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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

Natural shoreline vegetation preserves open spaces and beach recreation. © DNR Photo
Natural shoreline vegetation preserves open spaces and beach recreation.

© DNR Photo

August 2007

Beauty and the beach

Some find it unsightly, but scrubby vegetation is the foundation upon which a beach is built.

Kristy J. Rogers


Beach behavior

The eve of the fall's first snowfall hardly seemed an ideal time for a stroll on the beach, but there they were, the city manager, the city recreation director, state legislators, prominent business owners, city council members, representatives from the parks board and a DNR lakeshore supervisor walking the Lake Michigan shore at Two Rivers. The cold wind whipped past blowing sand and scrubby vegetation on Neshotah Beach, but they were talking about sunshine, lakefront festivals and summer tourism.

Lake Michigan levels have remained low for several years, and a permit first issued four years ago allowed the city to groom 1,156 feet of the public beach running along State Highway 42. Due to low water, more than 2,000 feet of beachfront was exposed at least 300 feet wide. In these low water conditions, the city saw opportunity.

People come to the coast in summer to feel the breeze, fly kites and see the sand, contended Two Rivers City Manager Greg Buckley. The city wanted its permit extended to groom the entire length and full width of the exposed lakefront to remove "unsightly" weeds. This is hardly pristine beachfront, Buckley said. If we don't groom the entire beach and remove the vegetation, it gives the impression that we don't have enough community pride to care for our beach. If people want to see "natural" beach, they can drive up the coast a few miles and go to one of the state properties like Point Beach.

Kelley O'Connor, the DNR Lakeshore Basin Supervisor who oversees several hundred miles of Lake Michigan and Green Bay shoreline, explained how the beachfront serves an important purpose: Plants like rush and bulrush anchor the sand, stave off shoreland erosion and buffer the nearshore area from the erosive forces of wind and water, she said. Moreover, the huge expanses of lakebed exposed as the water recedes is public property, held under the Public Trust Doctrine for public benefit. The whippy clumps of beach grasses (called "marram") stabilize the shore, protect against floods and reduce the amount of sand blowing into nearby parking lots, concession stands and roads.

The local state senator and representative weighed in, backing up their constituents' desire for a tidy, well-groomed beach.

Noted wetland ecologist Don Reed, who was in the Two Rivers area at a Nature Conservancy meeting, read about the beach grooming debate in the newspaper. On a walk down the same beachfront the next day, he identified several threatened and endangered species of beach vegetation that he noted in a letter of support for protecting the area from more intensive grooming.

For several years lower water levels in Lake Michigan, Green Bay and Lake Superior have left both private and public lakefront property owners like the City of Two Rivers with additional beachfront. Piers, moorings, docks, boat launches, public swimming and play areas extend farther from the shoreline to the water when levels drop, but low water levels also present an opportunity to do shoreline repairs.

Nature has wasted no time in claiming many of these newly exposed areas. Vegetation has quickly taken hold and, in the case of Lake Michigan, sand dunes have begun to form. As the vegetation thrives and the dunes rise, the calls from lakefront property owners like the City of Two Rivers increase.

"During the summer, I received 10-15 calls per day," said Mike Hanaway former DNR water management specialist. "All the questions centered on a common theme – What can I do with the beach?"

In terms of what is best for the natural ecosystem, the answer is: "Do nothing." Unfortunately the question isn't that easy or simple. Well-meaning people want different things from the shoreline. Some want a clear, smooth path where they can walk barefoot along the water; others seek an unobstructed view of the lake. The City of Two Rivers desires a beach that will draw people to community events. Still others want a beachfront free of exotic invasive grasses like Phragmites and loosestrife.

Beach grooming loosens the soil but can also seal in bacteria. Courtesy of City of Racine Health Department
Beach grooming loosens the soil but can also seal in bacteria.

© Courtesy of City of Racine Health Department

No matter the reason, the decision to mow, grade, groom or otherwise manipulate the beach should not be taken lightly. Recent studies by coastal ecologists at Michigan State University in East Lansing and Grand Valley State University in Allendale, Mich. explain some of the consequences of changing the natural processes by which plants colonize a beachfront:

  • Clearing a swath of vegetation through a coastal marsh produces a fundamental change in the chemical and physical conditions in near-shore waters. These changes negatively affect the larval forms of important game fish, reducing or eliminating habitat for species including yellow perch, smallmouth bass and largemouth bass.

  • Adult fish netted adjacent to undisturbed areas were present in greater numbers and greater varieties than adjacent to "groomed" areas.

  • Invertebrate communities upon which fish depend for food and nutrient cycling were reduced by vegetation removal and grooming. The number of individual organisms collected adjacent to undisturbed beaches was 29 times greater, on average, than adjacent to raked or cleared areas.

  • Beach grooming and repeated mowing rapidly destroys stands of ecologically important plants such as the naturally deep-rooted and long-lived rush and bulrush, which serve to anchor underlying sand and soil.

  • The removal of vegetation increases the movement of sand and erosion of shoreline areas.

One of the most pronounced changes in the past five years can be seen on the western shore of Green Bay. Low water levels have promoted the growth of submergent plants (species that grow completely underwater) and emergent plants (species that grow underwater and extend above the surface). Both types of plants provide critical nursery habitat for fish that need to find shelter in extremely shallow waters, such as yellow perch and minnows.

