Nature Out of Balance: How Invasive Species Are Changing the Planet

Nature Out of Balance: How Invasive Species Are Changing the Planet — page 5
Accidental Hitchhikers Accidental Hitchhikers We move species accidentally in lots of different ways For example early humans probably had seeds from plants in their hair and clothes or on their tools dropping them as they traveled to new regions But the main source of accidental movement of species today is international trade The globalization of our economies economies and culture has also caused the globalization of many species Insects can hitchhike on the fruits and vegetables grain and wood that we get from and send all over the world Snails slugs and bugs can also be hidden on plants traveling from faraway places to our gardens Reptiles and amphibians can travel to new homes in cargo containers Scientists esti mate that more than 10,000 species a day are being carried in ships ballast water taken onboard in one place to balance the ship and its load and then dumped in another part of the world when it unloads including fish shellfish algae fungi viruses and bacteria The more stuff we buy and sell the more non native species move around Even the stuff we throw away including all the plastic that ends up in the oceans carries countless creatures from one continent to another Scientists say that our trash could be responsible for a new wave of invasive species on our coasts Mussels barnacles and sea squirts can survive for years attached to plastic and eventually wash up on distant shores ready to take up residence The massive 2011 earthquake and tsunami in Japan pulled five million tons of debris into the Pacific Ocean Currents and storms carried some of it all the way to the west coast of North America Everything from small pieces of plastic to docks and entire fishing boats served as rafts for a mass migration of marine creatures Researchers have found almost 300 species that survived the trip Ballast water emptied from ships moves species around the world every day PHIL AUGUSTAVO Getty Images Debris from the 2011 Japanese earthquake and tsunami like this boat that washed up on an Oregon beach two years later carried hundreds of species to North America STEVEN RUMRILL SHELLFISH PROGRAM leader OREGON department of FISH and wildlife 10