The secret agents protecting our crops and gardens


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Lacewings are fantastic predators and are easy to rear and release.
Dan Papacek & Tony Meredith (Bugs for Bugs), Author provided

Lizzy Lowe, Macquarie University and Manu Saunders, University of New England

Insect pests cause a huge amount of damage to crops globally. In Australia alone, pests are responsible for around A$360 million of crop losses a year. Controlling pest outbreaks is crucial for food security and human health. Since the 1940s, our primary defence against crop pests has been synthetic pesticides. But using pesticides comes at a huge cost.

Not all bugs are bad!

Bees, flies and butterflies help to pollinate our plants. Decomposers like beetles and worms help break down wastes and return nutrients to the soil. Meanwhile, predators and parasites help control the species that are pests. One of the biggest environmental problems with pesticides is that they can affect these beneficial species as well as the pests they’re targeting.

Predatory insects and spiders control pests with none of the health and environmental risks of chemicals. So when we kill these species with insecticides, we are shooting ourselves in the foot.




Read more:
The real cost of pesticides in Australia’s food boom


Losing insects also has flow-on effects for larger animals that rely on them for food. Because invertebrates have such important roles to play in our environment, losing them to insecticides can completely change how ecosystems function.

An alternative to insecticides

Biological control (or biocontrol) relies on “secret agents” – the natural enemies (predators and parasitoids) of pests that live freely in the ecosystems around us.

There is a huge range of predatory invertebrates that eat pests. They include dragonflies, preying mantids, beetles (including ladybugs), lacewings, spiders, mites, wasps, and even some flies.

Parasitoids, meanwhile, are insects that lay their eggs in the bodies of other invertebrates. Their larvae extract nutrients from the host during their development, which ultimately kills the host. Wasps are best known for this strategy but there are also parasitoid flies and beetles.

Lady birds are voracious predators ready to eat pests in crops and gardens.
Manu Saunders

Predators and parasitoids are useful because they use pest insects, like caterpillars and aphids, as food to reproduce and grow their populations. We walk past many of these hard working agents every day without knowing it.

One biocontrol method that gardeners and land managers use is called augmentation. This simply means raising lots of live individuals of particular natural enemies, like ladybirds or wasps, and releasing them into an area to control pests.

Alternatively, gardeners might change the local environment to encourage these natural enemies to move in on their own. They might include natural insectariums or planting different types of vegetation to encourage diverse invertebrate communities. There is increasing evidence of the success of these strategies in organic farming so we should be thinking about using them more broadly.

Selecting your insects

If you want to release biocontrol agents, you need to choose them carefully, just like human special agents. Like any introduced plant or animal, there is a risk that good bugs could become pests (if they feed on the wrong insects, for example).

Selecting biological control agents requires close collaboration between managers, skilled entomologists and other scientists. For each new species, they identify the pest and some potential predators. They look at the predator’s life cycle and resource needs, and consider how it interacts not just with pests, but with other insects too. If agents are coming in from overseas, they also need to be cleared by government biosecurity.

Parasiotid wasps, lacewings, predatory mites, ladybird beetles, and nematodes are all common biocontrol agents. These species are relatively easy to raise in large numbers and work well when released into the field. Spiders are also a really important predator of many pest insects, but they’re often overlooked in the biocontrol game because they are harder to breed – and for some reason people don’t always like releasing large numbers of spiders.

Many biocontrol agents are enemies of pests in general, preying on aphids, caterpillars and fruit flies alike. It’s important to have generalists around for every day pest control, but sometimes a more targeted approach is needed. This is when specialised predators or parasitoids come in. These are species that only target specific pests like leaf miners, beetles, scale insects or spider mites. This way the target pest can be managed with no risk of the parasitoids accidentally attacking other beneficial invertebrates.

Raising good bugs

It’s very exciting to get live insects in the mail!
Lizzy Lowe

Once a biocontrol agent has been selected, greenhouses or lab facilities start raising a large population. This is an emerging market in Australia, but there are already a number of companies in Australia who specialise in rearing biological control agents.

This is a tricky job because demand for the product is variable and is not easy to predict. Warmer seasons are the peak time for most pests, but problems can arise at any time of the year. In most cases the biocontrol company will maintain breeding colonies throughout the year and will be ready to ramp up production at a moment’s notice when a farmer identifies a pest problem. Each company usually provides 10-20 different biocontrol agents and are always looking for new species that might be useful.




