Are Offshore Islands the Answer to Australia’s Mammal Extinction Crisis?

Anyone who has travelled to Australia or even seen an episode of Border Force will be familiar with the strict border controls. How often have you whiled away a Sunday afternoon watching travellers trying to enter the country with a multitude of forbidden items from fresh vegetables, to woven mats and non-native plants. I can’t be the only one who has felt the paranoid fear that I’ve disembarked my flight carrying an illegal food item that one of the army of sniffer dogs will announce to the whole airport. What often appears like over the top national security is deemed warranted by a country wrangling with it’s own extinction crisis.

Since European settlement in the late 1700’s Australia’s endemic species have been put under constant introduced pressures, most notably from feral cats and dogs. Compared to elsewhere in the world it is in fact mammals which have suffered the most with a third of all recent global mammal extinctions happening down under.  In fact Australia has faced mammal extinctions at the rate of one per decade since the 1840’s.

Australia’s mammal fauna is often found nowhere else in the world as 86% of the 315 land mammals which Australia hosts are endemic. It is of little surprise that the introduction of predators such as cats and foxes has had a disastrous impact upon the wildlife once isolated for millions of years. It is believed with increasing scientific consensus that these new predators are a powerful driving force behind the vast numbers of mammal extinctions.

Unfortunately cats are now deeply entrenched within the ecosystem, thus making the situation more complicated. Solutions such as biological control with a cat killing disease or more simply better management of dingoes (who introduced predators are fearful of and actively avoid) have been suggested. However some scientists are calling for a similar approach to that of New Zealand; the use of offshore islands.

New Zealand has also suffered heavily from introduced predators as they have decimated the country’s bird population. However New Zealand took a different approach in their conservation measures and are now a world leader in the use of offshore islands in the fight against introduced predators. Unlike Australia they have policies and monitoring programs in place for the translocation of endangered species to these islands. A study by the University of Tasmania has shown that Australia has access to approximately 200 suitable, cat and fox free offshore islands with the potential for that number to rise with the eradication of cats and foxes from other islands.

The number of potential wildlfie refuge islands in Australia broken down by State/Territory and climate zones. Candidate islands were selected if they were: (i) fox and cat free (ii) between 1 and 10000 km square (iii) had at least 50% native vegetative cover (iv) were more than 1 km from the mainland and (v) were not within a World Heritage Area. Note the limited number with arid climates. Based on DEWHA, feral animals on offshore islands database 2010. Áine Nicholson, David Bowman and Grant Williamson

The number of potential wildlfie refuge islands in Australia broken down by State/Territory and climate zones. Candidate islands were selected if they were: (i) fox and cat free (ii) between 1 and 10000 km square (iii) had at least 50% native vegetative cover (iv) were more than 1 km from the mainland and (v) were not within a World Heritage Area. Note the limited number with arid climates. Based on DEWHA, feral animals on offshore islands database 2010. Áine Nicholson, David Bowman and Grant Williamson

 

The use of offshore islands is not without controversy as shown by Richard Branson’s ambitious plans to translocate captive lemurs onto his Caribbean island in an effort to conserve them. Conservationists warned against the impact an introduction of lemurs could have upon native species with the chair of the International Union for the Conservation of Nature’s Species Survival Commission (IUCN SSC) claiming it may contravene the IUCN’s code for translocations. The IUCN’s code for translocations has been put in place to avoid a repetition of the devastating impact Cane Toads had once introduced to Australia.

Another criticism of using offshore islands is that the method is akin to the creation of mini zoos, certainly in the case of Australia’s offshore islands the climate is such that fenced enclosures would be needed to conserve relocated inland mammals. However the authors of the analysis of suitable islands claim that arguing over perceived naturalness is a distraction from the real threat of extinction, especially when many islands have already been affected by land clearing and changes in ecology thanks to man.

Perhaps the ticking clock is the key argument for the use of offshore islands as a conservation tool. The faded black and white images of the last thylacine (Thylacinus cynocephalusare an iconic reminder of how close we came to saving a species. Last year, the last known Christmas Island Forest Skink (Emoia nativitatisi) also died alone in a zoo. Both species outlived the mechanisms put in place to protect them by a few mere months. Both of these examples are important reminders of the consequences of acting too slow in conservation.

 

For More Information

Ship Australia’s Wildlife Out To Sea to Save it From Extinction 

To Save Australia’s Mammals We Need a Change of Heart

Richard Branson’s Lemur Plan Raises Alarm

The Last Known Christmas Island Forest Skink

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Emily Stewart
Owner of Inspirewildlife - a site dedicated to sharing positive conservation news stories from around the world. Zoo Management Graduate from University of Chester
Emily Stewart

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