Dune Ecology

June 23, 2018


 

Kitchel Lindquist Hartger Dunes near Grand Haven Michigan and in Ferrysburg, Michigan

The high wooded dunes rise above the Grand River, as they have for several thousand years, a part of the landscape both residents and tourists in the Tri-Cities area enjoy.    For a closer look, people can follow a self-guided nature trail through the dunes.  On Earth Day, the community pitches in and picks up debris blown into the dunes by the winter winds.  It’s a favorite place for people whether they simply look at it as a familiar part of the landscape, or use it for walking or cross country skiing in the winter for it abounds in wildlife, grasses, flowers, and trees. It’s a good place to study the lessons of ecology.

These Dunes, near the shore of Lake Michigan and on the north bank of the Grand River are a gift from the river and the west wind; water and wind currents carried sand deposited by Ice Age Glaciers 4,000 years ago.  It is a perfect place to study how a dune land changes over decades, centuries, millennia.  It is a good place to observe dynamic changes from  season to season, and even from hour to hour.     Ecologists say dunes are dynamic because they change rapidly.

First to develop the discipline of ecology, Henry Chandler Cowles published his work in l899. His scientific studies of the sand dunes along Lake Michigan in Indiana and Michigan pointed out the relationships between the shifting sands of the dunes and the changing plant communities that survive under harsh conditions.  The scientific observations Cowles made in the Indiana and Michigan sand dunes made him the father of ecology.  He saw that plants and animals change more rapidly in the dunes than in other places, therefore the dunes  made a perfect outdoor laboratory. Cowles’ observations on one group of plants replacing another is called succession.  Each stage in dune succession depends upon an earlier stage.  The first plants to grow were perhaps nourished by a dead fish that washed ashore. Insects such as the springtail and bacteria and molds broke the fish down into nutrients the plants could use. After their root systems stabilized the sand, and helped build the dune, other plants were able to establish themselves nourished by nutrients in a layer of topsoil formed by decaying matter.

Here is how the dune ecosystem changes with time:

0-20 years Beach grasses

20-50 years Cottonwood, beach grasses, cherry, willow, herbs

50-l00 years Increasing variety of shrubs, trees, and herbs, Jack pine may dominate

l00-years Black oak may be among the first forest dominants

Oak and hickory_l00-l,000 years  Beech and maple climax forest (extension_bulletin E-l529 Sea Grant)

Marram grass and sand reed grass are not discouraged by the harsh environment of a sand dune: hot, desert like conditions in the summer, strong winds, and cold arctic conditions in the winter.  Dune plants are adapted to extreme heat, cold, and a lack of moisture. The marram grass and the sand reed grass hold the fort on the fore dune by binding the sand with their huge, hair like root systems that may extend down to the water table for a hundred feet. Their stems grow upward even when covered by sand repeatedly.    On these dunes, 52 acres, there is a surprising diversity of life which makes its dune scape an ever changing panorama: plants especially adapted to the dune bloom, each in their season: A self-guided nature trail with  numbered stations shows the succession of plants in the dunes along the footpath are: horsetails, interdunal ponds or pannes with rushes, sedges and various insects and amphibians. A delicate looking yet hardy plant bearberry or kinnikinick was used by the Native Americans as tobacco, and there are junipers of two types, an endangered species: Pitcher’s thistle, pines, dune grasses, poison ivy, sand cherry, and various types of hardwoods such as red oak.  On top of the highest dune are beech and maple. There are also witchhazel trees that bloom in October and sassafras that turn brilliant colors of red and orange in autumn. Some trees are entwined with bittersweet with orange fruit birds feed upon.    Dune forests can grow up on dunes that have been pioneered by grasses and shrubs which stabilize the sand and over the years  help to build a layer of topsoil that can support tall trees.  In the spring, wildflowers such as trillium grow in profusion on south slopes of forested dunes where they can absorb more sunlight. In the open sunny areas of the dune, the yellow hairy puccoon flourishes: its gray green color and fuzzy leaves help it to reflect light and retain water.

Migrating birds rest in the high tree branches while permanent residents such as the pileated woodpecker and the horned owl go about earning their livings in their particular niches.  Whitetail deer browse on vegetation and red fox feeds upon everything from berries and insects to frogs and small mammals such as the white-footed mouse.  With the climax forest, the dunes have produced a diverse community of plants and animals that are an important part of the Great Lakes’ ecosystem. It may have taken a_thousand years between the time the first grasses colonized the sand and the tall trees found enough nutrients for theirseeds to grow.  These dunes are not replaceable. They are of more value to the whole ecosystem as dunes rather than as industrial sand or real estate. They protect inland areas from wind damage since wind blowing off the lake will glance off of a tall dune and rise up into the air.  They also protect inland areas from flooding, but perhaps their most appreciated value is their beauty.  Dune plants may be able to live through harsh summer and winter weather but, they cannot stand up to off the road vehicles or heavy foot traffic.  Building houses on dunes may also cause wind erosion when the plants stabilizing the dunes are removed. This is called a blowout and it forms a saddle shaped or U shaped depression in a stable sand dune.  In the past, many Lake Michigan dunes were trucked away load by load since their fine sand has industrial uses.

In order to protect Michigan’s coastal sand dunes, the state government passed a law in l989 that will prevent harmful development and protect the dunes we still have left. Governor Blanchard signed the bill into law at Kitchel Lindquist Hartger Dunes. Henry Chandler Cowles would have been proud.

