Overseeding prairie and savanna remnants

This post is concerned not with new plantings, but with planting remnant prairies or savannas that have become heavily degraded with invasive shrubs. The first two phases in the restoration of such sites are:

1. Clearing the brush by cutting and treating
2. Burning after clearing, preferably annually for at least 5 years. Either spring or fall burns can be done.

Those two phases should never be reversed. Burning before clearing will top-kill brush, but will not eradicate it, and the dormant root-stock will send up one or many resprouts.

In the growing season after the first burn the understory flora of the site should be monitored carefully and a species list developed. Since the site has been degraded, there will likely be a rather impoverished flora. This is why overseeding (sometimes called interseeding) is recommended. Planting should be done soon after the site has been burned. Fall burns are preferable because many species require a cold, moist treatment in order to germinate. However, if the site must be burned in the spring, planting can still be done, provided the burn has taken place early enough.

The seed mix should reflect the native flora of the area being restored. The mix should contain as many species as can be obtained, either by collecting from nearby sites (recommended), or purchased. At least 50 species should be used, including both forbs and grasses. NRCS recommends a very dense seeding rate. "For instance, if the seed used was hand-collected from a local source, the NRCS specifies a minimum seeding rate of 50 seeds per square foot. An additional provision is that the seeding rate should be adjusted so that no single species amounts to more than 20% of the seeds in each square foot. NRCS also specifies that at least 25 seeds per square foot must be native grasses or sedges and at least 5 species of grasses and 15 species of forbs and legumes must be seeded. These criteria are applied by NRCS for both prairie and oak savanna restorations.

Note that the number of species given in the previous paragraph is a minimum and great effort should be expended to plant more species. If only small amounts of hard-to-get species are available, then they should not be placed in the general seed mix, but hand planted separately in suitable parts of the savanna." Quoted from http://oaksavannas.org

Since these recommendations are for prairie plantings on bare ground, they are higher than needed for overseeding, However, the higher the seeding rate, the better is the chance of success,

Details on planting oak savannas, including seed mixes suitable for Midwest habitats, can be found at the following link: http://oaksavannas.org/seeds-planting.html

Because many species take quite a few years to become established from seed, don't expect great results the first year or two. In fact, some species may not sppear as flowering plants for 5-7 years. Also, warm-season grasses  usually take three years to become established. Because of this, repeating the overseeding several years running is a good idea.

Several factors will affect the success of overseeding. The germination rate of hand-collected seed can vary widely from species to species and for the same species from year to year. Also, growing conditions will be strongly affected by the weather, especially by temperature and rainfall. If planting is done in a drought  year, it must be repeated the following year.

One of the interesting things about overseeding is that species will sort themselves out with time. This is not surprising, because most natural area sites are heterogeneous, with dry, dry-mesic, mesic, and wet-mesic parts. Thus, if Echinacea pallida is planted uniformly over the whole site, four or five years down the line it may be found primarily in the dry-mesic areas, because this is where it competes best with the rest of the flora.

Some thoughts about restoration ecology

Restoration ecology is quite a new discipline.

I did a search of the principal scientific journals (using JSTOR) with the Search term “restoration ecology” . The first “hits” (4) were in 1984 (all insignificant), 3 in 1985, and 5 in 1986. A brief report of a symposium on Restoration Ecology was published by Aber and Jordan (Restoration Ecology: An Environmental Middle Ground; BioScience Vol. 35, page 399). The term  Restoration Ecology started to become widely used after a 1986 symposium on the subject held at the UW-Madison Arboretum. It was after that symposium that the journal “Restoration and Management Notes” (now called “Ecological Restoration”) was established at the Arboretum by William Jordan. The Society of Ecological Restoration itself arose out of that same symposium and became “official” in 1989.

There are now a number of universities across North America that offer  degrees or programs in Restoration Ecology. Interestingly, few of these are what might be called “major” or “research” universities.

When I thought about Restoration Ecology as a “discipline” I thought immediately of the widely cited quote of Louis Pasteur: “There are no applied sciences, but only applications of science.” (Ils n’existe pas des sciences appliquées, mais seulement des applications de la science.)

More simply put, the restoration ecologist is dealing with the applications of plant ecology, a basic science (and a branch of botany).

If I were a student starting out and interested in restoration ecology, I would not enroll in a department or program in Restoration Ecology. Rather, I would look for a university that had a strong program in botany with advanced courses in plant population ecology and plant physiological ecology. I would also look for a university that offered or supported summer internship programs that would give me the chance to get out in the field and do “hands on” work. While I was working in the field (probably pulling weeds), I would be thinking about the basic science related to the plants I was seeing.

Whether I stopped with a Bachelor’s degree, or went on for a Master’s or Ph.D. would depend on my goals and on my abilities.  If I wanted to do research, I would not stop at a Master’s, but get a Ph.D. I would look for a professor who would give me a good basic research problem in plant ecology, preferably with an herbaceous plant.

My 60-year’s experience in science may be of some use here. I was a botany major as an undergraduate, and I spent the summer after receiving my B.Sc. degree  at the Ohio Agricultural Experiment Station in Wooster, Ohio, where I was able to associate with all sorts of field workers. Although my graduate work was in basic science, I never forgot my field experiences. Later, when I decided to work in microbial ecology, I was quite comfortable out in the field. 

