Author: Euan Ritchie

By Dana M Bergstrom (University of Wollongong), Euan Ritchie (Deakin University), Lesley Hughes (Macquarie University) and Michael Depledge (University of Exeter).

This article is republished from The Conversation under a Creative Commons license. Read the original article.

In 1992, 1,700 scientists warned that human beings and the natural world were “on a collision course”. Seventeen years later, scientists described planetary boundaries within which humans and other life could have a “safe space to operate”. These are environmental thresholds, such as the amount of carbon dioxide in the atmosphere and changes in land use.

Crossing such boundaries was considered a risk that would cause environmental changes so profound, they genuinely posed an existential threat to humanity.

This grave reality is what our major research paper, published today, confronts.

In what may be the most comprehensive evaluation of the environmental state of play in Australia, we show major and iconic ecosystems are collapsing across the continent and into Antarctica. These systems sustain life, and evidence of their demise shows we’re exceeding planetary boundaries.

We found 19 Australian ecosystems met our criteria to be classified as “collapsing”. This includes the arid interior, savannas and mangroves of northern Australia, the Great Barrier Reef, Shark Bay, southern Australia’s kelp and alpine ash forests, tundra on Macquarie Island, and moss beds in Antarctica.

We define collapse as the state where ecosystems have changed in a substantial, negative way from their original state – such as species or habitat loss, or reduced vegetation or coral cover – and are unlikely to recover.

The good and bad news

Ecosystems consist of living and non-living components, and their interactions. They work like a super-complex engine: when some components are removed or stop working, knock-on consequences can lead to system failure.

Our study is based on measured data and observations, not modelling or predictions for the future. Encouragingly, not all ecosystems we examined have collapsed across their entire range. We still have, for instance, some intact reefs on the Great Barrier Reef, especially in deeper waters. And northern Australia has some of the most intact and least-modified stretches of savanna woodlands on Earth.

Still, collapses are happening, including in regions critical for growing food. This includes the Murray-Darling Basin, which covers around 14% of Australia’s landmass. Its rivers and other freshwater systems support more than 30% of Australia’s food production.

The effects of floods, fires, heatwaves and storms do not stop at farm gates; they’re felt equally in agricultural areas and natural ecosystems. We shouldn’t forget how towns ran out of drinking water during the recent drought.

Drinking water is also at risk when ecosystems collapse in our water catchments. In Victoria, for example, the degradation of giant Mountain Ash forests greatly reduces the amount of water flowing through the Thompson catchment, threatening nearly five million people’s drinking water in Melbourne.

This is a dire wake-up call — not just a warning. Put bluntly, current changes across the continent, and their potential outcomes, pose an existential threat to our survival, and other life we share environments with.

In investigating patterns of collapse, we found most ecosystems experience multiple, concurrent pressures from both global climate change and regional human impacts (such as land clearing). Pressures are often additive and extreme.

Take the last 11 years in Western Australia as an example.

In the summer of 2010 and 2011, a heatwave spanning more than 300,000 square kilometres ravaged both marine and land ecosystems. The extreme heat devastated forests and woodlands, kelp forests, seagrass meadows and coral reefs. This catastrophe was followed by two cyclones.

A record-breaking, marine heatwave in late 2019 dealt a further blow. And another marine heatwave is predicted for this April.

These 19 ecosystems are collapsing: read about each

① Great Barrier Reef

 

The Great Barrier Reef is the world’s largest coral reef system, extending over 2,300 kilometres. It is home to over 5,000 species of mollusk, 1,500 species of fish, 400 species of coral and around 240 species of birds. It spreads over almost 4,000 individual reefs, 900 continental islands, 300 coral cays and 150 inshore mangrove islands.

In the last 30 years, climate change and many regional pressures have combined to cause ecosystem collapse across the reef, with shallower reefs worse off than deeper reefs. These pressures include five mass coral bleaching events since 1998, marine heatwaves, major tropical cyclones, freshwater floods from extreme high rainfall events, flood sediment and pollution, ocean acidification and crown of thorns starfish outbreaks.

Major feedback loops that compound the pressures are now establishing. From 1985–2017, the reef lost half of all coral cover due to five massive bleaching events, of which two were consecutive (2016, 2017). In 2017, 67% of corals died along a 700km stretch.

The reef provides around A$12 trillion of ecosystem services and over 64,000 jobs. The Australian and Queensland governments have committed billions into reef protection but there are significant challenges to overcome.

Pressures:

• Temperature
• Ocean acidification
• Salinity change
• Native species interactions
• Heatwave
• Flood
• Storm
• Habitat change/loss
• Runoff / pollution
• Other (dredging, fishing, boat strikes, ship fouling, tourism debris)

② Australian Tropical Savannas

 

Australia’s tropical savannas sweep across more than 1 million square kilometres of northern Australia, from the western Kimberley region, WA, to the eastern edge of Queensland’s tropical coast. Savanna woodlands and forests have mainly gum trees over an understory of tall grasses and very ancient, poor soils.

These savannas are currently the least altered and unpolluted in the world, but they’re changing fast because of agriculture, mining and the effects of poor management decisions of the past. Land clearing has removed vegetation permanently, reducing food availability for wildlife. Climate change is adding further pressures as rains increase in the wet season, and dry seasons are becoming hotter and last longer.

Add in cat predation, the presence of cane toads, livestock encroachment and increasing bush fire frequency, and it becomes clear why Kakadu National Park is now a hot spot for mammal extinction.

Of particular urgency is the impact of a weed called giant African Gamba grass. It grows up to 4 m in height and produces up to 74,000 seeds per square metre. This adds a huge fuel load for fires, which burn 12 times more intensely than native grass fires, with flames penetrating and killing tree canopy. Gamba grass fires are very expensive to fight, cause loss of livestock and agricultural assets, and diminish the financial viability of the low carbon farming initiative of “savanna burning”.

Damage to the savannas affects the cultural, spiritual and socioeconomic livelihoods of First Nations communities. Loss of ecosystem services, production and pastoral lands is around A$113 million per year.

Pressures:

• Rainfall changes
• Temperature
• Increasing CO2
• Storm
• Fire
• Habitat change/loss/ mining
• Invasive species
• Livestock impacts/ harvesting
• Water extraction
• Human-lit fire

③ Mangrove Forests, Gulf of Carpentaria

 

In late 2015, nearly 40 million mangrove trees, representing around one million tons of carbon, died along 1,000 kilometres of the Gulf of Carpentaria. They succumbed to multiple pressures, including extremely high temperatures (39°C for 18 days), prolonged drought conditions, along with feral pigs, scrub fires and invasive weeds.

But most significant was the additive effect of severe El Niño conditions, which effectively pushed the sea away from the coast. This led to a short-term, extreme drop in mean sea level of around 20 centimetres, taking seawater away from mangrove roots.

