164
Planning for persistence in a changing world
Darling, 1985 ; Opdam et al. , 1999 ; Parmesan & Yohe,
2003 ; Felton et al. , 2009 ).
Despite the importance of dynamic processes such
as climate in continually shaping biological systems, a
recent review of the conservation planning literature
showed that about 80 per cent of studies assume that
neither biodiversity nor the processes threatening the
persistence of biodiversity change over time (Pressey
et al. , 2007 ). This is despite the fact that a decade has
now elapsed since the fi rst demonstrations of dynamic
approaches to planning protected area networks to
promote the long - term persistence of biodiversity
(Cowling et al. , 1999 ).
Second, even if we successfully conserve processes
that generate and maintain biodiversity, the resulting
pattern that we see today is only one brief snapshot of
a continuously changing system. As if huge spatial
complexity isn ’ t challenge enough for conservation,
ecosystems are continuously changing over time
(Chapter 3 ), species ’ distributions and abundances
expand and contract (Figure 7.1 ), land bridges
between continents come and go with changes in sea
level and communities are thrown together and then
separate.
Deep history leaves a signature in the structure of
present - day communities (Box 7.1 ). For example,
modern marine bivalve assemblages show a clear
break in species ’ ages corresponding with recovery
from the end - Cretaceous mass extinction event (Krug
et al. , 2009 ). Pleistocene climatic change has promoted
massive movements of species populations, often
forming novel assemblages, and alternatively isolating
and rejoining populations, generating speciation in
some lineages and strong phylogenetic structure in
many others (e.g. Riddle & Hafner, 1999, 2006 ; Hewitt,
2000 ; Bush & de Oliviera, 2006 ; Avise, 2009 ). To
provide a specifi c example, Neotoma woodrats appear
to have tracked oscillating climates through time by
changes in their body size (Smith et al. , 1995 ).
The biology of many species thus plays out across
time as much as across space, and conservation efforts
must therefore track an ever - moving target.
Third, threats to biodiversity change in type, distribution and severity over time (for an analysis focused
on changing threats on islands, see Whittaker &
Fern á ndez - Palacios, 2007 ). If conservation is about
buffering samples of biodiversity from threats, then
both the nature of the buffers employed, and where
they are instigated, must depend on the type, location
and intensity of threats and how these change through
time. The cost (e.g. social, economic, political) of
particular conservation action relative to its likely
benefi t is also highly dynamic, so conservation plans
must be continually updated to refl ect changing social
and economic circumstances.
7.2 USING THE PAST TO
UNDERSTAND THE PRESENT AND
PREDICT THE FUTURE
To ensure long - term persistence of biodiversity, conservation is a dynamic problem in which we must plan
for future changes in biodiversity pattern and process,
as well as our changing ability to instigate conservation action. Much of conservation is about trying
to build scenarios about the future and acting
accordingly.
The past is the most obvious place to look for guidance about what will happen in the future (Chapter 3 ).
Consider a few simple questions and the critical importance to conservation of long - term ecology quickly
becomes clear:
• How quickly have species ’ distributions responded to
past changes in environmental conditions such as fi re
regimes, habitat availability and climate?
• How quickly have species evolved in response to
changing environmental conditions?
• Where are the places with high rates of extinction
and speciation?
• Which places across the planet have acted as refugia
during past periods of environmental change, and
might these prove good long - term investments for
conservation?
• Do changes in species ’ distributions occur predictably in relation to environmental conditions?
• How does variability in a species ’ current abundance
or distribution compare with past fl uctuations?
• As species head towards extinction, do they show
stereotypical patterns of geographical range collapse?
Clearly, a long - term perspective is essential if we are
to make progress in answering these kinds of questions
and using them to guide present and future conservation activity.
Human transformation of the planet began long
before the science of ecology. While dramatic environmental changes such as Amazonian deforestation are
accelerating, and can be observed more or less in real
time (Shimabukuro et al. , 2006 ; Hansen et al. , 2008 ),
much of the damage and change that humans have
wrought on ecosystems occurred hundreds to thousands of years ago, and recent human impacts are
Planning for persistence in a changing world
Darling, 1985 ; Opdam et al. , 1999 ; Parmesan & Yohe,
2003 ; Felton et al. , 2009 ).
