DERBY, Australia — While Spanish sailors packed in dirt to stabilize the bottom of ships sailing from the Americas in the 16th century, they were unaware that they were also helping tiny stowaways aboard. Research suggests that tropical fire ants sailed across the Pacific Ocean, joining Europeans over the centuries as they landed and colonized landmasses across the world. Then, in the early 2000s, tropical fire ants (Solenopsis geminata) were detected on Melville Island in the Tiwi Islands, a picturesque archipelago off the coast of Darwin, the capital of Australia’s Northern Territory. Here, they were able to flourish, according to researchers, and have since become naturalized in parts of the Australian tropics while dominating the environment, eating small mammals, and potentially deterring nesting birds. “The ants have a huge impact on native birds and animals on the Tiwi Islands,” said Stanley Tipungwuti, a ranger on the islands where most identify as Aboriginal or Torres Strait Islander. But after two decades of effort, and the work of the Tiwi Ranger team, tropical fire ants are deemed no more on Merville Island: In 2025, the species was completely eradicated, according to Ben Hoffmann, who was part of the eradication program from its inception. That same year, the Tiwi Island Rangers received the Territory Indigenous Natural Resource Management Award in Darwin for their efforts. The Tiwi Rangers were the 2025 winners of the Territory NRM Indigenous Natural Resource Management Award. Image by the Territory Natural Resource Management Award, supplied by Tiwi Resources. Hoffmann, principal research…This article was originally published on Mongabay

PORT HUGHES, Australia — Situated midway along the Great Southern Reef that spans Australia’s southern coastline, the waters off Port Hughes typically teem with life. The coastal hamlet northwest of Adelaide plays host to a multitude of coral, bivalve and fish species. But in late March, the largest and longest harmful algal bloom (HAB) in Australian history arrived to Port Hughes, depleting its waters’ rich biodiversity. The bloom had first appeared elsewhere off the state of South Australia’s coast a year earlier, causing eye and skin irritation and respiratory symptoms among beachgoers. Then, along with waves of acrid-smelling sea foam, scores of dead marine animals began washing ashore. In Port Hughes, the HAB’s impacts were most visible below the surface. The town’s wooden jetty had previously been one of the most consistent locations in South Australia to observe temperate species, said Stefan Andrews, co-founder of the Great Southern Reef Foundation, a conservation advocacy group. But by mid-April, when Mongabay joined Andrews on a dive, the site was drab compared with vibrant photographs taken in February and March. Under the jetty, sponges and corals that had previously adorned its pylons in a brilliantly hued mosaic appeared colorless. Apart from a short-headed seahorse (Hippocampus breviceps) — a “sign of hope,” Andrews called it — little life was visible in the murky waters. The reef, he said, had become quieter, lacking the sounds of snapping shrimp and other creatures that once played in the underwater soundtrack. “There’s a sense of loss when you…This article was originally published on Mongabay