When tree planting actually damages ecosystems



Giraffes prefer the open space and scattered trees of the African savanna.
Volodymyr Burdiak/Shutterstock

Kate Parr, University of Liverpool and Caroline Lehmann, University of Edinburgh

Tree planting has been widely promoted as a solution to climate change, because plants absorb the climate-warming gases from Earth’s atmosphere as they grow. World leaders have already committed to restoring 350m hectares of forest by 2030 and a recent report suggested that reforesting a billion hectares of land could store a massive 205 gigatonnes of carbon – two thirds of all the carbon released into the atmosphere since the Industrial Revolution.

Many of those trees could be planted in tropical grassy biomes according to the report. These are the savannas and grasslands that cover large swathes of the globe and have a grassy ground layer and variable tree cover. Like forests, these ecosystems play a major role in the global carbon balance. Studies have estimated that grasslands store up to 30% of the world’s carbon that’s tied up in soil. Covering 20% of Earth’s land surface, they contain huge reserves of biodiversity, comparable in areas to tropical forest. These are the landscapes with lions, elephants and vast herds of wildebeest.

Gorongosa, Mozambique. The habitat here is open, well-lit and with few trees.
Caroline Lehmann, Author provided

Savannas and grasslands are home to nearly one billion people, many of whom raise livestock and grow crops. Tropical grassy biomes were the cradle of humankind – where modern humans first evolved – and they are where important food crops such as millet and sorghum originated, which millions eat today. And, yet among the usual threats of climate change and wildlife habitat loss, these ecosystems face a new threat – tree planting.

It might sound like a good idea, but planting trees here would be damaging. Unlike forests, ecosystems in the tropics that are dominated by grass can be degraded not only by losing trees, but by gaining them too.




Read more:
Reforesting an area the size of the US needed to help avert climate breakdown, say researchers – are they right?


Where more trees isn’t the answer

Increasing the tree cover in savanna and grassland can mean plant and animal species which prefer open, well-lit environments are pushed out. Studies from South Africa, Australia and Brazil indicate that unique biodiversity is lost as tree cover increases.

This is because adding trees can alter how these grassy ecosystems function. More trees means fires are less likely, but regular fire removes vegetation that shades ground layer plants. Not only do herbivores like zebra and antelope that feed on grass have less to eat, but more trees may also increase their risk of being eaten as predators have more cover.

A mosaic of grassland and forest in Gabon.
Kate Parr, Author provided

More trees can also reduce the amount of water in streams and rivers. As a result of humans suppressing wildfires in the Brazilian savannas, tree cover increased and the amount of rain reaching the ground shrank. One study found that in grasslands, shrublands and cropland worldwide where forests were created, streams shrank by 52% and 13% of all streams dried up completely for at least a year.

Grassy ecosystems in the tropics provide surface water for people to drink and grazing land for their livestock, not to mention fuel, food, building materials and medicinal plants. Tree planting here could harm the livelihoods of millions.

Losing ancient grassy ecosystems to forests won’t necessarily be a net benefit to the climate either. Landscapes covered by forest tend to be darker in colour than savanna and grassland, which might mean they also absorb more heat. As drought and wildfires become more frequent, grasslands may be a more reliable carbon sink than forests.




Read more:
Exaggerating how much CO₂ can be absorbed by tree planting risks deterring crucial climate action


Redefine forests

How have we reached the point where the unique tropical savannas and grasslands of the world are viewed as suitable for wholesale “restoration” as forests?

At the root of the problem is that these grassy ecosystems are fundamentally misunderstood. The Food and Agricultural Organisation of the UN defines any area that’s half a hectare in size with more than 10% tree cover as forest. This assumes that landscapes like an African savanna are degraded because they have fewer trees and so need to be reforested. The grassy ground layer houses a unique range of species, but the assumption that forests are more important threatens grassy ecosystems across the tropics and beyond, including in Madagascar, India and Brazil.

A flowering aloe in Madagascan grassland.
Caroline Lehmann, Author provided

“Forest” should be redefined to ensure savannas and grasslands are recognised as important systems in their own right, with their own irreplaceable benefits to people and other species. It’s essential people know what degradation looks like in open, sunlit ecosystems with fewer trees, so as to restore ecosystems that are actually degraded with more sensitivity.

