Why Invasives Are a Problem

Imagine hiking your favorite trail on Mt. Hood, keeping a lookout for your favorite native wildflowers.  Sadly, today, there are only a few blooms left!  Instead, you find a field full of [insert species here].  Tarnation!  

But…wait?  Aren’t “invasive plants” just plants we don’t like that come from somewhere else?  

Well, not exactly.  Most non-native species tend to stay put; land managers aren’t too concerned about them.  However, there are some “bad actors” that are particularly costly and concerning, and for a range of reasons.

A key source of concern about certain invasive species is reduction of diversity and the possible takeover of a single species (or ‘monoculture’).  For some, this argument, and by extension, the preservation of native species, is enough.  Two additional concerns, though, spring from the threat of monoculture:  reduced stormwater infiltration, and forest failure.

Some invasive species don’t even need to form a monoculture to have an economic impact.  Many species of concern are a problem if even one plant is present; throughout Oregon, the economic impact of invasive plants is noticeable.

Invasive species can actually increase erosion along streambanks and limit the growth of shade trees over waterways.  More sun means increased water temperature, reducing oxygen levels for fish while encouraging algal growth.

And some species present human health concerns.