A legal hearing has begun which could see plans for Cinderford's Northern Quarter challenged over claims that planners had not paid enough attention to the area's wildlife.
Forest of Dean District Council declined to comment ahead of the two-day High Court hearing in London.
When a Friends of the Earth group launched its legal challenge in April last year, the authority said it was "surprised and disappointed".
'Very important place'
Campaigners argue the district council adopted the plans without having undertaken an appropriate assessment of the core strategy.
If the authority loses the hearing, it would have to reconsider its core strategy and area action plan which were approved by government inspectors in January last year.
Friends of the Earth spokesperson Mary Newton said: "This site has European protected species. There are 12 different species of bat recorded here, there are great crested newt and dormice."
Another campaigner, Simon Glover from the Butterfly Conservation group, said the area was good for wildlife because of the individual ecosystems all working together.
"We have got a number of lakes, a number of open grassland areas and then the woodland, so it is a very important place," he said.
"It is no coincidence that the bats are here - they are here because of the moths and all the other interactions of wildlife."
Watch video Cinderford Northern Quarter legal challenge over area's wildlife online without registration, duration hours minute second in high quality. This video was added by user 2b3n4m5q7 15 May 2013, don't forget to share it with your friends and acquaintances, it has been viewed on our site 212 once and liked it 1 people.