Read more:
Birds, bees and bugs: your garden is an ecosystem, and it needs looking after


When it comes to getting the agents to the farmers, the bugs can be shipped as eggs (ready to hatch on arrival), or as live adults ready to disperse and lay their own eggs. The packages are express posted in boxes designed to keep the insects cool and safe.

Once the farmer or natural resource manager receives the bugs, applying them is quite simple. The secret agents are released among the crops, usually by hand, but in some special cases they may be airlifted in via specialised drones!

Drones can be used to deploy biological control agents.
Nathan Roy (Aerobugs)

It’s important to monitor the pests and the biological control agents after release to check that the agents are working. Some farmers are happy to do this themselves but most biological control companies have experts to visit the farms and keep an eye on all parties.

Can I use good bugs in my garden?

The ConversationIf you have a problem with a pest like aphids it is possible to buy predators such as ladybirds or lacewings to quickly deal with the problem. But for long term pest control, there are probably already some natural enemies living in your garden! The easiest and cheapest way to help them is to put the insecticides away and ensure your garden is a friendly environment for secret agents.

Lizzy Lowe, Postdoctoral researcher, Macquarie University and Manu Saunders, Research fellow, University of New England

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

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Going to ground: how used coffee beans can help your garden and your health



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Coffee’s usefulness doesn’t have to end here.
Yanadhorn/Shutterstock.com

Tien Huynh, RMIT University

Did you know that your morning cup of coffee contributes to six million tonnes of spent coffee grounds going to landfill every year? This does not have to be the fate of your caffeine addiction and there are many opportunities to up-cycle spent coffee grounds into valuable commodities.

From fresh fruit, to roasted bean, to used up grounds, coffee’s chemical composition offers a range of uses beyond making your daily brew.




Read more:
Sustainable shopping: here’s how to find coffee that doesn’t cost the Earth


Potential applications range from biofuels, to health products, and fertiliser for farms or your garden. So why are we throwing this precious product away?

The answer is that processing and production can be more complex than you might imagine – even when we’re talking about simply using coffee grounds in your garden. What’s more, many recycling initiatives to turn waste coffee into valuable commodities are still in their early stages.

When composted properly, coffee can be an excellent fertiliser.
Author provided

You may have noticed that some cafes now offer free spent coffee grounds for customers to take home and use in the garden. In theory, this is a great initiative but the reality is that fresh coffee grounds are high in caffeine, chlorogenic acid and tannins that are beneficial to humans but toxic to plants.

The spent coffee must be detoxified by composting for a minimum of 98 days for plants to benefit from the potassium and nitrogen contained in the roasted beans. Without adequate composting, the benefits are scant (see below). So if you do take some coffee grounds home from your local cafe, make sure you compost them before sprinkling them on the veggie patch.

Parsley plants after 70 days in soil containing a) 21 days composted spent coffee; b) fresh spent coffee grounds; c) newspaper; d) soil only; and e) fertiliser.
Brendan Janissen, unpublished experimental results., Author provided

The good news is that properly composted coffee grounds offer a cheap alternative to agro-industrial fertilisers, potentially helping urban communities become greener and more sustainable. Savvy businesses have begun processing coffee grounds on a commercial scale, turning them into nutrient-rich fertilisers or soil conditioners in convenient pellets for use in the garden.

The coffee berries before harvest.
Author provided

But why stop there? A potentially even more valuable ingredient is the chlorogenic acid. Although toxic to plants, as mentioned above, chlorogenic acid has potential as a natural health supplement for humans, because of its antioxidant, anticancer and neuroprotective properties.




Read more:
Where’s that bean been? Coffee’s journey from crop to cafe


The whole coffee production process is abundant in chlorogenic acid, particularly in raw coffee beans. Chlorogenic acid conversion efficiency is even better from green coffee pulp, with a 50% recovery rate, compared with 19% for spent coffee grounds.

As undersized and imperfect beans are discarded at this raw stage, many businesses have seized the opportunity to market green coffee extracts as a weight loss product, although more research is needed to confirm this potential.

Roasted coffee beans ready for grinding.
Author provided

The list doesn’t end there. Coffee waste can be used to create a diverse list of chemicals, including enzymes and hormones for digestion of common biological compounds and to improve plant growth; and feedstocks for high-end crops such as mushrooms. Coffee oil has even been trialled as a fuel for London buses.