Calls for global tree planting programmes to cool the climate need to think carefully about the real implications for all of Earth’s ecosystems. The right trees need to be planted in the right places. Otherwise, we risk a situation where we miss the savanna for the trees, and these ancient grassy ecosystems are lost forever.The Conversation

Kate Parr, Professor of Tropical Ecology, University of Liverpool and Caroline Lehmann, Senior Lecturer in Biogeography, University of Edinburgh

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

Climate change will make QLD’s ecosystems unrecognisable – it’s up to us if we want to stop that



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It’s not just about the Great Barrier Reef. Queensland’s rainforests – particularly in the mountains – will also change thanks to a warming climate.
Shutterstock

Sarah Boulter, Griffith University

Climate change and those whose job it is to talk about current and future climate impacts are often classed as the “harbingers of doom”. For the world’s biodiversity, the predictions are grim – loss of species, loss of pollination, dying coral reefs.

The reality is that without human intervention, ecosystems will reshape themselves in response to climate change, what we can think of as “autonomous adaptation”. For us humans – we need to decide if we need or want to change that course.

For those who look after natural systems, our job description has changed. Until now we have scrambled to protect or restore what we could fairly confidently consider to be “natural”. Under climate change knowing what that should look like is hard to decide.

If the Great Barrier Reef still has a few pretty fish and coral in the future, and only scientists know they are different species to the past, does that matter? It’s an extreme example, but it is a good analogy for the types of decisions we might need to make.




Read more:
Year-on-year bleaching threatens Great Barrier Reef’s World Heritage status


In Queensland, the government has just launched the Biodiversity and Ecosystem Climate Adaptation Plan for Queensland focused on what is considered important for making these decisions. The plan is high level, but is an important first step toward preparing the sector for the future.

Changing ecosystems

For the rest of Queensland’s ecosystems the story is much the same as the Great Barrier Reef. There are the obvious regions at risk. Our coastal floodplains and wetlands are potentially under threat from both sides, with housing and development making a landward march and the sea pushing in from the other side. These ecosystems literally have nowhere to go in the crush.

It’s a similar story for species and ecosystems that specialise on cool, high altitude mountaintops. These small, isolated populations rely on cool conditions. As the temperature warms, if they can’t change their behaviour (for instance, by taking refuge in cool spots or crevices during hot times), then it is unlikely they will survive without human intervention such as translocation.




Read more:
Climate change could empty wildlife from Australia’s rainforests


We are all too familiar with the risk of coral reefs dying and becoming a habitat for algae, but some of our less high profile ecosystems face similar transformations. Our tropical savannah woodlands cover much of the top third of Queensland. An iconic ecosystem of the north, massive weed invasions and highly altered fire regimes might threaten to make them unrecognisable.

Changing fire patterns and invasive species could see dramatic changes in Queensland’s savannah woodlands.
Shutterstock

So where to from here?

From the grim predictions we must rally to find a way forward. Critically for those who must manage our natural areas it’s about thinking about what we want to get out of our efforts.

Conservation property owners, both public (for instance, national parks) and private (for instance, not-for-profit conservation groups), must decide what their resources can achieve. Throwing money at a species we cannot save under climate change may be better replaced by focusing on making sure we have species diversity or water quality. It’s a hard reality to swallow, but pragmatism is part of the climate change equation.

We led the development of the Queensland plan, and were encouraged to discover a sector that had a great deal of knowledge, experience and willingness. The challenge for the Queensland government is to usefully channel that energy into tackling the problem.

Valuing biodiversity

One of the clearest messages from many of the people we spoke to was about how biodiversity and ecosystems are valued by the wider community. Or not. There was a clear sense that we need to make biodiversity and ecosystems a priority.

The Great Barrier Reef is already seeing major climate impacts, particularly bleaching.
Shutterstock

It’s easy to categorise biodiversity and conservation as a “green” issue. But aside from the intrinsic value or personal health and recreation value that most of us place on natural areas, without biodiversity we risk losing things other than a good fishing spot.

Every farmer knows the importance of clean water and fertile soil to their economic prosperity. But when our cities bulge, or property is in danger from fire, we prioritise short-term economic returns, more houses or reducing fire risk over biodiversity almost every time.

Of course, this is not to say the balance should be flipped, but climate change is challenging our politicians, planners and us as the Queensland community to take responsibility for the effects our choices have on our biodiversity and ecosystems. As the pressure increases to adapt in other sectors, we should seek options that could help – rather than hinder – adaptation in natural systems.

