Published: 7 January 2013

Islands are assets for biodiversity conservation

David Dall, Julie Quinn and Karl Bossard

A major exercise to assess the biodiversity and ecological security of our offshore islands has identified their importance in helping minimise the impact of pests – such as cane toads – on Australia’s biodiversity.

Knowledge and experience gained from offshore islands is key to managing the impact of pest animals on native biodiversity, such as the detrimental effects of cane toads on populations of predatory goannas, also known as monitor lizards.

Credit: David Dall / Australian Pest Animal Strategy

Australia’s islands are diverse in their form and character. Under a recent initiative of the Australian Government’s Department of Sustainability, Environment, Water, Population and Communities, researchers catalogued more than 8000 islands in Australian waters, almost half larger than one hectare.

The rich biodiversity of these islands is difficult to adequately protect due to a number of factors. These include the sheer number of islands, the different types of tenure, the challenges of accessing and working on many of them, and overall limitations on resources.

Many islands host endemic sub-species of mainland animals. They also provide a refuge for populations of native species once widespread on the mainland, but now extinct or in decline, as a result of factors that include predation by feral animals such as exotic rats, foxes, cats and pigs, competition from rabbits and goats, or poisoning from eating cane toads.¹

The Australian Government’s Offshore Island Initiative assessed the presence of feral and invasive animals on all islands larger than 20 hectares, determined the key elements of the natural biodiversity on all islands larger than 200 hectares, and used this information to define 100 priority islands of high conservation status.²

These findings are useful when developing ways to protect island populations of key native predator species at risk from the spread of cane toads across northern Australia. The Australian Government’s cane toad Threat Abatement Plan (TAP) notes that: ‘Neither the technologies nor the resources required to contain and eradicate cane toad numbers on a continental scale are available’. A key objective of the TAP is finding ways to ‘reduce the impact of cane toads on populations of priority native species and ecological communities’.

Cane toads have now colonised much of northern Australia, affecting many endemic species.

Credit: David Dall / Australian Pest Animal Strategy

The Offshore Islands database has enabled the identification and description of important communities of threatened – mostly predatory – species on 99 islands off northern Australian coasts, with some of the most significant found off the Northern Territory’s Arnhem Coast.

Closer inspection of just two of these islands – Groote Eylandt and Marchinbar Island – reveals a range of similarities and differences between the two, and illustrates the general importance of islands as assets for biodiversity conservation.

Both islands are Aboriginal-owned under the Aboriginal Land Rights (NT) Act and the rights of their traditional owners are recognised. Those traditional owners thus decide what conservation activities should take place on their land, and conservation planning is undertaken with the relevant communities.

Groote Eylandt is the largest of a group of about 40 islands, approximately 40 km from the mainland in the Gulf of Carpentaria. With an area of almost 230,000 hectares, it is the third largest offshore Australian island, after Melville Island in the Northern Territory and Kangaroo Island in South Australia.

Groote Eylandt has a population of about 1000 people and a major manganese mining operation. As a consequence, the island is subject to a continual stream of traffic, both people and cargo.

It also hosts a diversity of high-quality forest, woodland, vine thicket, heathland and swamp ecosystems, and is inhabited by at least 12 important reptile and mammal predator species. These include an abundant natural population of the northern quoll, Dasyurus hallucatus, which is listed as critically endangered in the Northern Territory and may have been lost from the Northern Territory mainland as a result of cane toad colonisation. As well, Groote Eylandt is home to Merten’s water monitor (Varanus metensi) and the yellow-spotted monitor (Varanus panoptes panoptes), both of which are listed as vulnerable in the Northern Territory.

The Anindilyakwa Rangers were established in 2002 to help protect the Groote Eylandt archipelago’s unique natural and cultural values. In 2006, the islands in the archipelago were declared as the Anindilyakwa Indigenous Protected Area (IPA), which has a management plan that prioritises the most important values for protection and management from the perspective of the traditional owners.

In contrast, the much smaller Marchinbar Island – around 21,000 hectares in size – is found at the extreme north-eastern end of the chain of islands that form the Wessel Islands Group in Arnhem Land, and is only 2 km from the closest member of that group, Guluwuru Island.