Two severe tropical cyclones and damaging floods have since hampered its recovery. Continued tidal rafting of dead trunks is curtailing the establishment of seedlings and damaging remaining trees. And the decomposition of dead roots is probably affecting nursery habitat for fish and crustaceans.

The damage is expected to have lasting repercussions on the local economy and livelihoods of the region. The Gulf of Carpentaria fishing industry is worth A$30 million per year. First Nation people and recreational fishers also use the area. Ecosystem services from mangroves are worth around A$250,000 per hectare per year.

Pressures:

• Rainfall changes- drought
• Temperature
• Salinity change
• Sea level change – extreme lows
• Heatwave
• Flood
• Storm
• Habitat change/loss – erosion
• Invasive species
• Livestock impacts
• Water extraction
• Runoff
• Human-lit fire
• Other

④ Wet Tropical Rainforest, North Queensland

 

The wet tropics of North Queensland span around 450 kilometres, with rainforest covering around 1.85 million hectares. The region contains extraordinary diversity, with more than 3,000 plant species and over 60 vertebrate species found nowhere else on Earth. Although tropical rainforests make up only 0.1% of Australia’s landmass, they’re also home to over 50% of its ferns, butterflies and birds, and over 20% of freshwater fish, mammals, orchids, frogs and reptiles.

It’s for this reason and others, such as the significant First Nations cultural values, that the wet tropics are a World Heritage Area.

But they experience a range of pressures, many of which compound each other. These include habitat fragmentation, fringe livestock grazing, increased urbanisation, more frequent and severe fires and invasive plants and animals. Climate change poses perhaps the greatest threat overall.

Many of the region’s plants and animals live in discrete elevation bands: a “Goldilocks” combination of the right habitat and microclimate. As air temperatures increase and extremes in weather worsen, species’ areas of suitable habitat shrink. Some species have already moved to higher elevations and/or experienced striking local population declines. For example, in November 2018, a heatwave killed one-third of all spectacled flying foxes. And two possum species have disappeared from habitat under an altitude of 600 metres.

There have been four major storms or cyclones in 13 years. One event brought up to 2 m of rain, and the storm surge (seawater) inundated coastal rainforest. In 2006, one cyclone killed 35% of the regional cassowary populations, and cars and dogs killed many more as the birds left the destroyed forest.

The wet tropics are visited by around 5 million tourists per year, contributing over A$400 million to the region’s economy. In 2015, the wet tropics were valued at over A$5 billion per year, due to ecosystem services such as carbon sequestration, biodiversity protection, and soil and water resources.

Pressures:

• Climate change
• Extreme weather and climatic events (heatwaves, floods, cyclones, extended dry seasons)
• Species interactions (such as snake losing prey due to flooding)
• Invasive plants and animals
• Habitat fragmentation and destruction
• Logging and land clearing
• Altered fire regimes (more frequent and severe fires)
• Erosion, sediment runoff and pollution
• Overgrazing
• Tourism
• Urbanisation
• Chytrid fungus

⑤ Western-central Arid Zones

 

The arid zone covers around 43% of Australia and is characterised by low lands, generally less than 300 metres in elevation, occasionally punctuated by a few big hills (higher than 1,000 metres). Vegetation ranges from woodlands, shrublands and grasslands to rangelands and desert dunes. There are isolated freshwater systems through the arid zone including waterholes and lakes, underground water, clay pans and springs fed by the Great Artesian Basin.

Widespread pastoral activities over the last 100 years have altered large areas of the arid zone from their pre-European states. Changes include major loss of habitats, reduction in small mammal populations, and livestock trampling of delicate biotic soil crusts (which maintain soil and dune stability and water infiltration).

There are more than 200 weed species. Some were planted for pasture, shade trees or to suppress dust, and dispersed by machinery, vehicles and floods. The most threatening is buffel grass. It has invaded extensive areas, wreaking havoc through degradation, habitat loss and biodiversity decline. Like Gamba grass in the north, in combination with extreme heatwaves, buffel grass has altered fire frequency and intensity. Hot fires now reach well into the tree canopy, killing the trees, as well as shrubs and native grasses.

Introduced feral animals include cattle, goats, camels, foxes, cats and pigs.

The arid zone rangelands are also economically important and contribute approximately A$4.4 billion per year to Australia’s economy through tourism, pastoralism and agriculture combined.

Pressures:

• Rainfall changes
• Temperature
• Heat wave
• Fire
• Habitat change/loss
• Invasive species
• Livestock
• Water extraction

⑥ Georgina Gidgee Woodlands, central Australia

 

Georgina gidgee is a keystone tree, a species that holds an ecosystem together, and dominates low open woodlands. It occurs naturally in small patches (up to 10 hectares) in the arid zone, growing mostly along watercourses and in clay depressions between spinifex grass dunes. Georgina gidgee woodlands are important hot spots for life, acting as refuges for native rodents, small marsupials, red kangaroos and bats. They provide permanent or temporary habitat for more than 80 bird species, and animals such as lizards and ants.

Georgina gidgee woodlands are heading for collapse due to a range of pressures including climate change, fire, overgrazing, wood collection, weeds, feral animals and changes in water flow. For example, harvesting for fence posts in the Brigalow Belt, Queensland, cleared 7.4 million ha of gidgee and associated ecosystems by 1998. What remains still suffers extensive loss through pastoral activities.

As mature trees are relatively long-lived (over 200 years), their recovery is slow. Without significant intervention, this ecosystem will turn into a desert.

The consequences of desertification include loss of shade for cattle, loss of water catchment surface for refilling the artesian basin, and loss of biodiversity and ecosystem function associated with their role in stabilising ancient dunes. Loss of vegetation also increases the number of giant, regional dust storms, which can travel all the way to the major cities in eastern Australia.

Pressures:

• Rainfall changes
• Temperature
• Heat wave
• Fire
• Habitat change/loss
• Invasive species
• Livestock
• Water extraction
• Other

⑦ Ningaloo Reef, northern Western Australia

 

Ningaloo and adjacent reefs are within the World Heritage listed Ningaloo Coast, and comprise an ecosystem of immense biodiversity, and national and international ecological importance. It’s home to megafauna such as migrating whale sharks and whales, turtles, corals, and economically important habitat for fisheries.

The ecosystem is threatened by rising ocean temperatures, ocean acidification, and increasingly intense and severe weather events such as marine heatwaves and tropical cyclones. Coral bleaching events have been recorded from 1990 to 2019, causing substantial reef-wide death (such as around 80% loss of coral cover of Bundegi Reef).

Fish numbers have also decreased, especially in recreational fishing areas. Pressures from human use and water quality exacerbates these changes. And crown-of-thorns starfish and carnivorous snails hamper their recovery from bleaching.

