144
Systematic conservation planning: past, present and future
Associated with the use of species surrogates (in particular using umbrella species, keystone species and
focal species) to achieve representation is the concept
of achieving functional or ecological redundancy,
which refers to the situation where there are multiple
species within an ecosystem that play similar ecological roles. Achieving functional redundancy is seen as
important objective, because the consequences of
losing all of the species that perform a particular ecological function within an ecosystem (e.g. losing all of
the algae feeders from a coral reef) could result in a
dramatic shift to a lower biodiversity system. Thus, the
amount of functional redundancy in a system is of
considerable importance in terms of retaining ecosystem integrity (Walker, 1992 ).
This approach requires that species with similar
ecological roles (termed functional groups) are identifi ed, along with the key processes that maintain ecological integrity. Conservation efforts can then be
aimed at maintaining a full suite of functional groups,
and functional groups with little or no redundancy
should be prioritized for conservation action (Walker,
1992 ).
The functional redundancy concept has been enthusiastically applied to the problem of conserving coral
reef ecosystems (Steneck & Dethier, 1994 ; Bellwood
et al ., 2004 ). Coral reefs are particularly prone to collapsing from a high diversity system to a low diversity
system dominated by algae and a few species of fi sh
(Scheffer et al ., 2001 ) although, until recently, the
causes of such phase shifts were poorly understood.
Recent comparative analysis of functional groups in
coral reefs from around the world strongly suggests
that high species diversity provides the potential for
functional redundancy (Bellwood et al ., 2004 ). Hence,
Caribbean reefs that are lacking several critical functional groups, or have groups represented by a small
number of species, have been particularly prone to
phase shifts to low diversity systems (Scheffer et al .,
2001 ). However, it should be noted that even in high
diversity coral reef systems, such as the Great Barrier
Reef in Australia, there are still some functional groups
with low redundancy (e.g. that are represented by a
small number of species) (Bellwood et al ., 2003 ).
Despite the support of concepts such as functional
redundancy by some systematic conservation planners, the overall level of support for species - based surrogates has been variable (Beger et al ., 2003, 2007 ;
Faith et al ., 2004a ). Since it is unlikely that it will
ever be possible to measure the true variation of
biodiversity within or between regions, or the overall
functional role played by all species in a region, the true
effectiveness of a species - based surrogate is indeterminable. Moreover, the underlying assumption that the
needs of a particular surrogate group of indicator
species will ensure the long - term persistence of all of
biodiversity may never be true as all individual species,
have, by defi nition, evolved to have their own specialized needs (see discussion on individualism in Chapter
3 ) and these needs will never be captured by a
surrogate.
Because of this, many recent conservation planning
exercises have used sets of species covering entire taxa
(i.e. all birds, all mammals, etc.), or assemblages of
species in a given area (e.g. combining plant, vertebrate and invertebrate data), as a surrogate for biodiversity in developing a conservation plan (Chapter 5 ,
and see, for example, Williams et al ., 1996 ; Sarakinos
et al ., 2001 ). In the case study outlined in Box 6.2 , 53
species were identifi ed that, when taken together, were
considered representative of the system in Maputaland.
These data were then combined with other data layers
in a systematic conservation planning exercise.
Environmental s urrogates
In the last decade, systematic conservation planning
studies have predominantly used environmental surrogates as general surrogates for biodiversity representation (e.g. Carwardine et al ., 2008 ; Klein et al ., 2008 ).
‘ Environmental surrogate ’ is a generic term covering
land or ecological classifi cations based primarily on
physical and climatic variables, which can incorporate
some biotic variables, such as vegetation type (Margules
& Sarkar, 2007 ). These variables are assumed to correlate with the patterns of species distribution, and
have been argued by some to be more useful than
species - based surrogates (compare: Ara ú jo et al ., 2001,
2003, 2004a ; Ferrier, 2002 ; Lombard et al ., 2003 ;
Faith et al ., 2004a ).
Environmental surrogates are often used because
these data are usually more readily available compared
to more detailed biological data. In the Californian
marine case study outlined in Box 6.3 , a number of key
habitats and a range of different depth classes were
considered good environmental surrogates. In the
Maputuland case study outlined in Box 6.2 , it was
argued that capturing the 44 land - cover types, as well
as the 53 species, was the most effective way to get a
representative system.
