Download The Balance of Nature and Human Impact. Klaus

Book reviews
The Balance of Nature and Human Impact.
Klaus Rohde, editor.
Cambridge, UK: Cambridge University Press, 2013.
426 pp. ISBN 97811070109614 (hardcover), $99
Human impact on the natural environment has
reached unprecedented levels. Humans are present
on all continents; almost all ecosystems have been
modified by human activities through habitat loss
and fragmentation, overexploitation, pollution, and
invasive species. More than 35% of the land area is
used for agriculture and built-up areas, 40% of the
terrestrial productivity is appropriated by humans,
50% of all coral reefs are lost or degraded, 70% of
recognized marine fisheries are fully exploited, overexploited or depleted; humans use more than 50% of
the available runoff of fresh water. In addition,
human emissions of greenhouse gases and other pollutants have been associated with global climatic
changes. The scale of the human impact on the
planet now has global consequences; thus, many scientists argue that the world has entered a new era
designated the Anthropocene.
This book summarizes ecological responses to
global environmental change; it is relevant to interested readers of different backgrounds trying to understand why scientists are worried about current
environmental change. Evidence shows that in geological times species have appeared and disappeared
as the climate and ecosystems changed. Ecosystems
are dynamic and adapted to those changes, however,
as clearly demonstrated in Chapter 13, past climatic
changes have occurred over large temporal scales,
while human-induced impacts are occurring at a
much faster rate. The question then is: will populations, communities, and ecosystems be able to respond to these fast changes in the environment or
will the earth lose a large part of its biological diversity? This is discussed in detail in Part V, which is
particularly interesting to students and the general
public; it gives an overview of the impacts of
human activities for a range of taxonomic groups.
The book starts with Kevin Gaston’s foreword and
an analogy between stability concepts needed for sea
kayaking and instability in the natural world caused
by human impact. This is an excellent introduction
to the book. Humans are changing the stability conditions in the natural environment, ultimately population managers need to understand if disturbance
of natural systems will require small adjustments to
retain populations and communities at the same
level (primary or initial stability in kayaking that
enables the kayak to rock in the water) or if it will
cause large disturbance and ‘‘tipping points’’ that
1017
rapidly throw populations and communities from
one state to another (secondary or final stability in
kayaking which is a measure of how readily a kayak
capsizes). Equilibrium states will differ in the
number of individuals, populations, species, and
communities they can support and this will have
large consequences for ecosystem services provided
to humans. Simpler ecosystems (with fewer species)
are less resilient and have less multifunctionality
(Maestre et al. 2012) thus, delivering fewer ecosystem
services. The challenge for humans will be to understand how much impact and change the planet’s natural environment supports before the occurrence of
‘‘tipping points’’ that will jeopardize the planet’s capacity to deliver the ecosystem services that support
seven billion people (probably nine billion by 2050).
Ecosystem services are not at all mentioned in this
book; this is a lost opportunity as this framework
can help conservation biologists talk to the general
public and to politicians (Fisher et al. 2008).
The Balance of Nature and Human Impact, edited
by Klaus Rohde at the University of New England,
Armidale, Australia, is composed of 27 chapters, each
written by a specialist or specialists who have summarized information for their respective areas of
study. Thirty authors contributed their expertise to
the book. Rohde’s book has chapters that are written
primarily for those seeking reviews of current knowledge about specific topics, but most suit students
and the interested general public. It covers marine,
freshwater, and terrestrial environments; and a range
of taxonomic groups, from plants to nematodes,
birds, and mammals.
The book has seven parts. The first focuses on
nonequilibrium and equilibrium in populations and
meta-populations. Part II focuses on communities,
including key examples of nonequilibrium conditions
such as the paradox of the plankton and how fire
affects alternative stable states in communities; stability in communities of ectoparasites in fish and
mammals are also examined and this section finishes
with a macroecological approach of the equilibrium/
nonequilibrium debate using bird populations and
communities. Parts III and IV examine equilibrium
or nonequilibrium states at a macroecological scale
looking at the effect of geographic scales and latitude. Part V focuses on the effects caused by invading species, habitat loss, and climatic change that
emphasize nonequilibrium conditions. Part VI examines the importance of autecology and Part VII has
concluding remarks that are clearly written and presented; this section summarizes the main messages of
the book.