The ConversationWith abundant waste supplies due to the popularity of coffee consumption, by recycling the byproducts, perhaps we can enjoy one of our favourite beverages without too much guilt.

Tien Huynh, Senior Lecturer in the School of Sciences, RMIT University

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

Don’t worry, the chance of dying from potting mix is very slim



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Potting mix is known to carry harmful bacteria and fungi.
Photo by Markus Spiske on Unsplash

Peter Collignon, Australian National University

Gardening is generally a healthy and pleasurable hobby or occupation. However, any activity carries some risk – and gardening is no exception.

Potting mix is known to carry harmful bacteria and fungi. And there have been reports of deaths from diseases, such as the Legionnaires’ disease (a lung infection), that have been attributed to bacteria in potting mix.

Many bacteria and fungi that can cause infections in people live in soil and water. So it’s not surprising that potting mix can also have in it bacteria and fungi that may on occasion cause harm to people, and in rare cases even kill them. But it’s important to note that, overall, the risk is very low.




Read more:
The science is in: gardening is good for you


Fertilising more than plants

Potting mix is usually a mixture of inorganic and organic material. It’s also often at a higher temperature compared to soil because of where and how it’s stored, so it retains heat for longer. Bacteria and fungi generally grow better and reach higher numbers when they are in moist and warm environments.

Potting mix is usually warmer than soil, which makes it a better environment for bacteria and fungi to grow.
from shutterstock.com

If bacteria or fungi are already present in low numbers, they can quickly grow to very high numbers in optimal conditions. This includes many bacteria in soil that can cause problems in people – such as strains of nocardia (causes nocardiosis, an infection of the lungs or whole body), legionella (causes Legionnaires’ disease), and clostridium (causes tetanus).

Numerous fungi can also be present in soil and potting mix. In certain areas of the world, soil contains fungi that can invade if inhaled and cause disease. These include the lung infection histoplasmosis, which is caused by a fungus that lives mainly in parts of the United States, but also in some parts of Central and South America, Africa, Asia, and Australia.

Protecting ourselves

The risk to most people of becoming infected with any of these bacterial or fungal diseases is very low. Disease is more likely to be a risk when the micro-organisms are present in very high numbers.

Bacteria or fungi also need to be introduced into our bodies to cause disease. This usually happens through inhalation, where the organisms go into the lungs. It can also occur through the skin, such as with the chronic fungal infection sporotrichosis, also known as “rose gardener’s disease”. If, for any reason, micro-organisms are present in high numbers, then the exposure and risk will be higher.

A fungal infection known as rose gardener’s disease can happen with the organism entering the skin directly through an injury.
from shutterstock.com

There are many things we can do to protect ourselves from introducing bacteria or fungi into our bodies. The most essential is basic hygiene.

If people smoke, eat or drink without first washing their hands, they are at an increased risk of legionella infection from potting mix. This implies direct inhalation isn’t the only way for the bacteria to enter the body, but that oral intake of micro-organisms via contaminated hands is also a risk.

Another added protection measure is wearing gloves. This doesn’t mean you should then not wash your hands before eating. A physical barrier in addition to washing hands obviously provides better protection.




Read more:
(At least) five reasons you should wear gardening gloves


Masks can be worn in high-risk situations, such as when opening a bag of potting mix. Directing the bag away from the gardener when opened, and being in a well-ventilated area, will decrease any inhalation risk.

Signs of infection

People who have a lower immunity, such as those with diseases such as HIV or lymphoma, are more at risk of catching something from potting mix. So it’s even more important they use extra appropriate precautions, including wearing masks when in higher-risk situations.

Simple safety provisions can protect us from harmful bacteria and fungi.
Shutterstock

The symptoms or signs of infection acquired from soil or potting mix depend on where the infection is and what micro-organism is causing it. With potting mix, the main worry is legionella longbeachae. This generally causes a lung infection such as pneumonia.

Symptoms can initially be fever, aches and pains, which are fairly general of illness. But as the infection involves more of the respiratory tract, cough, shortness of breath and/or pain on breathing may develop.

Treatment

While potting-mix-linked legionella infections are uncommon, cases have occurred in countries including Australia, Japan and the US.

