April 2011 - Parks & Recreation - 76

plants, and limit food resources available
to local wildlife. Some invasive plants-
such as the notorious Southeastern invasive, kudzu-even have the ability to
change a landscape.
The USDA Forest Service has identified
invasive species as one of four significant
threats impairing our nation's ecosystems-including those in local and state
park systems. And park professionals invest enormous energy, time, and resources into protecting their natural spaces and
keeping ecosystems healthy. A proactive,
knowledgeable approach is key.

Eco-Trouble
Invasive plant culprits come in several
types: vines, grasses, and small shrubs.
Vines, such as Japanese honeysuckle, porcelain-berry, and mile-a-minute
weed, can shade and drape over native shrubs. Others, like bittersweet,
wrap tightly, like a heavy boa constrictor,

adding enough woody biomass to fell mature trees. Such a canopy opening invites
even more viney growth.
Grasses like Japanese stiltgrass can
crowd out native wildflowers and other plants, creating a near-monoculture
on the forest floor. And invasive shrubs
such as butterfly bush overtake stream
banks or forest edges, crowding out native plants. Add in burgeoning white-tail
deer populations that consume dwindling
native foliage but avoid invasives, and forest quality deteriorates. " Urban forests
are under a severe threat for long-term
survival as ... a real forest community, "
says forest ecologist Carole Bergmann,
who works for Maryland National Capital
Park and Planning Commission in Montgomery County.
Certain parks and natural areas may
be more at risk than others. Well-used
parks and forestlands are easy targets for
invasives, as are forest edges and trails.

Dense urban areas with skinny stream
valleys are almost regularly overtaken
by invasives because of frequent use.
" The biggest, overarching concern
is biodiversity, " explains Jennifer Naegle, restoration ecologist for OC Parks
in Orange County, California. Because
invasive f lora can create a monoculture, an infested natural area that once
hosted more than 10 plant species may
only have one to three species. And that
means fewer types of wildlife. " You're tilting the balance towards one [or a few] animal species that's able to use it [for food
or habitat], " Naegle explains.

Cause to Take up Arms
Bergmann realized that invasives were a
problem while creating plant inventories.
" In park after park, instead of getting lists
of 200 natives, I would get a list of 100 natives and dozens of invasives, " says Bergmann, whose personal nemesis is oriental

Mulcher maintains life
on the edge

fficials from Five Rivers MetroParks in Dayton, Ohio, looked over the edge-and didn't like
what they saw. Rather than peering into a dark
abyss, however, these officials were looking at
edge habitats-those succession areas where
two differing ecosystems collide. Despite their best efforts, it was
clear that the brushy, woodland habitat was overtaking the grassland or prairie. And that was bad news for the wildlife that relies
on these fragile ecosystems for their survival. The park system
turned to a mechanical mulcher to help maintain these dynamic
areas to help ensure the survival of the many animals who call the
edge " home. "
With over 15,000 acres of land spread across 25 parks, the Five
Rivers MetroParks system includes numerous competing ecosystems which support their own indigenous wildlife. But the woodland tracts grow much more rapidly and aggressively than their
prairie counterparts-eventually crowding out grasses and replacing them with saplings, brush, and soon trees. Before long,
the grasslands are merely a memory, having been replaced by

74 Parks & Recreation

APRIL 2011

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April 2011 - Parks & Recreation

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