Biology Reference
In-Depth Information
2.1 Introduction
Early detection monitoring forms the foundation of all invasive plant management
programs, and is often coupled with rapid response to control incipient populations
of undesirable invaders. Collectively, early detection and rapid response provide the
first line of defense against plant colonizations. Compared with the spread and
equilibrium phases of invasions, the colonization and, to a somewhat lesser degree,
establishment phases are typically the only points at which eradication is possible
(Rejmanek and Pitcairn 2002). Once invading species have established populations,
or are in the process of subsequently spreading into new areas, eradication quickly
becomes unfeasible. Thus, prevention of new invasions into a management unit is
predicated primarily on an effective early detection and response program.
Invasive plants are managed within local project areas, preserves or agency
units, counties, states, nations, and continents. Although priorities and challenges
vary among these different types of management units, there are certain issues com-
mon to all which we emphasize in this chapter. One major issue is the daunting task
of accounting for large numbers of potentially invading species within large areas.
Resources will never be sufficient to monitor all invading species in all places.
Guidelines are needed on how best to narrow search parameters for the types of
species that are poised to invade and focus efforts on areas where they are most
likely to invade and/or are most important to protect from invasion.
Optimized
monitoring plan
Prioritized
monitoring plan
Generalized
monitoring plan
Total area within the management unit
Fig. 2.1
A generalized example demonstrating how the relative proportion of sampling area can
decline with each successive monitoring approach
