Pristine paradise to rubbish dump: the same Pacific island, 23 years apart



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The same beach on Henderson Island, in 1992 and 2015.

Jennifer Lavers, University of Tasmania and Alexander Bond, Royal Society for the Protection of Birds

A few weeks ago, the world woke to the story of Henderson Island, the “South Pacific island of rubbish”. Our research revealed it as a place littered with plastic garbage, washed there by ocean currents.

This was a story we had been waiting to tell for more than a year, keeping our discoveries under wraps while we worked our way through mountains of data and photographs.

Our May 2017 video story detailing the rubbish on Henderson Island.

Everyone wanted to know how the plastic got there, and fortunately that is a question that our understanding of ocean currents can help us answer. But the question we couldn’t answer was: when did it all start to go so wrong?

This is the million-dollar question for so many wild species and spaces – all too often we only notice a problem once it’s too big to deny, or perhaps even solve. So when did Henderson’s sad story start? The answer is: surprisingly recently.

An eloquent photo

During our research we had reached out to those who had previously worked on Henderson Island or in nearby areas, to gain a better understanding of what forces contributed to the enormous piles of rubbish that have floated to Henderson’s sandy beaches.

Then, after our research was published and the world was busy reading about 37 million plastic items washed up on a remote south Pacific island, we received an email from Professor Marshall Weisler from the University of Queensland, who had seen the news and got in touch.

In 1992, he had done archaeological surveys on Henderson Island. The photos he shared from that expedition provided a rare glimpse into the beginning of this chapter of Henderson Island’s story, before it became known as “garbage island”.

Henderson Island in happier times.
Marshall Weisler, Author provided
The same stretch of beach in 2015.
Jennifer Lavers, Author provided

There are only 23 years between these two photos, and the transformation is terrifying – from pristine South Pacific gem to the final resting place for enormous quantities of the world’s waste.

Remember, this is not waste that was dumped directly by human hands. It was washed here on ocean currents, meaning that this is not just about one beach – it shows how much the pollution problem has grown in the entire ocean system in little more than two decades.

To us, Henderson Island was a brutal wake-up call, and there are undoubtedly other garbage islands out there, inundated and overwhelmed by the waste generated in the name of progress. Although the amount of trash on Henderson is staggering – an average of 3,570 new pieces arrive each day on one beach alone – it represents a minute fraction of the rubbish produced around the globe.

Cleanup confounded

In the wake of the story, the other big question we received (and one we should have seen coming) was: can I help you clean up Henderson Island? The answer is no, for a very long list of reasons – some obvious, some not.

To quote a brilliant colleague, what matters is this: if all we ever do is clean up, that is all we will ever do. With thousands of new plastic items washing up on Henderson Island every day, the answer is clear.

The solution doesn’t require travel to a remote island, only the courage to look within. We need to change our behaviour, to turn off the tap and stem the tide of trash in the ocean. Our oceans, our islands, and our planet demand, and deserve it.

However difficult those changes may be, what choice do we have?

Prevention, not cure

While grappling with the scale of the plastics issue can at times be overwhelming, there are simple things you can do to make a difference. The solutions aren’t always perfect, but each success will keep you, your family, and your community motivated to reduce plastic use.

First, ask yourself this: when did it become acceptable for something created from non-renewable petrochemicals, extracted from the depths of the Earth and shipped around the globe, to be referred to as “single use” or “disposable”? Your relationship with plastic begins with the language you use.

But don’t stop there: here are a couple of facts illustrating how you can challenge yourself and make a difference.

Challenge: switch to bamboo toothbrushes, which cost just a few dollars each and are available from a range of online retailers or wholefood shops.

Challenge: switch to products that use crushed apricot kernels, coconut shell, coffee grounds, or sea salts as natural exfoliants.

The ConversationThese are only small changes, and you can undoubtedly think of many more. But we need to start turning the tide if we are to stop more pristine places being deluged with our garbage.

