Environmental Engineering Reference
In-Depth Information
also reducing wildfi re threats to humans and built
environments in fi re-prone areas, is certainly of the
most challenging issues in the land management and
restoration of MCR woodlands and shrublands.
gent traits (e.g. they are not sclerephyllous, and many
of them do not resprout after fi re) (Verd ú
et al
. 2003 ).
Therefore, MCRs show a long-standing common back-
ground of characteristic woody taxa that have sur-
vived drastic climate change, both slow and fast. An
open question is whether these species will endure pro-
jected climate change in their respective MCRs, in a
human-altered and much more fragmented habitat.
Climate change
must be taken into account when
restoring ecosystems at the present time, considering
that they should be functional by the middle of the
twenty - fi rst century under changed climate. It has
become increasingly clear that knowledge of the past
is not necessarily a good - or even suffi cient - guide for
understanding or planning for the future (Pahl-Wostl
2007). This is particularly so when considering the
adaptability and acclimation capability of various
species or functional types to a projected new climate,
and the associated fi re regime conditions. For example,
no one knows how ecotypes and genotypes of Mediter-
ranean plant species will respond to the projected
intensifi cation of drought and new, more severe fi re
regimes. Taking a precautionary principle, it is proba-
bly wise to fully explore the adaptation and acclimation
potential of native species beyond local seed sources
(Crowe & Parker 2008) before assisting the migration
of currently alien species or subspecies from drier
areas. To cope with the
uncertainty
induced by climate
change, restoration and management must be
adap-
tive
, trying to improve ecosystem resistance and/or
resilience, and managing landscapes to facilitate
species migration (Stephens
et al
. 2010 ).
Increased knowledge of the pattern of climate vari-
ability may be used to plan restoration activities. In
many Mediterranean semi-arid and arid regions, inter-
annual variability in precipitation is strongly associ-
ated to El Niño Southern Oscillation (ENSO). Increased
rainfall during ENSO events is crucial for plant recruit-
ment and productivity in these systems and may cause
long-lasting effects on vegetation depending on the
prevalent herbivore pressure (Holmgren & Scheffer
2001 ). Indeed, fi eld studies in arid zones of North
America have indicated that successful recruitment
of woody vegetation takes place during rainy ENSO
events, especially when herbivores were excluded
(Bowers 1997 ).
Holmgren and Scheffer (2001) proposed that
increased tree and shrub establishment during rainy
ENSO events could be improved by controlling main
herbivores, thereby facilitating a switch of degraded
11.3.1
Evaluation and social involvement
Ecological restoration has a strong socio-economic
component, particularly in highly populated areas
such as the MCRs, where human societies have co-
evolved with landscapes for centuries or millennia.
Thus, social actors should participate in defi ning the
objectives of restoration actions and through the eval-
uation process. The ecosystem service approach (Mil-
lennium Ecosystem Assessment (MA) 2005) provides
an excellent opportunity to involve people and encour-
age participative management. There are many exam-
ples of such initiatives, and on the use of decision - making
tools, such as multicriteria decision models, to support
the identifi cation of restoration targets in MCRs (Díaz-
Balteiro & Romero 2008 ).
In order to improve our understanding of the success
or failure of restoration actions, there is a need for
long-term monitoring and evaluation of restoration
actions. Evaluating ecological restoration success on
the ecosystem and landscape scales can be performed
using carefully selected suites of indicators (e.g.
Aronson & Le Floc ' h 1996 ; Vallauri
et al
. 2005 ).
Although widely accepted standard protocols are not
yet available, recent initiatives integrate biophysical
and socio-economic aspects of restoration projects (e.g.
Bautista & Alloza 2009, for Mediterranean Basin
woodlands and shrublands).
11.3.2
Restoration and climate change
Woody vegetation that evolved in the Mediterranean
Basin during the Pliocene shares common features
such as sclerophylly, evergreeness and the ability to
resprout after fi re of many species (Blondel & Aronson
1999). However, these life-history traits are associated
to Tertiary lineages that arose from tropical and tem-
perate ancestors prior to the appearance of Mediter-
ranean climate conditions in the last 3-5 million years
(Herrera 1992; Blondel
et al
. 2010), and the Quater-
nary taxa evolved under Mediterranean climate in the
various MCRs in the world do not show such conver-
