Scientists believe floating debris – plastic bottles and other litter – could be responsible for transporting alien species across the oceans, a process that often leads to diversity loss, as native species are preyed upon or outnumbered by new marauding species. The contents of ships and aircraft were previously regarded as humankind’s prime means of spreading species around the globe. But according to Jeff McNeely, chief scientist at the World Conservation Union: ‘Compared to boats, man-made debris is longer-lasting, more pervasive and travels more slowly – all factors that could favour survival of colonists.