The Grangegorman Development Agency has spent almost €5,000 commissioning a survey of the bat population on the site of DIT's new campus, amid concerns about the potential impact of the proposed development on its nocturnal inhabitants.

While it claims the discovery of one species – the common pipistrelle bat – on the site during a 2009 survey will not delay the overall project, it has also acknowledged that it will have to pay for bat mitigation measures.

However, it could not say how much this is expected to cost at this stage.

The agency was responding to concerns raised by An Taisce about the future of the site's bat population.

In a recent submission to the agency's draft strategic plan, it argued that "no decision should be made without the results and proposed mitigation measures of the bat survey".

A spokesman for the GDA told the Sunday Tribune that a bat survey was carried out in July 2009, and that it has spent a total of €4,738 on such research to date. This found that pipistrelle bats were present on the site.

"While the report states that there are potential bat roosting sites in Grangegorman, there were no definite sites found," he said.

"Activity during the survey was found to be extremely poor, with few bats being recorded on detector. Diversity was also low, with only a single species, the common pipistrelle, being recorded hunting or commuting on site."

"As no major bat roost or activity was found it is not envisaged that there will be a delay in the project, however, the GDA will continue to assess the situation."

The spokesman added that the report had found that due to the planned implementation of the recommended mitigation and enhancement measures , along with the "very limited" use of the site by the bats, the proposed development is expected to have "a negligible impact on bats and those observed on site should almost certainly persist".

"The measures set out may even encourage further use of the area by these animals," the spokesman added. "If the loss of any mature trees and hedgerows is compensated for by replacement planting and provision of linear corridors then such measures would almost certainly benefit local bat populations."