Implementing Science-Based Invasive Plant Management - Management of Invasive Weeds - page 340

High

No action

Restore

or

or

let go

improve

Need
more
information

Risk of
invasion

Monitor

or

Protect

maintain

Low

Low High

Land value for conservation or protection

Fig. 17.4 Assessment of management priorities for a region based on the relative value of differ-
ent sites for conservation and/or production, and their relative degree of risk of invasion (modified
from Hobbs and Humphries 1995 in Radosevich et al. 2007)

occupied by invasive plants. Specific approaches to prioritize species of invasive
plants for management are discussed later. The approach proposed by Hobbs and
Humphries (Fig. 17.4) depicts four categories of management based on the charac-
teristics of the site. These are as follows:

● Sites of high value that are relatively undisturbed, i.e., the risk of invasion is low
(prevent/protect)
● Locations of high value that are subject to greater levels of disturbance (risk)
and, hence, are more susceptible to invasion (protect and improve)
● Sites of low value that are subject to low levels of disturbance (monitor)
● Sites of low value that are subject to high levels of disturbance (“let go”)

Unfortunately, the prevailing trend is one of transition from the bottom right (protect) to
the top left (let go) of Fig. 17.4 as plant communities come into higher risk of invasion by
exotic plants from continued environmental degradation (Hobbs and Humphries 1995).

17.4 Approaches for Management of Invasive Plants

Rejmánek (2000) reviews the approaches used to achieve prevention, eradication, or
control of invasive plants. These approaches are as follows: stochastic , empirical-taxon