Invasive sandbar willow in a wetland

Now that we have invasive brush mostly under control in our upland sites, we are starting to do some  work in our wetlands. Unfortunately, the habitat and the species are different in the wetlands, requiring new approaches.

Although we have found scattered buckthorn and honeysuckle in the wetland, the principal woody plants have been several species of willows. Some, such as pussy willow (Salix discolor), are benign, even desirable. However, the sandbar willow (Salix interior) is another matter. It forms large, dense clones that crowd out any other species. A scan of the literature brought up no control articles, but a lot of work on how to get this species established in order to stabilize stream banks and other erodible areas. Thus, when we started to work on sandbar willow we were starting from deep ignorance.

Except for the burns, most of our work is done in the winter, when cold weather provides a firm footing. Most of the sandbar willow stems are of fairly small diameter, so that a brush cutter can usually be used. All cut stems are treated with 20% Garlon 4 in oil, which is our standard procedure for upland shrubs.

Although this procedure  killed the dormant buds of the cut stems, we were ignorant of the fact that this species of willow root suckers prolifically. By late summer the clones were bright green with new shoots, as the photo below shows.

The bright green is due to a large number of root suckers in a sandbar willow clone that had been cut and treated.

I felt rather foolish, because we have had a lot of experience dealing with other root suckering species (aspen, sumac), and I should have anticipated this. Well, nobody told us either.

Now that we know about root suckering, we can also predict that prescribed fire will be ineffective in eradicating this species. The photo below shows a clone just after prescribed fire in April 2013. The fire effectively top-kills, but the roots, of course, are unharmed. In fact, running fire through these clones may be exactly the wrong thing to do. The second bright green patch in the photo above is probably a willow clone that was burned in our 24 April 2013 spring burn.

Clone of sandbar willow just after a prescribed burn. The fire burns primarily around the edges of the clone, since because of shading there is less fuel in the center.

To eradicate root-suckering aspen, girdling is the solution. However, girdling a large, dense clone of sandbar willow would seem to be a daunting task! Any suggestions?

Summer 2014 internships in restoration ecology

The Prairie Enthusiasts has just announced their summer internship program. As an added attraction, new sites  have been added in northwestern Dane County.

Six internships in restoration ecology will be available through The Prairie Enthusiasts in the summer of 2014. Work will be carried out at several outstanding Wisconsin prairie and savanna sites in western Dane County and eastern Iowa County.

These are full-time positions for 12 weeks (8 hours a day, 5 days a week) from Tuesday May 27 through Friday August 15, 2014 and pay $10.25 per hour. Those interested should be in college at least at the sophomore level and have a demonstrated interest in restoration ecology or rare species and ecosystem conservation. Also desirable is a major in a field related to restoration ecology such as biology, botany, conservation, forestry, environmental studies, environmental engineering, zoology, wildlife, or soils. Applicants must be able to perform sustained physical work outdoors. A valid driver’s license is required.

Sites: The Empire-Sauk chapter of the Prairie Enthusiasts manages a number of high-quality sites in western Dane County and eastern Iowa County near the villages of Black Earth, Mount Horeb, Mazomanie, and Barneveld. These include remnant and restored prairies, oak savannas, oak woodlands, and wetlands.

Work: The interns will be working together as a team. As an intern in this supervised practical experience, you will spend the summer outdoors where you will learn by doing a number of tasks in broad-scale landscape restoration and management, including work in prairie, savanna, woodland, wetland, and cold-water stream habitats. The primary focus of activities is the control of invasive species, but some time will be spent on seed collecting and planting, plant ecology and identification, seed orchard maintenance, fencing and boundary posting, and endangered species monitoring. The internship will give you the opportunity to become familiar with both native and alien plants, and many specialized grassland and savanna insects, amphibians, reptiles, birds, and mammals.  You will also learn from professional ecologists and experienced practitioners in restoration about the conservation significance and goals of the various preserves, the habitat needs of rare and declining species, and a variety of restoration techniques, strategies, and philosophies that are employed at these sites.  Some use of power tools and herbicides will be involved.

Interns are responsible for their travel, housing, and other living expenses, and are encouraged to carpool between residence and worksites. Sturdy work boots, gloves and clothing, as well as sun, rain, and insect protection are required. All tools will be provided. Academic credit may be available for participation in this program; each intern is responsible for making academic credit arrangements with her/his university.

How to Apply:      The application deadline to ensure consideration is Friday, February 21, 2014. Apply by email to kmbrock@charter.net. Please include a cover letter describing your background and interests, plus a resume which contains details of relevant college course work and previous work and volunteer experience. Be as detailed as necessary to describe your background, interests, and what you wish to gain from this internship. Your application should consist of a single computer file and your last name should be the first word of the file name.

Summer 2013 Prairie Enthusiasts interns

Webinar on role of fire in oak woodland and savanna is now "live"

Gregory Nowacki’s important webinar is now “live”:

Oak, Fire, & Mesophication

Past, current, and future trends of oak in the eastern United States

This is an important overview on the role of fire in oak woodland and oak savanna restoration and management.

Here is the link: http://www.oakfirescience.com/webinars/

The webinar is hosted by the Oak Woodlands and Forests Fire Consortium