A study has revealed the importance of a continuous, connected habitat as a key factor in stabilising the decline in the British hedgehog population.
A study commissioned by the People’s Trust for Endangered Species (PTES), and the British Hedgehog Preservation Society (BHPS) investigating the minimal viable population figures of hedgehogs in rural and urban habitats has revealed the importance of a continuous, connected habitat as a key factor in stabilising the decrease in numbers.
Dr. Tom Moorhouse from Oxford University’s Wildlife Conservation Research Unit (WildCRU) led the research. He explained: “A minimal viable population, or MVP, is the number of individual animals required to make a self-sustaining population. Numbers are dependent on a range of variables including mortality rate, litter sizes, predation, food abundance, weather conditions, type and quality of habitats. In essence, hedgehog populations in habitats that vary a lot in these factors need to be larger than in habitats that provide more favourable, stable, conditions.”
Hedgehogs in rural habitats are likely to experience relatively high predation risk, and substantial fluctuations in temperature, breeding rates and food supply. In such habitats the MVP may be an estimated 120-250 individuals, which at typical hedgehog densities would require 3.8 - 57km2 of connected habitat.
By contrast urban areas (e.g. playing fields or gardens) often provide habitats where temperatures and food supply are relatively high and constant, and where predation risk is low. In such stable habitats the estimated hedgehog MVP was between 32-60 individuals, requiring a minimum of 0.9 - 2.4km2 of connected habitat.
The study confirms the importance of habitat connectivity (continuous, connected habitat) in urban landscapes in ensuring the survival of localised populations of hedgehogs. Habitat fragmentation for hedgehogs occurs from obstacles such as garden fencing, buildings and highways which can severely damage accessibility to areas of vegetation, food, potential nest sites and mates - all of which harm their ability to form a self-sustaining stable population. Dr Tom Moorhouse confirms: “The recommendations made from the study are useful in highlighting that hedgehogs are likely to need larger areas of habitat than we suspected, and underlines the importance of connecting gardens in urban areas.” In other words, 0.9 - 2.4km2 of gardens can only support a viable population if the hedgehogs can get into them!
Hedgehog numbers have been in rapid decline for more than a decade in Britain and studies such as this are vital in planning conservation efforts. Henry Johnson, Hedgehog Officer of PTES said: “We know that hedgehogs can roam an average of 2km each night looking for food, temporary shelter and mates. With this new information on the requirements for viable populations of hedgehogs it is clearly more important than ever that we try and avoid fragmentation in their habitats.”
Professor David Macdonald, Director of the WildCRU emphasised: “This is a trail-blazing example of how detailed research provides evidence that could change the way we live with nature. In the WildCRU we often say it’s much easier to be interesting than to be useful, but with our hedgehog project we’ve scored the double: from prickles to practicality!” He added, “NIMBYISM famously leads to double standards in people’s dealings with nature, but in this case, we really do want hedgehogs in our back yard!”
To help counteract the decline in hedgehog numbers, PTES and BHPS launched Hedgehog Street, an online hub of information, advice and ways for people to get involved in preserving the species. Hedgehog Street now boasts almost 29,000 Hedgehog Champions supporting hedgehogs across the UK. Central to the campaign is the importance of linking up urban gardens to provide larger areas for hedgehogs to roam in. Fay Vass, CEO of BHPS explains, “A gap of just 13cm2 will be sufficient to allow hedgehogs passage. This can easily be achieved by removing a brick from a garden wall, digging a channel under the fence or cutting a small hole. This will allow hedgehogs to make the most of the gardens in your street and cause minimal disruption to you and your neighbours.”
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Information on how to make your garden hedgehog-friendly is available at the Hedgehog Street website, with details of how to become a ‘Hedgehog Champion’ and an A-Z guide of tips for helping hedgehogs at this time of year.
Visit: www.hedgehogstreet.org
