Environmental Engineering Reference
In-Depth Information
9
Management of invasive terrestrial plants
Jodie S. Holt
9.1 Introduction
Management of terrestrial plants is based on principles common to management
of all organisms, regardless of the type or identity. In practice, however, plants
possess features that necessitate unique approaches and tools for management.
As sessile organisms that are rooted to the ground, plants possess adaptations,
or evolved traits, that result in survival and reproduction in particular environ-
ments. Tremendous genetic variation occurs among terrestrial plants and in add-
ition, most plants possess plasticity, or the ability to change growth and form in
response to environmental factors. For these reasons management techniques may
not apply uniformly across all environments or work equally well on all parts of
the same plant.
9.2 Classifi cation of weeds and invasive plants
Management of weeds and invasive plants generally requires some level of identifi -
cation of the plants in question. Invasive plants are most often vascular seed plants
and most are also fl owering plants (angiosperms). Some notable exceptions occur
(e.g. some ferns, which are seedless, and conifers, seed plants that have no fl owers,
are considered weeds). Angiosperms are further divided into dicots and monocots
(the classes Dicotyledones and Monocotyledones). In situations where broad-scale
or non-selective methods of weed control are used, distinction among grasses and
sedges (monocot) and broadleaf (dicot) plants may be suffi cient for identifi cation
purposes. In other situations, successful management depends on knowing the
specifi c identity of the undesirable plant and having some understanding of its
characteristics and life history, including mode of reproduction (Radosevich et al .
2007).
In addition to taxonomical classifi cation, weeds and invasive plants are classi-
fi ed by their length of life cycle (annual, completing the life cycle in 1 year or less;
biennial, living longer than 1 but less than 2 years; or perennial, living longer than
2 years), season of growth (winter or summer), and time and method of reproduc-
tion. Perennial plants may resprout every year from below-ground reproductive
structures that store carbohydrates over the winter (Fig. 9.1). h is seasonality in
 
 
 
 
 
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