Seeds from an aspen float through the air and land on the ground. . . .
squirrels transport acorns and bury them in the soil. . . . young bears
travel on foot away from their mothers who become hostile towards them. .
. . water carries willow branches downstream where they become implanted
into the bank and begin to grow. Organisms have always had the
ability to spread, although, geographic obstacles, such as oceans, lakes, mountains, and
deserts, often restrict this movement .
This, of course, all changed when humans made it possible to travel
the globe. We began to experiment with "attractive"
plants from other countries. Although these plants are a common
component of many household gardens some have escaped our
control. They have become weeds in the environment, causing
many natural resources challenges.
ecosystem under consideration, and 2)
whose introduction causes or is likely to cause economic or
environmental harm or harm to human health" (invasivespecies.gov).
Invasive, exotic plants are problematic because they may form
dense, homogenous plant communities. Imagine the wetland in
the picture before purple loosestrife was introduced into the
country. It would be filled with
cattails, rushes, sedges, and ferns. It would be
full of diversity, creating varied habitats and food sources for
wildlife. Now it is a vast plantation of purple loosestrife with no
particular importance to most wildlife that once lived there.
Keystone College is attempting to manage Japanese knotweed on its property
through cutting and herbicidal
treatment. An untreated section on the trail has been left for interpretive purposes. The treated areas have had limited
success. However,
several years of effort may eliminate Japanese knotweed from
Keystone.
Keystone's efforts to eliminate Japanese knotweed is a
combination of
Multiflora Rose
mechanical (cutting), and chemical (spraying with a
herbicide)
control. These forms of control are often used when controlling
noxious plants. A third control method is through the use of
biological agents that feed on, or infect the noxious plants. Such a
method is being used in an attempt to manage purple
loosestrife. In
this case, a non-native beetle is being released to consume some of the
purple loosestrife populations.
