CHAPTER 6 • Coastal Environmental Management in Southeast Australia:The Roles of Ecology
III
an end in itself, with little evaluation of the success or failure of its desired outcomes
(reviewed by Eliot 1985; Race 1985).
Restoring wetlands can have many forms, including increasing on changing drainage channels, altering the tidal regime (Zedler 1996), building banks or levees, or recreating new wetlands de novo (Griffiths 1995). These are all very large experimental
manipulations. Nevertheless, they are seldom treated as such and the outcomes of restoration are seldom interpreted within an experimental framework. The need or desire for restoration usually comes from a series of observations that the habitat under
consideration is degraded or damaged in some way - usually with respect to the diversity or abundances of animals and/or plants. For example, the managerial decision
to change tidal flushing in patches of urban wetland around Homebush Bay (Port
Jackson, New South Wales, Australia) was based on the perception that these habitats
were d~pauperate in marine benthic macrofauna in contrast to similar habitats with
better tidal flushing (Berents 1993). Inadequate flushing by tidal waters from the nearby
bay was therefore proposed as the reason for the depauperate nature of the fauna.
Sinillarly, tidal flow was restored to Batiquidos Lagoon (Calif., USA) to compensate for
loss of habitat for fish in Los Angeles harbour (Zedler 1996). The observations were that
i. there had been much loss of habitat and
ii. Batiquidos Lagoon was of little value because it was non-tidal.
The managerial decision to change totally the tidal regime to the area was based on
the model that tidal flushing is necessary to provide suitable habitat for fish. Such
models lead to the hypothesis (prediction) that enhanced tidal flushing will
i. increase density and/or abundances of benthic macrofauna and
ii. increase areas of habitat for fish and, ultimately, increase density/abundances of fish.
Hence, the decision is made to alter tidal flushing.
Unfortunately, with respect to most restoration projects, this is where the scientific process stops (reviewed by Kentula et al. 1992). In many instances, the necessary tests of the
prediction are not made (no monitoring is done of the predicted changes; Race and
Fonseca 1996). The managerial actions are simply assumed to have had the desired effects.
In some cases at least, this is because monitoring (on other equivalent measurements)
after restoration is not legally required by the conditions of the permit (or other
permissions) (Race and Fonseca 1996). In many cases, it is because, although monitoring is required, the design of such monitoring has not been thought out in the framework of experimental design. (Kentula et al. 1992; Chapman and Underwood 1997a).
Although the precise definitions of restoration often vary from project to project, they
are often based on what society wants, rather than what is ecologically feasible. It is extremely common to suggest successful recovery to an historic or previous condition (Bradshaw 1987; Brinson and Rheinhardt 1996; Cairnes 1996). This is meaningless because
i. there is no realistic way to determine which previous condition is the appropriate
one (Botkin 1990) and
ii. there is increasing evidence that nature is not equilibrial or balanced (see earlier);
temporal change and spatial variation are natural.
III
an end in itself, with little evaluation of the success or failure of its desired outcomes
(reviewed by Eliot 1985; Race 1985).
Restoring wetlands can have many forms, including increasing on changing drainage channels, altering the tidal regime (Zedler 1996), building banks or levees, or recreating new wetlands de novo (Griffiths 1995). These are all very large experimental
manipulations. Nevertheless, they are seldom treated as such and the outcomes of restoration are seldom interpreted within an experimental framework. The need or desire for restoration usually comes from a series of observations that the habitat under
consideration is degraded or damaged in some way - usually with respect to the diversity or abundances of animals and/or plants. For example, the managerial decision
to change tidal flushing in patches of urban wetland around Homebush Bay (Port
Jackson, New South Wales, Australia) was based on the perception that these habitats
were d~pauperate in marine benthic macrofauna in contrast to similar habitats with
better tidal flushing (Berents 1993). Inadequate flushing by tidal waters from the nearby
bay was therefore proposed as the reason for the depauperate nature of the fauna.
Sinillarly, tidal flow was restored to Batiquidos Lagoon (Calif., USA) to compensate for
loss of habitat for fish in Los Angeles harbour (Zedler 1996). The observations were that
i. there had been much loss of habitat and
ii. Batiquidos Lagoon was of little value because it was non-tidal.
The managerial decision to change totally the tidal regime to the area was based on
the model that tidal flushing is necessary to provide suitable habitat for fish. Such
models lead to the hypothesis (prediction) that enhanced tidal flushing will
i. increase density and/or abundances of benthic macrofauna and
ii. increase areas of habitat for fish and, ultimately, increase density/abundances of fish.
Hence, the decision is made to alter tidal flushing.
Unfortunately, with respect to most restoration projects, this is where the scientific process stops (reviewed by Kentula et al. 1992). In many instances, the necessary tests of the
prediction are not made (no monitoring is done of the predicted changes; Race and
Fonseca 1996). The managerial actions are simply assumed to have had the desired effects.
In some cases at least, this is because monitoring (on other equivalent measurements)
after restoration is not legally required by the conditions of the permit (or other
permissions) (Race and Fonseca 1996). In many cases, it is because, although monitoring is required, the design of such monitoring has not been thought out in the framework of experimental design. (Kentula et al. 1992; Chapman and Underwood 1997a).
Although the precise definitions of restoration often vary from project to project, they
are often based on what society wants, rather than what is ecologically feasible. It is extremely common to suggest successful recovery to an historic or previous condition (Bradshaw 1987; Brinson and Rheinhardt 1996; Cairnes 1996). This is meaningless because
i. there is no realistic way to determine which previous condition is the appropriate
one (Botkin 1990) and
ii. there is increasing evidence that nature is not equilibrial or balanced (see earlier);
temporal change and spatial variation are natural.