76
Basic biogeography: estimating biodiversity and mapping nature
A number of prominent schemes for strategic
conservation planning (e.g. IUCN ’ s biogeographical
regions approach, WWF ecoregions; see Chapter 5 )
make use of biogeographical regionalization schemes
in constructing their analyses, and it is interesting to
speculate how adopting the more recently proposed
amendments might affect these conservation planning
exercises.
4.5 MAPPING FUNCTION
In Chapter 3 it was stated that, from a functionalist
perspective, a central goal of conservation is to restore
and maintain ecosystem processes. These processes
include: nutrient and hydrological cycles; ecological
processes such as pollination; genetic exchange; and,
ultimately, evolutionary processes such as adaptation
and speciation. Many of these processes, or aspects of
them, can be quantifi ed and represented in maps, as
can the functional ecological units within which they
operate: biomes, ecosystems and communities.
The concepts involved here are foundational to
modern ecology, and an investigation of the history of
these ideas quickly reveals the dualism between functionalism and compositionalism. Many of the key
papers discussed below are reproduced with commentary in the excellent volume edited by Real & Brown
(1991) , to which we refer readers who want to dig a
little deeper.
4.5.1 Biomes, e cosystems and c ommunities
The ecosystem is one of the most widely used and
poorly defi ned concepts in modern ecology. It has been
applied at almost every spatial scale, from the global to
the local, and is frequently used as a catch - all term that
can mean almost anything from habitat patches to
landscapes and geographical regions. The concept
itself dates back to a paper by Tansley (1935) , who
described what he meant by an ecosystem in these
terms:
‘ … the whole system (in the sense of physics), including not only the organism - complex, but also the
whole complex of physical factors forming what we
call the environment of the biome – the habitat
factors in the widest sense … the basic units of
nature on the face of the earth … and there is
outlined 21 continental subregions that were similar
to those constructed by de Candolle based solely on
plants some 56 years earlier.
Biogeographical regions have traditionally been
drawn up separately for animals and plants (Figure
4.10 ). The zoogeographical regions of Sclater and
Wallace have largely survived into modern times, and
differ somewhat from those for plants – the phytogeographical kingdoms/regions (Good, 1947 – 1974 ;
Takhtajan, 1986 ) – for reasons summarized by Cox
(2001) . One of the fi rst phytogeographical schemes
was Ronald Good ’ s Floristic Kingdoms, based on coincidence of distribution of unrelated taxa of fl owering
plants. Good identifi ed six separate ‘ kingdoms ’ and
various sub - kingdoms, provinces and, fi nally, fl oristic
regions. The remarkable fynbos fl ora in South Africa
merited a kingdom of its own.
While much of the terminology and the basic notions
have survived from the early attempts at geographically
sub - dividing the globe, recent approaches to revising
and updating depictions of regions have incorporated
more than a century of additional data on distributions
and taxonomy but, more importantly, have emphasized
different criteria for revising regional boundaries
(Figure 4.10 ). Cox (2001) argued for more consistent
apportioning of numbers of endemic taxa to delineate
a more equitable set of kingdoms and regions, maintained separate zoogeographical and phytogeographical regions, and also argued for removal of the
‘ Wallacean ’ zone of islands lying between Southeast
Asia and Australasia from any of the regions, owing to
its extreme biogeographical complexity.
Alternatively, Morrone (2002) used a panbiogeographical approach: fi rst, to argue for a unifi ed animal
and plant set of regions; and second, to base those
regions on the historical evolutionary affi nities associated with tectonic fragmentation of the Laurasian and
Gondwanan land masses into modern continents and
major islands. The most signifi cant innovation from
Morrone ’ s approach was to divide the South American
and Australian continents into two separate regions –
one with historical affi nities to an eastern Gondwana
biota, and the other with affi nities to a western
Gondwana biota. However, the most recent global
analysis of zoogeographical regions, by Kreft and Jetz
(2010) , using modern multivariate classifi cation techniques largely rejects Morrone ’ s suggestions and in fact
essentially reaffi rms the classic Wallacean framework,
while also providing a quantitative basis for identifi cation of the six main regions and sub - divisions of them.
