One of four remaining populations of the carnivorous "rainbow plant", unique to Perth, could be wiped out after a planning approvals process WA's most prominent scientists have called "disastrous" and "seriously flawed".
Alison Baird Reserve, known as Yule Brook, in the Kenwick foothills, is home to one of four remnant populations of byblis gigantea, listed internationally as critically endangered and by the state as threatened.
The plant, which survives by catching and digesting insects, has only ever occurred in Perth wetlands.
The Yule Brook population, consisting of two single plants, is the only one protected by fencing and the only one for which detailed studies exist.
But the City of Gosnells applied to rezone its immediate surrounds for industrial development, without a buffer zone - a proposal University of WA biologist Hans Lambers labelled 'disastrous'.
He said there was no environmental impact study done for the Greater Brixton Street Wetlands Bush Forever site, of which the reserve is part, during the application.
He and other high-profile WA scientists, including former Kings Park directors Stephen Hopper and Kingsley Dixon, who is also WA Scientist of the Year, voiced their alarm to the WA Planning Commission.
"We consider this a serious oversight ... a serious flaw in the environmental assessment process," they submitted.
"[This] is the highest biodiversity Bush Forever Site in the Perth region ... it includes multiple Matters of National Environmental Significance listed under the Federal EPBC Act.
"[The site] was omitted from all assessment in the studies commissioned by the City of Gosnells and thus none of the potential direct and indirect impacts ... were determined or discussed."
But the Planning Commission recommended Planning Minister Donna Faragher sign off on the rezoning without modification, despite recent criticism for its approving development at another wetland after incomplete environmental assessments.
Professor Lambers said the 35-hectare reserve was arguably the Swan Coastal Plain's most precious.
It was home to more than 300 plant species, about a quarter of the number found in the whole of England; and to at least 26 carnivorous plant species, more than in the whole of Europe.
It contained 18 threatened plant species, three federally listed threatened plant complexes and other plant species listed as rare.
"Areas like this make Perth the most biodiverse city in the world. It is something to be proud of and look after," Professor Lambers said.
"If this goes ahead, Alison Baird Reserve and surrounding wetland areas will deteriorate beyond repair. It will be a tremendous loss for humanity and science."
The rainbow plant used to be widespread in Perth wetlands, Curtin University research fellow Adam Cross said.
Only 20 years ago, Dr Cross said, carpets of them glistened in the sun, hence the "rainbow" common name coined by an early WA botanist – who was referring to an area that is now a large industrial car park.
He said all wetlands relied on water catchment from their surrounds, but continuing development surrounding Alison Baird Reserve had prevented water trickling in over time.
The ground had steadily dried over the past seven years - bad news for the rainbow plant, which needed water present in the soil for long enough to reach maturity.
"If the surrounding landscape is developed that water won't reach the wetland," he said.
"There is a seed bank, but this year we found two plants. If this population was to be lost in the wild that is a quarter of the entire known populations left in the world.
"The other three are all declining and facing similar risks. Chances are the entire species will be lost."
He said while development had to happen in Perth, often it appeared due diligence was not done regarding site biodiversity.
Greens MP Lynn MacLaren raised concerns about the unclear conservation status of the reserve under the government's draft Green Growth Plan, intended to guide development in Perth to 2050.
Her submission said the plan marked the reserve purple for "Industrial Class of Action", but also green for "Specific Commitments" – which were not specified. To confuse things further, it was also listed as a Phase 1 Conservation Reserve.
She said government staffers explained these inconsistencies to concerned community members as potential errors.
"It is not good enough to present such a shoddy draft to the public and only fix the errors at a final stage when the public no longer have opportunity to comment," she wrote in her submission.
Gosnells chief executive Ian Cowie said the City had undertaken detailed planning for the area over 15 years after the state identified it as a major major future employment centre.
It had completed numerous detailed and independently peer-reviewed environmental and water management studies for the area, mapping sensitive sites.
While buffers around sensitive areas were not defined during the rezoning process, more detailed stages of planning would now occur, including evelopment of a structure plan, to establish suitable buffers between environmental assets and future development areas.
"A key focus of the more detailed planning will be to protect the flora and fauna within the Brixton Street Wetlands," he said.
"The City is aware of the critical importance of continuing to protect the Greater Brixton Street wetlands. The proposal has been developed in close collaboration with environmental agencies, and future direction on the project will continue to be informed by advice from State Government agencies including the Department of Parks and Wildlife and the Environmental Protection Authority."
WAPC chairman Eric Lumsden said the WAPC had received 92 submissions on the rezoning of the area adjacent to the wetlands and confirmed buffer zones would be considered at a later stage of the planning process.
"The Environmental Protection Authority assessed the land subject to rezoning, and provided advice on flora and vegetation, and the inland waters' environmental quality," he said.
"The EPA determined that an environmental impact assessment of the region scheme amendments was not required."
Alison Baird Reserve is owned by the University of WA, which also owns Shenton Park's Underwood Avenue Bush Forever site, whose future is similarly uncertain under the Green Growth Plan.
