Weed Management and Invasive Species Control - Project Planning and Management for Ecological Restoration - page 185

Chapter 12
Weed Management and Invasive Species Control
Weed management and the control of invasive plant species are critical first-year activities and
generally must be carried out for several more years until the desired vegetation becomes well
established. In fact, many professional practitioners consider weed and invasives control to be the
single most important activity on a restoration project site after plant installation. Invasive species
control is sometimes the most time-consuming, labor-intensive, and costly component of an eco-
logical restoration project.
Defining Weeds and Invasive Species
A weed in agronomic terms is any undesired, uncultivated plant that grows in profusion so as to
crowd out a desired crop—in our case, desired native vegetation. Weeds are typically nonnative
plants that are invasive—that is, they aggressively compete with the native vegetation. From an
agricultural point of view, many native plants can be weeds if they interfere with the growing or
harvesting of agricultural crops. From an ecological point of view, many ornamental landscape
plants can become weeds. From the point of view of a restoration practitioner, weeds are invasive,
generally nonnative plants that interfere with the development of a restoration project site.
Invasive plants are not always nonnative species. The forests of the southeastern United States
demonstrate this in places where lowland forest species were not cleared for agriculture because
the land was not suitable. After agricultural activity was abandoned, the various species of the
lowland forest were able to invade the large expanses of fallow field. With no seed bank and few
numbers of the upland forest species represented, the lowland forest was able to expand its range
and take over an area that was previously a different forest assemblage (Clewell and Aronson 2013).
An “invasive species” is any species (usually nonnative) that occupies space and uses resources
in a landscape that would normally be occupied by native species. When we use the term invasive
species , we are usually talking about nonnative invasive plant species; however, there are also many
invasive animal species, including aquatic organisms, that can adversely affect the outcome of a
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