Aggressive plants take over

By Tim Scordato

Invasive species are crowding, competing with and destroying DeKalb’s native flora and fauna.

There is a growing concern among the local community about the effects of these dangerous plants and animals.

Biology graduate student Allison Sacerdote is studying the effects of the invasive plant buckthorn (Rhamnaceae) in the area.

Common Buckthorn is a tree or shrub with dark green foliage and small black berries. It’s named after its small spiny twigs that branch out to imitate thorns. It can grow up to 25 feet and was brought over from Eurasia for ornamental purposes.

The plant then spread through the Midwest, terrorizing native species through physical and chemical means.

Aside from out-competing other plants for resources, the plant produces poisonous berries. They work as a laxative on animals feeding on them.

When the plant colonizes a certain area, animals such as the local birds will have no other food sources to choose from.

The birds will repetitively eat the berries and soon excrete them until the birds eventually starve and the seeds from the berries are sufficiently spread, Sacerdote said

Sacerdote said the plant secretes a chemical from the stem and leaves, which acts as endocrine disrupters for animals such as the salamander.

She is studying the effects of this harmful chemical on the blue-spotted salamander and frog population at MacArthur Woods Nature Preserve and Ryerson Conservation area in Lake County.

The plant seems to harm the growth and production of the salamander eggs and also alter the sex of the native frogs, she said.

Sacerdote said one of the best ways to destroy the plant is to chain saw through the stump and diligently apply the herbicide Garlon 4 (triclopyr ester) to the open wound.

However, others are researching more natural methods of dealing with invasive species.

S. Raghu from the Natural History Survey in Champaign is researching the relocation of natural predators for another Midwestern problem plant, garlic mustard (Alliaria petiolata).

He said he would like to see the introduction of the Ceutorhynchus, a species of weevil, in the Midwest to resolve the garlic mustard overpopulation problem along forest floors. However, the insects are still being tested for observable damage to other native plants and are awaiting USDA approval.

Associate professor of biology Carl Von Ende said reed canary grass (Phalaris arundinacea) is another highly populated invasive species in DeKalb.

Farmers use the grass for hay in domestic settings, but the grass grows rampant in wild marshlands or on creek banks. It is destroying a variety of plants and taking over as a single alpha species.