Permission for construction of a bypass around the town of Killaloe is being challenged in the High Court.
The development means loss of woodlands and species associated with that ecosystem, including otters, salmon, lamprey, swans, and kingfishers, it is claimed.
Environmentalist Peter Sweetman and an environmental protection company, The Swans and the Snails Ltd, claim the project involving construction of a 170-metre bridge over the river Shannon will result in irreversible destruction of a woodlands habitat.
The habitat of alluvial wet willow-alder-ash woodland is located on the western side of the proposed bridge.
Leave to bring the challenge to the bypass was granted, on an ex parte application by Mr Justice Michael Peart, who returned the matter to early July.