What’s happening

Invasive species are any species (plant, animal, seed or even spores) not native to where they’ve landed. Generally an invasive species spreads quickly and aggressively. This can have a big impact on the ecosystem it’s been introduced to. The many cycles and systems in a habitat are in place to create balance between all the living things in that ecosystem. When an invasive species is introduced, it can upset the natural balance and lead to unintended consequences. A 2017 study in the journal Nature Communications found that over one third of all introductions in the past 200 years occurred after 1970 and the rate of introductions is showing no sign of slowing down.

The more we travel, and the more our economies are interdependent, the more invasive species are able to hitchhike to another place. Areas of our economy like horticulture, aquaculture, agriculture, tourism and commerce are all ports of entry for our uninvited guests. Insects can hide in lumber, pallets and crates and cause massive destruction, like the notorious emerald ash borer. Many aquatic invasives come from ballast-water, nets or on the bottom of boats, and imported plants can bring insects and seed-and-berry escape artists. Japanese Knotweed is so invasive that cutting it down and burning it still doesn’t get rid of it! Watch out if you go to Florida, the unintended release of the Burmese Pythons has allowed them to grow in population there!

What are the effects?

Invasive species are one of the biggest causes of loss of biodiversity and extinction.^[2] In the case of the Burmese Pythons in the Everglades, their presence has been devastating to wood storks and woodrats, both endangered species.^[1]

Generally an invasive species doesn’t have natural predators or controls. With nothing stopping the invasives from taking over, the native wildlife doesn’t have any defense and cannot out-compete it. Competing for food, water, and shelter, invasives that crowd out the natives can actually change the food web making them a “global threat to food security and livelihoods.”^[3]

Climate change is making the problem bigger.^[4] Changing weather patterns and habitats make it more hospitable for species to live in areas they’ve never been able to live in before. We can see this in the increase in Lyme-carrying ticks that have traveled further north and no longer have long winters keeping them at bay. A study in Canada found that mosquito-borne diseases have increased 10% as mosquitos that carry these diseases have increased their range and numbers due to climate change.^[5]