B&Bs for birds and bees: transform your garden or balcony into a wildlife haven



Wes Mountain/The Conversation, CC BY-NC

Judith Friedlander, University of Technology Sydney

Just like humans, animals like living near coastal plains and waterways. In fact, cities such as Sydney and Melbourne are “biodiversity hotspots” – boasting fresh water, varied topographies and relatively rich soil to sustain and nourish life.

Recent research showed urban areas can support a greater range of animals and insects than some bushland and rural habitat, if we revegetate with biodiversity in mind.




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Urban regeneration is especially important now, amid unfathomable estimates that more than one billion animals were killed in the recent bushfires. Even before the fires, we were in the middle of a mass extinction event in Australia and around the world.

Losing animals, especially pollinators such as bees, has huge implications for biodiversity and food supplies.

My team and I are creating a B&B Highway – a series of nest boxes, artificial hollows and pollinating plants – in Sydney and coastal urban areas of New South Wales. These essentially act as “bed and breakfasts” where creatures such as birds, bees, butterflies and bats can rest and recharge. Everyday Australians can also build a B&B in their own backyards or on balconies.

City living for climate refugees

I spoke to Charles Sturt University ecologist Dr Watson about the importance of protecting animals such as pollinators during the climate crisis. He said:

The current drought has devastated inland areas – anything that can move has cleared out, with many birds and other mobile animals retreating to the wetter, more temperate forests to the south and east.

So, when considering the wider impacts of these fires […] we need to include these climate refugees in our thinking.

Native birds like the white-winged triller have been spotted in urban areas.
Shutterstock

Many woodland birds such as honeyeaters and parrots have moved in droves to cities, including Sydney, over the last few years because of droughts and climate change, attracted to the rich variety of berries, fruits and seeds.

I also spoke to BirdLife Australia’s Holly Parsons, who said last year’s Aussie Backyard Bird Count recorded other inland birds – such as the white-winged triller, the crimson chat, pied honeyeater, rainforest pigeons and doves – outside their usual range, attracted to the richer food variety in coastal cities.




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What’s more, there have been increased sightings of powerful owls in Sydney and Melbourne, squirrel gliders in Albury, marbled geckos in Melbourne, and blue-tongue lizards in urban gardens across south-east Australia.

With so many birds and pollinators flocking to the cities, it’s important we support them with vegetated regions they can shelter in, such as through the B&B Highway we’re developing.

The B&B Highway: an urban restoration project

B&Bs on our “highway” are green sanctuaries, containing pollinating plants, water and shelters such as beehives and nesting boxes.




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We’re setting up B&Bs across New South Wales in schools and community centres, with plans to expand them in Melbourne, Brisbane and other major cities. In fact, by mid-2020, we’ll have 30 B&Bs located across five different Sydney municipalities, with more planned outside Sydney.

The NSW Department of Education is also developing an associated curriculum for primary and early high school students to engage them in ecosystem restoration.

One of the biodiversity havens the author developed to attract pollinators.
Author provided

If you have space in your garden, or even on a balcony, you can help too. Here’s how.

For birds

Find out what bird species live in your area and which are endangered using the Birdata directory. Then select plants native to your area – your local nursery can help you out here.

The type of plants will vary on whether your local birds feed on insects, nectar, seed, fruit or meat. Use the guide below.



Wes Mountain/The Conversation, CC BY-ND

More tips

Plant dense shrubs to allow smaller birds, such as the superb fairy-wren, to hide from predatory birds.

Order hollows and nesting boxes from La Trobe University to house birds, possums, gliders and bats.

Put out water for birds, insects and other animals. Bird baths should be elevated to enable escape from predators. Clean water stations and bowls regularly.

For native stingless bees

If you live on the eastern seaboard from Sydney northward, consider installing a native stingless beehive. They require very little maintenance, and no permits or special training.

These bees are perfect for garden pollination. Suppliers of bees and hives can be found online – sometimes you can even rescue an endangered hive.

