Surprising ways you might be spreading invasive species

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Your cottage may not look like it’s in Roswell, New Mexico, but chances are you’ve had at least a few alien encounters. No, not spaceships and little green men—we mean invasive plants and animals that aren’t native to your area but have been introduced and taken hold, with sometimes disastrous results.

You probably know not to plant purple loosestrife or dog-strangling vine, and you’ve probably seen the signs cautioning you not to transport firewood—but there are lots of other ways to spread invasive species without even knowing you’re acting as a carrier. Here are some ways you may be helping the alien invasion.

Not cleaning the mud off your ATVs, bikes, and sneakers

Seeds and plants get stuck in mud, mud gets on your tires or shoes, and then you head somewhere else for a ride or hike. Boom—invasive species, especially tenacious plants like garlic mustard and dog-strangling vine, are spread. Wash your bike or ATV thoroughly before heading to another location, and clean the mud from your shoes once your hike is finished. Ideally, let your vehicles or shoes dry in the sun for a couple of days to make sure you’re not giving a lift to invasive hitchhikers.

Not brushing your dog after a romp in the woods

Same principle as cleaning the mud off your tires or shoes: seeds can be transported on Fido’s fur and feet, helping invasive species spread from one place to another. Wipe off your pooch’s feet and give him a good brushing.

Releasing your goldfish into a pond

Goldfish aren’t native to Canada, and they’ve become invasive nuisances in many waterways, eating fish eggs, larvae, and aquatic plants—meaning they compete with and eat native fish. Although they’re not always able to compete with native fish in a healthy ecosystem, their ability to tolerate poor water quality means they can proliferate in places where the native population is already struggling.

Disposing of bait and bait water improperly

Never release live bait into a body of water—always dispose of bait and bait water on land, at least 30 metres away from the shore. And don’t transport live bait from one place to another: in some provinces, it’s actually illegal to transport some forms of bait overland. Live bait from one region can quickly become invasive in another. If you’ve been boating, dump your bilge water and rinse your livewell before you leave a body of water—bringing water from one place to another is a great way to spread invasive species and harmful pathogens.

Not letting your boat dry thoroughly before moving it

Some invaders, like zebra and quagga mussels, are easy to spot and clean off your watercraft—but some aren’t so obvious. For invisible invaders, it’s best to let your watercraft and any equipment dry in the sun for two to seven days before transporting them to another body of water. Don’t have that kind of time? Cleaning your boat with water over 50°C or with pressurized water over 250 psi can accomplish the same task. If you’re using a personal watercraft, make sure to flush out the jet drive by running the engine once the craft is out of the water and on your trailer.

Dumping aquarium plants into natural waterways

Many popular water garden or aquarium plants aren’t native, and can become invasive in local ecosystems. If you’re getting rid of water plants, leave them to dry out in the sun or freeze them, then dispose of them in the garbage or in your local green box program. And when you’re purchasing plants for an outdoor water garden, make sure to check to make sure you’re not buying an invasive species unknowingly.

Composting invasive plants

If you do find invasive plants in your garden, don’t simply add them to your compost pile, and don’t include them in your yard waste bag—invasive species can spread even if they’ve been uprooted. Instead, put uprooted plants in a black plastic garbage bag and leave them in the sun for two days. This will make sure the plants can’t sprout any new roots and grow elsewhere.

Moving plants from your city garden to the cottage

Moving plants around from one area to another isn’t a great idea—what might stay under control in one area might become invasive in another. Work with a reputable nursery to select native and non-invasive species to ensure your garden stays healthy and as biodiverse as possible.