222
Applied island biogeography
sity and for abundances of wildlife (e.g. see Gascon
et al. , 1999 ; Gates & Donald, 2000 ).
Conservation requires pragmatic decision - making.
As we continue to fragment landscapes, island effects
may inform such decision - making, but should not be
oversimplifi ed. There is no single message, and no
single island effect; indeed, insularity may sometimes
bring positive as well as negative effects (Lockwood &
Moulton, 1994 ). Island effects may be weak or strong.
The implications of insularity vary, depending on such
factors as the type(s) of organism involved, the type(s)
of landscapes involved, the nature of the environmental dynamics, the biogeographical setting and the
nature of human use and involvement in the system
being fragmented.
In closing this chapter, we return to the basic question posed in the introduction: is it realistic to expect
habitat islands to behave according to the same principles as real islands? Our answer is yes , but caution is
needed in the island theories and models we are using.
Island systems of generally restricted spatial extent
and most importantly similar age and intrinsic rates of
change in time to habitat islands (e.g. Terborgh et al. ,
2001, 2006 ; Cody, 2006 ) will probably continue to
offer more relevant principles for the understanding of
processes such as relaxation in habitat islands and
their more effective preservation.
As island biogeography moves towards new syntheses and theories, we anticipate that this body of work
will become increasingly helpful for understanding
and conserving our natural world.
FOR DISCUSSION
1 In what circumstances are scattered protected areas
of modest size better than a few large ones?
2 What is the relationship between the SLOSS debate
and nestedness?
3 How important is it to take account of underlying
biogeographical structure within a region when applying island models to projecting species extinctions?
4 Is there any optimal slope ( z ) value for models
projecting species losses based on species – area relationships, and what is the relevance of such models if
no account is taken of efforts made to mitigate these
losses?
5 How important is connectivity between patches for
maintaining species diversity in a landscape?
low population density, slow life history, small geographical range, ‘ ecological naivety ’ , is currently one
of the great challenges of conservation biology. Studies
on islands, nature ’ s test tubes and the location of a
high proportion of globally threatened species, will
certainly offer signifi cant insights in this research
program.
4 Matrix: The number of species held in a reserve
(or reserve system) is actually less important than the
conservation of those species which cannot survive
outside the remnants (e.g. Newmark, 1991 ). Some
recent efforts have been made to move beyond an
exclusive focus on (forest) fragments and towards
understanding the role of such habitat islands within
mixed - use landscapes. This switch in emphasis comes
under varying headers. For example, Watson et al .
(2005) show that the incidence functions of woodland
bird species in three different landscapes in the
Canberra area of Australia differ signifi cantly, seemingly as a function of differences in properties of the
landscape matrix within which the woodlands are
embedded. Hence, Watson et al . ( 2005 ) join others (e.g.
Ewers & Didham, 2006 ) in calling for greater attention
to ‘ matrix effects ’ .
J.B. Hughes et al . (2002) adopted a slightly different
approach within their study in southern Costa Rica,
focusing on the extent to which native forest species
make use of the surrounding countryside. They found
that some 46 per cent of bird species foraged often kilometres away from extensive areas of native forest.
Although they stress that not all species can be so
readily accommodated outside large tracts of native
forests, their work supports the importance of developing ‘ countryside ’ landscapes that are biodiversity -
friendly and penetrable by native fauna (as Harris,
1984 ). Daily and colleagues (e.g. Daily et al ., 2001,
2003 ) coin the term ‘ countryside biogeography ’ for
this switch in attention from remnants per se to the way
in which remnants function within whole landscapes.
This switch in emphasis is similar to that promoted by
Rosenzweig (2003) under the heading ‘ reconciliation
ecology ’ . But whether we label it ‘ matrix effects ’ ,
‘ countryside biogeography ’ or ‘ reconciliation ecology ’ ,
the common element is a realization that effective conservation must include consideration of what happens
outside reserves. The way we shape the countryside,
whether we farm intensively or extensively, whether we
retain hedgerows and trees within mixed landscapes,
can all have profound implications for regional diver-
Applied island biogeography
sity and for abundances of wildlife (e.g. see Gascon
et al. , 1999 ; Gates & Donald, 2000 ).