Basic biogeography: estimating biodiversity and mapping nature
A number of prominent schemes for strategic
conservation planning (e.g. IUCN ’ s biogeographical
regions approach, WWF ecoregions; see Chapter 5 )
make use of biogeographical regionalization schemes
in constructing their analyses, and it is interesting to
speculate how adopting the more recently proposed
amendments might affect these conservation planning
exercises.
4.5 MAPPING FUNCTION
In Chapter 3 it was stated that, from a functionalist
perspective, a central goal of conservation is to restore
and maintain ecosystem processes. These processes
include: nutrient and hydrological cycles; ecological
processes such as pollination; genetic exchange; and,
ultimately, evolutionary processes such as adaptation
and speciation. Many of these processes, or aspects of
them, can be quantifi ed and represented in maps, as
can the functional ecological units within which they
operate: biomes, ecosystems and communities.
The concepts involved here are foundational to
modern ecology, and an investigation of the history of
these ideas quickly reveals the dualism between functionalism and compositionalism. Many of the key
papers discussed below are reproduced with commentary in the excellent volume edited by Real & Brown
(1991) , to which we refer readers who want to dig a
little deeper.
4.5.1 Biomes, e cosystems and c ommunities
The ecosystem is one of the most widely used and
poorly defi ned concepts in modern ecology. It has been
applied at almost every spatial scale, from the global to
the local, and is frequently used as a catch - all term that
can mean almost anything from habitat patches to
landscapes and geographical regions. The concept
itself dates back to a paper by Tansley (1935) , who
described what he meant by an ecosystem in these
terms:
‘ … the whole system (in the sense of physics), including not only the organism - complex, but also the
whole complex of physical factors forming what we
call the environment of the biome – the habitat
factors in the widest sense … the basic units of
nature on the face of the earth … and there is
outlined 21 continental subregions that were similar
to those constructed by de Candolle based solely on
plants some 56 years earlier.
Biogeographical regions have traditionally been
drawn up separately for animals and plants (Figure
4.10 ). The zoogeographical regions of Sclater and
Wallace have largely survived into modern times, and
differ somewhat from those for plants – the phytogeographical kingdoms/regions (Good, 1947 – 1974 ;
Takhtajan, 1986 ) – for reasons summarized by Cox
(2001) . One of the fi rst phytogeographical schemes
was Ronald Good ’ s Floristic Kingdoms, based on coincidence of distribution of unrelated taxa of fl owering
plants. Good identifi ed six separate ‘ kingdoms ’ and
various sub - kingdoms, provinces and, fi nally, fl oristic
regions. The remarkable fynbos fl ora in South Africa
merited a kingdom of its own.
While much of the terminology and the basic notions
have survived from the early attempts at geographically
sub - dividing the globe, recent approaches to revising
and updating depictions of regions have incorporated
more than a century of additional data on distributions
and taxonomy but, more importantly, have emphasized
different criteria for revising regional boundaries
(Figure 4.10 ). Cox (2001) argued for more consistent
apportioning of numbers of endemic taxa to delineate
a more equitable set of kingdoms and regions, maintained separate zoogeographical and phytogeographical regions, and also argued for removal of the
‘ Wallacean ’ zone of islands lying between Southeast
Asia and Australasia from any of the regions, owing to
its extreme biogeographical complexity.
Alternatively, Morrone (2002) used a panbiogeographical approach: fi rst, to argue for a unifi ed animal
and plant set of regions; and second, to base those
regions on the historical evolutionary affi nities associated with tectonic fragmentation of the Laurasian and
Gondwanan land masses into modern continents and
major islands. The most signifi cant innovation from
Morrone ’ s approach was to divide the South American
and Australian continents into two separate regions –
one with historical affi nities to an eastern Gondwana
biota, and the other with affi nities to a western
Gondwana biota. However, the most recent global
analysis of zoogeographical regions, by Kreft and Jetz
(2010) , using modern multivariate classifi cation techniques largely rejects Morrone ’ s suggestions and in fact
essentially reaffi rms the classic Wallacean framework,
while also providing a quantitative basis for identifi cation of the six main regions and sub - divisions of them.