Lord Howe Island cloud forest species thrive after rodent eradication program
Mist hangs in the air, embracing the giant mosses and clusters of tree orchids that adorn the summit of the majestic Mount Gower on Lord Howe Island.
Ascending into this rare island cloud forest is like stepping into a fairytale — a hushed and secret world, carpeted in a tapestry of rich greens, rare palms, and twisted trees veiled in lichens.
As the canopy closes over, an otherworldly place emerges, an enchanting reward for those who have made the rugged and arduous climb to the island's highest peak.
Above, providence petrels circle and call, while in the shaded, cooler air below, flightless Lord Howe Island woodhens scurry through the ground cover.
Remnants of an extinct shield volcano, Mt Gower and the adjacent Mount Lidgbird have stood for millennia as sentinels at the Jurassic-like southern end of the World Heritage-listed Lord Howe Island.
Even in clear weather, their summits are often enveloped in clouds, that form as warm, moist ocean winds hit the mountains and are forced to suddenly rise and rapidly cool.
"There are not many islands in the world with very tall mountains that stick up so high into the atmosphere they create their own cloud, so it is pretty special," the island's resident biologist and naturalist, Ian Hutton, said.
The fragile ecosystem thriving here at altitudes above 750 metres is home to plants and animals found nowhere else on the planet — the combination of a geographical "sky island", sitting atop an earthly one.
"Probably 85 per cent of the plants on Mt Gower are only found on Lord Howe Island, and many of those just on the very summit," he said.
"Some plants have evolved over millions of years just to live on that summit … living on those plants are certain species of beetles and snails that have evolved just to live on those plants."
Officially known as the Gnarled Mossy Cloud Forest, the ecosystem is classified as a critically endangered ecological community, a known biodiversity hotspot.
In recent decades the ecosystem has struggled to survive, threatened by rodents and climate changes.
It's five years since a widescale, $15 million eradication program rid the island of more than 300,000 mice and rats.
Introduced owl species were also removed from the island, an 11-kilometre-long crescent in the Tasman Sea, 600 kilometres east of Port Macquarie.
"The rodent eradication project wasn't about killing rats; it was about actually protecting this environment," Lord Howe Island Board chief executive Suzie Christensen said.
"They [rodents] are responsible for five species of bird that became extinct, 13 invertebrates and a lot of critically endangered animals on the island.
"Because of our location and small amount of habitat, the rodents were the biggest threat to the ecology and biodiversity of the island … and the bounce-back has been enormous."
Mr Hutton said the program laid the groundwork for a swift and remarkable environmental resurgence, highlighted by the recovery of more than 30 species of threatened flora and fauna, including birds, insects and snails.
"We are just now, five years later, seeing the beginning of [an ecological] renaissance of this island," he said.
Trek to a paradise reclaimed
One man who has held a front-row seat to the environmental transformation is fifth-generation islander Jack Shick.
The 63-year-old trekker estimates he has scaled the 875-metre-tall Mt Gower about 2,400 times, following in the footsteps of his father and grandfather, who were both mountain guides.
"This is my backyard," he said. "I guess where your grassroots are is where your heart is.
"It's just amazing the changes that are happening in the forest — it has blown me out of the water really.
"I thought it would change but I just can't believe how quickly things have been happening."
The trek up Mt Gower involves a rugged climb, and ropes are needed to safely haul the intrepid up steep sections with dramatic drop-offs.
Surprisingly tame endemic currawongs watch on quietly from cliff-side trees, as Mr Shick leads a group up the mountain.
He regularly stops to marvel at the number of palm seedlings carpeting the forest floor.
The critically endangered little mountain palm — a species found only in the cloud forest in an area of less than 4 square kilometres — is thriving now that the rodents have been removed.
"There are so many more seeds now from the palms. The rats would have eaten all those seeds," Mr Shick said.
"The number of palms coming back now is just unbelievable."