Coastal residences may feel that investing in a seawall to protect their homes from rising sea levels is worthwhile even if it means sacrificing a scrap of coastal wetland, but there are opportunities to satisfy both human needs and biodiversity needs. We hope the Queensland plan can help promote those opportunities.

Cath Moran contributed to developing this article.The Conversation

Sarah Boulter, Research Fellow, National Climate Change Adaptation Research Facility, Griffith University

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

Ecosystems across Australia are collapsing under climate change


Rebecca Harris, University of Tasmania; David Bowman, University of Tasmania, and Linda Beaumont, Macquarie University

To the chagrin of the tourist industry, the Great Barrier Reef has become a notorious victim of climate change. But it is not the only Australian ecosystem on the brink of collapse.




Read more:
It’s official: 2016’s Great Barrier Reef bleaching was unlike anything that went before


Our research, recently published in Nature Climate Change, describes a series of sudden and catastrophic ecosystem shifts that have occurred recently across Australia.

These changes, caused by the combined stress of gradual climate change and extreme weather events, are overwhelming ecosystems’ natural resilience.

Variable climate

Australia is one of the most climatically variable places in the world. It is filled with ecosystems adapted to this variability, whether that means living in scorching heat, bitter cold or a climate that cycles between the two.

Despite land clearing, mining and other activities that transform the natural landscape, Australia retains large tracts of near-pristine natural systems.

Many of these regions are iconic, sustaining tourism and outdoor activities and providing valuable ecological services – particularly fisheries and water resources. Yet even here, the combined stress of gradual climate change and extreme weather events is causing environmental changes. These changes are often abrupt and potentially irreversible.

They include wildlife and plant population collapses, the local extinction of native species, the loss of ancient, highly diverse ecosystems and the creation of previously unseen ecological communities invaded by new plants and animals.

Australia’s average temperature (both air and sea) has increased by about 1°C since the start of the 19th century. We are now experiencing longer, more frequent and more intense heatwaves, more extreme fire weather and longer fire seasons, changes to rainfall seasonality, and droughts that may be historically unusual.




Read more:
Recent Australian droughts may be the worst in 800 years


The interval between these events has also shortened, which means even ecosystems adapted to extremes and high natural variability are struggling.

As climate change accelerates, the magnitude and frequency of extreme events is expected to continue increasing.

What is ecosystem collapse?

Gradual climate change can be thought of as an ongoing “press”, on which the “pulse” of extreme events are now superimposed. In combination, “presses” and “pulses” are more likely to push systems to collapse.

We identified ecosystems across Australia that have recently experienced catastrophic changes, including:

  • kelp forests shifting to seaweed turfs following a single marine heatwave in 2011;

  • the destruction of Gondwanan refugia by wildfire ignited by lightning storms in 2016;

  • dieback of floodplain forests along the Murray River following the millennial drought in 2001–2009;

  • large-scale conversion of alpine forest to shrubland due to repeated fires from 2003–2014;

  • community-level boom and bust in the arid zone following extreme rainfall in 2011–2012, and

  • mangrove dieback across a 1,000km stretch of the Gulf of Carpentaria after a weak monsoon in 2015-2016.

Of these six case studies, only the Murray River forest had previously experienced substantial human disturbance. The others have had negligible exposure to stressors, highlighting that undisturbed systems are not necessarily more resilient to climate change.

The case studies provide a range of examples of how presses and pulses can interact to push an ecosystem to a “tipping point”. In some cases, a single extreme event may be sufficient to cause an irreversible regime shift.

In other systems, a single extreme event may only be sufficient to tip the ecosystem over the edge when gradual declines in populations have already occurred. More frequent extreme events can also lead to population collapse if a species does not have enough time to recover between events.




Read more:
Climate change could alter ocean food chains, leading to far fewer fish in the sea


But not all examples can be directly linked to a single weather event, or a series of events. These are most likely caused by multiple interacting climate “presses” and “pulses”. It’s worth remembering that extreme biological responses do not always manifest as an impact on the dominant species. Cascading interactions can trigger ecosystem-wide responses to extreme events.

The cost of intervention

Once an ecosystem goes into steep decline – with key species dying out and crucial interactions no longer possible – there are important consequences.