The impacts of these combined global and local pressures are felt in tourism and commercial fisheries, which are worth around A$1.5 billion per year for the region.

Pressures:

• Temperature
• Ocean acidification
• Sea level change
• Heat wave
• Storm
• Habitat change/loss
• Livestock harvesting
• Water extraction
• Runoff / pollution

⑧ Shark Bay Seagrass Communities, Western Australia

 

Shark Bay, a World Heritage Area, is the home to one of world’s largest (4,300 square kilometres) and most diverse seagrass meadows. It’s a carbon storage hotspot, holding 350 million tons of carbon.

It supports an extensive food web, and diverse fauna including tiger sharks, and around 10% of the world’s dugongs, manta rays, dolphins, and green and loggerhead turtles. Southern right and humpback whales also use Shark Bay as a migratory staging post.

Over a background of chronic increases in seawater temperatures, Shark Bay experienced an unprecedented marine heatwave in the summer of 2010-11, lasting more than 10 weeks. Meanwhile, flooding from a tropical storm over the Gascoyne River catchment covered the bottom of the bay in up to 10 centimetres of mud. About a quarter of all sea grasses died, with limited recovery since.

This saw major decreases in dugongs (68% decrease), sea snakes (77% decrease). Populations of bottlenose dolphins, pied cormorants and green sea turtles decreased by 35–40%. Another marine heatwave hit in December 2019, and another is predicted for March 2021

The failure of major seagrass recovery has led to the release of millions of tons of carbon dioxide as organic sediments breakdown. The ecosystem collapse caused major disruption to the local commercial fishing industry, when the scallop and crab commercial fishery had to close for five years.

Pressures:

• Temperature
• Ocean acidification
• Heat wave
• Flood
• Storm
• Habitat change/loss
• Livestock harvesting
• Other

⑨ Murray Darling River Basin — waterways

 

The Murray-Darling Basin is Australia’s largest river system with 23 river valleys and over 77,000 kilometres of watercourses. The basin has more than 30,000 wetlands (400 wetlands are considered “high value” in Victoria alone) home to 46 species of native fish and 120 species of water birds. Some wetlands are recognised internationally as globally important.

The overall health of the river system is poor. Since European settlement, the river and tributaries have become highly regulated, with significant water diversion for agriculture and urban uses. These impacts have been exacerbated by increasing temperatures, declining average rainfall and severe droughts, further reducing water flows (by 40% since the mid-1990s).

Salinisation (saltier water), toxic algal blooms, hypoxia (low oxygen), introduced fish species, erosion, bushfire ash and nutrient runoff also contribute to declining water quality. Today, native fish populations are just 10% of pre-European numbers. Some 20 mass fish deaths, including of threatened species, have occurred since the 1960s.

The ecosystem is increasingly non-functional with decreasing freshwater biodiversity, and loss of ecosystem services and cultural values. The 2011 plan to improve the basin set a target to recover water for the environment, diverting it from irrigation. This was estimated to cost A$542 million annually, but the additional water has added A$3–8 billion worth of ecosystem services to the entire basin.

Despite the last drought ending, and rivers are flowing again, troubles are still emerging with recent reports of toxic algal blooms.

Pressures:

• Rainfall changes
• Temperature
• Water level change
• Heat wave
• Flood
• Fire
• Habitat change/loss
• Invasive species
• Livestock/harvesting
• Water extraction
• Runoff/pollution
• Other

⑩ Murray-Darling River Basin — riverine

 

The Murray Darling Basin covers around 14% of Australia’s land area, comprising low-lying undulating areas, extensive plains and parts of the Great Dividing Range. The basin is Australia’s most important water catchment – forests and wetlands cover over 100 million hectares of floodplains and adjacent riverbank areas. The mighty river red gum is key to the health of these ecosystems that depend on frequent flooding (once every three years) for growth and reproduction.Floodplain and riparian vegetation provide corridors and habitat for millions of animals, including water birds and 46 species of native fish. More than 2 million people live in the basin, and it’s home to 46 First Nations who care for at least 10,000 culturally significant places.

Over the last 200 years, humans have altered much of the basin, including the construction of weirs, irrigation channels, farm dams and municipal water reservoirs. All these changes affect the region’s water, and have significantly deteriorated riparian (bank-side) systems and populations of dependent species such as waterbirds.

Around 40% of the highly diverse ecosystems have been cleared or otherwise modified for logging and agricultural use. In 2008, an investigation of 1,600km of river estimated only 30% of the remaining river red gums were in good condition. Extraction of water for agriculture, including 1.8 million megalitres of groundwater, has increased soil salinity. The region is experiencing chronically raising temperatures, ongoing reductions in rainfall and increasingly long and severe droughts (2003–2009, 2017–2019).

Despite some restoration efforts, ecological collapse of riverine ecosystems continues. As tree deaths are becoming more widespread, forest canopy cover is reducing. Rivers flows and groundwater levels are decreasing, contributing to loss and degradation of habitat. Populations of birds, mammals and fish are shrinking. All these changes have flow-on impacts.

The basin is Australia’s main food bowl; 40% of food worth A$22 billion is produced annually. In addition, tourism contributes some A$8 billion each year. The droughts cut farm profits by 30%.

Pressures:

• Rainfall changes
• Temperature
• Heat wave
• Fire
• Habitat change/loss
• Invasive species
• Livestock/harvesting
• Water extraction

⑪ Montane and Sub-alpine Forests, South Australia, New South Wales and the Victorian highlands

 

Montane alpine ash and subalpine snowgum forests occupy the highest forested areas of the Australian Alps. Alpine ash are giants and can grow over 90 metres tall, although trees over 40m are rare across most of the alps today.

Intense fires kill both snowgums and alpine ash. Climate change is increasing the frequency of fire through droughts, longer snow-free periods, tree stress and dry lightning in storms. This is amplified by positive feedback, where regrowth after prescribed burns or bushfire is much more flammable than long-unburnt forest. From 2000 to 2019, 84% of the entire alpine ash forests in NSW and Victoria were burned, some areas up to three times. Now, 70% of alpine ash are immature trees and over 75% of snow gums are at their most flammable age.These forests are critical to the health of one of Australia’s most important water catchments. They also store large quantities of carbon, and surround high value utility and tourism infrastructure, such as Snowy Mountain power stations and ski resorts.

Increases in wildfire amplified by positive feedbacks place a heavy economic burden on these, as well as a health and safety impact on surrounding human populations.

Pressures:

• Rainfall changes
• Temperature
• Heatwave
• Storm
• Fire
• Habitat change/loss
• Invasive species
• Livestock / harvesting
• Human-lit fire

⑫ Great Southern Reef Kelp Forests, southern Australia

 

The Great Southern Reef extends along 8,100 kilometres of coast, covering 71,000 square kilometres from Brisbane, around the south coast of Australia and Tasmania, to well north of Perth. It comprises a large number of rocky temperate reefs that support lush kelp forests, dominated by golden kelp and, in colder areas, giant kelp. Kelp supports high levels of biodiversity including other seaweeds, sponges, crustaceans, starfish, abalone, fish and rock-lobsters.