So too, he says, is the resurgence in insect and bird populations, including the number of silver eyes, golden whistlers and black-winged petrels.
"I have been walking through here since I was a kid, and you think what you're seeing is normal, but now we are starting to see the real normal when things start to recover," he said.
From the summit, the island can be seen stretching out below, its coral lagoon sparkling along its western shore.
Emulating their distinctive sound, Mr Shick calls providence petrels down from the sky and the large seabirds land nearby.
Loading...The species nests almost entirely on the island and their nesting grounds on the slopes of Mt Gower and Mt Lidgbird are now safe from rat predation and owls.
The Lord Howe Island Board says in recent years their breeding success has jumped from 2 per cent to 50 per cent.
Sights and sounds of recovery
One of the most prominent signs of ecological recovery is the prevalence of cheeky, noisy Lord Howe Island woodhens.
Once pushed to the brink of extinction and confined to the summit regions of Mt Gower and Mt Lidgbird, the species is now thriving, scurrying across paths and through forests.
Their high-pitched staccato calls form part of the island's unique soundtrack, day and night.
In the 1970s, there were fewer than 30 birds left, so a captive-breeding program was started in 1980.
Once feral pigs and cats were removed from the island, the woodhen population rose to about 250.
It's the removal of egg-eating rodents, though, that has had the biggest impact.
"Our Lord Howe Island woodhen numbers have gone from about 200 woodhens five years ago, to over 2,000 now," Mr Hutton said.
The island's board reports the woodhens' behaviour has also changed — pairs are now breeding nearly year-round, producing multiple clutches of eggs.
Mr Hutton said insect life had also increased remarkably.
Earlier this year, while collecting specimens on Mt Gower for the Australian Museum in Sydney, he found a species of beetle that was thought to be extinct.
"I was out at night photographing insects and snails," he said.
"One of them turned out to be a species of beetle, a type of weevil, that had been declared extinct, and hadn't been collected since 1916.
"Yet there it was! I found some on a palm … so that's very exciting, to think there's a beetle presumed extinct, but it did survive."
According to the board, since the eradication of rodents, four of the five endangered land snail species have also been seen more regularly.
"They found snails they thought were extinct, and identified 10 new snail species, and found a wood-eating cockroach on the main island for the first time in 80 years," Ms Christensen said.
One species, the magnificent helicarionid land snail, only known to live on the upper slopes and summit of Mt Gower, was feared extinct until it was spotted again in 2022.
'Canary in the coal mine'
Scientists flock to Lord Howe Island, keen to study an environment that was untouched by humans until the late 18th century, when whalers stepped ashore to replenish food and water supplies.
Researchers say its isolation makes it an ideal "control" for studies looking into the impacts of climate change.
"Lord Howe Island, being this fairly intact ecosystem with 85 per cent of its forest still left, and fairly minimal impact, scientists can come here and study the real world in pretty pristine condition," Mr Hutton said.
These include studies of the cloud forest and the world's southernmost coral reef.
Professor Lesley Hughes, a climate scientist from the Australian Climate Council, said these rare and fragile environments were proving to be the "canary in the coal mine" for climate change.
"As the world is warming up, places like the cloud forest are getting much drier and they basically go into drought and can't exist anymore," Dr Hughes said.
"So, the cloud forest here is a really important ecosystem to monitor, to really see how climate change is progressing in vulnerable ecosystems."
Mr Hutton, who first arrived on Lord Howe Island in 1980 as a weather observer for the Bureau of Meteorology, has been involved in long-running climate change studies on the island.
"For about 15 years we have been putting temperature loggers at 100-metre intervals from sea level up, and a few across the summit," he said.
Loading...Mr Hutton, an author and photographer, uses drone technology to document changes on the mountain summits photographically.
"I am able to aerially map the summit and have a record year after year of changes," he said.
"When we have extreme dry years, and the cloud lifts off the mountain, we have seen a fairly significant impact on tree species, not just the small plants.
