SANTA CRUZ, Calif., Feb. 26 (UPI) -- University of California-Santa Cruz scientists have determined rats living on islands disrupt ecosystems on both land and sea.
Researchers said their findings have already helped make the case for this summer's first major rat eradication effort in the Aleutian Islands.
The UCSC scientists found the presence of rats on islands dramatically alters the intertidal zone, reducing the amount of seaweed and increasing the numbers of snails, barnacles, and other invertebrates.
Graduate student Carolyn Kurle, who led the study, said the changes result from the decimation of seabird populations by the rats.
"When you're on an island with rats, there are so few birds it's silent, in contrast to the cacophony on the islands without rats," Kurle said.
Some of the affected birds -- sea gulls and oystercatchers, in particular -- are major predators of invertebrates in the intertidal zone. In their absence, snails, limpets, and other grazers increase in abundance, eat more algae, and clear more space for other invertebrates to settle and grow, Kurle said, noting the result is a shoreline practically stripped bare of the usual cover of fleshy algae, or seaweed.
The study appears in the Proceedings of the National Academy of Sciences.