Different combinations of pressures cause kelp forest to degrade and collapse. These include coastal development, pollution, marine heatwaves, ocean acidification, and increased storm severity and frequency. For example, along 100 km of coastline reefs from Perth to Kalbarri, WA, most kelp forests have been lost and replaced with algal turfs. Giant kelp forests are now endangered.

The East Australian Current (thrust into popular culture via the film Finding Nemo) is frequently penetrating southward to Tasmania. This transports warm, nutrient- depleted waters, larvae of a NSW sea urchin and northern species of fish. The sea urchins severely damage the kelp forests, as does overfishing of large lobsters.

On conservatively estimates, the Great Southern Reef kelp forests generate at least A$10 billion per year in economic activity. Economic and social consequences of its decline include the collapse of the rock lobster, abalone and other fisheries, as well as impacts on Indigenous communities and decreases in tourism.

Pressures:

• Temperature
• Ocean acidification
• Native species interactions
• Heat waves
• Storms
• Habitat change/loss
• Harvesting
• Runoff/pollution
• Other

⑬ Mediterranean-type Forests and Woodlands

 

Forests and woodlands in south-west WA extend over 10,000 square kilometres. They include the northern jarrah forest, tuart forest and woodlands, and banksia woodlands. The woodlands experience a Mediterranean-type climate, with cool, wet winters and dry, hot summers.

Vulnerable parts of these forest ecosystems experienced substantial die-off during an acute drought associated with an extreme heat wave in 2010-2011. But warming and drying of the region has been chronic since the mid-1970s. Impact was locally severe with, for example, up to 60% of Menzies banksia dying in woodlands on the Swan Coastal Plains.

Die-off sites illustrate what can happen when these forests and woodlands don’t have enough water. If die-off occurs at larger scales, forest resources and ecosystem services (such as carbon storage and seed resources) are threatened. Increased fire is also a risk, with associated damage to property and widespread pollution from bushfire smoke, as was recently experienced invFebruary 2021.

Pressures:

• Rainfall changes
• Temperature
• Native species interactions
• Heatwave
• Storm
• Fire
• Habitat change/loss

⑭ Monaro Tablelands, South Eastern Highlands

 

The Monaro tablelands of south-east NSW are characterised by mosaics of grassy woodlands, grasslands and forests. These provide important habitat for a range of threatened plants and animal species, including koalas, spotted-tail quolls and dusky wood swallows, as well as 15 other smaller marsupial species, 95 bird species, 14 species of reptiles and more.

Like most other temperate grasslands and grassy woodlands in Australia, the Monaro ecosystems have declined since Indigenous burning regimes were replaced with livestock and feral herbivore grazing, along with clearing, cultivation and non-native plant invasions.

Tragically, since 2005, ribbon gums that once dominated the rolling plains have died in great numbers. This is likely associated with the Millennium drought, ongoing drying conditions and heatwaves, and exacerbated by invertebrate pest outbreaks. More recently, the catastrophic Black Summer bushfires burned extensive areas across the Monaro.

Widespread tree deaths are not only a loss of habitat for mammals, birds, reptiles and invertebrates, but significantly impact the economy through lack of shelter for livestock during the Monaro’s harsh winters and hot summers. The impacts on the landscape’s aesthetic also affects human well-being.

Pressures:

• Rainfall changes
• Temperature
• Native species interactions
• Heatwave
• Fire
• Habitat change/loss
• Invasive species
• Livestock/harvesting

⑮ Snowpatch Herbfields, Australian Alps

 

The snowpatch herbfields, made up of dwarf grasses and alpine herbs, are one of the rarest and most restricted ecosystems in Australia. They occur only on steep, south-east-facing slopes of alpine and high treeless subalpine zones, where snow persists into the spring and summer growing seasons.

Over the past 50 years, climate change has caused warming of almost 1°C, and substantial decrease in snow amount and depth, cover and persistence in the Australian alpine area. Fire has also become a major force with increased frequency, dry lightning storms and extreme fire weather. And feral horses trample vegetation and cause soil erosion. These pressures, and others, are collapsing the snow patch herbfield, replacing them with larger shrubs and grasses or just eroded ground.

The collapse of the snow patch herbfields highlights the plight of the Australian alpine ecosystems in general. The alps are regional economic powerhouses; visitors to the Australian Alps generate over A$1.3 billion and the area employs almost 20,000 people.

Pressures:

• Rainfall changes
• Temperature
• Storm
• Fire
• Habitat change/loss
• Invasive species
• Human-lit fire

⑯ Mountain Ash Forests, Victorian Central Highlands

 

The mountain ash ecosystem in the Central Highlands of Victoria supports the world’s tallest flowering plants. It’s among the world’s most carbon-dense forests, supporting an array of threatened forest-dependent species, and generating almost all of the water for the 5 million inhabitants of Melbourne (as well as communities and agriculturalists north of the Great Divide).

The mountain ash ecosystem is under enormous environmental pressure from widespread and recurrent wildfire, coupled with widespread clear-cut logging. Extensive old growth forests once dominated the ecosystem, but now just 1.16% of the ecosystem (1,886 hectares of 170,400 ha) is old growth. The widespread young forest is highly flammable and at extreme risk of reburning at high severity. This is especially due to increased temperatures and greater numbers of days marked as “extreme” on the forest fire danger index.

The collapse will have severe economic and social effects. The value of water from the ecosystem is 25.5 times greater than the value of the timber generated from the same ecosystem. The collapse of the ecosystem also poses an enormous threat for long-term carbon storage, biodiversity conservation and the billion-dollar tourism industry in regional Victoria.

Pressures:

• Rainfall changes
• Temperature
• Fire
• Habitat change/loss
• Invasive species
• Other

⑰ Gondwanan Conifer forests, Tasmania

 

The Tasmanian Wilderness World Heritage Area covers 15,800 square kilometres. One of its key values is the high concentration of ancient invertebrate animals and plants endemic to Tasmania (often called “palaeoendemics”). An iconic example is the genus Athrotaxis in the conifer family, which is considered one of the oldest surviving plant lineages on Earth — a living fossil.

There are two existing species of Athrotaxis: Pencil pines (Athrotaxis cupressoides) and king billy pines (Athrotaxi selaginoides). Both are very slow growing and can live for more than 1,000 years.

Like other palaeoendemics, Athrotaxis species can’t tolerate frequent or intense fire, and are restricted to fireproof landscapes. Around 30% of the range of king billy pines have been lost in the last 200 years, and half the pencil pines were burnt in the summer of 1960/61 by uncontrolled fires set by graziers to renew grasslands during an intense drought.

