US Army Corps of Engineers
Rock Island District

Why is the Corps Clearing Some of the Woodlands?

Red Rock is working to control invasive species in our woodlands, prairies and old fields.  Invasive species can be plants or animals that rapidly colonize sites and displace other species.  They can be native to an area or introduced from other places in the world.  By far the most insidious and detrimental invasive species are non-native, exotic species.  Control of exotic species is arguably the most important challenge facing resource management agencies and private landowners today.

For example, two species that Red Rock Project is most aggressively trying to control are autumn olive and Asian honeysuckle.  These shrubs were formerly considered valuable additions to tree plantations and wildlife shelterbelts.  Their merits include providing dense cover and producing ample fruits.  It was common practice in the 70’s, 80’s and 90’s to include these shrubs in plantation or shelterbelt design.  Both autumn olive and Asian honeysuckle’s native, natural range is in Asia.  Unfortunately, these species did too well in their “new” environments.  Left unchecked, they can dominate a site and displace the native flora and cause a detrimental decline in fauna as well.

By removing these species Red Rock intends to stimulate prairie and grassland communities, both of which have dramatic declines in recent years.  As a consequence, many grassland wildlife species, ranging from invertebrates to mammals and birds, are having disastrous drops in population.  Likewise, dense understory of exotic and shade tolerant native species prevent adequate oak regeneration in woodlands.  Broadly and generally speaking, this in turn leads to a poor quality forest and poor wildlife habitat.  Not all alien species are bad, and not all native species are good.  However, there is great risk anytime a non-native, exotic species is introduced into the environment.  Some of the worst introductions include emerald ash borer, Asian carp species, English sparrows and rats, to name a few.

It is our goal to manage our natural resources for the best possible outcome to benefit sustainable communities for Iowa’s native plants and animals.  It’s a daunting yet critical task for our environment.