A blue banded bee at a B&B rest stops in NSW.
Author provided

Also add bee-friendly plants – sting or no sting – to your garden, such as butterfly bush, bottlebrush, daisies, eucalyptus and angophora gum trees, grevillea, lavender, tea tree, honey myrtle and native rosemary.

For other insects

Wherever you are in Australia, you can buy or make your own insect hotel. There is no standard design, because our gardens host a wide range of native insects partial to different natural materials.

An insect hotel. Note the holes, at a variety of depths, drilled into the material.
Dietmar Rabich/Wikimedia Commons, CC BY-SA

Building your insect hotel

Use recycled materials (wooden pallets, small wooden box or frames) or natural materials (wood, bamboo, sticks, straw, stones and clay).

Fill gaps in the structure with smaller materials, such as clay and bamboo.

In the wood, drill holes ranging from three to ten millimetres wide for insects to live in. Vary hole depths for different insects – but don’t drill all the way through. They shouldn’t be deeper than 30 centimetres.

Give your hotel a roof so it stays dry, and don’t use toxic paints or varnishes.

Place your insect hotel in a sheltered spot, with the opening facing the sun in cool climates, and facing the morning sun in warmer climates.

Apartment-dwellers can place their insect hotels on a balcony near pot plants. North-facing is often best, but make sure it’s sheltered from harsh afternoon sunshine and heavy rain.The Conversation

Judith Friedlander, Post-graduate Researcher, Institute for Sustainable Futures, University of Technology Sydney

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

The world may lose half its sandy beaches by 2100. It’s not too late to save most of them



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John Church, UNSW

For many coastal regions, sea-level rise is a looming crisis threatening our coastal society, livelihoods and coastal ecosystems. A new study, published in Nature Climate Change, has reported the world will lose almost half of its valuable sandy beaches by 2100 as the ocean moves landward with rising sea levels.

Sandy beaches comprise about a third of the world’s coastline. And Australia, with nearly 12,000 kilometres at risk, could be hit hard.




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This is the first truly global study to attempt to quantify beach erosion. The results for the highest greenhouse gas emission scenario are alarming, but reducing emissions leads to lower rates of coastal erosion.

Our best hope for the future of the world’s coastlines and for Australia’s iconic beaches is to keep global warming as low as possible by urgently reducing greenhouse gas emissions.

Losing sand in coastal erosion

Two of the largest problems resulting from rising sea levels are coastal erosion and an already-observed increase in the frequency of coastal flooding events.

Erosion during storms can have dramatic consequences, particularly for coastal infrastructure. We saw this in 2016, when wild storms removed sand from beaches and damaged houses in Sydney.

After storms like this, beaches often gradually recover, because sand from deeper waters washes back to the shore over months to years, and in some cases, decades. These dramatic storms and the long-term sand supply make it difficult to identify any beach movement in the recent past from sea-level rise.

What we do know is that the rate of sea-level rise has accelerated. It has increased by half since 1993, and is continuing to accelerate from ongoing greenhouse gas emissions.

If we continue to emit high levels of greenhouse gases, this acceleration will continue through the 21st century and beyond. As a result, the supply of sand may not keep pace with rapidly rising sea levels.

Projections for the worst-case scenario

In the most recent Intergovernmental Panel on Climate Change (IPCC) report, released last year, the highest greenhouse gas emissions scenario resulted in global warming of more than 4°C (relative to pre-industrial temperatures) and a likely range of sea-level rise between 0.6 and 1.1 metres by 2100.

For this scenario, this new study projects a global average landward movement of the coastline in the range of 40 to 250 metres if there were no physical limits to shoreline movement, such as those imposed by sea walls or other coastal infrastructure.




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Sea-level rise is responsible for the vast majority of this beach loss, with faster loss during the latter decades of the 21st century when the rate of rise is larger. And sea levels will continue to rise for centuries, so beach erosion would continue well after 2100.

