42
Baselines, patterns and process
3.6 ADAPTIVE ECOSYSTEM
MANAGEMENT
The complexity of ecological systems and the uncertainty with which ecosystem changes can be predicted
raises dilemmas for ecosystems managers, who must
make decisions when knowledge is imperfect and
stakes are high (Funtowicz & Ravetz, 1994 ; Ravetz &
Funtowicz, 1999 ). The management of ecosystems
requires recognition that, for any given ecosystem,
there may be a range of possible ecosystem states and
an equally wide variety of societal responses to these
states (Ravetz & Funtowicz, 1999 ). This uncertainty,
complexity and plurality requires an adaptive approach
to ecosystem management, i.e. one that continually
monitors and evaluates the outcomes of management
interventions and adjusts conservation and management goals in the light of new scientifi c understanding,
inputs from stakeholders or ecological surprises
(Grumbine, 1994, 1997 ; Sabine et al ., 2004 ). Critically,
ecosystem managers need to know the position of ecological thresholds so that they can maintain desired
states or facilitate benefi cial changes through management interventions.
In Australian rangelands, Westoby et al . (1989)
described an opportunistic management system for
rangelands, based on the idea of state and transition
(see Section 3.4.1). This management approach
required understanding of the processes that drive
transitions between phases, along with a classifi cation
of known vegetation phases according to whether they
are favourable or unfavourable – primarily for livestock
owners, but the principle could equally be extended to
biodiversity conservation. Favourable transitions, such
as a change from saltbush to grass - dominated vegetation with scattered woody plants, could be facilitated
by de - stocking, whereas maintaining grazing pressure
would be more likely to cause a transition to shrub
cover, a phase less favourable for livestock (Westoby
et al ., 1989 ).
In the Kruger National Park (KNP), South Africa,
strategic adaptive ecosystem management (Figure 3.6 )
is used, with the aim of maintaining natural ecological
dynamics (Biggs & Rogers, 2003 ). KNP ecologists and
international collaborators have developed process -
orientated management goals, based on ecosystem
properties, known as Thresholds of Potential Concern
(TPC). These thresholds are points along a continuum
of ecological or environmental change, at which managers either intervene to guide ecosystem change, or at
the success of such reintroductions might depend on
the successful establishment of wild populations of
predators or, alternatively, on maintaining at least
some element of management of herbivore populations by humans (van Wieren, 1991 ).
Rewilding clearly offers a potential alternative to the
current target - driven, intensively managed approach
to conservation that is common in many parts of the
world and especially Europe. Its combination of functionalist objectives achieved through recreating past
assemblages also offers a fl exible approach that has
potential to be scaled up to encompass entire landscapes (see also Chapter 2 , Section 2.5.2 ).
3.5.4 The c hallenge of r apid
e nvironmental c hange
One of the potential problems of using baselines
derived from palaeoecology, historical records or
relict populations as guidelines for restoration and
conservation initiatives is that the environment may
have changed to such a degree that maintaining
historical species assemblages is no longer a viable
option. This issue is gaining increasing attention due
to the widespread concern with anthropogenic climate
change.
The most recent prediction of the Intergovernmental
Panel on Climate Change (IPCC) is that global temperatures could rise by between 1.1 and 6.4 ° C (2.0 and
11.5 ° F) during the 21st century, accompanied by
changes in precipitation regimes, extreme conditions
and seasonality (IPCC, 2007 ). Such changes, when
combined with ongoing destruction, fragmentation
and modifi cation of natural habitats and ecosystems,
and the anthropogenic transportation of non - native
species, will generate unique suites of environmental
conditions, novel ecosystems and novel communities
(see e.g. Willis & Bhagwat, 2009 ).
In such circumstances, identifying current or past
community compositions as target baselines will
become increasingly problematic and impractical
(Hannah et al ., 2002b ). Bush (2002) suggests that the
solution to this problem is to concentrate on conserving animal and plant niches rather than identifi able
communities, but the scientifi c challenges involved in
determining niche requirements at the species level on
the scale required are, of course, not trivial. Further
discussion of these challenges follows in Chapter 6 and
especially in Chapter 7 .
