355be applied early in the spring during a period when exotic annual species are actively
growing (yet slower-growing native species may be at risk) (Blackshaw 1991 ).
Given the limitations of imazapic (Morris et al. 2009 ) and glyphosate (Wilson et al.
2010 ; Kyser et al. 2012 ), adaptive management of restoration sites should incorpo-
rate mechanisms to learn and adjust application rates and timings to maximize
impact on B. tectorum persistence characteristics while minimizing nontarget
effects on seeded and resident native plants.
12.4.3.4 Revegetation
Because revegetation entails seeding desirable perennial plant species after wildfi res,
prescribed burning, or burning in concert with herbicide treatments (Table 12.1 ), our
analysis should be viewed in the context of how seeding provides additional benefi ts
when applied in an integrated manner. Accordingly, our analysis illustrates that seed-
ing reduced B. tectorum biomass production, but its effect on B. tectorum cover was
variable, especially in the long term (Fig. 12.3 ). Reduced biomass may be a conse-
quence of establishing perennial grasses competing for limiting soil resources and sub-
sequent decreases in the growth of exotic annual grasses (Leonard et al. 2008 ;
Hirsch-Schantz et al. 2014 ). Furthermore, the ability of seeding to reduce invasive
species depends on initial seedling establishment, and this effect is more pronounced
with greater time after seeding (Eiswerth et al. 2009 ; Pyke et al. 2013 ) and under
cooler and moister environmental conditions (Knutson et al. 2014 ). For example, when
successfully established, perennial grasses can stifl e reinvasion of B. tectorum (Reisner
et al. 2013 ; Munson et al. 2015 ), increase native vegetation structural diversity for
wildlife habitat (Arkle et al. 2014 ), and increase resilience to wildfi re disturbances
(Chambers et al. 2014a ). This interpretation of revegetation highlights the importance
of adequate monitoring to identify the factors responsible for success and failure and
anticipate how establishment will infl uence plant community dynamics on restoration
projects. Effectively integrating monitoring results within an adaptive management
framework may require numerous iterations combined with parallel research studies to
identify effective restoration species (Jones and Monaco 2007 ; Leger and Baughman
2014 ) and make adjustments for the presence of environmental vagaries and edaphic
limitations of the restoration site (Hardegree et al. 2012 ; Karl et al. 2012 ).
12.5 Assessing B. tectorum Management: A Case Study
of the BLM
The BLM manages the majority of public rangelands in the USA outside of Alaska,
the majority of these lands occur in the Great Basin region of the Western USA,
where 30 million ha are managed by the BLM for multiple uses (livestock grazing,
recreation, energy development, mining, etc.). These landscapes have highly vari-
able topography, soils, and weather and support a wide variety of wildlife and native
plant communities (West 1979 ). The climate is semiarid with the majority of the
12 Assessing Restoration and Management Needs for Ecosystems...