More than 72,000 hectares of western Tasmania have been burned by a cluster of bushfires, most of them ignited by a spectacular dry lightning storm that crossed the island on January 13.
The geographic scale of the fires can be seen on the Tasmanian Fire Service website. These fires pose an enormous, ongoing challenge to the fire service, with little immediate prospect of a speedy resolution to this crisis given the absence of soaking rains in the foreseeable future.
Thankfully there has been no loss of life and comparatively limited damage to property because most fires are in remote areas. But there is mounting concern about the environmental impacts of the fires to the Tasmanian World Heritage Wilderness, especially fires in the Walls of Jerusalem National Park and Cradle Mountain-Lake Saint Clair National Park. Bushwalking tracks, such as the popular Overland Track, have been closed until at least next week.
Faced with so many fires, the Tasmanian Fire Service has implemented a triage process, focusing on threats to life and property. This includes farmland, critical infrastructure such as major hydro-electric transmission lines, and also some core areas with extraordinary biodiversity values.
Remote area teams, including specialists from New Zealand to help exhausted fire crews, supported by water bombing aircraft, are fighting the fires in Cradle Mountain–Lake Saint Clair and Walls of Jerusalem National Parks.
Why are world heritage values threatened by these fires?
The fires are extremely destructive for two main reasons.
First, the fires are threatening vegetation that is unique to Tasmania, including iconic alpine species such as the Pencil Pine and cushion plants, as well as temperate rainforests.
Second, the fires are burning up large areas of organic soils upon which the unique Tasmanian vegetation depends. It is extremely unlikely burnt areas with the endemic alpine flora will ever fully recover given the slow growth of these species and the increased risk of subsequent fires given the change to more flammable vegetation and the slow accumulation of peat soils, which takes thousands of years.
Past fires have resulted in a permanent switch from the unique Tasmanian alpine vegetation to more fire-tolerant vegetation.
Is climate change the cause?
Destructive fires in the alpine zone are known to have occurred in western Tasmania in the past 10,000 years, yet these fires were extremely infrequent until European colonisation. Due to the reckless use of fire by prospectors, pastoralists, recreationalists and arsonists there has been a drastic contraction of much of Tasmania’s unique vegetation.
Since the declaration of the World Heritage Area, fire has been carefully regulated with a prohibition of campfires, which has sharply reduced the number of bushfires. Unfortunately, over the last decade there have been an increasing number of lightning storms that have ignited fires.
For instance, in 2013 the Giblin River fire that burned more than 45,000 ha was set off by a lightning storm, one of the largest fires in Tasmania in living memory.
The current fire season is shaping up to be truly extraordinary because of the sheer number of fires set by lightning, their duration, and erratic and destructive behaviour that has surprised many seasoned fire fighters. The root cause of the has been the record-breaking dry spring and the largely rain-free and consistently warm summer, which has left fuels and peat soils bone dry.
There are two ways to think about the recent fire situation in Tasmania. We can focus on the extreme climate conditions and unusual fire behaviour, or we can see what is happening as entirely predictable and consistent with climate change.
I have formed the latter view because the current fires are part of a global pattern of increasing destructive fires driven by extreme fire weather.
A critical feature of the current Tasmanian fires is the role of lightning storms – climate is not only creating the precursor weather conditions for the fires, it is also providing the storms that ignite them.
What can be done?
Obviously we need to maintain efforts to contain the fires in the iconic World Heritage Area. Given that such destructive fires are likely to become more common under a warming and drying climate we need to increase the capacity to attack fires quickly using both air craft and specially trained personnel.
However, under a warming climate the ecological niche of much of the unique Tasmanian vegetation is shrinking, so serious thought is required about moving species to artificially protected environments, such as botanical gardens. In the worse case scenario moving some species to sub-Antarctic island may not be far-fetched.
More fundamentally, the loss of vegetation that takes thousands of years to recover from disturbance is a warning shot that climate change has the potential to result in bushfires that will impact food security, water quality and critical infrastructure.
In other words, like the Pencil Pines, our ecological niche will be threatened.
Your lawn might not enjoy the summer, but there’s plenty of Australian wildlife that does. In urban backyards across the country, you can spot native wildlife that appreciates the hot weather.
Some visitors are conspicuous seasonal guests, while others require you to be a bit more observant. Here are a few to look out for before the temperatures cool off – although many are much easier to hear than to see, so keep your ears and eyes peeled.
