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Invasive Species becoming Challenge of the Future

Mike Gutzmer

The spread of invasive plants, animals and pathogens is considered one of the most serious ecological problems facing our nation in the 21st century, second only to habitat destruction. These species include plants, animals, and microbes that have been introduced into an environment where they did not evolve and often have no natural enemies to limit their reproduction and spread--frequently at the expense of native plants and animals and, sometimes, of entire ecosystems.   As if we didn’t have enough to worry about there is another blip on the radar screen of daily trudging against the wind.  

Many invaders cause huge losses in agriculture, livestock, fisheries, and other resource production systems. Some significantly alter ecosystems, resulting in costly damages due to increases in fire, flooding, and erosion. A few are vectors, or carriers, of human diseases. Tick borne diseases, West Nile virus, Hanta virus and a host of others too numerous to mention have invaded many regions of the U.S. Diagnosis and sometimes treatment are difficult with these invaders.  

Invasive species are a growing threat to the Department of the Interior's stewardship of the Nation's natural resources. They are currently estimated to infest more than 30 percent of the acreage of the National Park System in the lower 48 states. By various estimates, these species contribute to the decline of 35 to 46 percent of U.S. endangered and threatened species.  Indian lands represent some of the largest un-fragmented land parcels in the United States, but are also at some of the highest risk for invasive species damage. 

Invasive plants have created biological wastelands of more than 100 million acres in the United States. An area twice the size of Delaware is lost to invasive plants each year. Exotic animals and microbes add to this silent invasion that costs the nation more than a hundred billion dollars annually in lost resources and productivity and robs America of its biological heritage. Some of the general facts about invasive species are as follows;

• Prevention of boating/fishing: Many invasive plants grow rapidly in our lakes. The dense mats of vegetation they form can restrict or entirely prevent boating and fishing and may make the waterway entirely impassable.
• Loss of native plants and animals: Non-native plants often do not provide ideal habitat or food for fish and other aquatic animals. These plants crowd out native vegetation, and the animals that depend on native vegetation must relocate or perish.
• Loss of biodiversity: The spread of invasive species often reduces the biological diversity of the area and can disrupt the balance of the ecosystem.
• Loss of property value: The aesthetic appeal, recreational value and surrounding property values of a lake may quickly decline as the invasive species takes over.
• Expensive: Once exotic plants are established, they are almost impossible to eradicate and expensive to control. The United States has invested millions of dollars annually to manage these plants and repair the damage.

Unfortunately, invaders often go unnoticed until they have spread to many locations, making eradication difficult. Early detection and rapid response to invasions are essential if we are to prevent major damage to the health of our ecosystems and economy--an ounce of prevention is truly worth a pound of cure especially when referring to rapidly invading plant species. As humans we don’t ever seem to pay attention to something being gone until it affects our check book.    That one trait of human behavior needs to radically change in the 21^st Century. 

Rangeland and pastures comprise about 42% of the total land area of the United States. About three-quarters of all domestic livestock depend upon grazing lands for survival. Many ranges have had domestic stock grazing for more than 100 years and, as a result, the plant composition has changed greatly from the original ecosystems.

Western rangelands previously dominated by perennial bunchgrasses have been converted, primarily through overgrazing, to annual grasslands that are susceptible to invasion by introduced dicots. Today there are more than 300 rangeland weeds in the United States.

Some of the most problematic include smooth brome, leafy spurge, knapweed, musk thistle and purple loosestrife.  Kentucky bluegrass and Canada thistle are also on that list.    I wonder where they came from?   These invaders now common on rangeland cause an estimated loss of $2 billion annually in the United States, which is more than all other pests combined.

As if we don’t have enough to think about our landscape is changing before our very eyes and awareness, not apathy is the key.   Hopefully there are enough who still care and are aggressive and creative enough to start doing something about it.  Harmony with the natural world around us seems like a dying pursuit and something old timer’ thought about, when it should be a top priority in today’s world.  Maybe our next President will help guide policy in this area.   If he doesn’t, we better... Gutzmer is an environmental consultant with New Century Environmental, LLC and works with natural resource management and environmental issues in Nebraska, the Great Plains and the United States.   He can be reached at mgutzmer@allaboutlakes.com