ß The Author 2013. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved.
For permissions please email: [email protected].
1018
Each chapter of the book can be read independently but the sequence of the chapters is not the
best. The book is organized from small to large special scales, from populations to communities and
large geographic processes but lacks the introduction
of key ecological concepts that link parts I, II, and
III. Density-dependent regulation of populations,
evolutionary stable strategies, Taylor’s law, and the
criteria for defining equilibrial populations should
have been presented at the start of the book, followed by the case studies. There is a bias toward
case studies focusing on parasites which is refreshing
as parasitic interactions are, in general, under-represented in ecological books.
Part I—Equilibrium and nonequilibrium
in populations
The first chapter explains the crucial concept of density-dependent regulation and how it operates at the
population level in coral reefs; the authors stress that
loss of architectural complexity on reefs causes fish
populations to decline due to lack of refuges from
predation. Chapter 2 examines the abundance of ectoparasitic species in mammals and concludes that
the biological attributes of parasites are the primary
determinants of parasite dynamics; the interaction
with host-related and environmental factors results
in nonequilibrium conditions. Chapter 3 presents evidence suggesting that assemblages of ectoparasites in
fish live under nonequilibrium conditions.
Part II—Equilibrium and nonequilibrium
in communities
This section starts well with a conceptual chapter,
written by the editor, explaining the paradox of the
plankton and concluding that, contrary to expectations, open-ocean conditions are not homogeneous,
and aquatic environments provide many more niches
than previously thought; modeling plankton communities in homogeneous environments showed that
multi-species competition may lead to oscillation
and chaos, contributing to greater biodiversity.
Chapter 5 demonstrates that dramatic changes may
lead communities to change from one state to another, but exposure to a long history of instability
eventually will stabilize communities at a point
where some traits are lacking. Chapter 6 examines
ectoparasites living in the skin and on gills of fish
and concludes that there are many empty niches,
indicating nonequilibrium conditions. Chapter 7
compiles evidence of many studies looking at ectoparasites in mammals and concludes that there is
evidence supporting both equilibrium and
Book reviews
nonequilibrium conditions depending on the parasite, host, and scale of the study. Chapter 8 presents
a clear framework to define equilibrium at the population level, which is extremely useful. Brian McGill
then examines if populations and communities of
North American birds are at equilibrium. One weakness of this study, using data from the North
American Breeding Bird Survey, is that both rural
and wilderness sites were considered together. Rural
sites are likely to have populations and communities
that are impacted by human activities and unlikely to
be at equilibrium, whereas wilderness sites are more
likely to have stable conditions. The findings were
mixed which is not surprising as data for disturbed
and undisturbed sites were pooled together.
Part III—Equilibrium and
nonequilibrium on geographical scales
This section fails to mention the velocity of climatic
change (Loarie et al. 2009), its geographic patterns,
and its consequences for species endemism (Sandel
et al. 2011). Chapter 9 emphasizes that fauna and
flora on islands have suffered vast extinction events
that are attributed mainly to predation. A combination of warming climate, sea-level rise, and increased
intensity of tropical cyclones will be emerging threats
to insular species. Chapter 10 examines the dynamic
past and future of arctic vascular plants, highlighting
the importance of adaptations for dispersal, and loss
of genetic diversity.
Part IV—Latitudinal gradients
This section includes two chapters that focus on the
evolutionary consequences of global environmental
change. These were written for a specialised audience
and readers who understand the terminology and
jargon of evolutionary ecology. These two chapters
are not well integrated in the book and the links to
stability of nature are not clearly presented.