Climate change now threatens these and other palaeoendemic species through increased fire activity due to more dry lightning storms and drought. In January 2016, lightning storms ignited numerous fires that destroyed about 1% of the remaining pencil pines. These trees are unlikely to ever return. The loss of palaeo-endemics will profoundly diminish the region’s natural and cultural values.

Securing the survival of palaeoendemics under climate change requires costly management interventions. These include establishing fire breaks, targeted planned burning to reduce fuel surrounding the palaeoendemic refuges and active restoration programs. The Tasmanian Government and the University of Tasmania currently trial these measures.

Pressures:

• Rainfall changes
• Temperature
• Storm
• Fire
• Habitat change/loss
• Invasive species

⑱ Subantarctic Tundra, Macquarie Island

 

The World Heritage sub-Antarctic Macquarie Island is home to unique alpine tundra. Cushion plants and bryophytes (such as mosses) dominate this treeless ecosystem. This uninhabited island ecosystem is one of the rarest on the planet, occurring on only eight other oceanic, sub-Antarctic islands. It’s home to many invertebrate species, and is the breeding ground of thousands of seabirds and marine mammals.

The ecosystem is rapidly collapsing due to mass die-off of cushion plants. Wind, rain and regional climate patterns all have changed in recent years, due to greenhouse gas increases and loss of ozone. There have also been increases in average wind speed, sunshine hours, and “evapotranspiration” (the sum of evaporation from the land surface plus transpiration from plants). Winter rainfall, cyclones, and a drier atmosphere also appear to have increased.

This has resulted in surface drying and raised surface evaporation of cushions and byrophytes in summer, leading to their death. With plants under such stress, an unknown disease has emerged that has now devastated much of this fragile ecosystem. And this has led to the ecosystem losing World Heritage values.

Pressures:

• Rainfall changes
• Temperature
• Native species interactions
• Flood
• Storm
• Other

⑲ East Antarctica Moss Beds, Windmill Islands (66°S), Vestfold Hills (68°S)

 

Antarctic vegetation is limited to the small ice-free areas covering less than 0.4% of the continent. Algae, cyanobacterial mats (dense “mats” of microbes), lichens and mosses dominate the flora, and there are no flowering plants. Moss beds only occur in areas where enough moisture is available during the short summer growing season. Some of the most extensive and well-developed vegetation in continental Antarctica support century old moss “forests” near Australia’s Casey Station. These lush, green moss turfs support the majority of invertebrates in the ecosystem.From 2000 to 2013, the species composition in these Antarctic moss beds changed significantly. Moss species that can tolerate drier conditions expanded, while endemic moss, better adapted to frequent pulses of water from melted ice, declined. By 2008, half the mosses that had been green and healthy in 2003 suffered water stress, turning red or grey under drying conditions.This drying is likely due to a combination of climate change and ozone thinning,making it windier and lowering temperatures around coastal East Antarctica in summer. This makes water less available during the growing season, and less water means less moss growth.

Historically, human activity associated with research stations has reduced local moss populations, but drying appears to be more widespread than just in the Casey region. Recovery has been limited, and in the summer of 2019-20, an Antarctic heatwave melted nearby snow banks and glaciers, causing flooding. Some grey mosses greened within a month. However, others that didn’t receive floodwater remained grey, stressed or dead.

Pressures:

• Rainfall changes
• Native species interactions
• Heatwave
• Storm
• Habitat change/loss
• Water extraction
• Other

What to do about it?

Our brains trust comprises 38 experts from 21 universities, CSIRO and the federal Department of Agriculture Water and Environment. Beyond quantifying and reporting more doom and gloom, we asked the question: what can be done?

We devised a simple but tractable scheme called the 3As:

• Awareness of what is important
• Anticipation of what is coming down the line
• Action to stop the pressures or deal with impacts.

In our paper, we identify positive actions to help protect or restore ecosystems. Many are already happening. In some cases, ecosystems might be better left to recover by themselves, such as coral after a cyclone.

In other cases, active human intervention will be required – for example, placing artificial nesting boxes for Carnaby’s black cockatoos in areas where old trees have been removed.

“Future-ready” actions are also vital. This includes reinstating cultural burning practices, which have multiple values and benefits for Aboriginal communities and can help minimise the risk and strength of bushfires.

It might also include replanting banks along the Murray River with species better suited to warmer conditions.

Some actions may be small and localised, but have substantial positive benefits.

For example, billions of migrating Bogong moths, the main summer food for critically endangered mountain pygmy possums, have not arrived in their typical numbers in Australian alpine regions in recent years. This was further exacerbated by the 2019-20 fires. Brilliantly, Zoos Victoria anticipated this pressure and developed supplementary food — Bogong bikkies.

Other more challenging, global or large-scale actions must address the root cause of environmental threats, such as human population growth and per-capita consumption of environmental resources.

We must rapidly reduce greenhouse gas emissions to net-zero, remove or suppress invasive species such as feral cats and buffel grass, and stop widespread land clearing and other forms of habitat destruction.

Our lives depend on it

The multiple ecosystem collapses we have documented in Australia are a harbinger for environments globally.

The simplicity of the 3As is to show people can do something positive, either at the local level of a landcare group, or at the level of government departments and conservation agencies.

Our lives and those of our children, as well as our economies, societies and cultures, depend on it.

We simply cannot afford any further delay.

By Don Driscoll (Deakin University), April Reside (The University of Queensland), Brendan Wintle (University of Melbourne), Euan Ritchie (Deakin University), and Martine Maron (The University of Queensland).

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The independent review of Australia’s main environment law, released last week, provided a sobering but accurate appraisal of a dire situation.

The review was led by Professor Graeme Samuel and involved consultation with scientists, legal experts, industry and conservation organisations. Samuel’s report concluded Australia’s biodiversity is in decline and the law (the EPBC Act) “is not fit for current or future environmental challenges”.

The findings are no surprise to us. As ecologists, we’ve seen first hand how Australia’s nature laws and governance failure have permitted environmental degradation and destruction to the point that species face extinction. Even then, continued damage is routinely permitted.

And the findings aren’t news to many other Australians, who have watched wildlife and iconic places such as Kakadu and Kosciuszko national parks, and the Great Barrier Reef, decline at rates that have only accelerated since the act was introduced in 1999. Even globally recognisable wildlife, such as the platypus, now face a future that’s far from certain.

To reverse Australia’s appalling track record of protecting biodiversity, four major reforms recommended by Samuel must be implemented as a package.

1. Setting standards

One of the many failings of Australia’s environmental laws is there has never been a point beyond which no further impacts are acceptable.