Mike Hawley, DNR fisheries technician, has been conducting surveys using seine nets in the shallow waters along the western shore of Green Bay for the past 20 years. "The past few years we have seen a huge increase in the number of young-of-the-year yellow perch and minnow species found in our seine surveys and that is really encouraging," he said. "There are many factors that can influence fish populations, however I feel very strongly that this recent population boom is a direct result of the increased vegetated habitat."

Fish are not the only critters that benefit from the new habitat provided by lower water levels. Frogs and turtles, aquatic insects, muskrats and shorebirds all rely on these areas. When the water levels rise on the new vegetation, aquatic invertebrates thrive, providing a wonderful lunch for fish, frogs and shorebirds.

"Shorebirds feast on the aquatic invertebrates that become exposed when the water recedes," says Jeff Pritzl, the regional wildlife biologist in DNR's Northeast Region. "The real benefits for the shorebirds will come down the road, when the water levels increase and flood the new vegetation." When the water rises, more food grows amid the shallow plant life, and shallow protective cover forms. The sand dunes along Lake Michigan also provide unique habitat for several rare plant species.

"When Lake Michigan was high in the 1990s much of the beachfront dune habitat was destroyed," explains Carolyn Rock, naturalist at Whitefish Dunes State Park near Sturgeon Bay. "The lower water levels have allowed the frontal dunes to re-form and the vegetation to again flourish, but there are still plenty of places for swimmers and sunbathers to play near the water and relax on the sand."

Protecting rare species and habitat unique to our inland coasts has become a primary goal at Whitefish Dunes. Beach grooming has been reduced to help achieve this goal. Point Beach State Forest near Two Rivers has taken a similar approach to preserving shoreline habitat by completely eliminating beach grooming activities and promoting educational programs on natural dune creation processes.

If you have ever had sand blown into your eyes during a walk on the beach, or had to shovel sand off of your patio, then you can appreciate the benefits natural beaches provide for people. Beach vegetation is the most critical defense against sand erosion. It works in two ways. First, the roots hold the sand, anchoring it from underneath to stop it from blowing or eroding away. Second, the blades or leaves block and catch blowing sand. The accumulating sands create sand dunes. When the water level rises again, the dunes and vegetation protect the shoreline from erosion and flooding. Without dunes and dune vegetation, the soils that support buildings and roads near the shore would be washed away at a faster rate.

Beach vegetation also filters out and absorbs stormwater nutrients flowing toward the lakefront. By soaking up nutrients in runoff, beach plants and grasses help eliminate the food source for Cladophora – a truly stinky algae that grows in large mats and washes up on the shoreline. Once you've caught a whiff of decomposing Cladophora during a stroll on the beach, you won't forget it.

Phragmites, an exotic, reedy grass that grows in dense stands more than six feet high, crowds out other plants and colonizes disturbed areas, especially beachfronts that have been groomed. It grows thick and tall, eliminating the ability of natural vegetation to grow and thrive. It is also an eyesore, blocking lakefront views and inhibiting access to the water. "Once Phragmites has invaded it is very difficult to remove or control," says Bob Bultman, Door County invasives species coordinator. "Healthy natural vegetation is your best weapon against Phragmites."

Whenever the prospect of beach grooming is raised, it's worthwhile to remember that plant-free, groomed beaches come at a price – a price even the wealthiest communities cannot afford to pay. Look instead at the benefits the newly vegetated areas bring to fish, birds and humans living along the shore.

Kristy J. Rogers is the aquatic habitat coordinator for DNR's Northeast Region in Green Bay.

Beach behavior
What can you do to help protect natural beachfronts? Here are a few ideas to help you save our shores:
  • Reduce your footprint when visiting beach areas: Do not trample fragile beach grasses. Stay on marked paths. Do not feed the wildlife. Don't litter. Do not drive on the beach. Besides being illegal, it's terribly destructive.

  • Learn more about the value of natural shoreline vegetation, and discuss with your neighbors the benefits natural shorelands can bring to your community. Beach vegetation stabilizes the shore, slows flooding, filters runoff, provides nurseries for fish, birds and aquatic invertebrates, and stems shoreline erosion.

  • If you are a shoreline property owner, set a goal of restoring or protecting your shoreline so that at least 70 percent remains in a natural state. Keep piers, boats and the removal of vegetation to one area that is 30 percent or less of your total shoreline frontage. Please be aware that there are specific standards for vegetation removal, pier placement, etc. For more information, contact your local lakeshore association, find out about local ordinances and get involved in lakeshore restoration projects.

  • Work with local conservation groups, state park friends groups, nature preserves and neighbors to fight the spread of invasive species. Many groups hold work days to remove invasives and educate people about the disruptive presence of these plants in the environment.

  • Before altering shorelines or grooming beachfronts, contact your local DNR water management specialist to determine which activities require permits. You should also contact local zoning offices or town officials to find out if permits are required or if local expertise is available to guide your proposed renovations.
Under emergency rules adopted by the Natural Resources Board in June 2007, people who own beachfront property on the Great Lakes can get general permits to remove nuisance level deposits of algae, mussels and dead fish during the summer of 2007. The board reacted to complaints of increased populations of invasive species like zebra mussels and quagga mussels as well as blooms of the algae Cladophora. The general permit has a $50 application fee and is processed in less than 30 days.

Under the emergency rules, removals are limited to plant and animal nuisance deposits in the "swash zone" where wave action cycles on the beach. Total amount of material removed is limited to 3,000 cubic yards and equipment used to skim the deposits off the top of the lakebed must minimize impacts to the lakebed and surrounding vegetation. Contact Martin Griffin, DNR water regulation and zoning specialist, (608) 266-2996, for more information.