Parasitic storm birds
If you live in the north or east of Australia you may have noticed migratory Channel-billed cuckoos (Scythrops novaehollandiae) or Common Koels (Eudynamys scolopacea) descending on your suburb. Often referred to as “storm birds”, they turn up in summer to breed, then head back to New Guinea and Indonesia around March.
Channel-billed cuckoos make their presence known with raucous, maniacal crowing and squawking at all times of the day and night. And the incessant, worried-sounding calling of the Common Koel doesn’t win many fans, especially if you have one camped outside your bedroom window!
Both birds are parasitic cuckoos, laying their eggs in other birds’ nests and then leaving the host bird to raise the cuckoo chicks as their own. Cuckoo chicks grow faster than the host’s brood, demanding all of the food, and the host chicks often starve. To avoid being discovered and kicked out of the nest, some cuckoo chicks have even evolved to look very similar to the young of their host. If all goes according to plan, the adult host birds will rear a healthy brood of fledglings … the only problem is, they’re not theirs.
Keep a close eye on any magpie, crow or currawong nests in your area and see if you can spot the imposters’ fledglings. And maybe buy some earplugs.
In summer, newly independent (and hungry) quolls venture out on their own. These skilled nocturnal hunters feed on a variety of insects, frogs, small lizards and sometimes even possums and gliders. The backyard chicken coop also presents an attractive option to this cat-sized marsupial carnivore.
The particular species in your neighbourhood will depend on where you live. The Western quoll or chuditch (Dasyurus geoffroii) lives in Australia’s southwest; Northern quolls (D. hallocatus) are found in the tropics; Eastern quolls (D. viverrinus) are restricted to Tasmania; and along the east coast are the Tiger or Spotted-tail quolls (D. maculatus).
Unfortunately, and probably due to loss of habitat, predation by feral cats, and perhaps because some populations eat toxic cane toads, quolls have suffered severe range contractions. So if you are lucky enough to have these backyard visitors, it is truly a privilege.
While in some places they are maligned as cold-blooded poultry-killers, quoll-proofing your chicken coop with mesh wire should prevent raiding. To catch a glimpse, venture out quietly after dark with a torch.
Unassuming garden skinks
Do you hear rustling sounds as you walk past a garden bed? Or see a metallic flash as something dives off a sunny rock into a pile of leaf litter?
During summer we’re inundated with snake warnings from the media. But all of our native reptiles (not just snakes) become more active as temperatures rise, and you probably have a variety of skinks in your backyard relishing the warmer weather.
Skinks are amazingly diverse, ranging from the multitude of small, garden skinks (such as Lampropholis) to the well-known Blue-tongued lizard (Tiliqua scincoides). You can find them scurrying through leaf litter, basking on rocks, and sitting on fences and tree trunks – but never too far from cover.
Striped skinks (Ctenotus) are fast, efficient predators of all kinds of invertebrates. In fact, skinks are largely insectivorous, and thus are great natural pest controllers.
Grab a reptile field guide to work out which skink species are in your area. If you want to entice more skinks into your backyard, add some clumping native grasses, rocks, logs and leaf litter to your garden.
Australia’s largest butterflies
In certain parts of Queensland, summer brings one of the most delicate, spectacular backyard visitors: the Birdwing butterfly (Ornithoptera).
Far north Queensland is home to the Cairns Birdwing (O. priamus euphorion), the largest butterfly in Australia. From Maryborough to the New South Wales border you will find Richmond’s Birdwing (O. richmondia), which is slightly smaller but just as impressive.
Throughout summer you might witness a Birdwing’s mating dance, in which the female flies slowly from place to place and the male hovers above her. Females lay their eggs on the underside of native Dutchman’s pipe vines. If you have these plants in your garden, inspect them closely for short, fat caterpillars with insatiable appetites (they will probably eat all the leaves on your entire vine!). Make sure you have the native Dutchman’s pipe vine, as an introduced South American species called Aristolochia elegans is toxic to Birdwings.
These critters are just a few examples of the wildlife you might see in your yard. All kinds of native wildlife respond to the changing seasons. So if you’d like to find out what’s happening in your backyard this summer, get out there and take a look!
Last year’s record-breaking temperatures are having a devastating impact on the world’s coral reefs. For only the third time in recorded history, coral reefs are experiencing a global “bleaching” event (where corals turn white; some ultimately die).