The government almost never says “enough!”, whether it’s undermining wetlands for a new mine, or clearing woodlands for agriculture. Species continue to suffer death by a thousand cuts.

For example, the original distribution of the endangered southern black-throated finch of southern and central Queensland has shrunk to less than 10% due to land clearing and habitat degradation. Yet, further clearing was approved for coal mines, housing developments and sugar cane farms.

Biodiversity offsets, which aim to compensate for environmental damage by improving nature elsewhere, have for the most part been dreadfully ineffective. Instead they have been a tool to facilitate biodiversity loss.

The centre piece of Samuel’s report are proposed new National Environmental Standards. These would provide clear grounds for drawing a line in the sand on environmental damage.

Legal, rigorous enforcement of these standards could turn around Australia’s centuries-long record of destroying its natural heritage, and curb Australia’s appalling extinction rate — while also providing clarity and certainty for business.

Vital features of the standards Samuel recommends include:

• avoiding impacts on the critical habitat of threatened species
• avoiding impacts that could reduce the abundance of threatened species with already small and declining populations
• no net reduction in the population size of critically endangered and endangered species
• cumulative impacts must be explicitly considered for threatened species and communities
• offsets can only be used as a last resort, not as a routine part of business like they are at the moment.

Under the proposed National Environmental Standards, any new developments would need to be in places where environmental damage is avoided from the outset, with offsets only available if they’re ecologically feasible and effective.

2. Greater government accountability

The federal environment minister can make decisions with little requirement to publicly justify them.

In 2014, then environment minister Greg Hunt controversially approved an exemption to the EPBC Act for Western Australia’s shark cull. This was despite evidence the cull wouldn’t make people safer, would harm threatened species and would degrade marine ecosystems. Hunt could shirk the evidence, deny the impacts and make a politically expedient decision, with no mechanisms in place to call him to account.

Samuel’s report states the minister can make decisions that aren’t consistent with the National Environmental Standards — but only as a “rare exception”. He says these exceptions must be “demonstrably justified in the public interest”, and this justification must be published.

We think this epitomises democracy. Ministers can make decisions, but they must be open to public and robust scrutiny and explain how their decisions might affect environments and species.

Improved accountability will be one of the many benefits of Samuel’s proposed independent Environment Assurance Commissioner, which would be backed up by an Office of Compliance and Enforcement. Samuel says these must be free from political interference.

These are absolutely critical aspects of the reforms. Standards that aren’t audited or enforced are as worthless as an unfunded recovery plan.

3. Decent funding

Samuel urges improved resourcing because to date, funding to protect species and the environment has been grossly inadequate. For example, experts recently concluded up to 11 reptile species are at risk of extinction in the next 50 years in Australia, and limited funding is a key barrier to taking action.

And it has been proven time and again that lack of action due to under-resourcing leads to extinction. The recent extinction of the Christmas Island forest skink, the Christmas Island pipistrelle, and the Bramble Cay melomys were all attributable, in large part, to limited funding, both in the administration of the threatened species listing process, and in delivering urgent on-ground action.

We need only look to the COVID pandemic to know when faced with emergencies, the government can rapidly deploy substantial sums of money for urgent interventions. And we are well and truly in an environmental emergency.

Spending to care for the environment is not a cost that delivers no return. It’s an investment that delivers substantial benefits, from creating jobs to cleaner water and healthier people.

4. Increase ecological knowledge

Engaging experts is key to achieving Samuel’s long-overdue proposed reforms. He calls for the immediate creation of expert committees on sustainable development, Indigenous participation, conservation science, heritage, and water resources. This will help support the best available data collection to underpin important decisions.

Ultimately, though, much more investment in building ecological knowledge is required.

Australia has more than 1,900 listed threatened species and ecological communities, and most don’t even have active recovery plans. Ecologists will need to collect, analyse and interpret new, up-to-date data to make biodiversity conservation laws operational for most threatened species.

For example, while we know logging and fires threaten greater gliders, there’s still no recovery plan for this iconic forest possum. And recent research suggests there are actually three — not simply one — species of greater glider. Suspected interactions between climate change, fire and logging, and unexplained severe population declines, means significant new effort must be invested to set out a clear plan for their recovery.

Samuel recommends Regional Recovery Plans be adequately funded to help develop some knowledge. But we suggest substantial new environmental capacity is needed, including new ecological research positions, increased environmental monitoring infrastructure, and appropriate funding of recovery plans, to ensure enough knowledge supports decision making.

Cherry picking recommendations condemns our species

Samuel’s report has provided a path forward that could make a substantial difference to Australia’s shocking track record of biodiversity conservation and land stewardship.

But Environment Minister Sussan Ley’s response so far suggests the Morrison government plans to cherry pick from Samuel’s recommendations, and rush through changes without appropriate safeguards.

If the changes we outlined above aren’t implemented as a package, our precious natural heritage will continue to decline.

By Euan Ritchie (Deakin University), Ayesha Tulloch (University of Sydney), Don Driscoll  (Deakin University), Megan C Evans (UNSW), and Tim Doherty (University of Sydney).

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Australia’s Threatened Species Strategy — a five-year plan for protecting our imperilled species and ecosystems — fizzled to an end last year. A new 10-year plan is being developed to take its place, likely from March.

It comes as Australia’s list of threatened species continues to grow. Relatively recent extinctions, such as the Christmas Island forest skink, Bramble Cay melomys and smooth handfish, add to an already heavy toll.

Now, more than ever, Australia’s remarkable species and environments need strong and effective policies to strengthen their protection and boost their recovery.

So as we settle into the new year, let’s reflect on what’s worked and what must urgently be improved upon, to turn around Australia’s extinction crisis.

How effective was the first Threatened Species Strategy?

The Threatened Species Strategy is a key guiding document for biodiversity conservation at the national level. It identifies 70 priority species for conservation, made up of 20 birds, 20 mammals and 30 plants, such as the plains-wanderer, malleefowl, eastern quoll, greater bilby, black grevillea and Kakadu hibiscus.

These were considered among the most urgent in need of assistance of the more than 1,800 threatened species in Australia.

The strategy also identifies targets such as numbers of feral cats to be culled, and partnerships across industry, academia and government key to making the strategy successful.

The original strategy (2015-20) was eagerly welcomed for putting the national spotlight on threatened species conservation. It has certainly helped raise awareness of its priority species.

However, there’s little evidence the strategy has had a significant impact on threatened species conservation to date.

The midterm report in 2019 found only 35% of the priority species (14 in total) had improving trajectories compared to before the strategy (pre-2015). This number included six species — such as the brush-tailed rabbit-rat and western ringtail possum — that were still declining, but just at a slower rate.

On average, the trends of threatened mammal and bird populations across Australia are not increasing.

