MGK introduces new ant control solution: the Sumari system – PCT

On the western edge of the Aleutian Archipelago in Alaska, an archipelago that was accidentally colonized with rodents was given the shameful label of the “Rat Islands”. The non-native invaders were accidentally brought to these and other islands in the Aleutian chain through shipwrecks from the 18th century and the occupation of World War II. The resilient rodents, known to be some of the most harmful invasive animals, adapted and thrived in the new environment, eventually overwhelming the island’s ecosystems, disrupting the natural ecological order and driving off native species.

A coordinated conservation effort that has removed the rats from one of the islands formerly known as Rat Island is a new example of how ecosystems can fully revert to their natural state in just over a decade. The ecological boom on the newly named Hawadax Island (a return to the original Aleutian name meaning “the island there with two hills”) extended from land to the island’s interconnected marine community. The results of a study published in Scientific Reports and led by a researcher from the University of California at San Diego have documented the remarkable recovery.

“We were surprised that the level of recovery was developing so quickly – we thought it might take longer,” said Carolyn Kurle, associate professor in the Department of Ecology, Behavior, and Evolution at UC San Diego and lead author of the new study at the researchers UC Santa Cruz, Island Conservation, the U.S. Fish and Wildlife Service, and The Nature Conservancy.

Kurle has participated in research expeditions to more than 35 of the islands in the Aleutian chain. She and her colleagues conducted surveys at Hawadax in 2008 when the invasive rodents were dominating the island’s ecosystem. As a new, direct predator for native island species, the rats triggered a cascade of disruptions to the island’s food chain. They hunted shorebird eggs and chicks, which nearly wiped out the island’s breeding shorebird population. Without birds consuming herbivorous coastal invertebrates such as snails and limpets, the island’s tidal herbivores flourished, significantly reducing the abundance of seaweed.

To reverse these effects, the rats were removed in 2008 through a coordinated conservation strategy to save the native species on Hawadax. The effort marked a rare case in which researchers were able to compare ecosystem data from surveys during the dominance of rats five years later to a recovering ecosystem – a fully restored system after 11 years.

“You don’t often get the opportunity to go back to a remote location and collect data afterwards,” said Kurle, who found that the researchers also compared the survey data to naturally balanced ecosystems on neighboring islands that have never been infested with rats. “Sometimes it’s hard to say that a conservation effort has had any effect, but in this particular case we have taken a conservation effort that was expensive and difficult, and we actually showed it to work. But we didn’t expect it.” fast.”

After the rats were removed in Hawadax, the seabirds returned and again consumed the coastal invertebrates, which has allowed the kelp community to recover and rebound.

“Invasive rats are almost always direct predators of native animals when introduced to islands,” Kurle said. “When the birds returned, it created a completely different structure in the marine community on this island. It now has a structure that is closer to what we see on islands that have never been rat invaders.”

The researchers say more studies are needed that focus on understanding and measuring the direct and indirect effects of invaders, as well as the response of interconnected communities after those effects are removed, to underscore the broad conservation achievements that come with invasive eradication Species, especially on islands, are connected.

“This study confirms the profound effects of introduced species such as rats on entire fragile island ecosystems while demonstrating the remarkable conservation benefits of their removal,” said Donald Croll, co-author and professor in the Department of Ecology and Evolutionary Biology at UC Santa Cruz.

Source: UC-San Diego

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