Association of State Wetland Managers - Protecting the Nation's Wetlands.

The Compleat Wetlander: Natural and Manmade Ecosystems; Where are we headed?

This past week millions of people experienced heavy rains that flooded downtown areas from Detroit to DC to Portland, Maine.  The record was set on Long Island, NY where a whopping 13 inches fell, resulting in the declaration of a state of emergency as roads, basements and backyards flooded under the intense deluge.

Closer to home, I had my own moments of panic when I heard a loud explosion outside our house.  I grabbed my umbrella and cell
phone to investigate, anticipating a call to 911.  Outside in the pounding rain I found a
cw815141tree branch burning as it bobbed overhead on electric lines.  There were succeeding explosions from the transformers on poles close-by and loud snaps as electricity surged along the damaged wires.  The bad weather and vulnerable infrastructure had combined to create a deadly hazard and I suddenly felt keenly for the many people who had been in the storm’s path as it swept across the country.  Further reflection led me to think about the remarkable combination of natural and manmade infrastructure we take for granted and their sometimes surprising effects on each other.

Mankind has been tinkering with the natural environment for centuries, often with unintended consequences.  An example of this is the tragic story of the great Dustbowl which is sometimes described as “the worst manmade ecological disaster in American history.” The recovery from the dustbowl era led to many changes in land management and eventually the establishment of another manmade ecosystem described as the “corn-soybean ecosystem”.  This ecosystem is located on a landscape populated by perennial tall grass prairie, wet prairie, oak savannah and forests prior to European settlement.  Nowadays it is composed primarily of two plants that must be planted, fertilized and harvested every year to persist. Read more here.

But while the corn-soybean ecosystem is largely an intentional design, mankind has also managed to establish new ecosystems unknowingly.  The ‘plastisphere’ refers to a wholly new type of ecosystem that has evolved to live on the plastic and other garbage dumped into our oceans.  These plastics provide a refuge for pathogens and create new sources of toxic chemicals. Read more here.

How do manmade vs natural ecosystems differ?

A “natural ecosystem” is defined as a system in which there are significant interactions between living and nonliving processes (sometimes called biotic and abiotic).  Natural Ecosystem are broadly divided into two types:  terrestrial and aquatic.  They are generally self-regulating and self-sustaining in that they do not require external inputs to continue to exist. Examples of natural communities include deserts, forests and prairies.

A “manmade ecosystem” also has significant interactions between living and nonliving processes.  They can also be either terrestrial and/or aquatic. The difference is that manmade ecosystems require human efforts to sustain them—generally substantial effort.  For example, the corn-soybean ecosystem would likely shift from corn and soybeans to some combination of perennial plants within a season or two without the active intervention of man.  Read more here. The plastisphere would cease to exist without the ongoing introduction of manmade trash to the ocean. Examples of manmade ecosystems include cropfields, cities, man-made ponds, and cities.

In truth, all of us live in environments that exist along a continuum from natural to manmade ecosystems with remote areas of the nation at one end of the continuum and cities at the other. As a rule manmade ecosystems are greatly simplified when compared to natural ecosystems and, therefore, easier to disrupt and more vulnerable floods, drought, and other natural hazards.  A city cannot rebuild itself without human intervention after a flood.  A forest can.

Nowadays there is a great deal of talk about building communities that are resilient, i.e. better able to withstand floods, drought and other forms of natural catastrophe. But the only way to achieve that is to develop communities and cities that incorporate more of the complexity and redundancy found in natural ecosystems—that are not only more like natural ecosystems—but that incorporate and support natural ecosystems.

It is possible to envision a future where this is possible.  It happens already.  Watching the tree branch bounce and burn on that rainy evening, I called 911 and waited first for the fire department and then the power company to asses and repair the damage.  While I did so the rain put out the fire.  The nearby trees supported the broken branch, muting its bounces and preventing it from falling onto the road below.  The wood of the tree grounded the surges of electricity. Essentially, the natural ecosystem provided protection and insulation from the dangers of the manmade ecosystem.  It happens all the time and there are many actions we can take to care for natural ecosystems so they provide support and protection for the manmade ones.

To learn more about the differences between natural and artificial ecosystems, click here.



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