Humans force wild animals into tight spots, or send them far from home. We calculated just how big the impact is



Eric Fortin/Flickr, CC BY-NC-ND

Tim Doherty, University of Sydney; Don Driscoll, Deakin University, and Graeme Hays, Deakin University

The COVID pandemic has shown us that disruptions to the way we move around, complete daily activities and interact with each other can shatter our wellbeing.

This doesn’t apply only to humans. Wildlife across the globe find themselves in this situation every day, irrespective of a global pandemic.

Our latest research published today in Nature Ecology and Evolution has, for the first time, quantified the repercussions of logging, pollution, hunting, and other human disturbances, on the movements of a wide range of animal species.

Our findings were eye-opening. We found human disturbances, on average, restricted an animal’s movements by 37%, or increased it by 70%. That’s like needing to travel an extra 11 km to get to work each day (Australia’s average is 16 km).

Disruptions cascade through the ecosystem

The ability to travel is essential to animal survival because it allows animals to find mates, food and shelter, escape predators and competitors, and avoid disturbances and threats.




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And because animal movement is linked to many important ecological processes — such as pollination, seed dispersal and soil turnover — disruptions to movement can cascade through ecosystems.

Our study involved analysing published data on changes in animal movement in response to different types of disturbance or habitat modification by humans. This included agriculture, logging, grazing, recreation, hunting, and pollution, amongst others.

All up, we looked at 719 records of animal movement, spanning 208 studies and 167 species of birds, mammals, reptiles, fish, insects and amphibians. The size of the species we studied ranged from the sleepy orange butterfly to the white shark.

Species included in our study, clockwise from top-left: sleepy orange butterfly, southern leopard frog, tawny owl, white shark, diademed sifaka and red-eared slider turtle.
Photos adapted from Flickr under Creative Commons license CC BY 2.0. Clockwise from top-left: Anne Toal; Trish Hartmann; Les Pickstock; Elias Levy; John Crane; USFWS Midwest Region.

What we found

We found changes in movement are very common, with two-thirds of the 719 cases comprising an increase or decrease in movement of 20% or more. More than one-third of cases changed by 50% or more.

Whether an animal increases or decreases its movement in response to disturbance from humans depends on the situation.

Animals may run away from humans, or move further in search of food and nesting sites. For example, a 2020 study on koalas found their movements were longer and more directed in areas where habitats weren’t well connected, because they had to travel further to reach food patches.

Likewise, the daily movement distances of mountain brushtail possums in central Victoria were 57% higher in remnant bushland along roadsides, compared to large forest areas.

Land clearing can cause animals to move through risky areas in search of suitable habitat.
Tim Doherty, Author provided

Decreases in movement can occur where animals encounter barriers (such as highways), if they need to shelter from a disturbance, or can’t move as efficiently through altered habitats. In the United States, for example, researchers played a recording of humans talking and found it caused a 34% decrease in the speed that mountain lions move.

On the other hand, some decreases in movement occur where an animal actually benefits from habitat changes. A wide range of animals — including storks, vultures, crows, foxes, mongooses, hyenas and monitor lizards — have shorter movements around garbage dumps because they don’t have to move very far to get the food they need.

Huge changes in movement make animals vulnerable

Overall, we found the average increase in animal movement was +70% and the average decrease was -37%, which are substantial changes.

Imagine having to increase the distance you travel to work, the shops and to see family and friends, by 70%. You would spend a lot more time and energy travelling and have less time to rest or do fun things. And if you live in Melbourne, you know what substantial reductions in movement are like due to COVID-related lockdowns.

Examples of what a 70% increase (bottom left) and a 37% decrease (bottom right) in your normal home range (top) might look life if you lived in Melbourne.

In addition to greater energy expenditure, increased movements can mean animals need to move through risky areas where they are more vulnerable to predation.

And decreases in movement can be harmful if animals can’t find adequate food or disperse to find mates, or if ecological processes such as seed dispersal are disrupted.




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For example, flightless rails, birds native to New Zealand, are important for dispersing seeds. But research showed birds in areas of high human activity (campgrounds) moved 35–41% shorter distances than birds away from campgrounds. This could limit the population growth of plants if their seeds are not being dispersed as far.

When disturbances are unpredictable

We compared the effects of different disturbance types on animals by splitting them into two categories: human activities (such as hunting, military procedures and recreation like tourism) and habitat modification (such as agriculture and logging).

Both disturbance types can have severe impacts, ranging from a 90% decrease to 1,800% increase in movement for human activities, and a 97% decrease to a 3,300% increase for habitat modifications.

Changes in animal movement distances in response to different types of disturbance. Positive values mean movement was higher in disturbed compared to undisturbed areas.