So, if people develop symptoms that are ongoing and have had recent exposure to potting mix within the incubation period (two to ten days after exposure), they need to seek medical help and make it clear to that person that they were worried about potting mix being involved.

It’s important to note the potting mix connection because antibiotics needed to kill legionella are different to standard penicillin-like antibiotics often used to treat pneumonia acquired in the community.




Read more:
Are common garden chemicals a health risk?


The ConversationOverall, though, we need to keep these risks in perspective. Millions of people garden and all will be exposed to soil and/or potting mix. Very few of these infections occur in Australia and elsewhere. Fairly simple provisions such as washing hands, wearing gloves and – where necessary – wearing a mask will ensure rates of infection remain low.

Peter Collignon, Professor, infectious diseases and microbiology, Australian National University

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

(At least) five reasons you should wear gardening gloves



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Not just to avoid creepy crawlies.
from http://www.shutterstock.com

Mark Blaskovich, The University of Queensland

Gardening is a great way to relax, be one with nature and get your hands dirty. But lurking in that pleasant environment are some nasty bacteria and fungi, with the potential to cause you serious harm. So we need to be vigilant with gardening gloves and other protective wear.

Soils contain all sorts of bacteria and fungi, most of which are beneficial and do helpful things like breaking down organic matter. But just as there are pathogenic bacteria that live on your body amid the useful ones, some microorganisms in soil can cause serious damage when given the opportunity to enter the body. This commonly happens through cuts, scrapes or splinters.

Plants, animal manure, and compost are also sources of bacteria and fungi that can cause infections.


Read more – The science is in: gardening is good for you


1. Tetanus

Traditionally, the most common and well-known infection is tetanus, caused by Clostridium tetani, which lives in soil and manure. Infections occur through contamination of cuts and scrapes caused by things in contact with the soil, such as garden tools or rose thorns.

Fortunately, most people have been vaccinated against tetanus, which means even if you are infected, your body is able to fight back against the bacteria to prevent it becoming serious. Symptoms include weakness, stiffness and cramps, with the toxins released leading to muscular paralysis and difficulty chewing and swallowing – hence the common term for tetanus of lockjaw.

2. Sepsis

Bacteria such as Escherichia coli, Salmonella, Campylobacter jejuni, and Listeria monocytogenes are often present in gardens as a result of using cow, horse, chicken or other animal manure. Bacterial infections can lead to sepsis, where the bacteria enter the blood and rapidly grow, causing the body to respond with an inflammatory response that causes septic shock, organ failure, and, if not treated quickly enough, death.

A high-profile case recently occurred in England, where a 43-year-old solicitor and mother of two died five days after scratching her hand while gardening. This hits close to home, as a number of years ago my mother spent ten days in intensive care recovering from severe sepsis, believed to be caused by a splinter from the garden.

3. Legionellosis

Standing pools of water may hold Legionella pneumophila, the bacteria causing Legionnaires’ disease, more commonly known to be associated with outbreaks from contaminated air conditioning systems in buildings.


Read more: Are common garden chemicals a health risk?


Related bacteria, Legionella longbeachae, are found in soil and compost. In 2016 there were 29 confirmed cases of legionellosis in New Zealand, including a Wellington man who picked up the bug from handling potting mix.

Potting mix should be handled with gloves, while wearing a dust mask.
from http://www.shutterstock.com

Another ten cases were reported in Wellington in 2017, again associated with potting soil. In New Zealand and Australia, Legionella longbeachae from potting mix accounts for approximately half of reported cases of Legionnaires’ disease. There were around 400 total cases of Legionellosis in Australia in 2014.

The bacteria is usually inhaled, so wearing a dust mask when handling potting soil and dampening the soil to prevent dust are recommended.

4. Melioidosis

An additional concern for residents of northern Australia is an infection called melioidosis. These bacteria (Burkholderia pseudomallei) live in the soil but end up on the surface and in puddles after rain, entering the body through cuts or grazes, and sometimes through inhalation or drinking groundwater.

Infection causes a range of symptoms, such as cough and difficulty breathing, fever or sporadic fever, confusion, headache, and weight loss, with up to 21 days before these develop.


Read more: Five reasons not to spray the bugs in your garden this summer


In 2012, there were over 50 cases in the Northern Territory leading to three deaths, with another case receiving publicity in 2015. Preventative measures include wearing waterproof boots when walking in mud or puddles, gloves when handling muddy items, and, if you have a weakened immune system, avoiding being outdoors during heavy rain.