Australia’s reefs are feeling the impact, too. The US National Oceanic and Atmospheric Administration (NOAA) is in charge of producing global bleaching forecasts. Surprisingly, it isn’t the Great Barrier Reef facing the greatest threat this year, but Western Australia’s less well-known coral reefs.
NOAA predictions for the Western Australia (WA) are about as severe as they get: there is a 60% probability of the most severe bleaching (“Alert 2”) for all of April 2016.
In comparison, the Great Barrier Reef on Australia’s east coast has a 60% probability of milder bleaching (“Alert 1”) for most of March 2016 – obviously still a major concern, but not as severe as for the west.
And bleaching is not the only threat facing Western Austraia’s reefs. While we are well aware of the troubles of the Great Barrier Reef, we must make sure we don’t ignore its less famous western cousins.
El Niño and the western reefs
This has sparked some hope for the marine environments in WA, because water temperatures are usually cooler in El Niño than La Niña years.
But water temperatures over the past 12 months have been recorded at 1-3°C warmer than long-term summer averages. While this may seem insignificant, global coral mortality previously occurred at these temperatures in 1998 and was observed in all ocean basins in 2015.
NOAA’s bleaching alert spans most of WA’s coastline. This includes the major coral reef systems of the Abrolhos Islands, reefs in the Pilbara (including Barrow Island, the Montebello Islands, and Onslow) and the Kimberley (including the Rowley Shoals and Scott Reef).
The alert also surprisingly includes the World Heritage-listed Ningaloo Reef. We say “surprisingly” because Ningaloo normally avoids bleaching: it fringes the Western Australian coast and usually receives cooler water welling up from the deep, and from a cool northward flowing current.
That said, Ningaloo experienced massive bleaching in 2011 at Bundegi, on the western side of Exmouth Gulf, where live coral cover crashed from 80% to 6% – almost all the adult coral was killed.
Reefs in danger
WA’s coral reefs are unusual because most are isolated from major human populations. They are world renowned for the abundance of unique and iconic fauna they host, a stark contrast to the red deserts they directly neighbour.
Unfortunately, the last few years has seen a series of major environmental disturbances that have compromised the health of these coral reefs.
We recently undertook surveys of reefs from the Dampier Archipelago and Montebello Islands to the Muiron Islands and what struck us most was the depauperate state of the reefs. We saw a mosaic of impacts depending on where we surveyed.
Some places are still recovering from two major rounds of coral bleaching – the event of 2010-11 and another in the Pilbara in 2013. Some were beset by crown-of-thorns outbreaks, and some had high cover of dead branching Acropora (the most abundant coral that builds reefs) that were smothered in sediment, mostly from nearby dredging projects.
Ironically this region’s isolation is a double-edged sword — the severity of the situation, which could lead to long-term collapse of reef ecosystems, has gone largely unnoticed.
Isolation and the absence of human impacts might help coral reefs recover after coral bleaching. But it also means that few people are familiar with the region’s prolific coral reefs.
Without this understanding, there might not be sufficient public awareness to drive the action required to protect these areas in the face of mounting environmental pressures.
The future for WA’s coral reefs
Coral reefs rely on a range of ecological processes that keep the system resilient and able to function: processes such as the arrival of coral larvae, and removal of algae by herbivores.
However, human or environmental pressures can destabilise or weaken the system, and the ecosystem can swiftly collapse. Once a reef’s ecosystem processes have failed, they are much more difficult to restore than they were to remove, slowing the reef’s return to its optimal state.
Corals are archetypal ecosystem engineers: they provide the foundation for the diversity and abundance of all the other species in coral reef ecosystems. Greenhouse gas increases are contributing to more frequent and intense bleaching events.
Therefore, reefs need every chance to stay resilient by removing local human impacts and being actively restored. After all, without the foundation, there are no coral reefs.
It is time for the coral reefs of Australia’s west coast to be afforded the level of attention and resources devoted to the better known Great Barrier Reef. The system needs time to recover.
Christopher Doropoulos, OCE Postdoctoral Fellow, CSIRO; Damian Thomson, Experimental Scientist, CSIRO; Mat Vanderklift, Senior research scientist, CSIRO; Mick Haywood, Marine ecologist, CSIRO, and Russ Babcock, Senior Principal Research Scientist, CSIRO