The Iron River watershed is not immune to invasions by aliens.
Without proper action these unwelcome species threaten to overtake our lakes
and streams."Exotic" species—organisms introduced into habitats where
they are not native—can have a profound impact on natural plant and animal
communities. In a short amount of time, these non-native species can
severely alter and degrade native ecosystems and disrupt a biological
balance that took centuries to create.
Rusty Crayfish are native to streams in the Ohio, Kentucky, and Tennessee
region. Spread by anglers who use them as bait, Rusty Crayfish are prolific
and can severely reduce lake and stream vegetation, depriving native fish
and their prey of cover and food.
Purple Loosestrife (middle right) invades marshes and lakeshores,
replacing cattails and other wetland plants. The plant can form dense,
impenetrable stands which are unsuitable as cover, food, or nesting sites
for a wide range of native wetland animals including ducks, geese, bitterns,
muskrats, frogs, toads, and turtles. Many rare and endangered wetland plants
and animals are also at risk.
Eurasian Watermilfoil (bottom right) was accidentally introduced to North
America from Europe. It can form thick underwater stands of tangled stems
and vast mats of vegetation at the water’s surface. In shallow areas the
plant can interfere with water recreation such as boating, fishing, and
swimming. The plant’s floating canopy can also crowd out important native
water plants. Eurasian Watermilfoil can establish quickly by its ability to
reproduce through stem fragments and runners. A single segment of stem and
leaves can take root and form a new colony. Segments as small as two inches
can survive out of water for weeks and can accidentally be transported to
different lakes via fragments left on boat propellers or other watercraft
apparatus, especially boat trailers.