5. Rose gardener’s disease

A relatively rare infection is sporotrichosis, “rose gardener’s disease”, caused by a fungus (Sporothrix) that lives in soil and plant matter such as rose bushes and hay. Again, infections through skin cuts are most common, but inhalation can also occur.

Skin infection leads to a small bump up to 12 weeks later, which grows bigger and may develop into an open sore. An outbreak of ten cases was reported in the Northern Territory in 2014.

Aspergillus, usually Aspergillus fumigatus, and Cryptococcus neoformans are other fungi that can cause lung infections when inhaled, usually in people with weakened immune systems. Gardening activities such as turning over moist compost can release spores into the air.

Of course, there are plenty of other dangers in the garden that shouldn’t be ignored, ranging from poisonous spiders, snakes and stinging insects, to hazardous pesticides and fungicides, poisonous plants, and physical injuries from strains, over-exertion, sunburn, allergies, or sharp gardening tools.

The ConversationSo enjoy your time in the garden, but wear gloves and shoes, and a dust mask if handling potting soil or compost. And be aware if you do get a cut or scrape then end up with signs of infection, don’t delay seeing your doctor, and make sure you let them know what you’ve been doing.

Mark Blaskovich, Senior Research Officer, The University of Queensland

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

Five reasons not to spray the bugs in your garden this summer



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play4smee/Flickr, CC BY-NC

Lizzy Lowe, Macquarie University; Cameron Webb, University of Sydney, and Kate Umbers, Western Sydney University

The weather is getting warmer, and gardens are coming alive with bees, flies, butterflies, dragonflies, praying mantises, beetles, millipedes, centipedes, and spiders.

For some of us it is exciting to see these strange and wonderful creatures return. For others, it’s a sign to contact the local pest control company or go to the supermarket to stock up on sprays.

But while some bugs do us very few favours – like mozzies, snails and cockroaches – killing all insects and bugs isn’t always necessary or effective. It can also damage ecosystems and our own health.


Read more: The hidden secrets of insect poop


There are times when insecticides are needed (especially when pest populations are surging or the risk of disease is high) but you don’t have to reach for the spray every time. Here are five good reasons to avoid pesticides wherever possible, and live and let live.

1. Encourage the bees and butterflies, enjoy more fruits and flowers

Hover fly.
dakluza/flickr

Flowers and fruits are the focal points of even the smallest gardens, and many of our favourites rely on visits from insect pollinators. We all know about the benefits of European honey bees (Apis mellifera), but how about our “home grown” pollinators – our native bees, hover flies, beetles, moths and butterflies. All these species contribute to the pollination of our native plants and fruits and veggies.


Read more: The common herb that could bring bees buzzing to your garden


You can encourage these helpful pollinators by growing plants that flower at different times of the year (especially natives) and looking into sugar-water feeders or insect hotels.

2. Delight your decomposers, they’re like mini bulldozers

Slaters improve your soil quality.
Alan Kwok

To break down leaf litter and other organic waste you need decomposers. Worms, beetles and slaters will munch through decaying vegetation, releasing nutrients into the soil that can be used by plants.

The problem is that urban soils are frequently disturbed and can contain high levels of heavy metals that affects decomposer communities. If there are fewer “bugs” in the soil, decomposition is slower – so we need to conserve our underground allies.

You can help them out with compost heaps and worm farms that can be dug into the ground. It’s also good to keep some areas of your lawn un-mowed, and to create areas of leaf litter. Keeping your garden well-watered will also help your underground ecosystems, but be mindful of water restrictions and encouraging mosquitoes.

3. An army of beneficial bugs can eat your pests

Mantises and dragonflies are just some of the hundreds of fascinating and beautiful bugs we are lucky to see around our homes. Many of these wonderful creatures are predators of mozzies, house flies and cockroaches, yet people are using broad-spectrum insecticides which kill these beneficial bugs alongside the pests.

It may sound counterproductive to stop using pesticides in order to control pests around the home, but that’s exactly what organic farmers do. By reducing pesticides you allow populations of natural enemies to thrive.


Read more: Even ‘environmentally protective’ levels of pesticide devastate insect biodiversity


Many farmers grow specific plants to encourage beneficial insects, which has been shown to reduce the damage to their crops.

