{"id":701491,"date":"2026-05-29T04:55:37","date_gmt":"2026-05-29T04:55:37","guid":{"rendered":"https:\/\/www.newsbeep.com\/au\/701491\/"},"modified":"2026-05-29T04:55:37","modified_gmt":"2026-05-29T04:55:37","slug":"lord-howe-island-invertebrates-boom-after-rodent-eradication","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/au\/701491\/","title":{"rendered":"Lord Howe Island invertebrates boom after rodent eradication"},"content":{"rendered":"

A boom in cockroach numbers is not often welcome news, but Lord Howe Island is a special kind of place.<\/p>\n

Invertebrate creatures, including native cockroaches and other insects, are thriving on the World Heritage-listed site after the removal of invasive rodents seven years ago.<\/p>\n

The invertebrate life is seen as fundamental to the broader ecosystem, helping break down organic matter and providing food for birds and native animals.<\/p>\n

“It feels like the island is coming to life,” Sydney University honours student Maxim Adams said.<\/p>\n

“There’s been about a 60 per cent increase in invertebrates.”<\/p>\n

\"A<\/p>\n

A native Lord Howe Island cockroach, Panesthia lata, is one of the species rebounding on the island. (Supplied: Justin Gilligan)<\/p>\n

Mr Adams is co-lead in a study with the NSW Department of Climate Change, Energy, the Environment and Water (DCCEEW), published in Biological Invasions, examining how invertebrate communities have changed after the island-wide eradication of more than 300,000 rats and mice <\/a>in 2019.<\/p>\n

The team collected invertebrate specimens from 20 forest sites across the island before the eradication program in 2016\u201317, then again seven years later, and compared the results<\/a>.<\/p>\n

“It’s a dream job really, to be stuck on an island counting all the insects,” Mr Adams said.\"Two<\/p>\n

Maxim Adams and Nicholas Carlile (NSW DPI) under a banyan tree on Lord Howe Island. (Supplied: Justin Gilligan)<\/p>\n

The first study saw about 9,000 specimens collected, compared to 15,000 collected in the second survey.<\/p>\n

“Walking around on Lord Howe Island now, it feels more like a paradise of creatures and that’s a really special feeling,” Mr Adams said.<\/p>\n

“Invertebrates do the absolute heavy lifting of nutrient recycling, of fertilising the plants \u2026 all these wonderful ecosystem processes that make it this beautiful, lush spot we like to visit.”<\/p>\n

The strongest increases were observed among larger invertebrates: those more than 13 millimetres long.<\/p>\n

\"Native<\/p>\n

Native bush cockroaches on Lord Howe Island have bounced back strongly after the rodent eradication on the island. (Supplied: Justin Gilligan)<\/p>\n

“Isopods, which are woodlice and slaters, and native bush cockroaches seem to have increased the most,” Mr Adams said.<\/p>\n

“That matters because these animals are also an important food source for native predators including geckos and insect-eating birds.”<\/p>\n

One species of Lord Howe Island cockroach was believed to be extinct, before being rediscovered in 2023<\/a>.<\/p>\n

“It was the first sign these special invertebrates were starting to bounce back and we would be finding this unexpected diversity as the years progressed,” Mr Adams said.<\/p>\n

Mr Adams noted that while total invertebrate abundance increased, overall diversity patterns were mixed, with some groups increasing while others declined.<\/p>\n

A new ecosystem emerging\"Views<\/p>\n

Views over the top of Lord Howe Island from Mt Gower. (ABC News: Emma Siossian)<\/p>\n

The findings came after previous studies documenting the strong bounce back of seabirds and native land birds<\/a> after the rodent eradication, including the Lord Howe Island woodhen.<\/p>\n

But Mr Adams said it was unlikely the island’s ecosystem would return to the state it was in before rodents were introduced more than a century ago.<\/p>\n

“The ecosystem will reach some new equilibrium, which is probably a bit different to what was there before,” he said.<\/p>\n

\"A<\/p>\n

Numbers of the Lord Howe Island woodhen have increased dramatically in recent years. (Supplied: J Gilligan)<\/p>\n

“Part of the tragedy is that while some of these invertebrates have started to bounce back, others have [already] become extinct.”<\/p>\n

Mr Adams is a student under Professor Nathan Lo, who leads the Molecular Ecology, Evolution and Phylogenomics laboratory at Sydney University.<\/p>\n

Professor Lo said things were looking positive for the island’s biodiversity and the next step would be studying “higher-order predators” in the ecosystem, including geckos.<\/p>\n

\"A<\/p>\n

Nathan Lo says attention is turning to the island predators that eat the invertebrates. (Supplied: Daniel Cain)<\/p>\n

“Ian Hutton, director of the Lord Howe Museum, took me out into the forest in the north of the island one night a few weeks ago,” he said.<\/p>\n

“There were endemic geckos all over the place \u2014 these were only rarely seen prior to the eradication.<\/p>\n

“They are presumably eating all of the large invertebrates, in particular bush cockroaches and slaters, that have bounced back.”<\/p>\n

Professor Lo said work was also underway to sequence the DNA of all the invertebrate samples.<\/p>\n

“This will give us precise information about which critters have been present on the island over the last 10 years, and help with their longer-term biosecurity and conservation,” he said.<\/p>\n

\"A<\/p>\n

Lord Howe Island sits about 600 kilometres off the coast from Port Macquarie. (Supplied: Ian Hutton)<\/p>\n","protected":false},"excerpt":{"rendered":"A boom in cockroach numbers is not often welcome news, but Lord Howe Island is a special kind…\n","protected":false},"author":2,"featured_media":701492,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[64,63,2929,75,213428,55920,341601,341597,341600,341598,128,341599],"class_list":["post-701491","post","type-post","status-publish","format-standard","has-post-thumbnail","category-environment","tag-au","tag-australia","tag-conservation","tag-environment","tag-invertebrates","tag-lord-howe-island","tag-lord-howe-woodhen","tag-maxim-adams-study","tag-native-cockroach","tag-rodent-eradication","tag-science","tag-wildlife-bounces-back"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/701491","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=701491"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/701491\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/701492"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=701491"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=701491"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=701491"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}