Apart from their intrinsic worth, these areas can no longer supply fish, forest resources, or carbon storage. It may affect livestock and pasture quality, tourism, and water quality and supply.

Unfortunately, the sheer number of variables – between the species and terrain in each area, and the timing and severity of extreme weather events – makes predicting ecosystem collapses essentially impossible.

Targeted interventions, like the assisted recolonisation of plants and animals, reseeding an area that’s suffered forest loss, and actively protecting vulnerable ecosystems from destructive bushfires, may prevent a system from collapsing, but at considerable financial cost. And as the interval between extreme events shorten, the chance of a successful intervention falls.

Critically, intervention plans may need to be decided upon quickly, without full understanding of the ecological and evolutionary consequences.

How much are we willing to risk failure and any unintended consequences of active intervention? How much do we value “natural” and “pristine” ecosystems that will increasingly depend on protection from threats like invasive plants and more frequent fires?

We suspect the pervasive effects of the press and pulse of climate change means that, increasingly, the risks of doing nothing may outweigh the risks of acting.




Read more:
What is a pre-industrial climate and why does it matter?


The beginning of this century has seen an unprecedented number of widespread, catastrophic biological transformations in response to extreme weather events.

The ConversationThis constellation of unpredictable and sudden biological responses suggests that many seemingly healthy and undisturbed ecosystems are at a tipping point.

Rebecca Harris, Climate Research Fellow, University of Tasmania; David Bowman, Professor, Environmental Change Biology, University of Tasmania, and Linda Beaumont, Senior Lecturer, Macquarie University

This article was originally published on The Conversation. Read the original article.

Tweet streams: how social media can help keep tabs on ecosystems’ health



File 20170811 1159 km7y0f
Social media posts, such as this image uploaded to Flickr, can be repurposed for reef health monitoring.
Sarah Ackerman/Flickr/Wikimedia Commons, CC BY

Susanne Becken, Griffith University; Bela Stantic, Griffith University, and Rod Connolly, Griffith University

Social media platforms such as Twitter and Instagram could be a rich source of free information for scientists tasked with monitoring the health of coral reefs and other environmental assets, our new research suggests.

Ecosystems are under pressure all over the world, and monitoring their health is crucial. But scientific monitoring is very expensive, requiring a great deal of expertise, sophisticated instruments, and detailed analysis, often in specialised laboratories.

This expense – and the need to educate and engage the public – have helped to fuel the rise of citizen science, in which non-specialist members of the public help to make observations and compile data.

Our research suggests that the wealth of information posted on social media could be tapped in a similar way. Think of it as citizen science by people who don’t even realise they’re citizen scientists.


Read more: Feeling helpless about the Great Barrier Reef? Here’s one way you can help.


Smartphones and mobile internet connections have made it much easier for citizens to help gather scientific information. Examples of environmental monitoring apps include WilddogScan, Marine Debris Tracker, OakMapper and Journey North, which monitors the movements of Monarch butterflies.

Meanwhile, social media platforms such as Facebook, Twitter, Instagram and Flickr host vast amounts of information. While not posted explicitly for environmental monitoring, social media posts from a place like the Great Barrier Reef can contain useful information about the health (or otherwise) of the environment there.

Picture of health? You can learn a lot from holiday snaps posted online.
Paul Holloway/Wikimedia Commons, CC BY-SA

Twitter is a good resource for this type of “human sensing”, because data are freely available and the short posts are relatively easy to process. This approach could be particularly promising for popular places that are visited by many people.

In our research project, we downloaded almost 300,000 tweets posted from the Great Barrier Reef between July 1, 2016 and March 17, 2017.

After filtering for relevant keywords such as “fish”, “coral”, “turtle” or “bleach”, we cut this down to 13,344 potentially useful tweets. Some 61% of these tweets had geographic coordinates that allow spatial analysis. The heat map below shows the distribution of our tweets across the region.

Tweet heat map for the Great Barrier Reef.
Author provided

Twitter is known as place for sharing instantaneous opinions, perceptions and experiences. It is therefore reasonable to assume that if someone posts a tweet about the Great Barrier Reef from Cairns they are talking about a nearby part of the reef, so we can use the tweet’s geocoordinates as indicators of the broad geographic area to which the post is referring. Images associated with such tweets would help to verify this assumption.

