341extreme cases, these invasions create vegetation states that are perpetuated by high
litter production, frequent fi re occurrence, and fundamentally altered nutrient
cycling (Parker and Schimel 2010 ; Davies and Nafus 2013 ). Without intervention,
these ecosystems may remain in a degraded vegetation state where grazing live-
stock, soil disturbances, and recurring fi res will favor annual relative to perennial
species (Hobbs et al. 2007 ). Furthermore, net primary production and annual pre-
cipitation are highly variable in arid and semiarid ecosystems (Clinton et al. 2010 ),
which amplifi es their vulnerability to plant community disruption associated with
climate change (Bradley 2009 ).
Given the prevalence of Bromus invasions in the Western USA , the objectives of
this chapter are to (1) identify common characteristics responsible for the persis-
tence of problematic Bromus in this region; (2) illustrate how future research and
management can better address underlying processes responsible for annual grass
persistence through the adoption of adaptive management; (3) assess past research
efforts to control the problematic species, B. tectorum , with a case study of treat-
ment outcomes; and (4) assess management efforts to remediate landscapes
impacted by B. tectorum and improve greater sage-grouse ( Centrocercus urophasia-
nus Bonaparte; sage-grouse hereafter) habitat with a case study from the Great
Basin region of the Western USA. We conclude that adapting for the future will
need continued integration between research and management, greater understand-
ing of ecological processes, and long-term experiments to inform adaptive manage-
ment decisions. Although we emphasize heavily invaded ecosystems that require
long-term, continual management efforts, our assessment is also relevant to conser-
vation and preventative restoration projects.
12.2 Exotic Annual Bromus Grasses in Western USA
Ecosystems
Many Bromus impact semiarid and arid ecosystems of the Western USA (Brooks
et al. 2015 ; Germino et al. 2015 ; Atkinson and Brown 2015 ). While species have
unique distributions and climate suitability as described in previous chapters, here,
we review the fi ve most notable species in order to identify common characteristics
that must be addressed by restoration practitioners.
12.2.1 Bromus hordeaceus
Bromus hordeaceus L. (soft brome or chess) is a common component of California’s
annual grasslands. Compared to other species in annual grasslands, B. hordeaceus
has relatively shallow roots (Brown and Rice 2010), seed longevity is very short
irrespective of depth and duration of burial in seed banks, and seedling survival is
generally higher for seeds germinating at the soil surface (Jensen 2009 ). Like many
12 Assessing Restoration and Management Needs for Ecosystems...