Teasel control in a sedge meadow

The Skokie Lagoons bird monitoring team - Linda G., Mary Lou M., and Dolph W. - has struck again. These citizen scientists have made careful observations at key areas of the Skokie Lagoons preserve for years. This spring, though, they were dismayed to find that one of their favorite locations on their monitoring route had been invaded by teasel, a nonnative, invasive plant that is capable of crowding out all other vegetation. The sedge meadow area (north of the Willow Road parking lot) that had been formerly productive for shrubland birds was becoming disappointing birdwise, and the teasel invasion was a likely culprit.

The bird monitoring team took the initiative to contact the humble volunteer site stewards (including yours truly) and Forest Preserve District of Cook County (FPDCC) staff to make sure that the sedge meadow was included in the 2010 Skokie Lagoons management plan. With the stewards' enthusiastic approval, the bird monitors went on the offensive in July, braving the summer heat and humidity to cut the seed heads off the mature teasel plants and remove the stalks. In some areas, the prickly teasel stalks were taller than the volunteers!

Teasel towers over bird monitor Linda during a removal workday. Photo courtesy of Mary Lou.

On July 20, the FPDCC brought in the big guns: their contractor, Tallgrass Restoration, applied herbicide to teasel plants over the whole sedge meadow area. Within two weeks, much of the teasel was dying. Volunteers, including a local Boy Scout troop, continued to work to remove the dead stalks and to pull any new growth. Now that much of the teasel is gone, the meadow is already showing visible signs of recovery - some amazing wildflowers are emerging.

Teasel has a two-year life cycle, so the area will require continued work and monitoring. The plan going forward is to target the first-year growth of teasel (the low-to-the-ground rosette form) with herbicide this fall to preempt next spring's growth. By herbiciding in the fall, collateral damage to next spring's native plants is avoided. Linda and Dolph have obtained their herbicide operator and applicator licenses from the Illinois Department of Agriculture to help keep the program going (under the stewards' supervision, of course). The war on teasel is not yet won, but it's definitely moving ahead.

Red-headed woodpecker at Skokie Lagoons

We just got word from the Skokie Lagoons volunteer bird monitoring team - Linda G., Mary Lou M., and Dolph W. - that a red-headed woodpecker has been spotted visiting a nest hole at the Skokie Lagoons. This handsome woodpecker is classified as a bird of high regional and national importance because it has experienced major population declines due to lack of appropriate breeding habitat. This fine specimen was seen in a meadow area near Tower Road where volunteers have been clearing invasive brush for several years.

photo courtesy of bird monitor Mary Lou

The hard work done by habitat restoration volunteers in clearing the meadow of buckthorn and other overgrowth created a perfect nesting area for this important species, which is known to prefer recently cleared areas and dead barkless trees for nesting. It's hoped that the pair were successful in fledging their young and that they will come back next year. This is a big feather in your cap, volunteers!

UPDATE: Judy from Audubon - Chicago Region informs me that the red-headed woodpecker pair at the Skokie Lagoons is believed to be the only pair currently nesting anywhere in the forest preserves along the North Branch of the Chicago River in Cook County. This makes their presence that much more exciting!

Chicago River Day 2010

Saturday, May 8, was the annual Chicago River Day, sponsored by Friends of the Chicago River. Since the Skokie Lagoons are part of the Chicago River system - they are impoundments of the east fork of the North Branch of the Chicago River - we were pleased to host a group of eager River Day volunteers in addition to our regular crew.

It is springtime at the Lagoons, and that means it's time to pull garlic mustard as it sprouts. Garlic mustard (Alliaria sp.) is a small herbaceous plant native to Eurasia. As European settlers arrived in North America, they brought with them a variety of familiar plants from their old homelands. Garlic mustard can be eaten in salads or used as a cooking herb. As the name suggests, it tastes like garlic. While it is tasty and features pretty white flowers in the sprintime, garlic mustard is an invasive plant - it spreads rapidly, especially in disturbed areas such as road and trail edges, and crowds out native plants. Like European buckthorn (Rhamnus cathartica), another Lagoons invader, garlic mustard creates a monoculture where it grows. That means that only one species - garlic mustard - grows in a particular area. A healthy woodland will have a wide diversity of plant species on the forest floor. While the monoculture forest floor will look green, it is not a healthy community. Few, if any, native North American species will eat garlic mustard.



However, like buckthorn, garlic mustard can be controlled and removed through focused stewardship efforts. The key is to pull it in the spring, before it goes to seed. Garlic mustard is easily identified based upon its tall shoots, distinctive serrated leaves, small white flowers, and garlicky odor when the leaves are crushed.


On River Day, we pulled enough garlic mustard to fill fifteen large garbage bags! The aftermath is shown at left. We'll continue to monitor the area for resprouts so the restored section will remain clear of garlic mustard.

Why we burn brushpiles

Why do we burn brushpiles after we cut buckthorn and other invasive plants? There are several good reasons.

1. It's really fun.


2. Brushpiles are an eyesore, and burning allows us to dispose of them without running noisy wood chippers (also, we'd still have to dispose of the chips somehow).


3. Decaying buckthorn changes the chemistry of the soil on the forest floor.

I think (1) and (2) above are self-evident, but let's look at (3) for a moment. It turns out that buckthorn litter decomposes faster than native plant litter, and that this decomposition increases the carbon and nitrogen levels in the soil. Now, farmers and backyard gardeners know that nitrogen compounds are important for plant growth, so one might think that the binding of additional nitrogen in the soil would help plant growth. However, it seems that in Chicago-area woodlands, the additional nitrogen and other changes in soil chemistry actually prevent native plants from colonizing the area, effectively favoring the growth of nothing but more buckthorn. Yikes! I've also heard that buckthorn contains a toxin that prevents other plants from growing nearby (this phenomenon is called allelopathy), but I haven't been able to find a literature reference for this.

So, to prevent brushpiles from becoming eyesores, to keep excess nitrogen out of the soil, and to enjoy the crackling of the fire during our workday breaks, we burn brushpiles.

Reference:

Heneghan et al. (2006). "The invasive shrub European buckthorn (Rhamnus cathartica, L.) alters soil properties in Midwestern U.S. woodlands." Applied Soil Ecology 32:142–148.

Owl pellet

What's full of bones, kind of gross, and really interesting? An owl pellet!


Owls swallow their prey whole, and what they can't digest - hair, feathers, bones - they regurgitate in a neat little package. We found this one by the Tower Road boat launch during our workday.