Our analysis provides several interesting insights. First, keyword frequencies highlight what aspects of the Great Barrier Reef are most talked about, including activities such as diving (876 mentions of “dive” or “diving”, and 300 of “scuba”), features such as “beaches” (2,909 times), and favoured species such as “coral” (434) and “turtles” (378).

The tweets also reveal what is not talked about. For example, the word “bleach” appeared in only 94 of our sampled tweets. Furthermore, our results highlighted what aspects of the Great Barrier Reef people are most happy with, for example sailing and snorkelling, and which elements had negative connotations (such as the number of tweets expressing concern about dugong populations).

Casting the net wider

Clearly, this pool of data was large enough to undertake some interesting analysis. But generally speaking, the findings are more reflective of people’s experiences than of specific aspects of the environment’s health.

The quality of tweet information with regard to relevant incidents or changes could, however, be improved over time, for example with the help of a designated hashtag system that invites people to post their specific observations.


Read more: Survey: two-thirds of Great Barrier Reef tourists want to ‘see it before it’s gone’.


Similar alert systems and hashtags have been developed for extreme events and emergency situations, for example by the New South Wales Fire Service.

Tweets also often contain photographs – as do Instagram and Flickr posts – which can carry useful information. An image-based system, particularly in cases where photos carry time and location stamps, would help to address the lack of expertise of the person posting the image, because scientists can analyse and interpret the raw images themselves.

The Great Barrier Reef is, of course, already extensively monitored. But social media monitoring could be particularly beneficial in countries where more professional monitoring is unaffordable. Popular destinations in the Pacific or Southeast Asia, for example, could tap into social media to establish systems that simultaneously track visitors’ experiences as well as the health of the environment.

The ConversationWhile it is early days and more proof-of-concept research is needed, the technological possibilities of Big Data, machine learning and Artificial Intelligence will almost certainly make socially shared content a useful data source for a wide range of environmental monitoring in the future.

Susanne Becken, Professor of Sustainable Tourism and Director, Griffith Institute for Tourism, Griffith University; Bela Stantic, Professor, Director of Big data and smart analytics lab, Griffith University, and Rod Connolly, Professor in Marine Science, Griffith University

This article was originally published on The Conversation. Read the original article.

Things fall apart: why do the ecosystems we depend on collapse?


David Lindenmayer, Australian National University

People collapse, buildings collapse, economies collapse and even entire human civilizations collapse. Collapse is also common in the natural world – animal populations and ecosystems collapse. These collapses have the greatest impact on us when they affect resources our industries depend on, leaving ecosystems in tatters and sometimes ruining local economies.

In a new paper, I look at two natural resource industries – fisheries and forestry – that are highly susceptible to collapse.

From the infamous 1980s collapse of the Canadian cod industry to the apparent imminent collapse of the Heyfield sawmill in southern Victoria, we can see a recurring pattern. And by getting better at predicting this pattern, we might be able to avoid collapse in the future.

The stages of collapse

In fisheries, collapse follows a familiar pathway, which has up to eight stages. In a 1993 report for the US Marine Mammal Commission on harvesting ocean resources, L.M. Talbot described these stages:

  1. fishers discover a new fishery, or a new method of harvesting an existing stock

  2. fishers develop the new resource with little or no regulation

  3. major fishing effort results in over-capitalisation of the equipment used to harvest the resource – the value of the fishery can sometimes even be less than the investment fishers made

  4. fishers develop the capacity to catch more fish than the fishery can sustain

  5. fishery becomes depleted and the number of fish caught begins to decline

  6. fishers intensify their efforts to catch fish to offset the decline in harvest

  7. intensive fishing continues as fishers attempt to recoup investments in over-capitalised equipment

  8. fishery is depleted to such levels that it is no longer economic for fishers to go fishing. At this stage the fishery is fully collapsed.

In some cases, regulators attempt to manage the fishery as fishers intensify their efforts. Examples include putting in place quotas and economic subsidies, or reducing the fishing capacity of the fleets.

However, these are often belated and ineffective. This is particularly so given uncertainty about the fishing resource, lack of information on the ecology of the target species, and the fact that an industry with vested interests will lobby hard to protect those interests.

Subsidies at these stages – such as tax breaks and/or fuel rebates – may mean that fishing becomes artificially profitable. Fishers may remain in the industry and continue to overinvest to obtain a greater share of a dwindling resource.

