Biology Reference
In-Depth Information
nearshore geological processes or from human activities such as marsh filling and
diking. Generally, salt marshes cut-off from the ocean are converted to fresh or
brackish marshes that can be invaded by perennial monocots including the com-
mon reed grass (
Phragmites austalis
) and cattails (
Typha
spp.). Ecological effects
of
Phragmites
invasions and attempts at removal have been studied extensively in
the Northeast USA from Massachusetts to Maryland (Boumans et al. 2003;
Gratton and Denno 2006; Kimball and Able 2007; Teal and Weishar 2005).
Phragmites
invasions generally are less common and less well studied in the
southeastern US.
The economic value of various ecological functions associated with tidal salt
marshes (Costanza et al. 1997) has increased the interest of coastal managers to
restore modified and/or invaded salt marsh sites. Restoration goals for impounded
marshes typically, when stated, include reestablishment of tidal exchange, elimina-
tion of salt-intolerant and/or invasive grasses, and eventual development of ecologi-
cal attributes similar to natural or reference tidal marshes (Roman et al. 2002;
Warren et al. 2002). However, many problems and questions associated with marsh
restoration remain because of difficulties in defining which ecological characteris-
tics and/or which reference marshes should be considered. Evidence to date indi-
cates certain marsh characteristics remain dissimilar to natural marshes decades
after restoration (Craft et al. 2003; Zedler and West 2008). Coastal systems also can
be unstable and characterized by a long history of switching from one ecological
state to another (Booth et al. 1999; Zedler and West 2008), making determination
of an appropriate restoration target difficult. Furthermore, coastal marshes increas-
ingly are fringed by residential and commercial development making marsh condi-
tions inextricably connected to and dependent on the social, political, and economic
environment of coastal communities. The connection between marshes and local
human communities means that any restoration activities will be influenced by a
diverse array of stakeholders.
Plants frequently form the foundation for categorizing systems (e.g.,
Spartina
-
marsh), and plant management emerges as a primary activity in most restoration
projects (Young 2000; Young et al. 2005). When plant invasions are present, plant
eradication or control generally are required. Although the successful management
and restoration of plant invasions must be guided by ecological theory and accepted
research approaches (Neckles et al. 2002), managers universally recognize that a
strong theoretical background is only one part of the restoration process. Along
with ecological theory, a range of economic, political, and social factors can influ-
ence efforts to manage plant invasions as was shown in the case study involving
knapweed, an introduced species invading pastures and rangeland in Colorado
(Luken and Seastedt 2004)
This chapter focuses on what ostensibly is a salt marsh restoration project
located in coastal South Carolina, USA. We use the restoration project to illustrate
processes common to many efforts involving habitat restoration and invasive spe-
cies, namely how an initially simple instance of controlling plant invaders eventu-
ally developed into a complex case of ecosystem management. We attempt to
clarify the frequently conflicted nexus among researchers focused on testing for
