It sounds like something from a 1950s horror film, when movies like “The Blob” were popular. But this invasion actually is horrific. Invasive species of both plants and animals can outcompete the native species by overtaking habitat and food sources. It happens on both land and water and can quickly become out of control.
An invasive species is a plant or animal from another region of the world that doesn’t belong in their new environment. These invasions are nothing new, and in fact most of them are the fault of humans. English ivy, the bane of anyone who does restoration work in Central and Southern California, was brought to the United States by people who wanted to recreate the manicured green gardens of the British Isles. Nearly impossible to eradicate once it takes hold, it can choke out entire riparian corridors by outcompeting the native vegetation. Arundo donax, a reed that loves damp soils and was introduced to California for roofing materials and erosion control, has caused no end of problems along creek and river corridors and provides no known source of food or nesting habitat for native species. It also creates a fire hazard by increasing the probability and intensity of wildfires.
These are just two examples of many that cause problems for native habitats. There are many cases of voracious animals killing native plant species, causing erosion problems and endangering the native species. Often, if left unchecked, an invasive flora or fauna can outcompete the native species to the point of localized extinction; in extreme cases, they can cause the extinction of an entire species. They are not unique to our region, or dry land. It is thought that Charles Darwin, while exploring the world on the Beagle and while gathering information for what would become “On the Origin of Species,” introduced non-natives to sensitive habitats, carried there on the bottom of the ship he traveled on.
Invasive species are among the leading threat to wildlife, and the impact on both the natural ecosystems and economy impact caused costs billions of dollars each year. Above, I used two very visible examples, but anything can be invasive, not just plants, but any type of seed, bacteria, insect, animal or even eggs. Those that are introduced to a new environment and thrive, spreading and reproducing and potentially causing harm, are categorized as “invasive.”
It is important to keep in mind what is considered invasive when bringing new plants into your yard. The California Invasive Plant Council has an extensive database of what things not to plant in your garden. I started this column off with tumbleweeds because they are indeed invading the Carpinteria area. All one has to do is stroll alongside Santa Monica Creek to see where they have taken hold near the foothills. If you have a pet that you think would be happier in the wild, remember that pet might eat the native animals that live there. All one has to do is search Asian carp to get a sense of just how out of control one fish in the wrong place can get.
There are many organizations fighting invasive plant and animals around the globe, and I invite you to join in protecting native habitats and helping reduce the risk of potential harm by planting species that are approved in your areas.