Despite the importance of dynamic processes such
as climate in continually shaping biological systems, a
recent review of the conservation planning literature
showed that about 80 per cent of studies assume that
neither biodiversity nor the processes threatening the
persistence of biodiversity change over time (Pressey
et al. , 2007 ). This is despite the fact that a decade has
now elapsed since the fi rst demonstrations of dynamic
approaches to planning protected area networks to
promote the long - term persistence of biodiversity
(Cowling et al. , 1999 ).
Second, even if we successfully conserve processes
that generate and maintain biodiversity, the resulting
pattern that we see today is only one brief snapshot of
a continuously changing system. As if huge spatial
complexity isn ’ t challenge enough for conservation,
ecosystems are continuously changing over time
(Chapter 3 ), species ’ distributions and abundances
expand and contract (Figure 7.1 ), land bridges
between continents come and go with changes in sea
level and communities are thrown together and then
separate.
Deep history leaves a signature in the structure of
present - day communities (Box 7.1 ). For example,
modern marine bivalve assemblages show a clear
break in species ’ ages corresponding with recovery
from the end - Cretaceous mass extinction event (Krug
et al. , 2009 ). Pleistocene climatic change has promoted
massive movements of species populations, often
forming novel assemblages, and alternatively isolating
and rejoining populations, generating speciation in
some lineages and strong phylogenetic structure in
many others (e.g. Riddle & Hafner, 1999, 2006 ; Hewitt,
2000 ; Bush & de Oliviera, 2006 ; Avise, 2009 ). To
provide a specifi c example, Neotoma woodrats appear
to have tracked oscillating climates through time by
changes in their body size (Smith et al. , 1995 ).
The biology of many species thus plays out across
time as much as across space, and conservation efforts
must therefore track an ever - moving target.
Third, threats to biodiversity change in type, distribution and severity over time (for an analysis focused
on changing threats on islands, see Whittaker &
Fern á ndez - Palacios, 2007 ). If conservation is about
buffering samples of biodiversity from threats, then
both the nature of the buffers employed, and where
they are instigated, must depend on the type, location
and intensity of threats and how these change through
time. The cost (e.g. social, economic, political) of
particular conservation action relative to its likely
benefi t is also highly dynamic, so conservation plans
must be continually updated to refl ect changing social
and economic circumstances.
7.2 USING THE PAST TO
UNDERSTAND THE PRESENT AND
PREDICT THE FUTURE
To ensure long - term persistence of biodiversity, conservation is a dynamic problem in which we must plan
for future changes in biodiversity pattern and process,
as well as our changing ability to instigate conservation action. Much of conservation is about trying
to build scenarios about the future and acting
accordingly.
The past is the most obvious place to look for guidance about what will happen in the future (Chapter 3 ).
Consider a few simple questions and the critical importance to conservation of long - term ecology quickly
becomes clear:
• How quickly have species ’ distributions responded to
past changes in environmental conditions such as fi re
regimes, habitat availability and climate?
• How quickly have species evolved in response to
changing environmental conditions?
• Where are the places with high rates of extinction
and speciation?
• Which places across the planet have acted as refugia
during past periods of environmental change, and
might these prove good long - term investments for
conservation?
• Do changes in species ’ distributions occur predictably in relation to environmental conditions?
• How does variability in a species ’ current abundance
or distribution compare with past fl uctuations?
• As species head towards extinction, do they show
stereotypical patterns of geographical range collapse?
Clearly, a long - term perspective is essential if we are
to make progress in answering these kinds of questions
and using them to guide present and future conservation activity.
Human transformation of the planet began long
before the science of ecology. While dramatic environmental changes such as Amazonian deforestation are
accelerating, and can be observed more or less in real
time (Shimabukuro et al. , 2006 ; Hansen et al. , 2008 ),
much of the damage and change that humans have
wrought on ecosystems occurred hundreds to thousands of years ago, and recent human impacts are