Research could help stop housing increase from impacting our bat species

Serotine bat. Picture: Hugh Clark / Bat Conservation Trust

Serotine bat. Picture: Hugh Clark / Bat Conservation Trust - Credit: Hugh Clark / Bat Conservation Tr

An increase in housing throughout Norfolk over the next decade could have a big impact on the bat population, new research has suggested.

The Barbastelle bat (Barbastella barbastellus). Picture: NTPL/BCT/Hugh Clark.

The Barbastelle bat (Barbastella barbastellus). Picture: NTPL/BCT/Hugh Clark. - Credit: �NTPL/BCT/Hugh Clark

And to help stop the decrease in the county's bat species, the British Trust of Ornithology (BTO) has released research data which it hopes can inform planning decisions, not only here but nationwide.

It is estimated a total of 66,442 houses are set to be built throughout Norfolk over the next 10 years, which could result in the loss of the bat's habitat.

In some areas, including Thetford Forest and north-west Norwich, the rare barbastelle bat is predicted to decline by 97pc.

Over the whole of Norfolk the population would only decline by 1.9pc, because the developers would be building on a small area of the county.

The Leisler's bat. Picture: Mark Carmody

The Leisler's bat. Picture: Mark Carmody - Credit: Archant

Dr Jenni Border, from the BTO and lead author of the research, said although county-wide the number decrease may be small, if more houses are built there would be more of an impact.

She said: 'The effect of housing depended on the type of habitat that was replaced. For example, new developments around forest habitats would have greater impact than developing in existing urban areas.

Most Read

'We are hoping the research could be used as a tool to help make planning decisions. The research suggests there would be a 60pc reduction on the negative affect just by changing where we put the houses because then the bat's habitat is not being destroyed.'

The study used data which was collected by volunteers who have taken part in the BTO's Norfolk Bat Survey.

Areas around Thetford Forest is one of the places where bad species could decline. Picture: Sonya Du

Areas around Thetford Forest is one of the places where bad species could decline. Picture: Sonya Duncan - Credit: Eastern Daily Press � 2015

Sensors were put in areas around Norfolk and the bat's activity was monitored over a number of days. Dr Border then analysed how the removal of the bat's habitat would affect their numbers in certain areas.

Norfolk County Council worked with the BTO during the study.

David White, senior green infrastructure officer for the authority, said: 'The natural environment team recognises that housing developments have the potential to impact bat species.

'We work with district planning authorities and Natural England, the statutory body, to ensure impacts on bats from development are minimised, and that wildlife legislation is met.'

What do you think? Email

To take part in the Norfolk Bat Survey or for more information visit

Why are bats important?

The research found the two most affected species of bats would be the barbastelle and serotine.

Dr Border said bats are an important mammal.

She said: 'It is not just that it is nice to have a species flying around and living.

'They are good pollutants, spread seeds and they are good for pest control as they eat bugs on farm crops.

'Bats are an ecological indicator. They are quite widespread and diverse and represent different habitats and we can model what happens with other species. The research suggests the housing would also affect other wildlife like birds and invertebrates.'

She added: 'I think now people are becoming more engaged with bats. In history they have a bad reputation as being ugly and horrible. But I think people are coming round to them.'

What else is being done to help bats?

The construction of roads has the potential to impact bat populations, through loss of roosts and cutting off areas used as commuting routes.

Bats are reluctant to fly across open spaces which are created by roads.

They also like to fly close to the ground and therefore this could result in collisions between traffic and bats.

Bat gantries or bat bridges are built over the roads - made from wire mesh strung high over the carriageway between two poles - and are intended to replicate removed hedgerows and trees, giving the bat a reference point for sonar, so they avoid roads.

But a study in 2015 into £350,000 bat bridges on the A11 concluded those gantries were not effective in guiding bats safely over the road.

Stuart Newson, from the BTO, said: 'There is no evidence to say the bat bridges work. But there is no other option. I think it is the area which would be really helpful if there is more work to see what actually works.'