Biology Reference
In-Depth Information
the conclusion that simply controlling plants would not adequately define restora-
tion success and that long-term monitoring to characterize trends in various eco-
logical parameters was essential.
4.2.3 Project Design
Previous research suggested that salt stress may be sufficient to control certain plant
invaders (Burdick et al. 2001; Bart and Hartman 2002; Farnsworth and Meyerson
2003), and thus it was decided that a new channel would be excavated to bring salt
water into the system. A modified before-after-control-impact (BACI) monitoring
design was chosen to assess the effects of reconnection on various ecosystem
characteristics. BACI designs typically are applied in situations where the before
condition represents a predisturbance state (Green 1979; Stewart-Oaten et al. 1992;
Wiens and Parker 1995). The question in most BACI studies is whether changes in
an unimpacted environment can be attributed to an identified disturbance yet to
occur. At Sandpiper Pond we were interested in whether the current reconnection
would lead to system changes.
Selection of a BACI experimental design required both a delay in channel
excavation to allow collection of “before” data and the selection of reference or
control sites. A relatively short 3-4 months delay in channel excavation was
agreed to because of funding and scheduling concerns. For example, channel
construction had to be completed before the beginning of spring loggerhead sea
turtle nesting. The limited delay only allowed for collection of seasonally
restricted, winter to early spring, before data. The selection of control sites and
ability to optimize the detection of significant impact effects in typical BACI
studies is a subject of much concern (Underwood 1994; Benedetti-Cecchi 2001).
For the Sandpiper study, we selected two control sites: a saltwater pond (Jetty
Pond) created when the Murrells Inlet jetties were constructed and at approxi-
mately the same time as the impoundment of Sandpiper Pond, and a salt marsh
(Huntington Marsh) located on the backside of Huntington Beach State Park just
west of Sandpiper Pond. Jetty Pond (33:31:30 N, 79:02:12 W) was approximately
the same size as Sandpiper but remained connected to the ocean and was sur-
rounded by developing salt marshes predominated by
Spartina alterniflora
,
Spartina patens
,
Salicornia virginica
, and
Limonium carolinianum
. Huntington
Marsh (33:30:48 N, 79:03:22 W) specifically was chosen to represent a high-
marsh environment and was predominated by
Juncus roemerianus
. Rationale for
selecting a high-marsh site was driven by the observation that remnant popula-
tions of
J. roemerianus
still existed around Sandpiper Pond, and
J. roemerianus
represented a likely early “colonist” if opening the channel had the desired effect.
Multiple control or reference locations also were chosen to reduce limitations of
the BACI design (Underwood 1994) and because a priori information did not
suggest selection of a “correct” restoration target in view of the potentially strong
system modification by the plant invaders.