Marchinbar has a small human population centred on a family outstation, with relatively low rates of outside visitation and material contact. The island also has natural populations of the northern quoll and has the only natural population in the Northern Territory of the mainland golden bandicoot (Isoodon auratus auratus), which is listed as vulnerable under the Environment Protection and Biodiversity Conservation (EPBC) Act.

Among the native predators threatened by the spread of cane toads is the northern quoll, Dasyurus hallucatus, a type of native cat. Now absent from many parts of the mainland, they have been listed as endangered under the EPBC Act (although it is listed as near-threatened by the IUCN). Surviving natural populations are found on Groote Eylandt and Marchinbar island.

Credit: Wildlife Explorer/Wikimedia Commons licensed under Creative Commons CC BY 3.0

Potential risks and invasion routes of pest animals – such as cane toads, which are currently not present on either island – are quite different for the two islands. For Groote Eylandt, the major risk is through ‘stowaway’ toads in cargo and luggage; for Marchinbar, the greatest risk is from natural invasion by a process of ‘island-hopping’.

Not surprisingly, the approaches adopted by the traditional owners and agencies responsible for managing the islands’ environments and biodiversity reflect the different nature of the risks.

The traditional owners of two islands adjacent to Marchinbar Island have built their capacity to monitor and manage biodiversity through a project to relocate mainland populations of the northern quoll to the islands. This has led to development of a community ranger program, the Gumurr Marthakal Rangers, who now focus on land and sea management issues throughout the island group. Both the Gumurr Marthakal Rangers and the Anindilyakwa Rangers are supported by the Australian Government’s Working on Country Program.

Marchinbar Island is within a consultation area for the proposed Marthakal IPA, which encompasses islands of the Elcho, Wessels and English Company groups. A draft management plan for the proposed IPA locates Marchinbar Island within a specific management zone and recognises that although cane toads – and other pests such as black rats and feral cats – are not known to be on these islands, there is a constant threat of their invasion.

The plan includes activities to ‘guard against establishment of cane toads’ and other pests on these outer islands, primarily through annual inspections including ‘listen and look’ searches at freshwater sources on the islands.

On Groote Eylandt, the continual movement of people and goods significantly increases the risk of arrival of cane toads as well as other pests. In a novel and important site-based approach, a sniffer dog searches freight that is brought into the island from the mainland. At the same time, a cane toad awareness program aims to maximise the likelihood of toads that get past frontline defences are recognised, captured and destroyed.

There are many other site-based approaches that can be – and are being – used to manage risks to key assets from invasion by cane toads and other pests. As we have described here, activities supported and delivered by a range of stakeholders can achieve outcomes that help to protect Australia’s biodiversity from the negative impacts of pest animals, such as the devastating cane toad.

More information:

Feral animals on offshore islands, http://www.environment.gov.au/biodiversity/invasive/ferals/islands/index.html

Prioritisation of offshore island assets, http://www.environment.gov.au/biodiversity/invasive/publications/offshore-islands.html

Australian Pest Animal Strategy, http://www.apas.net.au/

¹ Australian governments have developed the Australian Pest Animal Strategy (http://www.apas.net.au/) to help address the impacts of existing animal pests, and prevent establishment of new ones. The strategy identifies the importance of key environmental assets, such as offshore islands, and supports the development and delivery of targeted approaches to help maintain their endemic biodiversity.
² See the report: Prioritisation of high conservation status offshore islands

Published: 17 January 2013

Crunch time for metals recycling?

Alex Serpo

With the world facing a rare-earth metals crisis, a paper published in the leading journal Science last year examined how far we are from cradle-to-cradle metal recycling, and identified future constraints and opportunities.

End-of-life recycling rates for commonly used metals such as iron, copper, zinc and lead are above 50 per cent. However, rare earths and other lesser known metals are seldom, if ever, recycled.

Credit: © rihardzz/istockphoto

In the paper, ‘Challenges in metal recycling’ written by US researcher, Barbara Reck, the author identifies a modern paradigm shift in metals use – today, humans exploit virtually every stable element in the periodic table.

