Defining a regional approach for invasive plant research and management - Invasive Plants: Ecological and Agricultural Aspects - page 136

ment (e.g., Fig. 4) it should be possible to project areal expansion of the spe-
cies over time. Such determinations for exotic invasive species are invaluable
to land managers because the consequences of management or no action can
be determined and policies justified.
Management-level studies
Land managers are responsible for a wide range of actions in response to
plant invasions including invasive plant mapping, monitoring, and habitat
treatment and restoration. However, the tools available for managers to effec-
tively address plant invasions are limited and invasive plant research pro-
grams can play a valuable role in the development, application and evaluation
of tools, methods and approaches that land managers might use to manage
plant invasions. Traditionally, the development of tools for land managers has
not been the focus of invasive plant research projects. Moreover, many inva-
sive plant research efforts have been unresponsive to land manager needs and
biased toward small-scale, short-term results in sometimes artificial environ-
ments, which thereby limits their applicability [47]. The applicability of
many invasive plant research projects have also been limited because they
often fail to incorporate interacting, complex processes that operate at large
scales (e.g., fire, herbivory, succession, land use change, disturbance corri-
dors such as roads and riparian zones) that land managers must explicitly
consider in their management programs. Within our research program, we
attempt to overcome these obstacles by initiating research projects designed
to develop tools and approaches for invasive plant prevention, detection, con-
trol and restoration.
Prevention and detection
A critical question central to invasive plant management is “How can man-
agers accurately and cost-effectively inventory and monitor non-native inva-
sive plants across large landscapes?” This question is particularly important
since many non-native invasive plants are easiest to control when populations
are small. Owing to limited finances and personnel to sample, inventory, and
monitor large areas, the development of methods such as remote sensing to
detect invasive plant species is needed.
A wide range of remote sensing techniques have been utilized to detect
invasive species, from coarse-scale satellite imagery to fine-scale aerial pho-
tography taken from fixed-wing aircraft. Processing and analysis varies from
photo-interpretation techniques used to identify invasive species infestations
by color, pattern, shape, or photo-texture, to analyses of spectral signatures
using image-processing software. Despite the advocacy of remote sensing as a
key to early detection of plant invasions, the results have generally been mixed
[87-91], and may be of best use over large landscapes with limited access such
as wilderness and roadless areas.