Other targets, such as killing two million feral cats by 2020, were not explicitly linked to measurable conservation outcomes, such as an increase in populations of threatened native animals. Because of this, it’s difficult to judge their success.

What needs to change?

The previous strategy focused very heavily on feral cats as a threat and less so on other important and potentially compounding threats, particularly habitat destruction and degradation.

For instance, land clearing has contributed to a similar number of extinctions in Australia (62 species) as introduced animals such as feral cats (64).

In fact, 2018 research found agricultural activities affect at least 73% of invertebrates, 82% of birds, 69% of amphibians and 73% of mammals listed as threatened in Australia. Urban development and climate change threaten up to 33% and 56% of threatened species, respectively.

Other important threats to native Australian species include pollution, feral herbivores (such as horses and goats), very frequent or hot bushfires and weeds. Buffel grass was recently identified as a major emerging threat to Australia’s biodiversity, with the risk being as high as the threat posed by cats and foxes.

Five vital improvements

We made a submission to the Morrison government when the Threatened Species Strategy was under review. Below, we detail our key recommendations.

1. A holistic and evidence-based approach encompassing the full range of threats

This includes reducing rates of land clearing — a major and ongoing issue, but largely overlooked in the previous strategy.

2. Formal prioritisation of focal species, threats and actions

The previous strategy focused heavily on a small subset of the more than 1,800 threatened species and ecosystems in Australia. It mostly disregarded frog, reptile, fish and invertebrate species also threatened with extinction.

To reduce bias towards primarily “charismatic” species, the federal government should use an evidence-based prioritisation approach, known as “decision science”, like they do in New South Wales, New Zealand and Canada. This would ensure funds are spent on the most feasible and beneficial recovery efforts.

3. Targets linked to clear and measurable conservation outcomes

Some targets in the first Threatened Species Strategy were difficult to measure, not explicitly linked to conservation outcomes, or weak. Targets need to be more specific.

For example, a target to “improve the trajectory” of threatened species could be achieved if extinction is occurring at a slightly slower rate. Alternatively, a target to “improve the conservation status” of a species is achieved if new assessments rate it as “vulnerable” rather than “endangered”.

4. Significant financial investment from government

Investing in conservation reduces biodiversity loss. A 2019 study found Australia’s listed threatened species could be recovered for about A$1.7 billion per year. This money could be raised by removing harmful subsidies that directly threaten biodiversity, such as those to industries emitting large volumes of greenhouse gases.

The first strategy featured a call for co-investment from industry. But this failed to attract much private sector interest, meaning many important projects aimed at conserving species did not proceed.

5. Government leadership, coordination and policy alignment

The Threatened Species Strategy should be aligned with Australia’s international obligations such as the United Nation’s Sustainable Development Goals and the federal Environment Protection and Biodiversity Conservation Act 1999 (which is also currently being reviewed). This will help foster a more coherent and efficient national approach to threatened species conservation.

There are also incredible opportunities to better align threatened species conservation with policies and investment in climate change mitigation and sustainable agriculture.

The benefits of investing heavily in wildlife reach beyond preventing extinctions. It would generate many jobs, including in regional and Indigenous communities.

Protecting our natural heritage is an investment, not a cost. Now is the time to seize this opportunity.

Mammals are extraordinarily successful animals, occupying Earth’s skies, seas and land, but many species also face significant threats and uncertain futures.

In this 35-minute presentation, I share stories about dingoes, bandicoots, tree kangaroos, bears and other mammals, highlighting their ecological and cultural importance, and how science is aiding their conservation.

By Don Driscoll (Deakin University),Bob Pressey (James Cook University), Euan Ritchie (Deakin University), and Noel D Preece (James Cook University).

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Ecologists and conservation experts in government, industry and universities are routinely constrained in communicating scientific evidence on threatened species, mining, logging and other threats to the environment, our new research has found.

Our study, just published, shows how important scientific information about environmental threats often does not reach the public or decision-makers, including government ministers.

In some cases, scientists self-censor information for fear of damaging their careers, losing funding or being misrepresented in the media. In others, senior managers or ministers’ officers prevented researchers from speaking truthfully on scientific matters.

This information blackout, termed “science suppression”, can hide environmentally damaging practices and policies from public scrutiny. The practice is detrimental to both nature and democracy.

Code of silence

Our online survey ran from October 25, 2018, to February 11, 2019. Through advertising and other means, we targeted Australian ecologists, conservation scientists, conservation policy makers and environmental consultants. This included academics, government employees and scientists working for industry such as consultants and non-government organisations.

Some 220 people responded to the survey, comprising:

• 88 working in universities
• 79 working in local, state or federal government
• 47 working in industry, such as environmental consulting and environmental NGOs
• 6 who could not be classified.

In a series of multiple-choice and open-ended questions, we asked respondents about the prevalence and consequences of suppressing science communication.

About half (52%) of government respondents, 38% from industry and 9% from universities had been prohibited from communicating scientific information.

Communications via traditional (40%) and social (25%) media were most commonly prohibited across all workplaces. There were also instances of internal communications (15%), conference presentations (11%) and journal papers (5%) being prohibited.

‘Ministers are not receiving full information’

Some 75% of respondents reported having refrained from making a contribution to public discussion when given the opportunity – most commonly in traditional media or social media. A small number of respondents self-censored conference presentations (9%) and peer-reviewed papers (7%).

Factors constraining commentary from government respondents included senior management (82%), workplace policy (72%), a minister’s office (63%) and middle management (62%).

Fear of barriers to advancement (49%) and concern about media misrepresentation (49%) also discouraged public communication by government respondents.

Almost 60% of government respondents and 36% of industry respondents reported unduly modified internal communications.

One government respondent said:

Due to ‘risk management’ in the public sector […] ministers are not receiving full information and advice and/or this is being ‘massaged’ by advisors (sic).

University respondents, more than other workplaces, avoided public commentary out of fear of how they would be represented by the media (76%), fear of being drawn beyond their expertise (73%), stress (55%), fear that funding might be affected (53%) and uncertainty about their area of expertise (52%).

One university respondent said:

I proposed an article in The Conversation about the impacts of mining […] The uni I worked at didn’t like the idea as they received funding from (the mining company).

Critical conservation issues suppressed

Information suppression was most common on the issue of threatened species. Around half of industry and government respondents, and 28% of university respondents, said their commentary on the topic was constrained.

Government respondents also reported being constrained in commenting on logging and climate change.

One government respondent said:

We are often forbidden (from) talking about the true impacts of, say, a threatening process […] especially if the government is doing little to mitigate the threat […] In this way the public often remains ‘in the dark’ about the true state and trends of many species.

University respondents were most commonly constrained in talking about feral animals. A university respondent said:

By being blocked from reporting on the dodgy dealings of my university with regards to my research and its outcomes I feel like I’m not doing my job properly. The university actively avoids any mention of my study species or project due to vested financial interests in some key habitat.

