Saving
The Sinking Salt Marshes: Comparing Restoration Case Studies to Louisiana’s
Breaux Act
Published
2005
Louisiana loses twenty-five to thirty-five
square miles of coastal marsh each year to the Gulf of Mexico (Britsch
and Dunbar 1993 in DeLaune et al. 2003). The natural replenishment
of sediments from the Mississippi River has been impeded by dams
and other flood control measures, and can not compensate for
sea level rise and natural subsidence (DeLaune
et al. 2003). Although these controls are designed to protect
other communities upstream, they are detrimental to the coastal
areas in southern Louisiana.
Coastal wetlands are a valuable resource
to both wildlife and humans. Salt marshes provide a unique habitat
for wildlife, especially migratory birds. Seventy percent of
commercial fisheries are supported by these habitats for part
or all of their lives (Save
the Bay 2005). In recent years a general acceptance that
the value of coastal wetlands has historically been underestimated
has lead to restoration of these projects.
Coastal
marshes dissipate tidal energy and are important natural protections
of coastlines, especially delta areas like Louisiana which suffer
the most from rising sea level (Kentula
2000). In addition to man-made constructions like sea walls,
coastal management strategies now include natural approaches such
as salt marsh restoration. Restoration is the enhancement or recreation
of degraded habitat using ecological engineering techniques. Mitigation
refers to the construction of new habitats in compensation for
those damaged by development projects.
Determining the success of restoration projects
The successful restoration of coastal wetlands is much more difficult
than policy makers and scientists tend to admit. The current policy
protecting the coastal and freshwater wetlands often assumes that
a restored or created habitat will fully replace the functions and
values of a natural system within a relatively short time. However,
Zedler and Callaway (1999) demonstrate restoration projects rarely
follow hypothetical trajectory models due to unforeseen dynamics
and an underestimated complexity of the systems. They later suggest
that progress, not success was a more appropriate way to describe
the evaluation of the effectiveness of restoration projects (Zedler
and Callaway 2000).
The word “success” in terms of restoration is misleading,
because it can be used in various contexts (Kentula
2000). Compliance
success can be reached by fulfilling requirements of an agreement
or permit with a governing agency. This often focuses on the acreage
of replacement (for mitigation) or the creation of minimal qualities
of habitat characteristics and simply fulfilling the project goals.
Functional success refers to the restoration of ecological values,
so that the system is biologically healthy and sustainable (Kentula
2000). Despite the governmental regulations, it is common to achieve
compliance success without functional success.
Often the failure to reach functional success is based on short-term
planning or inadequate understanding of the local ecosystem. These
shortcomings often include inappropriate location, unnatural shape,
excess sedimentation and/or erosion, unsuitable substrate, limited
nutrients or organic matter, and inadequate edge area around the
restoration site (Zedler and Callaway
2000). In addition to the
difficulty in obtaining full functional success, it is also more
difficult to
determine and requires more advanced monitoring techniques (Kentula
2000).
In many areas, including Louisiana, the goal of restoration is
to improve the overall ecosystem function with a series of restoration
projects (Steyer and Llewellyn 2000). Landscape success is achieved
when a restoration area contributes to the ecological integrity
of
surrounding ecosystems (Kentula 2000). This is the type of success
focused on in Louisiana, where projects are selected by a task
force comprised of federal and state agencies (Steyer
and Llewellyn 2000).
Their objective is to prioritize projects that will efficiently
allocate federal funds and effectively restore the coastal landscape,
based
on the evaluation of past projects.
The importance of monitoring restoration projects
The assessment of restoration projects is crucial for the improvement
of restoration techniques. Monitoring is used to regularly evaluate
the progress of a restoration project. Despite its importance, monitoring
is often the least supported step of restoration projects due to lack
of funding, commitment of time, appropriate control or reference sites,
standard protocol, sound science, and hypothesis testing (Steyer
and Llewellyn 2000). Monitoring required to fulfill a permit is
often discontinued before full assessment of the project process can
be completed. Or, in other cases the indicators used do not capture
the data to suggest reasons for successes or failures (Zedler
and Callaway 1999). This demonstrates a need to develop monitoring
techniques for salt marsh restoration projects.
If used correctly, monitoring can be used to update the current
understanding of social and ecological change (Steyer
and Llewellyn 2000). Adaptive
management is the term used to describe projects that take
account of monitoring results in the planning process.
This process allows
for flexibility so that if deviations from the original
plan occur, a process has been developed to ensure that the restoration
plan
continues to progress. Even the most well-planned projects
can face unexpected problems (Zedler
and Callaway 2000),
and adaptive
management
provides methods of managing and anticipating such events.
