Francis Skalicky, For the News-Leader 6:05 a.m. CT March 1, 2017

Sometimes, introducing invasive plants and animals into a habitat is the equivalent of throwing a wrench into the cogs of a machine:In some cases, the machine continues to operate, but at a much-reduced efficiency. In other cases, the machine shuts down completely.

This week, Feb. 27-March 3 is National Invasive Species Awareness Week. The purpose of this week is to bring attention to all non-native species that pose threats to our outdoor habitats. Unfortunately for our habitats and native species that reside in them, there are a large number of non-native invaders and many of them can be harmful to our ecosystems.

Invasive species whichin most casesare non-native exotic species are nothing new. A variety of animals and plants have been introduced to North America in the 500-plus years that the continent has been explored, settled and developed. Some were introduced on purpose, others by accident. These introduced species are collectively known as exotic species because theyre not indigenous to North America. The opposite of exotic is native. Native species are the plants and animals that were the original inhabitants of our landscape.

Some exotic plants such as kudzu and fescue are well-known to people, but there are many others. Some have become so common that we dont realize theyre not from around here. Take, for instance, the two most common types of crabgrass found in residential yards hairy crabgrass (Digitaria sanguinalis) and smooth crabgrass (Digitaria ischaemum). Neither is native to North America; they were introduced here, probably in the 19th century.

And those dandelions that pop up each spring to the annoyance of many lawn-lovers? Theyre also from Europe and Asia and were established here through intentional plantings by early European settlers.

On the animal side, zebra mussels and Asian carp are highly publicized exotics that have made the news as threats to aquatic habitats in parts of the U.S. Gypsy moths and emerald ash borers are well-known non-native tree pests that pose both habitat and financial threats to forests in the eastern and central parts of the country.

One of our less-publicized exotic animals is the house mouse (Mus musculus). This common pest, which is the mouse species we commonly encounter in homes and other domestic dwellings, wasnt here when Europeans first arrived. It had numerous introductions to North America via the ships of explorers and colonists.

There are several species of native mice, butdue to the house mouses reproductive capabilities and the availability of habitat (houses, garages, storage sheds, etc.), this exotic rodent probably far outnumbers its native cousins in the U.S. Another pest the Norway rat (Rattus norvegicus) is an exotic species that came to North America on the ships of early European visitors.

Though the exotic species that have come here are varied, the reasons theyve become abundant are similar: Exotic species were introduced into areas that had few of the natural controls (browsing animals, predators, harsher weather, etc.) that kept them in line in their native lands and, as a result, these newcomers flourished. This abundance has often come at the expense of native plants that formed the foundation of our habitats.

When exotic species invade an area and crowd out the plants and animals that occurred naturally in that location, habitats often change for the worse: The insects that were attracted to native flowers go elsewhere, the native birds cant find nesting areas because theyre occupied by exotic birds and other animals that needed these species for some part of their life cycles are also negatively impacted.

Wise conservation practices utilizing native species pay by enriching our economy and quality of life. Conversely, exotic invasions can have negative financial repercussions. Gypsy moths and emerald ash borers are already having an effect on the timber industry. In addition to negatively impacting aquatic life, fishing and recreational boating; thick mats of the aquatic invasive plant hydrilla can clog intake structures at power generation and water supply facilities. When exotic plants such as musk thistle, spotted knapweed or Johnson grass take over pastures and fields, they can turn what had been money-making acres into financially unproductive tracts of land.

Information about invasive species can also be found at http://www.missouriconservation.org

Francis Skalicky is the media specialist for the Missouri Department of Conservations Southwest Region. For more information about conservation issues, call 417-895-6880.

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Invasive exotic species damage ecosystem and economy - Springfield News-Leader