Invasion USA

Almost halfway through the week, I was informed that this is National Invasive Species Awareness week. To celebrate, I pulled yellow archangel, a spreading ground cover on Saturday morning. Invasive species are exactly what they sound like- species that invade an area they are not native to. They can damage an ecosystem and also cause economic harm.

Yellow archangel, named for its yellow flower (not shown- it's January)

Several crop pests, like the stinkbug, cause millions of dollars of damage to produce annually. It hails from Asia and was first spotted in the US in Allentown, PA, near my home at the time. I was living in stinkbug Ground Zero, which explains why I had a house full of these strange bugs I’d never seen before.

Stinkbug (courtesy Rutgers University)

Since this is Nature Minute and not The Economist, we’ll focus on ecosystem damage caused by invasives. Invasive species can be anything. In my outdoor rambles I’ve come across invasive birds, amphibians, and plants. Each can negatively impact an ecosystem in its own way. Though they don’t belong, they are able to thrive in absence of a biological control.

The American bullfrog is an introduced species in the Pacific Northwest. We will probably never get rid of them here. They have a voracious appetite and will just about anything that fits in its mouth. That includes the tadpoles of native amphibians. Lucky for us, great blue herons enjoy a nice fat frog.

American bullfrog

Scotch broom, my mortal enemy, is one of many invasive plants I work to eradicate from my conservation property. It is the devil’s weed, coming in the form of a shrub (or tree if it goes to old growth) which crowds out other plants that native animals eat. The animals could browse on Scotch broom if they wanted to, but it contains toxins. On the plus side, as a legume, it fixes nitrogen in the soil. However, most plants here are adapted to lower nitrogen soil and can suffer from an excess of it. The most effective (and time-consuming) way to eliminate Scotch broom is by hand. But take don’t rejoice over that cleared area too much; seeds remain viable for decades so removal requires vigilance.

Forest of old growth Scotch broom

Other problematic invasive species include Asian carp in the Mississippi River, nutria (a rodent of unusual size) in Louisiana and the Northwest, Himalayan blackberries everywhere, feral pigs and kudzu (a Japanese vine) in the South, zebra mussels in freshwater nationwide, and pythons in the Everglades.

Rodent of unusual size- nutria (courtesy of The Last Word on Nothing)

Kudzu swallowing a house (courtesy of Smithsonian Museum of Natural History)

Check with your state Agriculture Department to see what invasive species are near you. Remove what you can and check guidelines for preventing their spread.

Rutgers University: https://njaes.rutgers.edu/stinkbug/identify.asp

The Last Word on Nothing: http://www.lastwordonnothing.com/2014/08/11/snark-week-evil-has-a-new-name-and-buck-teeth/

Smithsonian Natural History: http://nmnh.typepad.com/the_plant_press/2014/05/china-expedition-2013-a-tale-of-typhoon-tossed-kudzu-by-ashley-n-egan.html