"If the trees die up there and they do fall over, potentially it is letting weeds into that environment, and also just opening up the light, and many plants have evolved to live in the dark shade, and they won't cope with that."
Reef studies of global importance
Dr Hughes said the island's reef was acting as a similar "canary" highlighting the impacts of climate change on reefs around the globe.
In February this year, Lord Howe Island experienced a significant coral bleaching event.
"Coral reefs all around the world are really being badly affected by warming oceans," she said.
"Our oceans are actually absorbing more than 90 per cent of the extra heat in the Earth's system."
Dr Hughes said marine heatwaves were stressing corals and causing them to dispel the symbiotic algae that provided their food source.
"If the stress goes on for too long, they bleach and die," she said.
Professor Bill Leggat, of the University of Newcastle's School of Environmental and Life Sciences, is part of a team, including staff from the University of New South Wales and the state Department of Primary Industries, which is monitoring the impact of coral bleaching on Lord Howe Island.
"When climate predictions suggested corals were going to bleach, we went over in January before the coral bleaching occurred and did some baseline studies and now, we've been back a number of times to follow how severe the bleaching has been," he said.
"Lord Howe had a bleaching event in 2010 and 2011, also one in 2019, and now in 2024 … this event was one of the worst they have recorded.
"Some reef areas were having 50 per cent bleaching, which is pretty high."
Professor Leggat said there were already signs of recovery on Lord Howe Island's reef, but the warming climate remained a concern.
"Unfortunately, corals around the world have been undergoing a bleaching event for the past year. It started in the Northern Hemisphere," he said.
"We didn't see coral bleaching events before 1980, so it's very concerning.
"When you are seeing these impacts from climate change on Lord Howe Island, which is incredibly isolated, the reef is well-managed and it's not subjected to other stressors … it's really a worrying sign for all reefs around the world."
Professor Leggat said a "greener economy" and reducing other stressors on coral reefs would help preserve them for future generations.
"We will continue monitoring the Lord Howe reef and looking at recovery, and that's so we can understand the impact of the bleaching event, what corals have survived, how they have recovered, and give some information for future events," he said.
At a local scale, he said, managers and communities could help to protect coral reefs by minimising other stressors, such as damaging runoff and disturbances, and look at better managing fisheries efforts.
"Corals are a bit like humans, if they are stressed and have multiple stressors, they get sicker and they die quicker," he said.
Former Lord Howe Island ranger turned reef tour operator Dean Hiscox said the island's reef had the distinction of being influenced by tropical, sub-tropical and temperate ocean currents.
"It provides this really unique combination of different species that flourish in a pristine, really healthy marine system," he said.
These species include the double-header wrasse and a local variety of clownfish.
"Not only are they unique and have wonderful characters, but they also provide us with a really good benchmark of reef health," he said.
Loading...Mr Hiscox takes water temperature readings of the lagoon every day and said he felt helpless in February this year when readings reached the "danger zone" above 26 degrees Celsius, leading to the bleaching event.
"For us, that is incredibly sad," he said, before noting that Lord Howe Island had been able to recover from previous bleaching events.
"We now know that if we go from an El Niño weather pattern to a La Niña cycle, that will traditionally bring cooler air and ocean temperatures to this region and then we will go into a couple of cooler seasons," he said.
"We have seen our reef rebound really, really strongly given enough time for recovery."
Environmental stewards
Moving forward, the focus is on preserving the unique island environment.
Mr Hiscox said sustainability was something the island's 400-strong population "lived and breathed".
"There's a good reason it remains so beautiful and unspoilt, and that is because the islanders themselves have taken a strong sense of pride and stewardship in the environment," he said.
"It's part of our existence."
Lord Howe Island Brewery and Nursery owner Tim Maxwell said business operators also supported the ethos to put environmental protection ahead of profits.
