BY KATIE - MYGREENPOD, 15 June '18

Almost one in five British mammal species face high risk of extinction

Nearly a fifth of Britain’s mammal species face a high risk of extinction, according to the first comprehensive review of their populations for more than 20 years.

According to the report, launched by The Mammal Society and Natural England, the red squirrel, wildcat and the grey long-eared bat are all facing severe threats to their survival.

The review also found other mammals such as the hedgehog and water vole have seen their populations decline by up to 66% over the past 20 years.

’Unacceptably high’ uncertainty levels

Climate change, loss of habitat, the use of pesticides and road deaths are all putting pressure on some of the best loved and most recognisable of Britain’s 58 terrestrial mammals, whose current status, historical and recent population trends, threats, and future prospects have all been assessed in the review.

Prof Fiona Mathews, Mammal Society chair and professor of Environmental Biology at the University of Sussex, said, ‘This is happening on our own doorstep so it falls upon all of us to try and do what we can to ensure that our threatened species do not go the way of the lynx, wolf and elk and disappear from our shores forever.’

The Mammal Society is now calling for more research to be carried out urgently to get a clearer and more accurate picture of Britain’s mammal populations. For many species, including common animals such as rabbits and moles, very little information is available.

Last month, the society launched a Mammal Mapper app so that any Nature lover could record sightings of local mammals using just their smartphone.

‘The report highlights an urgent requirement for more research to assess population densities in key habitats because at present, uncertainty levels are unacceptably high. It is possible that declines in many species are being overlooked because a lack of robust evidence precludes assessment. There is also an urgent need to quantify precisely the scale of declines in species such as the hedgehog, rabbit, water vole and grey long-eared bat. Effective and evidence-based strategies for mammal conservation and management must be developed before it is too late.’

PROF FIONA MATHEWS
Lead author of the Review of the Population and Conservation Status of British Mammals

Otters and beavers among ‘success stories’

The report does highlight that some British mammal populations are in more robust health. Five species have increased in numbers in 20 years, and 18 species have increased their geographical range.

The otter, polecat, beaver, wild boar are all now found in more locations than they were 20 years ago, though many of the ‘success stories’ are species recently introduced to Great Britain, such as the grey squirrel and muntjac deer.

Surprisingly, given their importance to both humans and wildlife, there is very little information on species such as brown rats and house mice: their population estimates are around 7 million and 5 million respectively, but could in reality be much higher or lower.

Natural England Senior Specialist for Mammals, Katherine Walsh, who coordinated the project, said the project ‘has significantly improved our understanding of the current status of terrestrial mammals known to breed in Great Britain, which is essential to underpin our efforts to protect them and their habitats.’

The numbers

HEDGEHOG
Current estimated population of 522,000 is 66% lower than estimated in the previous comprehensive review in 1995.

Hedgehogs are struggling because the insects they prey upon are declining from changes in agricultural practice and pesticide use, human influence through road accidents and loss of nesting habitat.

They may also face increased threats from badgers whose population has doubled in the same period to around 562,000.

RED SQUIRREL
There has been marked decline in the distribution of red squirrels since 1995, which has been linked to ever increasing grey squirrel numbers.

The invasive species now outnumbers the red squirrel 10:1. Disease epidemics, including squirrel pox which is transmitted by grey squirrels, and competition for resources are factors for reducing red numbers as well as an increase in the planting of Sitka spruce trees — native to North America — which are less favourable to red squirrels.

RABBIT
The rabbit is classified as globally threatened, and in Britain its population is likely to have declined by about 9% since 1995, now standing at around 36 million.

Other surveys, based on the numbers of animals culled, or primarily focused on recording bird numbers, have recorded larger drops of 24% between 1995 and 2014 and 48% between 1995 and 2012 in Britain respectively.

Localised populations can be extremely variable depending on scale of disease outbreaks, particularly of rabbit viral haemorrhagic disease and myxomatosis, and large-scale surveys are needed to understand the status of the British population more clearly.

The impact of culling on population size could be waning because of reduced demand for rabbit meat and fur.

ORKNEY VOLE
There is an urgent need for more information on this small animal. It was introduced to the Orkneys in Neolithic times, and is now an important part of the local ecosystem, where it is prey for numerous birds of prey including short-eared owls and hen harriers.

Not only has the vole suffered from changes to farming practices, but it is now at severe threat from stoats which have introduced to the islands in the last decade.

WATER VOLE
From a 1995 population of more than 1 million, water vole numbers now estimated to be just a tenth of that.

Threats from the American mink and changes in land management, including wetland drainage, arable cultivation and watercourse canalisation, are believed to have been largely responsible for their steep decline.