Study examines human transport of plant seeds

Article by: Tina Arons
Media Credit: Kat Hilsabeck
Issue date: 10/16/08 Section: La Vida

Experts say plant seeds hitch rides on our shoes like free taxis that take them to places where they may not be welcome.

But how far can they go?

Some may find the answer surprising.

European researchers studied seeds from two wild plants found along a national coastal trail in southern England and they found seeds can ride on shoes for miles.

Matthias C. Wichmann, a lead researcher at the Center for Ecology and Hydrology in Wallingford, England, said in an e-mail that few studies relate to human population density or movement with plant species distributions.

Long distance dispersal has potential for introducing species into new habitats, said Mark McGinley, a professor of biological sciences at Texas Tech.

"If you bring in a new plant, it could compete with the naturally occurring plants," he said, "and it may not be as good of a food source for animals."

Wichmann said studying plant movements may help researchers understand and potentially direct the impact of humans have on seed dispersal, including invasive-plant species and species of conservation interest.

For the study, Wichmann and his colleagues set up experiments in which participants wearing hiking shoes or rubber boots stepped into mud and then into a tray containing a specific number of seeds. Participants walked from about 3 feet to a little more than 3 miles.

Although more than half of seeds fell off their shoes within 16 or 17 feet, researchers found seeds regularly remained attached to shoes after three miles.

Wind generally disperses seeds within an 830-foot radius of their orgin, according to the study.

Scott Holaday, a Tech biological sciences professor, said plant species with seeds that travel away from the parent plant, often called "pioneer" plants, utilize water, wind and animals to travel to new places to germinate.

"They are normally strong competitors with other plants in the area," he said.

Several pioneer plants call West Texas home, Holaday said. Two of the most common are sandburs and goathead, which have sharp, spiny burs.

"These seed dispersal systems have been devised to cling to animals," he said, "and we are just another animal."

Wichmann offered a general rule of thumb: More human movement in an area equates to a greater potential for human-mediated dispersal and all of its associated effects.

Urban sites have higher potential and may often be the first place invasive species appear, but habitat suitability may be limited, he said. National parks and similar habitats often experience high visitor numbers that potentially makes them more susceptible than surrounding areas.

McGinley said human-seed dispersal occurs more easily in places without landscape maintenance.

"Many plants on campus are cut down before they make seeds," he said.

It also depends on the shoes, McGinley said. Footwear with mud in its treads is more prone to transport seeds than flat shoes.

"I think hiking boots would be a classic example," he said.

According to the study, pedestrians may disperse seeds in other ways than walking. They also may facilitate other means of transportation such as cars, boats or airplanes and thus potentially may carry seeds across much longer distances.

"The biggest problem is that we go everywhere now," Holaday said. "The animals of North America don't travel to Europe, but we do. We have the capability of moving things all over the globe, and it's only a matter of whether or not it can grow there."

Source: The Daily Toreador, Texas Tech University

Introducing Lauren Ebbecke, Washington Twp. Alliance's new Vice President

I am pleased to announce that Lauren Ebbecke is joining forces with the Washington Township Alliance to provide much needed professional assistance to our group. I have asked her to take a leadership role so she will become our new “vice president”.

Lauren is a biology teacher with the Wausau Schools and teaches at a local technical college. She has an undergraduate degree in Biology (with particular interest in ferns)and a masters in Natural Resources from UW Steven's Point. She has been active with many, many organizations including Audubon, a Land Trust, and renewable energy initiatives. She is also a successful grant writer.

Lauren will write short articles for our local newspaper give me a lot of help in engaging landowners. She does not live on the Island, but loves it and has visited several times.

I am very excited about this collaboration and feel that it will result in renewed energy for our alliance.

Save the date! Invasive Species Professional Coming to the Island!

Friday, September 5, 2008

If you would like a specialist to look at your land, or if you are interested in working with local landowners in the restoration and maintenance of native landscapes through invasive species control, please attend this event.

Dick Campbell who was recommended to us by Bill Ruff, Door County DNR Forester and Bob Bultman, Door County Invasive Species Team, is coming to the Island to talk with landowners about identifying and eradicating invasive species. He will also do surveys of the Island and give cost estimates to anyone needing the assistance of a professional.

Dick is currently the Owner and General Manager of Invasive Species Control Specialists and Co-Owner of BC Enterprises, Invasive Species Control Specialists both located in Sturgeon Bay. He is a certified and licensed applicator of herbicides to invasive and other plant species and specializes in eradicating invasive species from shoreline and inland areas.

He has an extensive background in education and marketing and comes highly recommended. He has worked with the DNR and World Wildlife.

Please call (535-0235) or email me (cindy.gaskill@yahoo.com) if you would like Dick to survey your property and we will add you to the schedule for the day. At this time of year, if you have phragmities, it will be the first priority. For further information on this plant, the WIFF Resource Center has videos or you may see the video on your computer at http://peaine.org/environment/phragmites/video/.

WFF Resource Center

The resource center which used to be located above Books Up the Road at Mann's Mercantile, is finally almost ready to re-open at the Wickman Farm, 648 Range Line, Washington Island.

There is an outside entrance to this facility which you are welcome to visit. Your comments and suggestions for further development of this resource will be appreciated.

It is expected that it will be fully operational the first part of July 2008.

Welcome to our new community site

Hello...

As many of you know, I have been involved with Wisconsin Family Forests for eight years and have a lot of hope for this organization as a vehicle to good community forestry.

The state organization made the decision to move from a printed version of our newsletter (which I enjoyed publishing for a few years) to a web presence. That is a hard transformation for me, as I know almost nothing about creating a website. However, I am learning something about blogging and think that it might be more appropriate for our community. Everyone can add ideas, etc., and we can operate democratically and capture the power of the whole of the community.

So, I ask your patience as I learn this new medium and welcome your concerns and questions. Scott Reed is going to help me with the parts of this I don't yet understand, and eventually I hope this is a positive addition to community connection and most of all, to the ecology and economics of the Islands.

Cindy Gaskill