In other words, we are now capitalising on every element’s unique physical and chemical properties, whereas for most of human history, we utilised only a handful of metals.

Another modern shift is that of recycling, a ubiquitous aspect of modern life. ‘The generation between 20 and 30 are now the first generation to have grown up with recycling bins as part of normal life,’ writes Reck from Yale University's Center for Industrial Ecology.

Reck adds, however, that the extent of modern metals recycling is well below potential.

'Metals are infinitely recyclable in principle. But in practice, recycling is often inefficient or essentially nonexistent because of limits imposed by social behaviour, product design, recycling technologies, and the thermodynamics of separation.'

She identifies two metrics that provide the most accurate measures of the rate of metals recycling – 'recycled content' and 'end-of-life recycling rate'.

Recycled content describes the share of scrap in metal production, which is important to get a sense of the magnitude of secondary supply. End-of-life recycling rate, on the other hand, is defined as the fraction of metal in discarded products that is reused in such a way as to retain its functional properties.

The paper makes reference to a United Nations’ panel that recently defined and quantified recycling rates for 60 elements. Two key trends are clear from this research.

The first is that end-of-life recycling rates for the commonly used base metals such as iron, copper, zinc and lead are above 50 per cent.

The second trend is that many trace elements are seldom, if ever, recycled. Most of these trace elements are increasingly used in small amounts for very precise technological purposes, such as red phosphors, high-strength magnets, thin-film solar cells, and computer chips.

In those applications, often involving highly comingled 'specialty metals', recovery can be so technologically and economically challenging that the attempt to recycle is seldom made.

'After millennia of products made almost entirely of a handful of metals, modern technology is today using almost every possible metal, but often only once. Few approaches could be more unsustainable,’ comments Reck.

Greater opportunities for collecting used metals have improved recycling rates over recent decades.

Credit: Bidgee under CC-BY-SA-3.0 via Wikimedia Commons

In her paper, Recki identifies lead as a notable exception : '...80 per cent of today’s lead use is for batteries in automobiles and for backup power supplies, and collection and pre-processing rates from these uses are estimated to be within 90–95 per cent as a result of stringent regulation worldwide. The result is a nearly closed-loop system for lead use in batteries.'

While improved product design and enhanced deployment of modern recycling methodology will both improve recycling rates, Reck identifies one activity that stands out as the key to increasing recovery.

'It seems mundane at first telling, but the activity with the greatest potential to improve metal recycling is collection,' she writes. 'Much improvement is possible, but limitations of many kinds – not all of them technological – will preclude complete closure of the materials cycle.'

Reck also identifies a perverse incentive when it comes to product design for recycling: the more advanced and highly engineered the product, the more difficult it is to recycle. This is particularly true for electronics products, but also applies to other goods like cars, aeroplanes and whitegoods.

Collectively, today’s high-tech products make use of almost every metal, in contrast to earlier products that used only a handful of the more common metals.

The paper identifies another paradox of modern materials recovery. 'It is not much of an exaggeration to say that we manufacture modern products with the best possible technologies we can devise, but generally recycle them with relatively basic approaches.

'It is unfortunate from a materials perspective that, for reasons of scale and economics, often only the more basic technologies (shredding, crushing, magnetic sorting) are routinely applied, whereas more advanced technologies (such as laser, near-infrared, or x-ray sorting) are limited to selected recyclate streams.'

The paper dismisses the common notions of infinite recyclability for bulk recycling of common metals.

'Markov chain modelling shows that a unit of the common metals iron, copper, or nickel is only reused two or three times before being lost, gainsaying the notion of metals being repeatedly recyclable.'

Reck’s concluding comments identify how materials substitution could help improve the sustainability of metals supplies.

'Sometimes, scarce metals can be replaced by more common metals with only modest loss of product performance. Examples are aluminum-doped zinc oxides substituting for indium tin oxides in liquid crystal.’

This is a lightly edited version of an article that first appeared in Business Environment Network (BEN) and is reproduced with permission.

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