In the deep valleys between sand dunes, wetlands with the same sort of living things found in ponds, may appear and then disappear when the weather becomes dry. Before the water disappears, tadpoles may change into frogs and toads. Salamanders may make their transformation from a water to a land animal.    With the climax forest, the dunes have produced a diverse community of plants and animals that are an important part of the Great Lakes’ ecosystem. It may have taken a thousand years between the time the first grasses colonized the sand and the tall trees found enough nutrients for their seeds to grow.  These dunes are not replaceable. They are of more value to the whole ecosystem as dunes rather than as industrial sand or real estate. They protect inland areas from wind damage since wind blowing off the lake will glance off of a tall dune and rise up into the air.  They also protect inland areas from flooding.  In the winter, people_cross country ski through scenic dune trails; in springtime, people come to admire the wildflowers and listen to the music of migrating birds; in the summer, people enjoy strolling through the cool forests and playing on the beaches. In autumn, the foliage changes to brilliant colors and dry leaves rustle underfoot.  Chipmunks scamper over fallen logs, their cheeks stuffed with beechnuts.     Hikers may be alarmed by a snake that rises in a pretty good imitation of a cobra, puffing out its hood to make itself seem fearsome although it is a perfectly harmless snake, and part of the dune ecosystem.  It is the eastern hognose snake (sometimes called the puff adder) with its shovel like nose the snake uses to burrow into the sand in search of it favorite food: toads. In fact, toads are the only food the puff adder will eat. There are also a few Mississauga rattlesnakes in the dunes , so if you take a hike, it’s a good idea to stay on the marked trails and keep your eyes open. There is a lot to see and enjoy.

Great Horned Owl

horned owl

wild flowers

wild flowers

Marram grass

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Since DDT and like pesticides were banned in 1972, the American Bald Eagles may be seen around the Great Lakes.

Read About how this happened in my book, The Dynamic Great Lakes. 

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Salmon Time in Lake Michigan

September 8, 2016


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Brooks’ big catch

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Aging pipelines could break and oil pollute Lake Michigan and Lake Huron: fish, birds all living things.

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I wrote to my congressman and got this interesting letter back.
Dear Mrs. Spring:
     Thank you for contacting me about Asian carp.  I appreciate hearing your views on this important matter.
     I have long been concerned about the threat posed to the Great Lakes by invasive species, including Asian carp.  These species are introduced from other ecosystems and often encounter few, if any, natural enemies in their new environments and, therefore, can wreak havoc on native species.
In an effort to address this issue, I cosponsored the National Invasive Species Act of 1996 (P.L. 104-332).  This law authorized the Army Corps of Engineers to build a dispersal barrier (Barrier I) in the Chicago Sanitary and Ship Canal (CSSC) to stop invasive species from entering Lake Michigan.  As co-chair of the Senate Great Lakes Task Force, I, along with the other members of the Task Force, have repeatedly sought and have been successful in securing authorizing language and funding for the Army Corps to complete and enhance the three electrical dispersal barriers in the CSSC.  Most recently, at the urging of Senator Mark Kirk (R-IL) and myself, the Army Corps of Engineers agreed to enhance the protections of the electric barriers at the CSSC by modifying some of the operating parameters, including increasing the barrier voltage by 15 percent this fall.
Congress provided $12,650,000 for the electric dispersal barriers in FY2011.  The Senate Committee-approved FY2012 Appropriations bill is consistent with the president’s request and includes $24,065,000 for these electric barriers.  The House-passed FY2012 appropriations bill includes $21,805,000 for the barrier project.
Some have suggested that a hydraulic, or physical, separation of the Mississippi River from the Great Lakes Basin, which also maintained commercial and recreational transport on these waterways, could serve as a long-term solution to the threat of the Asian carp getting to the Great Lakes.  At my request, the Water Resources Development Act of 2007 included a provision that authorized the Army Corps to study how to prevent the spread of aquatic invasive species between the Great Lakes and the Mississippi River Basins through the CSSC and other aquatic pathways.  This study, known as the Great Lakes and Mississippi River Interbasin Study (GLMRIS), includes an analysis of the hydraulic separation of the basins.  Congress provided $750,000 for the GLMRIS study in FY2011.  The FY2012 Senate Committee-approved appropriations bill included $3,000,000 for the GLMRIS and the House-approved appropriations bill included $3,000,000.
I have supported an expedited analysis of the separation option and have urged the Corps to move forward with the analysis.   On March 3, 2011, Senator Debbie Stabenow (D-MI) introduced the Stop Asian Carp Act (S.471).  This legislation, which I have co-sponsored, would require the physical separation analysis to be completed in 18 months rather than the current expected date of completion in 2015.
In addition to preventing Asian carp from moving from the Mississippi River Basin to the Great Lakes, it is important to do what we can to keep carp from entering the lakes through other means, such as importation.  I introduced the Asian Carp Prevention and Control Act (S.1421), which was signed into law by the president on December 14, 2010.  This law places the bighead carp on the list of injurious species under the Lacey Act.  Such a listing prevents the importation and interstate commerce of live Bighead carp without a permit, and as a result, lowers the risk of an introduction of this species in the Great Lakes.  We have already invested over $40 million on the construction and operation of the electric dispersal barriers, on Asian carp monitoring, and on studies. It would undermine these efforts to allow live Asian carp to be introduced into the Great Lakes because we did not do everything in our power to block other pathways of introduction into the Lakes.
     The Great Lakes hold one-fifth of the world’s freshwater, supply drinking water to tens of millions people, and support a $7 billion fishing industry.  We owe it to current and future generations to preserve this immensely important natural resource.
Sincerely,
Carl Levin

The Dynamic Great Lakes

December 14, 2011


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