Great Lakes Permaculture Portal

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Michigan’s Geoecology

Michigan’s geology was shaped through a series of events. The changes in geology shaped the formation of Michigan’s ecology. The interaction of the two is the geoecology.

Michigan’s landmass is partially comprised of one of the early continents. Some of this rock can be seen around Marquette, where it was forced upward after the formation of the midcontinent rift. Around 1.1 billion years ago, the tectonic plate Michigan rests upon began to crack. The tectonic plate was prevented from breaking when it bumped against a neighboring plate. The crack, the midcontinent rift, pushed Michigan’s landmass underwater.

Michigans state fossil

Polished Petoskey stone. Attribution: The Childrens Museum of Indianapolis

Under the sea and near to the equator, Michigan witnessed the Cambrian explosion, when multi-cellular life began to arise en mass. Over time, a giant coral reef formed in this sea. Then the Late Devonian mass extinction, ~350 million years ago, put an end to these reefs.

Fast forwarding through a few more mass extinction events and tectonic changes in the location of the plates to around 1 million years ago. By that point, Michigan was about where it is today. Instead of being covered in water though, it was covered in ice. Michigan is the only state that was completely covered by glaciers during the ice age.

As they ebbed and flowed across the landscape, before finally receding around 12,000 years ago, the glaciers pushed millions of years of built up sediment around. This action created streaks of sand across the land and exposed fossils of the coral that had died off, in the form of Petoskey stones.

Because the glaciers did not recede in a uniform fashion, this led to rising and lowering of water levels in the basins that are now the great lakes. The sediment left behind after water levels receded is a major contributor to soil structures in areas near the coasts, while the scraping of glaciers played a large role in the interior of the state.

With only 12,000 years of maturation since the glaciers receded, Michigan’s ecology is relatively young. The two dominant natural community structures underlying Michigan’s ecology are forests and wetlands. Prior to settlement, 95% of Michigan (~59 million acres) was covered in forest. Additionally, it is estimated that there were 11 million acres of wetlands (~17.7% of Michigan), including forested wetlands, of which only around 3 million acres remain.

Forests

 

Michigan Forest

Beech-maple forest inundated with water during the spring thaw. Beech trees retain their leaves through winter, making them easy to identify.

Michigan’s forests are dominated by oak hardwood in the center of the state, beech-maple by the coast and jack pine to the north where the glaciers left highly depleted sandy soil. Because logging was a major industry through our state’s history, most of the forests we have today were planted by humans. Many exist as mono-crops for continued harvest by logging companies.

Michigan Forest Communities details the plant communities that occur in these forests and can be used as a starting point for regenerative design. Many of the species found in these forests provide valuable yields, including nuts, fruits and lumber, that can be harvested sustainably.  Mark Shepard’s Restoration Agriculture provides a model for large scale productive ecological design in our climate.

 

Would love to see these systems in Michigan!

Mark Shepard’s Restoration Agriculture System based off of the Oak Savanna Biome

 

Wetlands

 

Reed harvesting is one management activity in Michigan's wetlands

Reeds are one wetland yield that can be sustainably harvested.

Wetlands play a strong ecological role in water retention and filtration. For existing wetlands, it might be wise to allow them to design themselves. The reality, however, is that we have greatly reduced the quality and quantity of wetlands in Michigan, and our pollution flows into them, causing changes in nutrient loads. This shift in available nutrients can lead to changes in the ecosystem infrastructure. These changes create opportunity for nuisance species like phragmites and purple loosestrife to take hold and dominate the area for years to come.

Some productive systems that may be implemented in managed wetlands are integrated rice and duck systems, chinampas, and aquaculture. Biomass harvest is another use for wetlands, and may be a productive way to manage opportunistic species. The systems one might utilize depends on the type of wetland one has access to, individual goals, as well as zoning and regulations.

 

References

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