"The environment is a lens that we all look through first," Mr Maxwell said.
"If you want to have a business interest on the island, you have to think first, 'Well, what impact is that going to have on the island and on the community?'
"For me, living here for only seven years, I've really noticed the difference when I go back to Sydney.
"Here, the proximity of living so close to what you affect is really a different mindset."
The island has reaped the benefits of a decision made in the 1950s to cap visitor numbers to 400 at any one time.
It's a tourism model that has prevented the over-development seen in other holiday hotspots on the mainland, and on some popular Australian islands.
Community consultation done recently by the Lord Howe Island Board as part of its 10-year strategic plan showed zero appetite for changing the cap.
Board chief executive Suzie Christensen said it provided a known quantity to all aspects of island life, including the number of daily flights, waste management, water and power provisions, freight considerations and built infrastructure.
"It works well for the island and our capacity to service those needs," she said.
"Mainly the island wants to retain the beauty of the place as a fairly unspoilt paradise."
To that end, under the island's Local Environment Plan, only 25 houses were approved for construction over the past 10 years, each with a minimum lot size of 3,000 square metres.
A hybrid solar farm that was switched on in 2021 now generates 67 per cent of the island's energy needs, and residents generally rely on tanks for their water.
Keeping pests out
After all the hard work to help the island recover from the effects of invasive species, biosecurity is paramount.
Biosecurity team leader Darryl Birch was involved in implementing the rat eradication program, and now works to ensure the pests do not return.
Nothing and no one arrives on Lord Howe Island without being scrutinised by a sniffer dog.
The dogs and their handlers carry out biosecurity checks when the island's supply ship leaves Port Macquarie every two weeks, and again when it docks.
The same checks are done for every flight that takes off bound for Lord Howe Island, and again after each one lands.
Every six weeks the island-based dogs are put to work sniffing out any potential rats, with a "second opinion" gathered every 12 weeks by dogs brought over from the mainland.
Mr Birch said these biosecurity measures would be in place indefinitely to protect the island from threats including rodents, insects, reptiles and plant pathogens.
"Lord Howe is a country in itself, relative to Australia, so everything from the mainland could potentially become an issue," he said.
"We have to be vigilant and the only way we can do that going forward is to use the citizens on the island to keep us informed of what's going on.
"There's a huge amount of pressure. It's such a unique and special place, so we have to work hard to protect it."
Protecting paradise
At a grassroots level, even visitors are doing their part.
Travellers to Lord Howe Island step onto an airport tarmac surrounded by endemic Kentia palms and lush fields, with a smell of ocean salt in the air.
Most eyes immediately lift southward to the breathtaking mountains.
It's easy to get caught up in the drive to protect the place.
Sydneysider Ian Sinclair fell in love with the island more than 20 years ago.
He joined a volunteer weeding group run by Mr Hutton, which aims to eradicate invasive plants including cat's claw creeper and bitou bush.
Mr Hutton started the program in 1995, and since then there have been about 100 weeding eco-tours on the island.
"This island is very special in a biodiversity sense so it's really nice to be able to do something to help that in a very simple way," Mr Sinclair said.
A lot was on the line when Mr Sinclair later brought his partner John Pemble to Lord Howe.
"When I brought John here 14 years ago, it was a bit of a test," he said.
"I thought, if he likes it, I'll keep him."
A proposal followed at the top of Mt Gower and the pair were married at the island's famous Ned's Beach.
They return several times a year and regularly work with the weeding group.
Mr Sinclair said it highlighted the value of "people power".
"This island is a piece of paradise that needs to be looked after," he said.
Credits
- Reporting: Emma Siossian and Hannah Ross
- Photography: Emma Siossian, Hannah Ross, Ian Hutton, Dean Hiscox and Jack Shick, Bree-anna Brunjes
- Video: Hannah Ross and Ian Hutton
- Digital production: Daniel Franklin
- Editor: Rachel Kelly