Conservation requires pragmatic decision - making.
As we continue to fragment landscapes, island effects
may inform such decision - making, but should not be
oversimplifi ed. There is no single message, and no
single island effect; indeed, insularity may sometimes
bring positive as well as negative effects (Lockwood &
Moulton, 1994 ). Island effects may be weak or strong.
The implications of insularity vary, depending on such
factors as the type(s) of organism involved, the type(s)
of landscapes involved, the nature of the environmental dynamics, the biogeographical setting and the
nature of human use and involvement in the system
being fragmented.
In closing this chapter, we return to the basic question posed in the introduction: is it realistic to expect
habitat islands to behave according to the same principles as real islands? Our answer is yes , but caution is
needed in the island theories and models we are using.
Island systems of generally restricted spatial extent
and most importantly similar age and intrinsic rates of
change in time to habitat islands (e.g. Terborgh et al. ,
2001, 2006 ; Cody, 2006 ) will probably continue to
offer more relevant principles for the understanding of
processes such as relaxation in habitat islands and
their more effective preservation.
As island biogeography moves towards new syntheses and theories, we anticipate that this body of work
will become increasingly helpful for understanding
and conserving our natural world.
FOR DISCUSSION
1 In what circumstances are scattered protected areas
of modest size better than a few large ones?
2 What is the relationship between the SLOSS debate
and nestedness?
3 How important is it to take account of underlying
biogeographical structure within a region when applying island models to projecting species extinctions?
4 Is there any optimal slope ( z ) value for models
projecting species losses based on species – area relationships, and what is the relevance of such models if
no account is taken of efforts made to mitigate these
losses?
5 How important is connectivity between patches for
maintaining species diversity in a landscape?
low population density, slow life history, small geographical range, ‘ ecological naivety ’ , is currently one
of the great challenges of conservation biology. Studies
on islands, nature ’ s test tubes and the location of a
high proportion of globally threatened species, will
certainly offer signifi cant insights in this research
program.
4 Matrix: The number of species held in a reserve
(or reserve system) is actually less important than the
conservation of those species which cannot survive
outside the remnants (e.g. Newmark, 1991 ). Some
recent efforts have been made to move beyond an
exclusive focus on (forest) fragments and towards
understanding the role of such habitat islands within
mixed - use landscapes. This switch in emphasis comes
under varying headers. For example, Watson et al .
(2005) show that the incidence functions of woodland
bird species in three different landscapes in the
Canberra area of Australia differ signifi cantly, seemingly as a function of differences in properties of the
landscape matrix within which the woodlands are
embedded. Hence, Watson et al . ( 2005 ) join others (e.g.
Ewers & Didham, 2006 ) in calling for greater attention
to ‘ matrix effects ’ .
J.B. Hughes et al . (2002) adopted a slightly different
approach within their study in southern Costa Rica,
focusing on the extent to which native forest species
make use of the surrounding countryside. They found
that some 46 per cent of bird species foraged often kilometres away from extensive areas of native forest.
Although they stress that not all species can be so
readily accommodated outside large tracts of native
forests, their work supports the importance of developing ‘ countryside ’ landscapes that are biodiversity -
friendly and penetrable by native fauna (as Harris,
1984 ). Daily and colleagues (e.g. Daily et al ., 2001,
2003 ) coin the term ‘ countryside biogeography ’ for
this switch in attention from remnants per se to the way
in which remnants function within whole landscapes.
This switch in emphasis is similar to that promoted by
Rosenzweig (2003) under the heading ‘ reconciliation
ecology ’ . But whether we label it ‘ matrix effects ’ ,
‘ countryside biogeography ’ or ‘ reconciliation ecology ’ ,
the common element is a realization that effective conservation must include consideration of what happens
outside reserves. The way we shape the countryside,
whether we farm intensively or extensively, whether we
retain hedgerows and trees within mixed landscapes,
can all have profound implications for regional diver-