Jennifer Lavers, Research Scientist, Institute for Marine and Antarctic Studies, University of Tasmania and Alexander Bond, Senior Conservation Scientist, Royal Society for the Protection of Birds

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

Mozzies are evolving to beat insecticides – except in Australia



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Mosquitoes are the main vectors for dengue and zika. Insecticides are our best weapon against them.
Anja Jonsson/Flickr

Ary Hoffmann, University of Melbourne; Nancy Margaret Endersby-Harshman, University of Melbourne, and Scott Ritchie, James Cook University

Chemical pesticides have been used for many years to control insect populations and remain the most important method of managing diseases carried by pests, including mosquitoes. However, insects have fought back by evolving resistance to many pesticides. There are now thousands of instances of evolved resistance, which make some chemical classes completely ineffective.

The Aedes mosquito, largely responsible for the spread of viruses like dengue and zika, has globally developed resistance to commonly used chemicals, including pyrethroids. Pyrethroids are the most used insecticides in the world, which includes the control of dengue outbreaks and quarantine breaches at air and sea ports.

In Asia and the Americas, pyrethroid resistance in Aedes mosquitoes is now widespread. In Australia, our mosquitoes have not developed these defences and pyrethroids are still very effective.

The difference lies in our stringent and careful protocols for chemical use. As the global community fights zika and other mosquito-borne diseases, there are lessons to be learned from Australia’s success.

Developing resistance

Mosquitoes usually become resistant to pyrethroids through the mutation of a sodium channel gene that controls the movement of ions across cell membranes. Mutations in a single gene are enough to make mosquitoes almost completely resistant to the level of pyrethroids used in insecticides.

The mutations first arises in a population by chance, and are rare. However, they rapidly spread as resistant females breed. The more times a mosquito population is exposed to the same chemical, the more the natural selection process favours their impervious offspring.

Eventually, when many individuals in a population carry the resistance mutation, the chemical becomes ineffective. This can happen where insecticide “fogging” is common practice. Overseas, fogging is sometimes undertaken across entire neighbourhoods, several times a month, despite concerns about its effectiveness as well as its environmental and health impacts.

A pest exterminator carries out insecticide fogging in an apartment block in Singapore.
EPA, Wallace Woon/AAP

Once resistance develops, it can spread to non-resistant mosquito populations in other areas. Pest species, including mosquitoes, are often highly mobile because they fly or are carried passively (in vehicles, ships and planes) at any stage of their life cycle. Their mobility means mutations spread quickly, crossing borders and possibly seas.

We can still control Australian mosquitoes

Despite this, Australian populations of Aedes mosquitoes remain susceptible to pyrethroids. Aedes aegypti (the yellow fever mosquito) is the main disease-carrying mosquito in Australia. Its population is restricted to urban areas of northern Queensland, where dengue can occur.

Recent research found that all Australian populations of this species are still vulnerable to pyrethroids. None of the hundreds of mosquitoes tested had any mutations in the sodium channel gene, despite the high incidence of such mutations in mosquito populations of South-East Asia.

A female Aedes aegypti mosquito during a feed.
James Gathany, CDC Prof Frank Hadley Collins/Wikimedia

We believe these mosquitoes remain vulnerable to pyrethroids because in Australia pressure to select for resistance has been low.

Australia does not carry out routine fogging. If dengue is detected in an area, pyrethoids are used in highly regimented and limited fashion. Spraying is restricted to the insides of premises within selected house blocks, and then only for a short period.

Importantly, water-filled artificial containers, which can serve as a habitat for larvae, are treated with insect growth regulators, which do not select for the pyrethroid resistance mutations.

Exporting resistance

With chemical resistance growing around the world, it is more urgent than ever that we co-ordinate action to control and reduce risk of resistance. Unfortunately, no global guidelines exist to minimise the evolution of resistance in mosquitoes.

Adopting pesticide resistance management strategies has proven to be effective against other pests – for example, the corn earworm (Helicoverpa armigera). Guidelines include rotating different class of pesticides to deny pests the chance to develop resistance, and investing in non-chemical options such as natural predators of target pests.

Resistance management strategies are particularly critical for new pesticides that have different modes of attack, such as preventing juvenile insects from moulting, or attacking various chemical receptors.

The ConversationTo prolong the effectiveness of pesticides, we must develop these strategies before resistance begins to develop. North Queensland may be an example to the rest of the world on the best path forward.

Ary Hoffmann, Professor, School of BioSciences and Bio21 Institute, University of Melbourne; Nancy Margaret Endersby-Harshman, Research fellow, University of Melbourne, and Scott Ritchie, Professorial Research Fellow, James Cook University

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