For southern Australia, the landward movement of the shoreline is projected to be more than 100 metres. This would damage many of Australia’s iconic tourist beaches such as Bondi, Manly and the Gold Coast. The movement in northern Australia is projected to be even larger, but more uncertain because of ongoing historical shoreline trends.

What happens if we mitigate our emissions

The above results are from a worst-case scenario. If greenhouse gas emissions were reduced such that the 2100 global temperature rose by about 2.5°C, instead of more than 4°C, then we’d reduce beach erosion by about a third of what’s projected in this worst-case scenario.

Current global policies would result in about 3°C of global warming.
That’s between the 4°C and the 2.5°C scenarios considered in this beach erosion study, implying our current policies will lead to significant beach erosion, including in Australia.

Mitigating our emissions even further, to achieve the Paris goal of keeping temperature rise to well below 2°C, would be a major step in reducing beach loss.

Why coastal erosion is hard to predict

Projecting sea-level rise and resulting beach erosion are particularly difficult, as both depend on many factors.

For sea level, the major problems are estimating the contribution of melting Antarctic ice flowing into the ocean, how sea level will change on a regional scale, and the amount of global warming.

The beach erosion calculated in this new study depends on several new databases. The databases of recent shoreline movement used to project ongoing natural factors might already be influenced by rising sea levels, possibly leading to an overestimate in the final calculations.




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The implications

Regardless of the exact numbers reported in this study, it’s clear we will have to adapt to the beach erosion we can no longer prevent, if we are to continue enjoying our beaches.

This means we need appropriate planning, such as beach nourishment (adding sand to beaches to combat erosion) and other soft and hard engineering solutions. In some cases, we’ll even need to retreat from the coast to allow the beach to migrate landward.

And if we are to continue to enjoy our sandy beaches into the future, we cannot allow ongoing and increasing greenhouse gas emissions. The world needs urgent, significant and sustained global mitigation of greenhouse gas emissions.The Conversation

John Church, Chair Professor, Climate Change Research Centre, UNSW

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

From crocodiles to krill, a warming world raises the ‘costs’ paid by developing embryos




Dustin Marshall, Monash University

Apart from mammals and birds, most animals develop as eggs exposed to the vagaries of the outside world. This development is energetically “costly”. Going from a tiny egg to a fully functioning organism can deplete up to 60% of the energy reserves provided by a parent.

In cold-blooded animals such as marine invertebrates (including sea stars and corals), fish and reptiles, and even insects, embryonic development is very sensitive to changes in the temperature of the environment.

Thus, in a warming world, many cold-blooded species face a new challenge: developing successfully despite rising temperatures.




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For our research, published today in Nature Ecology and Evolution, we mined existing literature for data on how temperature impacts the metabolic and development rates of 71 different species, ranging from tropical crocodiles to Antarctic krill.

We found over time, species tend to fine-tune their physiology so that the temperature of the place they inhabit is the temperature needed to minimise the “costs” of their embryonic development.

Temperature increases associated with global warming could substantially impact many of these species.

The perfect weather to grow an embryo

The energy costs of embryonic development are determined by two key rates. The “metabolic” rate refers to the rate at which energy is used by the embryo, and the “development” rate determines how long it takes the embryo to fully develop, and become an independent organism.

Both of these rates are heavily impacted by environmental temperature. Any change in temperature affecting them is therefore costly to an embryo’s development.

Generally, a 10°C increase in temperature will cause an embryo’s development and metabolic rate to more than triple.

This photo shows a developing sea urchin, from egg (top left) to larva, to a metamorphosed (matured into adult form) individual.
Dustin Marshall, Author provided

These effects partially cancel each other out. Higher temperatures increase the rate at which energy is used (metabolic), but shorten the developmental time.

But do they balance out effectively?

What are the costs?

For any species, there is one temperature that achieves the perfect energetic balance between relatively rapid development and low metabolism. This optimal temperature, also called the “Goldilocks” temperature, is neither too hot, nor too cold.