Baselines, patterns and process
3.6 ADAPTIVE ECOSYSTEM
MANAGEMENT
The complexity of ecological systems and the uncertainty with which ecosystem changes can be predicted
raises dilemmas for ecosystems managers, who must
make decisions when knowledge is imperfect and
stakes are high (Funtowicz & Ravetz, 1994 ; Ravetz &
Funtowicz, 1999 ). The management of ecosystems
requires recognition that, for any given ecosystem,
there may be a range of possible ecosystem states and
an equally wide variety of societal responses to these
states (Ravetz & Funtowicz, 1999 ). This uncertainty,
complexity and plurality requires an adaptive approach
to ecosystem management, i.e. one that continually
monitors and evaluates the outcomes of management
interventions and adjusts conservation and management goals in the light of new scientifi c understanding,
inputs from stakeholders or ecological surprises
(Grumbine, 1994, 1997 ; Sabine et al ., 2004 ). Critically,
ecosystem managers need to know the position of ecological thresholds so that they can maintain desired
states or facilitate benefi cial changes through management interventions.
In Australian rangelands, Westoby et al . (1989)
described an opportunistic management system for
rangelands, based on the idea of state and transition
(see Section 3.4.1). This management approach
required understanding of the processes that drive
transitions between phases, along with a classifi cation
of known vegetation phases according to whether they
are favourable or unfavourable – primarily for livestock
owners, but the principle could equally be extended to
biodiversity conservation. Favourable transitions, such
as a change from saltbush to grass - dominated vegetation with scattered woody plants, could be facilitated
by de - stocking, whereas maintaining grazing pressure
would be more likely to cause a transition to shrub
cover, a phase less favourable for livestock (Westoby
et al ., 1989 ).
In the Kruger National Park (KNP), South Africa,
strategic adaptive ecosystem management (Figure 3.6 )
is used, with the aim of maintaining natural ecological
dynamics (Biggs & Rogers, 2003 ). KNP ecologists and
international collaborators have developed process -
orientated management goals, based on ecosystem
properties, known as Thresholds of Potential Concern
(TPC). These thresholds are points along a continuum
of ecological or environmental change, at which managers either intervene to guide ecosystem change, or at
the success of such reintroductions might depend on
the successful establishment of wild populations of
predators or, alternatively, on maintaining at least
some element of management of herbivore populations by humans (van Wieren, 1991 ).
Rewilding clearly offers a potential alternative to the
current target - driven, intensively managed approach
to conservation that is common in many parts of the
world and especially Europe. Its combination of functionalist objectives achieved through recreating past
assemblages also offers a fl exible approach that has
potential to be scaled up to encompass entire landscapes (see also Chapter 2 , Section 2.5.2 ).
3.5.4 The c hallenge of r apid
e nvironmental c hange
One of the potential problems of using baselines
derived from palaeoecology, historical records or
relict populations as guidelines for restoration and
conservation initiatives is that the environment may
have changed to such a degree that maintaining
historical species assemblages is no longer a viable
option. This issue is gaining increasing attention due
to the widespread concern with anthropogenic climate
change.
The most recent prediction of the Intergovernmental
Panel on Climate Change (IPCC) is that global temperatures could rise by between 1.1 and 6.4 ° C (2.0 and
11.5 ° F) during the 21st century, accompanied by
changes in precipitation regimes, extreme conditions
and seasonality (IPCC, 2007 ). Such changes, when
combined with ongoing destruction, fragmentation
and modifi cation of natural habitats and ecosystems,
and the anthropogenic transportation of non - native
species, will generate unique suites of environmental
conditions, novel ecosystems and novel communities
(see e.g. Willis & Bhagwat, 2009 ).
In such circumstances, identifying current or past
community compositions as target baselines will
become increasingly problematic and impractical
(Hannah et al ., 2002b ). Bush (2002) suggests that the
solution to this problem is to concentrate on conserving animal and plant niches rather than identifi able
communities, but the scientifi c challenges involved in
determining niche requirements at the species level on
the scale required are, of course, not trivial. Further
discussion of these challenges follows in Chapter 6 and
especially in Chapter 7 .