Defining a regional approach for invasive plant research and management - Invasive Plants: Ecological and Agricultural Aspects - page 138

screening six herbicides at two rates of application over three application peri-
ods on sites with extensive P. recta infestations (densities often > 100
stems/m 2 ). Following herbicide applications, half of each plot was sown with
a native grass seed mix. A range of response variables, including P. recta con-
trol, and native and non-native species abundance and richness, were recorded
[95]. Plots are being monitored for several years to understand longer-term
implications of various herbicide and seeding treatments.
To complement the herbicide screening study, an experiment was estab-
lished to examine the importance of prescribed fire, herbicide application, and
native grass seeding on grassland restoration. In the PNW few studies have
been conducted on the response of invasive plant species to fire, and only one
limited study has explored the effects of fire on P. recta [96]. This information
is helpful to land managers because it remains unclear if fire, an increasingly
popular management tool, facilitates, inhibits or has no effect on the spread of
P. recta . Basic information on plant species and community responses to fire
are necessary for resource managers to assess ecological conditions and trends
following treatments, and for the development of post-fire management strate-
gies that enhance plant community restoration, wildlife habitat or other com-
ponents of biological diversity. In this study [97], three prescribed fire treat-
ments (spring, fall, and no burn) were used in combination with sowing a mix
of six native grass species and the application of the best performing herbicide
(over 1 year) from the previously described herbicide screening experiment.
Reductions of P. recta abundance and change in overall community structure
and composition, including native plants, are being evaluated.
Integrated tool experiments that combine invasive plant control with
restoration activities are likely to be more successful in creating sustainable
plant communities in the long-term. This study of fire, herbicide, and restora-
tion seeding, supports information on the ecology of P. recta , and provides
data on the species' response to fire, herbicide, and native seeding. Results
from this study provide land managers, especially those interested in promot-
ing native plant communities, guidance to integrate herbicides, fire, and native
plant seeding into an overall invasive plant control program.
Adaptive management and interaction with land managers
Conducting scientifically rigorous research is fundamental to our regional
research framework on invasive plant species. Scientific expertise from vari-
ous sources is being coordinated with land managers to produce information
about areas that are at-risk, human uses, and the land values associated with
those areas.
Land managers involved in our program represent the United States Forest
Service, United States Bureau of Land Management, Oregon Department of
Fish and Wildlife, Oregon Department of Forestry, The Nature Conservancy,
local weed management districts and private companies and landowners.