Plans to build a 14-kilometre bridge linking Cape Jervis on the Fleurieu Peninsula to land southeast of Penneshaw were revealed over the weekend by a group of South Australian engineering and design professionals calling themselves the Universal Bridging Consortium.

If built, the bridge, estimated to cost $4-$5 billion, would be four times bigger than any other bridge in Australia.

The group says the bridge would cut travel time to the island from the mainland to about 15 minutes and provide easier freight transport and tourist access to and from the island.

But Kangaroo Island conservation group Eco Action KI has warned the increased traffic and development that could result from the build could have a negative impact on the island’s ecotourism industry.

Eco Action KI member Fraser Vickery labelled the proposal “completely flawed” and damaging to the island’s flora and fauna.

“Kangaroo Island has still got all of its original species from when Europeans first settled here and we have to maintain those species to keep our ecosystem healthy,” he said.

“If we build a bridge there will be huge amounts of people coming over here, there will be development of infrastructure – roads and new buildings – and that will have huge impacts on the native wildlife.

“It won’t be an island that will be able to sustain its eco-tourism industry.”

Conservation Council SA chief executive Craig Wilkins agreed that the island’s “clean and green” image could be tainted by excess tourism and traffic on the island.

“A big part of the reason the environment on Kangaroo Island is so special is because of its remoteness and isolation,” he said.

“Being an island has helped keep ecosystems intact and free from many pests and diseases that are common on the mainland. A bridge would break down that natural barrier.

“It will also drive a big increase in vehicles – cars, trucks and buses are a huge hazard to many native animals and birds.”

Wilkins said Kangaroo Island was home to some of Australia’s highest quality roadside vegetation.

He added the bridge build could result in developers clearing native habitat to make way for even more new builds.

Greens MP Mark Parnell said while he thought the bridge could benefit tourists by creating more competition for ferry service provider Sealink, he said the project was a “bad investment” that would undermine the charm of Kangaroo Island.

“If you’ve got $5 billion in loose change down the back of the couch then this is not the project,” he said.

“The question really has to be what are the advantages to the environment, to the local residents and to the tourism industry?

“You’ve got people already flogging more bits of land on Kangaroo Island to build a golf course – the pressure for that land would increase three-fold if you had a bridge build there.

“It’s a bit like killing the goose that lays the golden egg – it would turn the island into a monopoly.”

Parnell said the bridge build could be potentially harmful to the environment when builders drill into the seabed to install support pillars to hold up the bridge.

He referred to recent development on Victoria’s Phillip Island, where conservationists had to fight to protect the island’s penguin rookery from becoming destroyed by subdivision and development.

“There’s also the Hindmarsh Island Bridge – that was a big problem for the Ngarrindjeri people who were very active in campaigning against it, trying to protect their sacred sites.

“Ultimately the push for the bridge was from the marina developer – the bridge and the development were inexplicably linked.”

Parnell said the island’s tourism industry would be worse off if a bridge were to be built, as more tourists would visit the island for day-trips rather than staying overnight.

“The best thing for the local economy would be to have tourists staying longer but having a bridge would make a day trip far more practical and easier for tourists.”

SA Tourism Industry Council CEO Shaun de Bruyn said while the council did not have a firm position on the proposed bridge, it was necessary to consider Kangaroo Island’s main drawcard as a destination for Australian wildlife and “pristine” natural environments.

Universal Bridging Consortium said in its statement announcing the bridge plans that partner-engineering firm, Lucid Consulting Australia, was “familiar with some of the island’s unique characteristics, which makes it so precious.”

Protection of the environment, wildlife and sea-life would be a “top priority” during its proposed pre-feasibility study, for which it is seeking $100,000 in State Government funding.

“There is obviously a myriad of economic and environmental considerations involved in a project of this magnitude, but they will also be identified and addressed in the proposed pre-feasibility study,” said Universal Bridging consortium partner Jason Semanic. .

Lucid CEI Anthony Di Marzo added: “We will team with local and global specialists to ensure that the pre-feasibility study identifies all potential risks to the island, coastal mainland and surrounding seas, so that the project can be considered holistically and risks suitably addressed.”

Kangaroo Island mayor Peter Clements told ABC Radio Adelaide this morning that the bridge plan was “overkill”.

“It would basically kill-off everything that means anything to Kangaroo Island and to people that come here to enjoy the tranquillity of the island,” he said.