The invasive carpet sea squirt (filtsjöpung), known as “sea vomit,” is rapidly spreading across the seafloor in Kosterhavet National Park, smothering organisms beneath it. Authorities say budget cuts have hampered monitoring and control, but they are now examining ways to slow the outbreak.

Rats and droppings were found at Prästholmsskolan in Boden, Sweden; control measures are underway and the school says it acted immediately. The principal notes rodents have been sighted on the school grounds.

The Metlakatla Indian Community, which has been at the forefront in the effort to control the invaders, has trapped more than 40,000 of them this year.

North Yarmouth, Maine removed about 80 ash trees from Baston Park after an emerald ash borer infestation was detected. The wood will be processed by the Cumberland Wood Bank for local heating under state-advised precautions.