This form of pest control in growing in popularity because spraying can result in insecticide resistance. Fortunately, it’s easy to encourage these bugs: they go where their prey is. If you have a good range of insects in your yard, these helpful predators are probably also present.

Jumping spiders are great at eating flies and other pests.
Craig Franke

4. Your garden will support more wildlife, both big and small

Spraying with broad-spectrum pesticides will kill off more than just insects and spiders – you’re also going after the animals that eat them. The more insects are around, the more birds, mammals, reptiles and frogs will thrive in your backyard.


Read more: Four unusual Australian animals to spot in your garden before summer is out


Baiting for snails, for example, will deter the blue-tongue lizards that eat them, so cage your vegetables to protect them instead. Keeping your garden well-watered, and including waterbaths, will also encourage a balanced ecosystem (but change the waterbaths regularly).

5. You and your family be happier and healthier

Engaging with nature increases well-being and stimulates learning in children. Insects are a fantastic way to engage with nature, and where better to do this than in your own back yard! Observing and experimenting on insects is a wonderful teaching tool for everything from life cycles to the scientific method. It will also teach your kids to value nature and live sustainably.

It’s also a hard truth that domestic pesticides present a significant risk of poisoning, especially for small children.

In reality, the risk of exposing your children to the pesticides far outweighs the nuisance of having a few bugs around. Instead, integrated pest management, which combines non-chemical techniques like cleaning of food residues, removal of potential nutrients, and sealing cracks and crevices, is safer for your family and your garden ecosystems.

Think globally, act locally

Your backyard has a surprising impact on the broader health of your neighbourhood, and gardens can make significant contributions to local biodiversity. Insects are an important part of ecosystem conservation, and encouraging them will improve the health of your local environment (and probably your health and well-being too).


Read more: Conservation efforts must include small animals. After all, they run the world


The ConversationIn the end, insects and spiders are not out to get you. For the sake of our kids and our environment, you should give them a chance.

Lizzy Lowe, Postdoctoral researcher, Macquarie University; Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of Sydney, and Kate Umbers, Lecturer in Zoology, Western Sydney University

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

How do we keep gardening in the face of a changing climate?



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Keep the climate in mind when you’re choosing what to plant.
shutterstock

Andrew Lowe, University of Adelaide

Since 1880, the average global temperature has increased by 0.8°℃, with large changes in rainfall redistribution. With these changing conditions upon us, and set to continue, gardeners will have to alter the way they do things. The Conversation

As climate largely determines the distribution of plants and animals – their “climate envelope” – a rapid shift in these conditions forces wild plants and animals to adapt, migrate or die.

Gardeners face the same changing conditions. If you look at the back of a seed packet, there is often a map showing the regions where these particular plants thrive. But with a rapidly changing climate, these regions are shifting.

In the future we will need to be more thoughtful about what we plant where. This will require more dynamic information and recommendations for gardeners.

The shifting climate

Changes in altitude significantly affect the temperature. As you walk up a hill, for every 100 metres of altitude you gain, the temperature drops by an average of 0.8℃.

Changes in latitude obviously have a bearing on the temperature too. It gets cooler as you move towards the poles and away from the Equator. An accurate rule of thumb is difficult to derive, because of the number of interacting and confounding factors. But generally speaking, a shift of 300 km north or south at sea level equates to roughly a 1℃ reduction in average temperature.

This means that due to warming over the past century or so, Adelaide now experiences the climate previously found in Port Pirie, whereas Sydney’s climate is now roughly what was previously found halfway to Coffs Harbour. The temperature difference is equivalent to a northward shift of approximately 250 km or drop in altitude of 100 m.

At current climate change trajectories, these shifts are set to continue and accelerate.

The plants in your garden might need to change.

Adaptation

Plants are already adapting to the changing climate. We can see that in the hopbush narrowing its leaves and other plants closing their pores. Both are adaptations to warmer, drier climates.

We have also seen some major shifts in the distribution of animal and plant communities over the past 50 years. Some of the most responsive species are small mobile insects like butterflies, but we have also seen changes among plants.

But while entire populations may be migrating or adapting, plants that grow in isolated conditions, such as fragmented bush remnants or even gardens, may not have this option. This problem is perhaps most acute for long-lived species like trees, many of which germinated hundreds of years ago under different climatic conditions. The climate conditions to which these old plants were best adapted have now changed significantly – a “climate lag”.