Part V—Impacts of humans on natural
systems: habitat loss, invasive species
and climate change
This section lacks a logical sequence between the
chapters, it starts with Chapter 13, in which
Michael Box summarizes the evidence for climatic
change and presents future scenarios as discussed
by the IPCC. Chapter 14 focuses on invasion, stressing that few corners of the planet are free from
invaders, and Chapter 15 stresses the importance of
studying emerging infectious diseases and new pathogens. Chapter 15 describes the importance of using
mathematical models to study invasive species.
1019
Book reviews
Chapter 16 concisely presents recent evidence of anthropogenic footprints on biodiversity, introduced
species, overexploitation, habitat loss, and climatic
change. It stresses that the ranges of species are
changing and moving polewards, mountane species
are moving to higher elevations, but only the highly
mobile species are responding, which in the long
term will have dramatic consequences for communities and ecosystems. Approaches to tackle conservation of rare species are discussed and it is suggested
that ‘‘threatened species should be managed as if all
stressors at play were responsible for the decline.’’
Chapter 17 focuses on the decline of amphibians,
emphasizing the role of pollution, habitat loss and
fragmentation, diseases and parasites, ultraviolet radiation, invasive species, road kills, exploitation by
humans, and climatic change. The chapter finishes
with a section on ‘‘What can be done?’’ and it involves active management by humans to prevent eminent species’ extinction. The effects of climatic
change on marine and terrestrial reptiles are considered in Chapter 19. Hugh Ford examines equilibrium
and nonequilibrium in Australian bird communities
in Chapter 20. He concludes that in arid zones there
is no evidence to support equilibrium, in Australian
forests, before European settlement and forest fragmentation, there is evidence supporting equilibrium
conditions in bird populations. Chapter 21 considers
the impacts of climatic change on population dynamics of insects and this section ends with
Chapter 22 on the future of coral reefs. Due to increase in sea-surface temperature and acidification of
the ocean, coral reefs are predicted to disappear by
2050 as CO2 concentrations in the atmosphere
exceed 510 ppm. Peter Sale then discusses ‘‘What
loss of coral might mean’’ and I have to agree that
‘‘the esthetic and ethical impacts are perhaps even
more important than . . . economic costs.’’ As a species with the power to transform the face of the
planet we have the responsibility to prevent the extinction of other species that coexist with us. This is
an ethical discussion that should be strongly
activated.
Part VI seems to be out of place and I could not
see the relevance in the context of this book.
Part VII—The overall view
This section includes two last chapters that are written for a wide audience. Chapter 25 summarizes previous chapters and the main messages of the book.
Chapter 26 presents a wide variety of facts on how
the Australian press and TV have misrepresented the
debate on climatic change. It is clearly argues that
powerful individuals (corporations) dictate the general public’s views on important scientific debates
that need a societal discussion (e.g., global climatic
change and our ethical responsibility toward preventing other species’ extinction and the deterioration of
ecosystem services). The main message of this book
is that understanding equilibrium and disequilibrium
conditions is fundamental to better predict the consequences of global environmental change on natural
systems and, I think, this is ultimately needed to
guarantee human long-term persistence on earth.
Aldina M. A. Franco
School of Environmental Sciences
University of East Anglia
Norwich NR4 7TJ, UK
E-mail: [email protected]
Advanced Access publication October 22, 2013
doi:10.1093/icb/ict099
References
Fisher B, et al. 2008. Integrating ecosystem services and economic theory. Ecol Appl 18:2050–67.
Loarie SR, Duffy PB, Hamilton H, Asner GP, Field CB,
Ackerly DD. 2009. The velocity of climate change. Nature
462:1052–5.
Maestre FT, et al. 2012. Plant species richness and ecosystem
multifunctionality in global drylands. Science 335:214–8.
Sandel B, Dalsgaard B, Davies RG, Gaston KJ, Sutherland WJ,
Svenning JC. 2011. The influence of late quaternary
climate-change velocity on species-endemism. Science
334:660–4.