Nature Out of Balance: How Invasive Species Are Changing the Planet
Introduction The first thing I see in Uplands Park a natural area near my home in Victoria British Columbia is the Garry oak trees with their huge trunks crooked branches rough gray bark and in summer leathery dark green leaves In spring the meadows around the trees are a blue blanket of camas flowers with patches of hot pink shooting stars delicate fawn lilies and bright yellow spring gold In the winter months the oaks sometimes look ghostly in the mist Deeper in the park though I see things that don’t belong First the bank of Himalayan blackberry Then the thickets of English hawthorn and Scotch broom Worst of all the English ivy which smothers everything on the ground and climbs up the oaks weakening and eventually killing them All these plants were brought by European settlers Even the animals I see in the park gray squirrels rabbits cats and sometimes rats came from elsewhere In April brightly colored wildflowers fill the Garry oak meadows in Uplands Park CHRIS JUNCK 66
Getting English ivy off Garry oaks is hard work and takes many hands MERRIE-ELLEN WILCOX The Europeans had other impacts too The Lekwungen Peoples once used these meadows to cultivate kwetlal camas which grows from a bulb that was an important part of the local diet They used fire to stop other plants from filling in the meadows so all available soil could be used for the camas But the settlers stopped the Lekwungen Peoples from using their traditional practices Today many of the big oaks are surrounded by dense thickets of snowberries and roses It’s considered too dangerous to burn the meadows because the fire might spread to all the houses that have been built nearby There’s always more to the story than we think So let’s keep walking to find out more about the plants and animals we call invasive species Camas bulbs were an important part of the traditional diet of Indigenous Peoples in the Pacific Northwest STEPHEN D SHAW LEY COLLECTION NEZ PERCE NATIONAL HISTORIC PARK
Chapter One Here There and Everywhere Depending on where you live you’ve probably heard about invasive species that spell Big Trouble They’re in the news They might be in your school grounds or even your backyard Experts might have visited your class to tell you about them And you might even have been part of a group of volunteers volunteers helping in the battle against them You’ll see a few of these invasion all-stars throughout the pages of this book The white fuzz on this little brown bat’s face means it has white-nose syndrome Caused by a fungus that likely came to North America from Europe white-nose syndrome is killing millions of bats PETE PATTVINA USFWS CC BY 2.0 Eco-Fact A native species is one that occurs naturally in a place having evolved there over a long period of time without any help from humans 88 But first What IsIs an Invasive Species Anyway What an Invasive Species Anyway Any type of organism a living thing such as a plant animal insect fish fungus virus or bacteria can be an invasive species It usually doesn’t misbehave in its home habitat where it has evolved as a native species But once it has been moved to a new area where it is a non-native species it begins to spread and become a bully causing problems for the native species there and often for humans as well That’s when we call it a non-native invasive species Although these organisms are blamed for everything from extinctions of native species to billions of dollars in damage to
crops and to nature they aren’t bad in themselves The real villains are us humans since we moved them to the new place whether by accident or on purpose Movers and Shakers Movers and Shakers Species can travel naturally sometimes thousands of miles to new regions and even to different continents In fact these invasions are an essential part of the history of life on Planet Earth If the first plants hadn’t invaded land from the ancient ocean about 500 million years ago Earth certainly wouldn’t be the amazing place it is now And if species of all kinds hadn’t traveled when the ice sheets melted after the Ice Age things would look very different from the way they do today Every species must have been invasive at some point or it wouldn’t have continued to exist Very small organisms like bacteria can be carried huge distances across oceans and continents by wind and air currents Larger organisms expand their ranges the areas in which they occur naturally by following the food and other conditions that they need But humans have also been moving species around by accident since they first left Africa more than 100,000 years ago and on purpose since they became farmers more than 10,000 years ago In fact most of the species that have spread to new places in the last several centuries were moved there by us We’re the all-star vector for non-native species Eco-Fact Not all invasive species are non-native Native species can also become invasive although they usually cause fewer problems Eco-Fact WeedWeed is simply a label we give to plants that grow where we don’t want them usually in our gardens and in farmers fields A weed typically grows or spreads rapidly and it can be a native species or a non-native species This modern liverwort’s ancestors were likely among the first land plants They managed to change the earth’s climate alter its soils and allow other life to evolve ED Reshike getty images
