Lord Howe’s epic con­ser­va­tion bat­tle

A mas­sive pest erad­i­ca­tion pro­gram will pave the way for the re­turn of a long lost species to its is­land home.

Australian Geographic - - Wild Australia - with John Pickrell JOHN PICKRELL is a for­mer AUS­TRALIAN GEO­GRAPHIC edi­tor. Fol­low him on Twit­ter: @john_pick­rell

AG READ­ERS will be fa­mil­iar with the ex­tinc­tion tale of the Lord Howe Is­land stick in­sect and its mirac­u­lous 2001 re­dis­cov­ery atop Balls Pyra­mid, a 551m-high rocky sea stack 23km south-east of the re­mote Pa­cific is­land (see AG 88 and 129).

Last Oc­to­ber, re­searchers in Aus­tralia and Ja­pan pub­lished a study in the jour­nal Cur­rent Bi­ol­ogy con­firm­ing the DNA of stick in­sects from the sea stack matches that of mu­seum col­lec­tion spec­i­mens his­tor­i­cally col­lected on Lord Howe. This con­firmed what was al­ready sus­pected: the in­sect never went ex­tinct. It’s also paved the way for an ex­cit­ing plan to rein­tro­duce the species to Lord Howe.

Cap­tive-breed­ing has been un­der­way since shortly af­ter the in­sect’s re­dis­cov­ery and re­sul­tant ‘in­sur­ance’ pop­u­la­tions are held in: Mel­bourne by Zoos Vic­to­ria; an en­clo­sure on the is­land by the Lord Howe Is­land Board (LHIB); and in Canada and the UK. But a Lord Howe rein­tro­duc­tion would see the un­usual-look­ing black in­sects re­turned to their nat­u­ral en­vi­ron­ment and free to re­colonise the en­tire is­land.

A sig­nif­i­cant hur­dle re­mains, how­ever: the re­moval from Lord Howe of two in­tro­duced pests that drove the in­sect to near-ex­tinc­tion on the is­land in the first place. One is the black rat, in­tro­duced in 1918 when SS Makambo ran aground on the is­land, and the other is the house mouse.To this end a mas­sive – and con­tro­ver­sial – erad­i­ca­tion ef­fort that will see 42 tonnes of poi­soned ce­real dropped across the is­land is planned for this win­ter.

As well as be­ing held re­spon­si­ble for the demise of the stick in­sect, rats are be­lieved to have led to the ex­tinc­tion of five bird species and 13 other in­ver­te­brates on the is­land. Get­ting rid of the ro­dents will not only al­low the stick in­sect’s re­turn, but also pro­tect an­other 70 species they threaten, in­clud­ing birds such as the Ker­madec pe­trel, masked booby and white-bel­lied storm pe­trel.

Both Aus­tralia and New Zealand have at­tempted mas­sive pest erad­i­ca­tion at­tempts on is­lands be­fore. In 2014, for ex­am­ple, Aus­tralia’s 12,800ha sub­antarc­tic Mac­quarie Is­land be­came the largest is­land to ever be cleared of pests, while NZ has been in­volved in clear­ing about 200 of the 1000 or so is­lands glob­ally sub­jected to erad­i­ca­tion ef­forts.

But such ef­forts have rarely been at­tempted on per­ma­nently pop­u­lated is­lands, hous­ing tourists, chil­dren and pet dogs. Lord Howe is the largest in­hab­ited is­land where an erad­i­ca­tion has been at­tempted. De­spite the hur­dles, the LHIB voted late last year to pro­ceed with the $9.5 mil­lion erad­i­ca­tion af­ter a pub­lic vote saw more than half the is­land’s 300 res­i­dents agree to the plan.

Pre­cise dates, which will be around June–July, are yet to be con­firmed, although it’s known the poi­son will be dropped in two in­stal­ments, sev­eral weeks apart.There’s a risk non-tar­get na­tive species will in­gest baits, and an am­bi­tious round-up is planned of two rare, en­demic birds – the Lord Howe wood­hen and Lord Howe cur­ra­wong.

With the help of bird­keep­ers and con­ser­va­tion­ists from Taronga

Zoo in Syd­ney, 200 wood­hens and

100 cur­ra­wongs will be caught and cared for in aviaries dur­ing the bait­ing. Taronga staff com­pleted a trial run with a much smaller num­ber of birds in 2013, which went off with­out any hitches. And sim­i­lar ef­forts have been used be­fore to suc­cess­fully pro­tect

NZ’s weka, a flight­less rel­a­tive of the wood­hen.

With any luck, the erad­i­ca­tion will be a big suc­cess and, later this year, sci­en­tists and the LHIB will be able to start think­ing about re­turn­ing the mar­vel­lously weird stick in­sects – or tree lob­sters, as they are pop­u­larly known – back to their nat­u­ral habi­tat.

I’ve seen them in cap­tiv­ity on the is­land and I’m very much look­ing for­ward to go­ing back one day and spot­ting one in the wild!

Look­ing weird and waxy, adult Lord Howe Is­land stick in­sects can grow to a length of 15cm.

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