Using such old trees as a source of seed to grow new plants in the local area can potentially risk establishing maladapted plants. But it’s not just established varieties that run this risk.

The habitat restoration industry has recognised this problem. Many organisations involved in habitat restoration have changed their seed-sourcing policies to mix seeds collected from local sources with those from more distant places. This introduces new adaptations to help cope with current and future conditions, through practices known as composite or climate-adjusted provenancing.

The shifting climate and your garden

Gardeners can typically ameliorate some of the more extreme influences of global warming. They can, for example, provide extra water or shade on extremely hot days. Such strategies can allow plants to thrive in gardens well outside their natural climatic envelope, and have been practised by gardeners around the world for centuries.

But with water bills rising and the need to become more sustainable, we should think more carefully about the seeds and seedlings we plant in our gardens. The climate envelope we mentioned earlier is shifting rapidly.

We will need to start using seeds that are better adapted to cope with warmer and, in many cases, drier conditions. Typically, these plants have thinner leaves or fewer pores. This requires more information on the location and properties of the seeds’ origin, and a more detailed matching of diverse seed sources to planting location.

As the climate changes, we need to be more selective with what we plant.

As the climate continues to change we will also need to introduce species not previously grown in areas, using those that are better adapted to the increasingly changed climatic conditions.
Plenty of tools are now available to help guide seed collection and species selection for planting. These include those offered through the National Climate Change Adaptation Research Facility and the Atlas for Living Australia, for instance.

But these resources are often aimed at expert or scientific audiences and need to be made more accessible for guiding gardening principles and plant selection for the public. The information needs to be intuitive and easy to understand. For example, we should produce lists of species that are likely to decline or benefit under future climate conditions in Australia’s major cities and towns, along with future growing areas suitable for some of our most popular garden species.

This won’t just be useful for a backyard gardener, either. Many exciting new gardening initiatives are being proposed, including rooftop gardens, which promote species conservation, carbon sequestration and heat conservation, and future city designs, which incorporate large-scale plantings and gardens for therapeutic benefits. All of these activities need to take the shifting climate into account, as well as the need to change practices to keep up with it.

Andrew Lowe, Professor of Plant Conservation Biology, University of Adelaide

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

Birdbath, food or water? How to attract your favourite birds to your garden


Grainne Cleary, Deakin University

This summer, when a rainbow lorikeet or kookaburra comes to visit your home, what will you do? Will you offer them a slice of apple, or simply watch until they take flight?

It brings many people joy to provide food and water for birds, to encourage them to stay a while and be given the chance to observe them more closely. But some people are reluctant to interact with birds in this way because they’re worried it might damage the birds’ health.

In contrast with other countries, little research has been done on the effects of feeding birds in Australia. As a result, there are no established guidelines around how to feed and provide water for local birds.

Kookaburra having a snack.
Photo supplied by Wanda Optland, provided by author.

That’s why we ran the Australian Bird Feeding and Watering Study. We asked nearly 3,000 people to monitor the birds that visited their feeding areas and birdbaths. We wanted to know if there was a difference in the species that visited different types of gardens.

We examined the numbers and types of birds visiting:

  • birdbaths where no food was provided
  • birdbaths where food was provided
  • bird-feeders where birdbaths were provided
  • places where only food was provided.

The early results from the winter stage of the Australian Bird Feeding and Watering Study suggest that if you provide food and water, you will get more birds in your garden. But the species you attract will depend on what exactly your garden has to offer.

Common bronzewings like to eat seeds.
Glenn Pure, CC BY-NC
Providing different combinations of food and water will attract different species.

Granivores

Granivores are seed-eating birds. They include species such as parrots, crested pigeons, sulphur-crested cockatoos, crimson rosellas and galahs.

Gang gang cockatoos refresh themselves in a garden.
Glenn Pure

We noticed a spike in the number of granivores in gardens where both food and birdbaths were provided. But when food was on offer, fewer granivores chose to use the birdbath. We don’t yet know exactly why this is, but it could be because these seed-eaters need less water, or they can get it more easily from other sources than they can food.

Also, most of the bird food sold in shops is seed-based. People who buy these products will naturally attract more seed-eating birds to their garden.

