Invasive Species in Our Lives

by John Cawood

Illustration: Lolium temulentumCrown vetch. Phragmites. Garlic mustard. Buckthorn. Spotted napweed. Reed canary grass.

Ask a restoration ecologist in Illinois, “How’s your summer going?” and you are likely to hear about some of these pests. We call these invasive species – organisms that are brought to a new area, often by humans, and take over quickly. In the plant world, invasives grow quickly and crowd out the native plants, like orchids, trillium, purple cone flower, and baby oak trees. Some plants poison the soil so other species cannot grow, and some produces 10s of thousands of seeds.

And it’s not just plants. The brown headed cowbird lays its eggs in the nests of native birds – its unhatched offspring replacing the unhatched offspring of the native birds. Today you are likely to hear about the voracious big-headed carp knocking on the doors of the Great Lakes – which were fundamentally changed in the 90s when zebra mussels and quagga mussels were accidentally introduced by passing freighters. Or the emerald ash borer decimating hundreds of thousands of Midwest ash trees.

Ecologists around the world are constantly in battle with these invaders, pulling weeds, shocking fish, chopping infected ash trees, and creating new bird habitat. But mostly pulling weeds… In pockets they are successful. In order to achieve success, constant attention must be provided to these areas. In our forest preserves and our Chicago parks we are fortunate to have site stewards who volunteer their time to do this work – removing acres upon acres of invasive species – in order to allow natives to prosper.

Successful invasive species management can be difficult to achieve, and even when it is achieved it must be justified. One of our favorite stories has to do with Mayor’s Native Landscaping awards, formerly given to dozens of Chicago residents every year for planting native prairie plants in their yards.

Then, along came the city’s Streets and Sanitation officers who cited several awardees for violating the city’s weed ordinance, with tickets around $600. They saw the tall, billowing prairie grasses as weeds! The ironic miscommunication has since been resolved, but it’s a good illustration of differences in perception about what a weed actually is. For example, a golden, ornamental daffodil would not be welcomed in the middle of a tallgrass prairie!

Invasives are prevalent in landscapes across our region, and around the world. Generally it takes many dedicated souls to keep them under control, and even after they are under control we need to answer the why question.

Throughout August, we'll be drawing parallels between managing invasives in nature and managing invasives in our lives. Check out the schedule of diverse indoor and outdoor events for restoring ourselves, our communities, and our planet.

Jesus told a parable about invasive weeds (cheatgrass) taking over the wheat fields. Nanette wrote a commentary on it over at Question the Text: The Cheatgrass Is In Us