But we found human activities caused much stronger increases in animal movement distances (averaging +35%) than habitat modifications (averaging +12%).

This might be because human activities are more episodic in nature. In other words, animals are more likely to run away from these unpredictable disturbances.




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For example, military manoeuvres in Norway led to 84% increase in the home range of moose. And when moose in Sweden were exposed to back-country skiers, their movement speed increased 33-fold.

In contrast, habitat modifications like logging generally represent more persistent changes to the environment, which animals can sometimes adapt to over time.

Moose head behind green bushes
Human activities can lead to huge changes in the movement of animals, such as moose.
Shutterstock

Reducing harms on wildlife

To reduce the harms we inflict on wildlife, we must protect habitats in relatively intact sea and landscapes from getting degraded or transformed. This could include establishing and managing new national parks and marine protected areas.

Where ecosystems are already modified, improving the connections between habitats and the availability of resources (food and water) can help animals move more easily and populations persist.

And with regards to human activities, which generally caused stronger increases in movement, better managing disturbances such as hunting, recreation and tourism can help to minimise or avoid impacts on animal movement. This could include, for example, establishing a no-take zone in a marine protected area, or enforcing restrictions to activities during breeding periods.




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The Conversation


Tim Doherty, ARC DECRA Fellow, University of Sydney; Don Driscoll, Professor in Terrestrial Ecology, Deakin University, and Graeme Hays, Professor of Marine Science, Deakin University

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

Get set for take-off in electric aircraft, the next transport disruption


Jake Whitehead, The University of Queensland and Michael Kane, Curtin University

Move aside electric cars, another disruption set to occur in the next decade is being ignored in current Australian transport infrastructure debates: electric aviation. Electric aircraft technology is rapidly developing locally and overseas, with the aim of potentially reducing emissions and operating costs by over 75%. Other countries are already planning for 100% electric short-haul plane fleets within a couple of decades.

Australia relies heavily on air transport. The country has the most domestic airline seats per person in the world. We have also witnessed flight passenger numbers double over the past 20 years.

Infrastructure projects are typically planned 20 or more years ahead. This makes it more important than ever that we start to adopt a disruptive lens in planning. It’s time to start accounting for electric aviation if we are to capitalise on its potential economic and environmental benefits.




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What can these aircraft do?

There are two main types of electric aircraft: short-haul planes and vertical take-off and landing (VTOL) vehicles, including drones.

The key issue affecting the uptake of electric aircraft is the need to ensure enough battery energy density to support commercial flights. While some major impediments are still to be overcome, we are likely to see short-haul electric flights locally before 2030. Small, two-to-four-seat, electric planes are already flying in Australia today.

An electric plane service has been launched in Perth.

A scan of global electric aircraft development suggests rapid advancements are likely over the coming decade. By 2022, nine-seat planes could be doing short-haul (500-1,000km) flights. Before 2030, small-to-medium 150-seat planes could be flying up to 500 kilometres. Short-range (100250 km) VTOL aircraft could also become viable in the 2020s.

If these breakthroughs occur, we could see small, commercial, electric aircraft operating on some of Australia’s busiest air routes, including Sydney-Melbourne or Brisbane, as well as opening up new, cost-effective travel routes to and from regional Australia.

Possible short-haul electric aircraft ranges of 500km and 1,000km around Melbourne, Sydney and Brisbane.
Author provided

Why go electric?

In addition to new export opportunities, as shown by MagniX, electric aviation could greatly reduce the financial and environmental costs of air transport in Australia.

Two major components of current airline costs
are fuel (27%) and maintenance (11%). Electric aircraft could deliver significant price reductions through reduced energy and maintenance costs.

Short-haul electric aircraft are particularly compelling given the inherent energy efficiency, simplicity and longevity of the battery-powered motor and drivetrain. No alternative fuel sources can deliver the same level of savings.

With conventional planes, a high-passenger, high-frequency model comes with a limiting environmental cost of burning fuel. Smaller electric aircraft can avoid the fuel costs and emissions resulting from high-frequency service models. This can lead to increased competition between airlines and between airports, further lowering costs.




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What are the implications of this disruption?

Air transport is generally organised in combinations of hub-and-spoke or point-to-point models. Smaller, more energy-efficient planes encourage point-to-point flights, which can also be the spokes on long-haul hub models. This means electric aircraft could lead to higher-frequency services, enabling more competitive point-to-point flights, and increase the dispersion of air services to smaller airports.

While benefiting smaller airports, electric aircraft could also improve the efficiency of some larger constrained airports.

For example, Australia’s largest airport, Sydney Airport, is efficient in both operations and costs. However, due to noise and pollution, physical and regulatory constraints – mainly aircraft movement caps and a curfew – can lead to congestion. With a significant number of sub-1,000km flights originating from Sydney, low-noise, zero-emission, electric aircraft could overcome some of these constraints, increasing airport efficiency and lowering costs.

