Badgers Blamed for Decline in British Hedgehog Population
Scientists argue that the increasing number of badgers, rather than pesticides or roads, is the primary reason for the dwindling hedgehog population in Britain.
The declining numbers of hedgehogs in Britain are primarily attributed to the growing badger population, a factor often overlooked by conservationists who typically blame pesticides, roads, and habitat loss. Evidence suggests a direct correlation between rising badger numbers and falling hedgehog populations across various habitats.
While commonly cited reasons for hedgehog decline include pesticide use and traffic, experts argue these factors are less significant. Insecticide use has generally decreased, and hedgehogs are disappearing even in areas with minimal chemical use. Similarly, hedgehog populations are often denser in busy suburban areas with more traffic, contradicting the idea that roads are the main threat.
This predator-prey relationship is particularly evident in urban and rural settings. At Kew Gardens, for example, hedgehogs vanished in the late 1980s as badger numbers increased. Similar patterns have been observed in Wytham Woods, where an experiment introduced hedgehogs that were quickly consumed by the resident badgers. Conversely, hedgehogs thrive on Scottish islands like South Uist, Islay, and Mull, as well as Orkney and Shetland, where badgers are absent.
Scientists point to a phenomenon known as 'mesopredator release,' where the absence of apex predators allows mid-level predators like badgers to flourish. This is exacerbated in Britain by a lack of natural predators for badgers, an abundance of human-provided food sources such as landfill and roadkill, and legal protections that have prevented significant badger culling.
The increased badger population, estimated at around half a million in Britain—twice the number from the 1980s—also impacts other species. Bumblebee nests, a favored food of badgers, are frequently raided, leading to a decline in bee populations as well.
Studies from cull zones aimed at reducing bovine tuberculosis in badgers have shown a rebound in hedgehog numbers. In amenity grasslands within cull zones, hedgehog population density increased significantly over five years, while areas without culling saw no change. This provides compelling evidence that badger predation is a critical factor in hedgehog survival.
The current hedgehog population is estimated to have roughly halved since the 1990s, a figure significantly less exaggerated than the widely quoted statistic of a 97% decline from the 1950s, which was based on anecdotal observations. The increase in badger numbers is linked to changes in land management, increased food availability from human waste, and legal protections, leading to unnaturally high densities. The plight of the hedgehog serves as a stark example of how ecological imbalances, particularly predator-prey dynamics, can lead to the decline of beloved species.