When the temperature is too cold for a certain species, development takes a long time. When it’s too hot, development time decreases while the metabolic rate continues to rise. An imbalance on either side can negatively impact a natural population’s resilience and ability to replenish.

As an embryo’s developmental costs increase past the optimum, mothers must invest more resources into each offspring to offset these costs.

When offspring become more costly to make, mothers make fewer, larger offspring. These offspring start life with fewer energy reserves, reducing their chances of successfully reproducing as adults themselves.

Thus, when it comes to embryonic development, higher-than ideal temperatures pack a nasty punch for natural populations.

Since the temperature dependencies of metabolic rate and development rate are fairly similar, the slight differences between them had gone unnoticed until recently.




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Embryos at risk

For each species in our study, we found a narrow band of temperatures that minimised developmental cost. Temperatures that were too high or too low caused massive blow-outs in the energy budget of developing embryos.

This means temperature increases associated with global warming are likely to have bigger impacts than previously predicted.

Predictions of how future temperature changes will affect organisms are often based on estimates of how temperature affects embryo survival. These measures suggest small temperature increases (1°C-2°C) do not reduce embryo survival by much.

But our study found the developmental costs are about twice as high, and we had underestimated the impacts of subtle temperature changes on embryo development.

In the warming animal kingdom, there are winners and losers

Some good news is our research suggests not all species are facing rising costs with rising temperatures, at least initially.

We’ve created a mathematical framework called the Developmental Cost Theory, which predicts some species will actually experience slightly lower developmental costs with minor increases in temperature.




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In particular, aquatic species (fish and invertebrates) in cool temperate waters seem likely to experience lower costs in the near future. In contrast, certain tropical aquatic species (including coral reef organisms) are already experiencing temperatures that exceed their optimum. This is likely to get worse.

It’s important to note that for all species, increasing environmental temperature will eventually come with costs.

Even if a slight temperature increase reduces costs for one species, too much of an increase will still have a negative impact. This is true for all the organisms we studied.

A key question now is: how quickly can species evolve to adapt to our warming climate?The Conversation

Dustin Marshall, Professor, Marine Evolutionary Ecology, Monash University

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

Transport is letting Australia down in the race to cut emissions



e2dan/Shutterstock

Philip Laird, University of Wollongong

At a time Australia is meant to be reducing its greenhouse emissions, the upward trend in transport sector emissions continues. The latest National Greenhouse Gas Inventory report released last week shows the transport sector emitted 102 million tonnes (Mt) of carbon dioxide equivalent (MtCO₂-e) in the 12 months to September 2019. This was 18.9% of Australia’s emissions.

Overall, the trend in emissions from all sectors have been essentially flat since 2013. If Australia is to reduce emissions, all sectors including transport must pull their weight.




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Overall trend emissions, by quarter, September 2009 to September 2019.
National Greenhouse Gas Inventory

Transport emissions have gone up 64% since 1990. That’s the largest percentage increase of any sector.

Transport emissions, actual and trend, by quarter, September 2009 to September 2019.
Source: National Greenhouse Gas Inventory

Transport sector emissions include the direct burning of fuels for road, rail, domestic aviation and domestic shipping, but exclude electricity for electric trains.

Transport emissions are now equal second with stationary energy (fuels consumed in the manufacturing, construction and commercial sectors and heating) at 18.9%. The electricity sector produces 33.6% of all emissions. The main reasons for transport emissions trending upwards are an over-dependence on cars with high average fuel use and an over-reliance on energy-intensive road freight.

Inevitable results of policy failure

Increasing transport emissions are a result of long-standing government policies on both sides of politics. In 2018, the Climate Council noted:

Australia’s cars are more polluting; our relative investment in and use of public and active transport options is lower than comparable countries; and we lack credible targets, policies, or plans to reduce greenhouse gas pollution from transport.

John Quiggin and Robin Smit recently wrote about vehicle fuel efficiency for The Conversation. They cited new research that indicates emissions from road transport will accelerate. This is largely due to increased sales of heavier vehicles, such as four-wheel drives, and diesel cars.




