And in addition to the revenue loss, the lower Gulf also faces accelerated biodiversity decline.

The figure, released by the Northern Gulf Resource Management Group (NGRMG), is based on an estimated 15 to 20 year recovery period with continued grazing and no human assistance.

According to NGRMG general manager Noeline Gross the total revenue loss to the region’s economy could be higher.

She said the figure was the best estimate the NGRMG could reach given the lack of recorded data on the Gulf’s previous flood recovery periods.

Ms Gross said little was known about how the region’s ecosystems would be able to rejuvenate without human assistance.

NGRMG have conducted extensive studies on the state of the native flora and fauna late last year prior to the recent floods, which they have compared with the “devastating” toll the recent floods have taken on the region.

Initial comparisons indicate land that was previously classed as “A” or ‘good’ condition was now in “D” condition.

Ms Gross said the land displayed a general lack of any perennial grasses and severe erosion, which resulted in a “hostile” environment for plant growth.

More than one million hectares of land was under water for up to 12 weeks earlier this year, the longest continuous inundation on record.

Ms Gross said the only comparable floods in the region were the 1974 wet season.

However, no scientific study was conducted to understand the length of time the region’s ecosystem took to recover.

She said NGRMG were thus left with little choice other than to rely on the recent testimonies of graziers who lived in the region at the time to estimate how long grass took to return and how the native fauna and flora managed to be restored to pre-flood levels.

“That’s why we’re recording and monitoring what’s going on in the region at the moment – so that future generations can benefit from what we’ve learnt,” she said.

Ms Gross said she planned to invite state and federal ministers to survey the devastated land firsthand in an effort to encourage action to assist recovery.

“I can write pages and pages on this event but once you actually stand on this country it is very obvious what’s going wrong,” she said.