Exotic Errors—How to Repair the Damage
During the years following discovery of the Northwest by Euro-Americans—and
continuing to the present—people have brought plants and animals to this
land from other landscapes, sometimes deliberately, sometimes accidentally.
Some of these 'exotic' plants are extremely adaptable to their new environments
and become easily established in landscape corridors (roads, rivers, clear-cuts,
mountaintops, etc.). Plants such as herb Robert, Scotch broom, Japanese knotweed,
reed canary grass, white pine bluster rust (a fungus) and many others have taken
over habitats, which displace or eliminate native species.
What should be done with these invaders?
First, it is important to consider a few points:
- Our failures and misunderstandings during the past allowed exotic species
to populate native habitats. If we maintain our current course, exotics will
continue their drive into native habitats.
- In nature, plants and animals move and are transported to new locations
by natural processes. Storms, global wind and ocean patterns, plate tectonics,
and animal migrations naturally mix species among continents and geographic
regions. These processes have occurred since the beginning of time and they
naturally upset the balance of life in order to create a new balance.
- Some exotic plants and animals are easily contained by simple measures,
while other species are so aggressive that they cannot be contained by human-devised
measures without substantial disturbance to the surrounding ecology.
- Most invasive species invade ecosystems disturbed by humans. If we are able
to stop the disturbance, the native community of plants and animals may return.
- It is most always the case in nature that plant or animal monocultures (the
existence of only one species) cannot last long. In the natural world, a diversity
of organisms usually replaces a monoculture.
- If we consider the 'big picture', only species provided with adaptations
to survive in a specific habitat will survive in the long-run. It is possible
that exotic species, which did not originally evolve in the local ecology,
will be weeded out by nature's many healing processes.
Teachers, hold a discussion with your students on invasive species. See what
measures students might devise for keeping exotics at bay. Options may include:
removal, management through the introduction of predators, establishment of
wilderness refugia for natives, patience, etc. Do your students feel that it
is their responsibility to repair damaged to ecosystems which was caused by
our ancestors?