Environmental Engineering Reference
In-Depth Information
3.4.3
Maintaining productive systems
may render it increasingly diffi cult to carry out tradi-
tional restoration which has as its aim the return of a
system to some historic state. However, it may still be
possible and desirable to do this in some circumstances,
particularly where society as a whole or local commu-
nity groups in particular are strongly motivated and
have the resources to do so. For instance, efforts to
restore prairie systems in urban remnants in Chicago
involve reinstating historic management practices and
ongoing removal of non-native plant species, but have
inspired both local groups and a city-wide movement,
the
Chicago Wilderness
( http://www.chicagowilderness.
org). In addition to these efforts, it may also be desira-
ble to try different approaches and aim for more future-
focused outcomes (Jackson & Hobbs 2009). A key
element in the response to climate change will most
likely be the need to actively plan for a varied set of
responses both at local and regional levels. Not doing
the same thing everywhere seems to be the best bet
when faced with an uncertain future. For instance, in
a restoration area, it may be useful to use different
mixes of species across the area, while such activities
as fi re management and grazing can be varied across
nature reserves.
Provision of a range of
ecosystem services
is essen-
tial to continued human existence on the planet, and
yet recent analyses suggest that humanity is living
beyond its means both by utilizing ecosystem services
at a greater rate than they can continue to be provided
and by degrading or transforming the ecosystems pro-
viding these services (Millennium Ecosystem Assess-
ment (MA) 2005). Food production, in particular, is a
key area of concern, with current agricultural prac-
tices in developed countries relying on high energy and
chemical inputs and often leading to on-site or down-
stream environmental degradation, despite recogni-
tion that a move to more sustainable practices is
essential (Kitzes
et al
. 2008 ; Pretty 2008 ). Meanwhile
in less developed parts of the world, subsistence
farming methods cannot supply suffi cient food to feed
growing populations or deal with climatic vagaries.
Similarly, global fi sheries are in decline, with over 60%
of fi sh stocks worldwide still requiring rebuilding, and
lower exploitation rates needed to reverse the collapse
of vulnerable species (Worm
et al
. 2009 ).
Reversing these trends is essential, even without
considering climate change. Often, simple changes in
practices can result in dramatic increases in productiv-
ity and its reliability. For instance, in arid areas where
ongoing degradation occurs, both broad-scale and
local actions can result in improved production (Bain-
bridge 2007a; Reynolds
et al
. 2007). As for conserva-
tion objectives mentioned above, current and future
climate change accentuates the need to implement
policies and practices which can help make ecosystems
and human societies more resilient to current and
future challenges.
3.4.5
Managing and restoring resilience
The word
resilience
is increasingly used as an impor-
tant property of both ecological and socio-ecological
systems, particularly in the context of responding to
and coping with climate change. But what does it
mean, really, and how can it be used in management
and restoration? In ecology, the term 'resilience' is
used for several purposes, but most commonly in refer-
ence to the ability of natural systems to recover from a
temporary
degradation
(cf. Holling 1996; Walker
et al
. 2004; see also Chapter 2). A focus on resilience
in conservation and ecosystem management may
increase our ability to understand and manage
socio -
ecological systems
by considering system-level proc-
esses and interactions, the integration of multiple
biotic and abiotic factors, interactions across spatial
and temporal scales and dynamic shifts in ecosystem
controls and management needs (e.g. Walker & Salt
2006). It also moves conservation beyond the concept
of static targets by explicitly acknowledging the need
to accommodate a shifting baseline (see Chapter 21).
Elmqvist
et al
. (2003) suggest that 'Resilience is neces-
sary to sustain desirable ecosystem states in variable
3.4.4 Restoring degraded systems - local
and regional
Ecological restoration
and
rehabilitation
can be
carried out for many reasons, including the return of
conservation or production value to systems which
have become degraded in some way (Hobbs & Norton
1996; Hobbs & Harris 2001). There was little consid-
eration until relatively recently of how restoration
efforts might be affected by climate change and how
practitioners might need to modify their goals and
approaches in the light of potential climate change
(Harris
et al
. 2006). As discussed above, climate change
