Review:
Having only recently reviewed a copy of Krebs' Ecology
I be wondered what this version might do. Copying out the chapter
headings almost gave the impression of deja vu with
most being the same. The idea that this was 'Ecology lite' proved
to be false once it was possible to get into the text in detail.
What we have here is a text which uses ecological principles
to re-direct people's thought away from the usual economic analysis
of the world. Its basic premise is that we need to re-organise
the way we think and act because it is becoming increasingly
obvious that business-as-usual isn't working.
We
start with an introduction to the subject along with its development.
This is fairly standard material but soon it becomes obvious
that there is a twist in this. Rather than outline the subject
it starts to comment on the scientific method and the way ecologists
work. That ecological problems are complex is highlighted by
two cases - Lyme Disease and Ross River Fever. The summary focusses
on what having and 'ecological world view' entails. In essence,
this chapter sets out Krebs' basic focus - the idea that ecology
is a perspective as well as a science. The aim as I see it from
this point is to show how and where ecology can be used to describe
our world and parameterise our actions. Chapter two looks at
the idea of ecological range starting with the concept of range
and the paradox of scales through to some of the key principles
we use e.g. Rapoport's Rule. A few key laws are summarised showing
how theory and practice meet. Chapter three asks why ranges
exist. Here the author takes a less usual perspective by using
scale to differentiate range delimiters. Global scales are controlled
by dispersal, regions by abiotic factors and local scales by
biotic controls. This is followed by consideration of the ecological
impacts of behaviour and the costs and benefits involved. Chapters
five and six are linked by their examination of population dynamics
with five focussing on changes in space and six with changes
in time. It is clear that species cannot expand indefinitely
(although humans seem to consider themselves immune which is
where this book comes in!) and that there are limits. Here,
spatial limits are reduced to resources whilst time limits are
a question of positive and negative population feedback. This
latter point is amplified in the next three chapters. The first
two look at factors which reduce population levels through predation,
herb ivory and competition interspecifically and infection and
parasites, intraspecifically. Since populations to thrive there
must be some positive trends and chapter 9 discusses these,
notably mutual interactions and commensalism. Chapter 10 focusses
on population regulation. As such it brings together the three
earlier chapters to show how this complexity actually drives
population dynamics. It also adds other features like demographics
to explain population levels. The next four chapters are also
linked by a common thread - community dynamics with each chapter
showing how one element works. The first is succession in chapter
11. Although hinted at in chapter six for species this works
at the community level. Allied to this is change in space but
with biodiversity rather than more conventional zonations explanations
leading the way. Communities are driven by energy and challenged
by change and so chapter 13's look at food webs provides the
former and chapter 14's consideration of disturbance ecology
the latter. This is also the point at which complexity ideas
can be put forward as an alternative model. Food webs were located
in a section on dynamics yet their is more to energy than this.
Chapters 15 and 16 make good this deficit by discussing the
role and development of energy flows (biotic) and nutrient cycling
(abiotic). Landscape ecology ties this together in chapter 17.
The final four chapters show how ecology can be used to study
and comment upon the increasing human use (and misuse) of our
planet's resources. Each chapter takes a different story and
although this is not comprehensive (nor was it meant to be with
the range of cases available) these are four highly topical
studies: fishing, pests, conservation and ecosystem services.
Each one of these has a significant (and growing) impact upon
people with fish stocks in decline, pests spreading through
global warming, conservation with too many losses against too
few wins and ecosystem services seen as the 'new' way to argue
for ecosystem conservation.
Overall
this is a text dominated by high quality production, colour
illustrations and careful, restrained use of some important
devices such as outlines and case studies to start and references
and questions to finish. Scattered through the text are images
of key ecologists and small essays illustrating some key points.
It is an excellent introduction to ecology and does much to
support the thesis of the ecological world view. This book deserves
the widest circulation and should be considered an essential
purchase for the institution library. Krebs has pulled off a
stunning double act in a small time span cementing his reputation
not just as an ecologist but also ecological writer.