Many forestry industries around the world show similar stages.

Native forest harvesting in Australia is a highly capital-intensive industry. It uses heavy machinery that costs a lot to purchase, leading to high interest repayments. Such efficient harvesting may not only employ relatively few people, but also outstrip the amount of timber that can be sustainably harvested (like stage four in fisheries collapse).

Significant amounts of timber and pulpwood need to be processed continuously to pay the interest and other bills for equipment (stage seven).

Moreover, logging may continue even though it is highly uneconomic to do so (stage eight) and other industries that are damaged by logging (such as the water and tourism industries) are significantly more economically lucrative.

Why do industries overharvest?

Fisheries and forestry often allocate greater harvest limits than the ecosystem can produce without declining.

One key reason this happens is that fish or timber allocations often don’t account for losses from natural events.

For example, the mountain ash forests of Victoria rely on severe wildfires to regenerate. They are also extensively logged for paper and timber production.

Yet the organisation responsible for scheduling of logging in these forests (VicForests) does not account for losses due to fire when calculating how much timber can be harvested. Major fires in 2009 badly damaged more than 52,000 hectares of this forest. But environmental accounting analyses indicate there has been relatively little change in sustained yield allocation since these fires.

Yet, modelling suggests that, over 80 years, wildfire will damage 45% of the forest estate. This amount should therefore should not be included as timber available for logging.

Another driver of the problem of resource over-commitment can be gaming, where stock availability and direct employment are deliberately overstated. This may be to secure the status and influence of a given institution with government, or for other reasons such as leverage in negotiations over access to resources.

The autobiography of Julia Gillard, the former Australian prime minister, suggests this occurred during debates over the fate of forests in Tasmania, alleging that Forestry Tasmania overstated forest available for harvest. Forestry Tasmania denied these allegations.

What can we do?

Early intervention in fisheries and forestry industries can prevent ecosystem and industry collapse. We also need to better ways to assess resources, including accounting for losses of resources due to natural disturbances.

However, in some cases resources have been so heavily over-committed that industry collapse is virtually inevitable. For example, environmental accounting work in the wet forests of the Central Highlands of Victoria suggests very little sawlog resource is left as a result of many decades of overcutting and associated wildfire. Clearfell logging makes these forests more prone to particularly severe fires.

The collapse of the sawlog industry is highly likely, even if there is no fire. This is clear from the pleas from sawmills for access to further forest resources – even when such extra resources basically do not exist.

Now the industry needs to transition to plantations for paper production and for timber (82% of all sawn timber already comes from plantations in the state).

Alternative industries like tourism that employ far more people and contribute more to the economy must be fostered. There are many examples to draw on – New Zealand is one of many.

When governments know in advance about likely industry collapse, then it is incumbent upon them to intervene earlier and help foster transitions to new (and often more lucrative) industries. This ensures that workers can find jobs in new sectors, and the transition is less painful for the community and less costly for taxpayers. Failure to do this is unethical.

The closure of the Hazelwood power station in Victoria is a classic example of a lack of planning for industry transition. The need to close Hazelwood was discussed in formal reports by the former State Electricity Commission more than 25 years ago.

The need to transition the native forest industry to plantations is equally clear and must be done as a matter of urgency.

The Conversation

David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University

This article was originally published on The Conversation. Read the original article.

The global road-building explosion is shattering nature


Bill Laurance, James Cook University

If you asked a friend to name the worst human threat to nature, what would they say? Global warming? Overhunting? Habitat fragmentation?

A new study suggests it is in fact road-building.

“Road-building” might sound innocuous, like “house maintenance” – or even positive, conjuring images of promoting economic growth. Many of us have been trained to think so.

But an unprecedented spate of road building is happening now, with around 25 million kilometres of new paved roads expected by 2050. And that’s causing many environmental researchers to perceive roads about as positively as a butterfly might see a spider web that’s just fatally trapped it.

A Malayan tapir killed along a road in Peninsular Malaysia.
WWF-Malaysia/Lau Ching Fong

Shattered

The new study, led by Pierre Ibisch at Eberswalde University for Sustainable Development, Germany, ambitiously attempted to map all of the roads and remaining ecosystems across Earth’s entire land surface.

Its headline conclusion is that roads have already sliced and diced Earth’s ecosystems into some 600,000 pieces. More than half of these are less than 1 square kilometre in size. Only 7% of the fragments are more than 100 square km.

