Red Alert: Britain’s mammals on the edge

Cover image: the hedgehog is one of Britain’s most popular mammals, but is threatened with extinction in the near future. © Peter Brooks

The hedgehog is one of Britain’s most familiar and beloved mammals, with thousands of the prickly critters hoovering up worms and beetles in the nation’s gardens. Unfortunately, most peoples’ first encounter with a hedgehog is at the roadside, where hundreds are struck by vehicles and killed every night. This mortality rate has earned the hedgehog a spot on the UK’s first official mammal Red List, produced in July 2020 by the Joint Nature Conservation Committee (JNCC) and other bodies, which assesses the risk of extinction to Britain’s 47 native mammals.

The IUCN Red List uses nine categories for assessing extinction risk. © IUCN Red List

The International Union for Conservation of Nature (IUCN) is one of the world’s largest conservation organisations. Since 1964 the IUCN has maintained a Red List, classifying the planet’s species according to their risk of extinction. Those at lowest risk are Least Concern (LC); those where extinction is likely are classified as Vulnerable (VU), Endangered (EN), and Critically Endangered (CR), with the chance of extinction increasing up the categories. Between LC and VU fall the Near Threatened (NT) species, and beyond CR are species which are Extinct (EX) or Extinct in the Wild (EW), only occurring in captivity. The Red List also includes Data Deficient (DD) species, for which too little is known to make a better assessment. The Red List takes all sorts of factors into consideration, including a species’ population size, how quickly it is declining, changes to its distribution, and the threats it faces.

National Red Lists differ from the global version in that they only consider populations of species living in one country. For Britain’s mammals, that’s a relatively simple task: since most of them can’t cross the English Channel from mainland Europe, the British populations are isolated, and the assessments don’t need to account for animals that might move in or out of the country. National Lists also include a Regionally Extinct (RE) category, for species which still live wild somewhere but have been extirpated in the country within the past 500 years.

The dormouse is Vulnerable due to loss of key habitat. © Leonardo Ancillotto

Britain’s mammal Red List paints a dire picture, with 45% of species extirpated or at risk of extinction. At greatest risk of extinction are the two species in the CR category: the European wildcat, restricted to a few dozen individuals in Scottish forests; and the greater mouse-eared bat, a species which has been rare since the 1900s and for which only one known individual remains in Britain. Included in the four EN and five VU species are some national favourites, including the hedgehog: the red squirrel, pushed out of its native range by the invasive grey squirrel from America; the water vole, famous as ‘Ratty’ from The Wind in the Willows, a favourite snack of invasive American mink; and the hazel dormouse, at risk due to loss of its preferred habitat in coppiced hazel woods. Less familiar characters, including the Orkney vole, and grey long-eared, serotine, and barbastelle bats, are also at high risk, as is the Eurasian beaver, only recently reintroduced to the country. All of these species need urgent action to reverse their declines: Vulnerable species are quite likely to go extinct within three (of their) generations, and Critically Endangered species are almost certain to be lost in the next decade. Habitat loss is a common culprit behind these declines, with invasive species and persecution also affecting some.

Britain also has five Near Threatened species, which while not at high risk of extinction yet, could easily be pushed over into one of the higher-risk categories. The NT category features the harvest mouse, at risk due to loss of grassland; the mountain hare, regularly culled across large upland estates; as well as Nathusius’ pipistrelle and Leisler’s bats, and the lesser white-toothed shrew, only found on the Channel Islands and the Isles of Scilly. At least for these species, we know what’s behind their declines, and can start to tackle the problems. But four mammals are Data Deficient, including the reintroduced wild boar, and the Alcathoe, Brandt’s and whiskered bats. For these species, we don’t even have enough data to classify them in a category, let alone prioritise conservation efforts; obtaining this data is a top priority.

The Eurasian lynx is one of several species with a strong case for reintroduction to the UK. © Jens Flachmann

You’ll have noticed that some of the species on the Red List have been reintroduced, having previously gone extinct in the UK. Wild boars were hunted to extinction for meat in the 1400s; by the 1500s, beavers had been pushed to extinction by fur trappers. Both of these species have made returns to Britain, but one character is conspicuously absent. Extirpated by 1680 for preying on livestock, the grey wolf is currently listed as Regionally Extinct. However, the species has persisted alongside humans in many parts of the world, and has begun expanding naturally back into its range. Wolves now occur naturally in almost every country in mainland Europe, but since they can’t reach Britain unaided, the only hope for their return to the UK is a human-assisted reintroduction. Other species, extirpated before the 1500 CE cut-off, aren’t categorised on the Red List, but all have proponents for their reintroduction: brown bears (extinct 1000 CE) and Eurasian lynx (400 CE) would help control deer populations wreaking havoc in our woodlands, while Eurasian elk (600 BCE) and reindeer (8000 BCE) would help restore the functioning of degraded ecosystems. Hardy breeds of pony and cattle could stand in for tarpan (7000 BCE) and aurochs (1000 BCE), both globally extinct species. However, all of these animals are large and, to some extent, dangerous to humans and livestock. Reintroducing them will take a big push and a lot of public goodwill.

Deciding which species need saving depends on many things, including predefined conservation priorities – species listed under the UK’s Biodiversity Action Plan already need to receive protection – funding allocations, and on what species contribute to supporting human society and the wider ecosystems we live in. Nevertheless, Red Lists like this one help to set conservation priorities. They tell us which species are at greatest risk of extinction, and why, helping to inform mitigation plans. Hopefully, this provides the impetus needed to start correcting Britain’s woeful record on protecting its own wildlife.

For more information, or to read the full Red List report: https://www.mammal.org.uk/science-research/red-list/

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