Systematic conservation planning: past, present and future
Associated with the use of species surrogates (in particular using umbrella species, keystone species and
focal species) to achieve representation is the concept
of achieving functional or ecological redundancy,
which refers to the situation where there are multiple
species within an ecosystem that play similar ecological roles. Achieving functional redundancy is seen as
important objective, because the consequences of
losing all of the species that perform a particular ecological function within an ecosystem (e.g. losing all of
the algae feeders from a coral reef) could result in a
dramatic shift to a lower biodiversity system. Thus, the
amount of functional redundancy in a system is of
considerable importance in terms of retaining ecosystem integrity (Walker, 1992 ).
This approach requires that species with similar
ecological roles (termed functional groups) are identifi ed, along with the key processes that maintain ecological integrity. Conservation efforts can then be
aimed at maintaining a full suite of functional groups,
and functional groups with little or no redundancy
should be prioritized for conservation action (Walker,
1992 ).
The functional redundancy concept has been enthusiastically applied to the problem of conserving coral
reef ecosystems (Steneck & Dethier, 1994 ; Bellwood
et al ., 2004 ). Coral reefs are particularly prone to collapsing from a high diversity system to a low diversity
system dominated by algae and a few species of fi sh
(Scheffer et al ., 2001 ) although, until recently, the
causes of such phase shifts were poorly understood.
Recent comparative analysis of functional groups in
coral reefs from around the world strongly suggests
that high species diversity provides the potential for
functional redundancy (Bellwood et al ., 2004 ). Hence,
Caribbean reefs that are lacking several critical functional groups, or have groups represented by a small
number of species, have been particularly prone to
phase shifts to low diversity systems (Scheffer et al .,
2001 ). However, it should be noted that even in high
diversity coral reef systems, such as the Great Barrier
Reef in Australia, there are still some functional groups
with low redundancy (e.g. that are represented by a
small number of species) (Bellwood et al ., 2003 ).
Despite the support of concepts such as functional
redundancy by some systematic conservation planners, the overall level of support for species - based surrogates has been variable (Beger et al ., 2003, 2007 ;
Faith et al ., 2004a ). Since it is unlikely that it will
ever be possible to measure the true variation of
biodiversity within or between regions, or the overall
functional role played by all species in a region, the true
effectiveness of a species - based surrogate is indeterminable. Moreover, the underlying assumption that the
needs of a particular surrogate group of indicator
species will ensure the long - term persistence of all of
biodiversity may never be true as all individual species,
have, by defi nition, evolved to have their own specialized needs (see discussion on individualism in Chapter
3 ) and these needs will never be captured by a
surrogate.
Because of this, many recent conservation planning
exercises have used sets of species covering entire taxa
(i.e. all birds, all mammals, etc.), or assemblages of
species in a given area (e.g. combining plant, vertebrate and invertebrate data), as a surrogate for biodiversity in developing a conservation plan (Chapter 5 ,
and see, for example, Williams et al ., 1996 ; Sarakinos
et al ., 2001 ). In the case study outlined in Box 6.2 , 53
species were identifi ed that, when taken together, were
considered representative of the system in Maputaland.
These data were then combined with other data layers
in a systematic conservation planning exercise.
Environmental s urrogates
In the last decade, systematic conservation planning
studies have predominantly used environmental surrogates as general surrogates for biodiversity representation (e.g. Carwardine et al ., 2008 ; Klein et al ., 2008 ).
‘ Environmental surrogate ’ is a generic term covering
land or ecological classifi cations based primarily on
physical and climatic variables, which can incorporate
some biotic variables, such as vegetation type (Margules
& Sarkar, 2007 ). These variables are assumed to correlate with the patterns of species distribution, and
have been argued by some to be more useful than
species - based surrogates (compare: Ara ú jo et al ., 2001,
2003, 2004a ; Ferrier, 2002 ; Lombard et al ., 2003 ;
Faith et al ., 2004a ).
Environmental surrogates are often used because
these data are usually more readily available compared
to more detailed biological data. In the Californian
marine case study outlined in Box 6.3 , a number of key
habitats and a range of different depth classes were
considered good environmental surrogates. In the
Maputuland case study outlined in Box 6.2 , it was
argued that capturing the 44 land - cover types, as well
as the 53 species, was the most effective way to get a
representative system.