THEY ARE SOLELY TO BLAME FOR THE LAT­TER'S DE­CLINE, SAYS CARLY PETTETT.

Given good habi­tat, hedge­hogs can prob­a­bly live along­side bad­gers.

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