Remaining roadless areas across the Earth.
P. Ibisch et al. Science (2016)

That’s not good news. Roads often open a Pandora’s box of ills for wilderness areas, promoting illegal deforestation, fires, mining and hunting.

In the Brazilian Amazon, for instance, our existing research shows that 95% of all forest destruction occurs within 5.5km of roads. The razing of the Amazon and other tropical forests produces more greenhouse gases than all motorised vehicles on Earth.

Animals are being imperilled too, by vehicle roadkill, habitat loss and hunting. In just the past decade, poachers invading the Congo Basin along the expanding network of logging roads have snared or gunned down two-thirds of all forest elephants for their valuable ivory tusks.

Deforestation along roads in the Brazilian Amazon.
Google Earth

Worse than it looks

As alarming as the study by Ibisch and colleagues sounds, it still probably underestimates the problem, because it is likely that the researchers missed half or more of all the roads on the planet.

That might sound incompetent on their part, but in fact keeping track of roads is a nightmarishly difficult task. Particularly in developing nations, illegal roads can appear overnight, and many countries lack the capacity to govern, much less map, their unruly frontier regions.

One might think that satellites and computers can keep track of roads, and that’s partly right. Most roads can be detected from space, if it’s not too cloudy, but it turns out that the maddening variety of road types, habitats, topographies, sun angles and linear features such as canals can fool even the smartest computers, none of which can map roads consistently.

The only solution is to use human eyes to map roads. That’s what Ibisch and his colleagues relied upon – a global crowdsourcing platform known as OpenStreetMap, which uses thousands of volunteers to map Earth’s roads.

Therein lies the problem. As the authors acknowledge, human mappers have worked far more prolifically in some areas than others. For instance, wealthier nations like Switzerland and Australia have quite accurate road maps. But in Indonesia, Peru or Cameroon, great swathes of land have been poorly studied.

A quick look at OpenStreetmap also shows that cities are far better mapped than hinterlands. For instance, in the Brazilian Amazon, my colleagues and I recently found 3km of illegal, unmapped roads for every 1km of legal, mapped road.

A logging truck blazes along a road in Malaysian Borneo.
Rhett Butler/Mongabay

What this implies is that the environmental toll of roads in developing nations – which sustain most of the planet’s critical tropical and subtropical forests – is considerably worse than estimated by the new study.

This is reflected in statistics like this: Earth’s wilderness areas have shrunk by a tenth in just the past two decades, as my colleagues and I reported earlier this year. Lush forests such as the Amazon, Congo Basin and Borneo are shrinking the fastest.

Road rage

The modern road tsunami is both necessary and scary. On one hand, nobody disputes that developing nations in particular need more and better roads. That’s the chief reason that around 90% of all new roads are being built in developing countries.

On the other hand, much of this ongoing road development is poorly planned or chaotic, leading to severe environmental damage.

For instance, the more than 53,000km of “development corridors” being planned or constructed in Africa to access minerals and open up remote lands for farming will have enormous environmental costs, our research suggests.

Orangutans in the wilds of northern Sumatra.
Suprayudi

This year, both the Ibisch study and our research have underscored how muddled the UN Sustainable Development Goals are with respect to vanishing wilderness areas across the planet.

For instance, the loss of roadless wilderness conflicts deeply with goals to combat harmful climate change and biodiversity loss, but could improve our capacity to feed people. These are tough trade-offs.

One way we’ve tried to promote a win-win approach is via a global road-mapping strategy that attempts to tell us where we should and shouldn’t build roads. The idea is to promote roads where we can most improve food production, while restricting them in places that cause environmental calamities.

Part of a global road-mapping strategy. Green areas have high environmental values where roads should be avoided. Red areas are where roads could improve agricultural production. And black areas are ‘conflict zones’ where both environmental values and potential road benefits are high.
W. F. Laurance et al. Nature (2014)

The bottom line is that if we’re smart and plan carefully, we can still increase food production and human equity across much of the world.

But if we don’t quickly change our careless road-building ways, we could end up opening up the world’s last wild places like a flayed fish – and that would be a catastrophe for nature and people too.

The Conversation

Bill Laurance, Distinguished Research Professor and Australian Laureate, James Cook University

This article was originally published on The Conversation. Read the original article.