The increased availability of short-haul, affordable air travel could actively compete with other transport services, including high-speed rail (HSR). Alternatively, if the planning of HSR projects takes account of electric aviation, these services could improve connectivity at regional rail hubs. This could strengthen the business cases for HSR projects by reducing the number of stops and travel times, and increasing overall network coverage.

Synchronised air and rail services could improve connections for travellers.
Chuyuss/Shutterstock

What about air freight?

Electric aircraft could also help air freight. International air freight volumes have increased by 80% in the last 20 years. Electric aircraft provide an opportunity to efficiently transport high-value products to key regional transport hubs, as well as directly to consumers via VTOL vehicles or drones.

If properly planned, electric aviation could complement existing freight services, including road, sea and air services. This would reduce the overall cost of transporting high-value goods.

Plan now for the coming disruption

Electric aircraft could significantly disrupt short-haul air transport within the next decade. How quickly will this technology affect conventional infrastructure? It is difficult to say given the many unknown factors. The uncertainties include step-change technologies, such as solid-state batteries, that could radically
accelerate the uptake and capabilities of electric aircraft.

What we do know today is that Australia is already struggling with disruptive technological changes in energy, telecommunications and even other transport segments. These challenges highlight the need to start taking account of disruptive technology when planning infrastructure. Where we see billions of dollars being invested in technological transformation, we need to assume disruption is coming.

With electric aircraft we have some time to prepare, so let’s not fall behind the eight ball again – as has happened with electric cars – and start to plan ahead.




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The Conversation


Jake Whitehead, Research Fellow, The University of Queensland and Michael Kane, Research Associate, Curtin University Sustainability Policy Institute,, Curtin University

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

Delaying shutting power stations will bring big disruption later: Climate Institute research


Michelle Grattan, University of Canberra

Modelling done for the Climate Institute indicates that without big policy changes Australia’s path to zero emissions from the electricity sector by 2050 would mean huge disruption after 2030.

The report, “A Switch in Time: Enabling the electricity sector’s transition to net zero emissions”, warns that a weak policy now means big adjustments later, and calls for a range of initiatives including a program to progressively shut down power stations.

Electricity emissions are about 30% of Australia’s total emissions. They have risen by 5.5% in the past two years due to some increasing demand and the scrapping of Labor’s carbon price.

Climate Institute CEO John Connor said the modelling found that a modest carbon price rising to $40 per tonne by 2030 would result in emissions reductions similar to the Coalition government’s 2030 target of 26-28% below 2005 levels.

But “this would result in almost no replacement of existing high-carbon power stations with clean energy; a 60% collapse in projected clean energy growth from 2020 followed by stagnation through most of the 2020s, and 98% of the sector’s 30 year carbon budget used up in the first 10 years”.

This meant that the action on climate after 2030 would have to be more extreme, Connor said.

“More than 80% of the coal-fired generation fleet would have to be closed in less than five years, and new clean energy capacity would have to jump four fold and keep rising. The impact of such a disruptive shift would be felt across the economy.”

The government currently has a “direct action” policy, while Labor is crafting a new version of emissions trading and related policies with the details still to be announced. The government plans a 2017 review of the policies needed for its 2030 and longer term targets.

The Climate Institute calls for the systematic retiring of existing high carbon generators on a timeline that would have them all stopped by 2035. The policy should facilitate replacing them with zero or near zero emission energy, it says.

There should be a well funded structural adjustment package for communities affected by the closures; energy efficient policies to minimise costs to energy users and further reduce emissions; and a carbon pricing mechanism capable of scaling up over time that provides a signal to investors.

“There is a low probability that a price of sufficient strength and reliability will emerge quickly”, so the other measures proposed would be needed to deliver a timely transition, the report says.

The report estimates the additional cost to build and operate the new power infrastructure would be about $50 billion over the 30 years 2020-2050. But it argues the disruptive costs to jobs, communities and energy security of other approaches would be more than this.

The preferred approach would represent an increase in retail energy prices of 3% a year although bills would not go up by this much if energy efficiency was improved.

The report says that while both major political parties “have acknowledged the need to achieve net zero emissions, existing climate and energy policies provide no prospect of reaching this goal”.

The research was done by leading electricity market modeller Jacobs to test the ability of policy options under discussion to reduce electricity emissions in line with the Paris commitment to limit global warming to 1.5-2°C.

– Reporting with James Whitmore

https://www.podbean.com/media/player/xdwwc-5e609a?from=yiiadmin

The Conversation

Michelle Grattan, Professorial Fellow, University of Canberra

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