Industry respondents, more than those from other sectors, were constrained in commenting on the impacts of mining, urban development and native vegetation clearing. One industry respondent said:

A project […] clearly had unacceptable impacts on a critically endangered species […] the approvals process ignored these impacts […] Not being able to speak out meant that no one in the process was willing or able to advocate for conservation or make the public aware of the problem.

The system is broken

Of those respondents who had communicated information publicly, 42% had been harassed or criticised for doing so. Of those, 83% believed the harassers were motivated by political or economic interests.

Some 77 respondents answered a question on whether they had suffered personal consequences as a result of suppressing information. Of these, 18% said they had suffered mental health effects. And 21% reported increased job insecurity, damage to their career, job loss, or had left the field.

One respondent said:

I declared the (action) unsafe to proceed. I was overruled and properties and assets were impacted. I was told to be silent or never have a job again.

Another said:

As a consultant working for companies that damage the environment, you have to believe you are having a positive impact, but after years of observing how broken the system is, not being legally able to speak out becomes harder to deal with.

Change is needed

We acknowledge that we receive grants involving contracts that restrict our academic freedom. And some of us self-censor to avoid risks to grants from government, resulting in personal moral conflict and a less informed public. When starting this research project, one of our colleagues declined to contribute for fear of losing funding and risking employment.

But Australia faces many complex and demanding environmental problems. It’s essential that scientists are free to communicate their knowledge on these issues.

Public servant codes of conduct should be revised to allow government scientists to speak freely about their research in both a public and private capacity. And government scientists and other staff should report to new, independent state and federal environment authorities, to minimise political and industry interference.

A free flow of information ensures government policy is backed by the best science. Conservation dollars would be more wisely invested, costly mistakes avoided and interventions more effectively targeted.

And importantly, it would help ensure the public is properly informed – a fundamental tenet of a flourishing democracy.

By Euan Ritchie (Deakin University), Courtney Marneweck (Clemson University), and Grant Linley (Charles Sturt University).

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Humans have long been inspired and transfixed by the Moon, and as we’re discovering, moonlight can also change the behaviour of Australian wildlife.

A collection of recently published research has illuminated how certain behaviours of animals – including potoroos, wallabies and quolls – change with variation in ambient light, phases of the Moon and cloud cover.

One study found small mammals were more active on cloudy nights. Another found variation in moonlight led to differing amounts of species captured in non-lethal traps. And a study on willie wagtails found males just love singing on a full moon.

These findings are interesting from a natural history perspective. But they’ll also help ecologists and conservation scientists better locate and study nocturnal animals, and learn how artificial light pollution is likely changing where animals can live and how they behave.

Moonlit predator-prey games of hide and seek

Most of Australia’s mammals are nocturnal, and some smaller species are thought to use the cover of darkness to avoid the attention of hungry predators. However, there’s much we don’t know about such relationships, especially because it can be difficult to study these interactions in the wild.

In the relatively diverse mammal community at Mt Rothwell, Victoria, we examined how variation in ambient light affected species’ activity, and how this might influence species interactions. Mt Rothwell is a fenced conservation reserve free of feral cats and foxes, and with minimal light pollution.

Over two years, we surveyed the responses of predator and prey species to different light levels from full, half and new moon phases.

Potential prey species in our study included eastern barred and southern brown bandicoots, long-nosed potoroos, brushtailed rock-wallabies, and brushtail and common ringtail possums. Eastern and spotted-tailed quolls are their potential predators.

Just as we predicted, we found that while there does appear to be relationships between cloud cover, Moon phase and mammal activity, these interactions depend on the sizes and types of mammals involved.

Both predators and prey generally increased their activity in darker conditions.
Smaller, prey species increased their activity when cloud cover was higher, and predators increased their activity during the half and new moon phases.

This suggests their deadly game of hide and seek might intensify on darker nights. And prey might have to trade off foraging time to reduce their chances of becoming the evening meal.

What happens in the wild?

It’s important to acknowledge that studies in sanctuaries such as Mt Rothwell might not always reflect well what goes on in the wild, including in areas where introduced predators, such as feral cats and red foxes, are found.

Another recent study, this time of small mammals in the wilds of Victoria’s Mallee region, sheds further light on the situation. The authors tested if variation in weather and Moon phase affected the numbers of five small mammal species – Bolam’s mouse, common dunnart, house mouse, southern ningaui, and western pygmy possum – captured in pitfall traps.

Pitfall traps are long fences small animals can’t climb over or through, so follow along the side until they fall into a bucket dug in the ground. Ecologists typically use these traps to capture and measure animals and then return them to the wild, unharmed.

At more than 260 sites and over more than 50,000 trap nights, they found wind speed, temperature and moonlight influenced which species were caught and in what numbers.

For example, captures of a small native rodent, Bolam’s mouse, and carnivorous marsupial, southern ningaui, decreased with more moonlight, whereas captures of pygmy possums were higher with more moonlight.

Moonlight songbird serenades

Research from last month has shown even species normally active by day may change their behaviour and activity by night.

It’s not uncommon to hear bird song by night, including the quintessentially Aussie warbling of magpies. Using bioacoustic recorders and song detection software, these researchers show the willie wagtail – another of Australia’s most recogisable and loved birds – is also a nighttime singer, particularly during the breeding season.

While both male and female wagtails sing by day, it is the males that are most vocal by night. And it seems the males aren’t afraid of a little stage-lighting either, singing more with increasing moonlight, with performances peaking during full moons.

This work provides insight into the importance and potential role of nocturnal song for birds, such as mate attraction or territory defence, and helps us to better understand these behaviours more generally.

Moonlight affects wildlife conservation

These studies, and others, can help inform wildlife conservation, as practically speaking, ecological surveys must consider the relative brightness of nights during which work occurred.

Depending on when and where we venture out to collect information about species, and what methods we use (camera traps, spotlighting, and non-lethal trapping) we might have higher or lower chances of detecting certain species. And this might affect our insights into species and ecosystems, and how we manage them.

As dark skies become rarer in many places around the world, it also begs a big question. To what extent is all the artificial light pollution in our cities and peri-urban areas affecting wildlife and ecosystems?

Pipistrelle bats, for example, will be roughly half as active around well-lit bridges than unlit bridges. They’ll also keep further away from well-lit bridges, and fly faster when near them.

This means artificial light might reduce the amount and connectivity of habitat available to some bat species in urban areas. This, in turn could affect their populations.

Research is underway around the world, examining the conservation significance of such issues in more detail, but it’s another timely reminder of the profound ways in which we influence the environments we share with other species.

The authors  acknowledge Yvette Pauligk, who contributed to our published work at Mt Rothwell, and that the traditional custodians of this land are the Wathaurong people of the Kulin nation.