We were, however, surprised to see crested pigeons visiting gardens where food was provided. These birds are only recent urban arrivals, and were previously restricted to semi-arid environments as opposed to the more urban areas where most of our citizen scientists lived. But crested pigeons are very adaptable and now compete fiercely for food and territory with the introduced spotted dove in some Australian gardens.

Many people derive great joy from feeding Australian birds.

Nectarivores

“Small” nectarivores are nectar-eating birds that weigh less than 20 grams. The main birds in this group are New Holland honeyeaters, eastern spinebills and Lewin’s honeyeaters.

The early results of our study suggest small nectarivores prefer gardens with birdbaths more than their granivore and insectivore friends. In fact, it seems that these small nectarivores like birdbaths so much, they will choose birdbaths over food when both are provided.

“Large” nectarivores are nectar-eating birds that weigh more than 20 grams. These species including noisy miners, rainbow lorikeets and red wattlebirds – seem to prioritise food over birdbaths. This may be because they’re looking for a source of protein that they can’t easily find in their natural environment.

Rainbow lorikeets seem to prioritise food over birdbaths.
Photo supplied by Wanda Optland, provided by author.

Honeyeaters – such as Lewin’s honeyeaters, blue-faced honeyeaters and noisy miners – will forage on nectar but will eat insects as well. They switch from one to the other, but once they have found their meal they will defend it vigorously from other birds.

Honeyeaters will forage on nectar but will consume invertebrates as well.
Photo by Wanda Optland, supplied by author.

Insectivores

Insectivores feed on insects, worms, and other invertebrates. Some insectivore species include superb fairy-wrens, willie wagtails and grey fantails.

Insectivores are most attracted to gardens where both food and water are provided. While superb fairy-wrens were frequently found in gardens where food was provided, willie wagtails and grey fantails preferred to visit gardens where only water is provided.

The striated thornbill feeds mainly on insects.
Glenn Pure, CC BY-NC

Many people have told me how confident fairy-wrens and willie wagtails can become around houses and gardens. These tiny birds can be bold and aggressive, and can work together to get what they want. A mum and dad fairy-wrens will conscript their older children into looking after younger ones – and siblings who refuse to help find food and defend territory may even be kicked out of the family. So these tough breeds have a competitive advantage in their new urban environments, and aren’t afraid to mix with or even chase off bigger birds.

Fairy wrens can become surprisingly bold around gardens and houses.
Photo by Wanda Optland, supplied by author.
Bolder than they look – a fairy wren eats from a citizen scientist’s hand.
Peter Brazier

You may be wondering exactly what type of seed to put out to attract which granivore, or which meat attracts a carnivore like a Kookaburra. I’m afraid we can’t yet say for sure, as we are yet to analyse the data on this question. Watch this space.

We don’t yet know exactly what offering will attract which bird.
Janette and Ron Ford

Could birds become reliant on humans for food?

Many people worry that birds will become reliant on humans to provide food for them. But this mightn’t be as big a concern as we once though.

The birds turning up at feeding areas and birdbaths are species that are highly adaptable. Many Australian birds live long lives, and relatively large brains when compared to their European counterparts. Some experts have argued that some Australian birds have evolved a larger brain to cope with feast and famine conditions in the Australian environment.

White browed scrubwrens feed mostly on insects.
Glenn Pure, CC BY-NC

Many Australian bird species can switch easily between estates and gardens in one area, be semi-nomadic, fully nomadic or seasonally migratory. This ability to adapt and switch between diets makes Australian bird species very resourceful, innovative and adaptable.

Of course, Australia also has birds that have highly specialised diets or habitats, and they’re the ones usually most threatened or limited to one territory – birds like the regent honeyeater or ground parrot. In this study, we’re concentrating on birds that are adapting to urban areas and turning up at birdbaths and feeding areas in gardens.

A crested pigeon tucks in.
Brad Walker

Building our knowledge of bird feeding behaviour

We plan to develop guidelines around providing food and water for birds in a way that has the highest conservation value for our feathered friends. But before we can do that, we need more data from you.

So please take part in the summer stage of the study and pass the word around to others who may wish to be involved.

The summer survey will run for four weeks, beginning on January 30 2017. Visit feedingbirds.org.auto download the complete report on our early findings or to register to take part in our summer study.

Different species may congregate at a feeding spot.
Brad Walker

The Conversation

Grainne Cleary, Researcher, School of Life and Environmental Sciences, Deakin University

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