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The government has ignored recommendations to adopt mandatory fuel-efficiency standards for road passenger vehicles. Australia is the only OECD country without such standards.

Research by Hugh Saddler found a marked increase in CO₂ emissions from burning diesel (up 21.7Mt between 2011 and 2018). A 2015 Turnbull government initiative to phase in from 2020 to 2025 a standard of 105g of CO₂ per kilometre for light vehicles was “shelved after internal opposition and criticism from the automotive lobby”.

At the same time, the uptake of electric vehicles is slow. Economist Ross Garnaut, in his 2019 book Superpower: Australia’s Low-Carbon Opportunity, sums it up:

Australia is late in preparation for and investment in electric road transport.




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Australia’s low transport energy efficiency (and so high CO₂ emissions) has also attracted overseas attention. The American Council for an Energy-Efficient Economy rates the world’s 25 largest energy users for sectors including transportation. In 2018, Australia slipped two places to 18th overall. It was 20th for transportation with just 6.5 points out of a possible 25 on nine criteria.

On four of these criteria, Australia scored zero: fuel economy of passenger vehicles, having no fuel-efficiency standards for passenger vehicles and heavy trucks, and having no smart freight programs.

For vehicle travel per capita, the score was half a point. For three metrics – freight task per GDP, use of public transport, and investment in rail transit versus roads – Australia scored just one point each.

Only in one metric, energy intensity of freight transport, did Australia get full marks. This was a result of the very high energy efficiency of the iron ore railways in Western Australia’s Pilbara region.

The International Monetary Fund (IMF) has also questioned the Australian government’s preference for funding roads rather than more energy-efficient rail transport. The IMF says Australia should be spending more on infrastructure, but this should be on rail, airports and seaports, rather than roads.

What can be done

The first thing is to acknowledge that our preferred passenger transport modes of cars and planes cause more emissions than trains, buses, cycling and walking. For example, CO₂ emissions per passenger km can be 171 grams for a passenger car as against 41g for domestic rail.


Data source: Greenhouse gas reporting: conversion factors 2019

For freight, our high dependence on trucks rather than rail or sea freight increases emissions by a factor of three.




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A 1996 report, Transport and Greenhouse, from what is now the federal Bureau of Infrastructure, Transport and Regional Economics (BITRE), reviewed no fewer than 16 measures (including five “no regrets” measures) to cut transport emissions. In a 2002 report, Greenhouse Policy Options for Transport, BITRE offered 11 measures to reduce vehicle kilometres travelled (VKT), nine measures to reduce emissions per VKT, and four road-pricing measures (mass-distance charges for heavy trucks, tolls, internalising transport externalities and emission charging).

BITRE last appeared to revisit this important issue in a 2009 report on transport emission projections to 2020. This report projected a total of 103.87Mt CO₂-e for 2019. Actual 2019 transport emissions will be about 102Mt.

It’s important to note that BITRE’s 2009 projection was on a business-as-usual basis. The current level of about 4 tonnes a year per person is where Australia was in 2000.

Clearly, Australia needs to do better. As well as the BITRE remedies, another remedy would be to adopt a 2002 National Action Plan approved by the Australian Transport Council in collaboration with the Commonwealth, state and territory governments. The plan included, within ten years, “programs that encourage people to take fewer trips by car” and a shift “from predominantly fixed to predominantly variable costs” to “ensure that transport users experience more of the true cost of their travel choices”. This did not proceed.

However, New Zealand has effectively adopted this approach for many years. Petrol excise is now 66.524 cents per litre (just 42.3c/l in Australia) and the revenue goes to the National Land Transport Fund for roads and alternatives to roads, resulting also in lower registration fees for cars. New Zealand has had mass distance pricing for heavy trucks for 40 years. These measures have not stopped its economy performing well.

Why do measures that would reduce transport emissions continue to be so elusive in Australia?The Conversation

Philip Laird, Honorary Principal Fellow, University of Wollongong

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