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THE WILSON JOURNAL OF ORNITHOLOGY • Voi 124. No. 3. September 2012 
would resonate at different speeds. He recom¬ 
mends lhal we loo look at Froot Loops under 
blacklight and watch the chewing Wint-o-Green 
LifeSavers in the dark, hut then describes how 
these things should be relevant to life. (The inci¬ 
dental fluorescence of Froot Loops is particularly 
relevant to why the fluorescence of some parrot 
pigments remains a functional mystery.) The book 
does have a few limitations, which are necessary 
for a book of this scope. For example, it includes 
no details on the physiology or neurobiology of 
vision. Rut the chapter on measuring light will be 
especially helpful to those getting into work on 
plumage coloration. 
Ornithologists will find that this book was not 
written especially for them. This is no surprise 
given the great breadth of the topic. Consequently, 
the main topics of current research interest in birds 
are not high-lighted above others merely because 
they are popular. From my own perspective, 1 wish 
Johnsen had focused more attention on some recent 
discoveries from birds that have broad application 
for all of life—e.g., the production of structural 
coloration through interference from ‘quasi-or¬ 
dered’ nanostructures. Thus, ornithologists may 
not consider Optics of Life to be required reading. 
However, what Johnsen knows and communi¬ 
cates clearly is fundamental and important to life. 
It seems to me that ornithologists who read this 
book and master this material will be well poised 
to make the next generation of discoveries about 
the Optics of Ornithology.—RICHARD O. PRUM. 
William Robertson Coe Professor of Omitholo- 
gy.Yale University, Peabody Museum of Natural 
History, P. O. Box 20815. New Haven. Connecti¬ 
cut, USA; e-mail: richard.pmm@yale.edu 
TROPHIC INTERACTIONS: PREDATORS. 
PREY AND THE CHANGING DYNAMICS OF 
NATURE. Edited by John Terborgh. and James 
A. Estes. Island Press, Washington. D.C., USA. 
2010: 464 pages. ISBN: 978-1-56726-487 $47.50 
(paper).—Top-down or bottom-up? What is the 
strongest driver of ecological processes in nature? 
John Terborgh and James Estes tackle this 50-year 
old question in their four-part book. Leading experts 
in aquatic systems, terrestrial systems, predator-prey 
dynamics, and food webs provide evidence that 
strong relationships exist between predators and the 
entire ecosystem in which they reside, supporting 
the green hypothesis posed by Hairston. Smith 
Slobodkin (HSS; 1960) that predators have an 
important role in ecosystem functions and specifi¬ 
cally ecosystem producers. Each chapter and section 
contributes to the mounting evidence from expen- 
mental, observational, and opportunistic studies that 
suggest cascading impacts from predators have a 
key role in ecosystem processes. 
Chapter one provides the foundation that top- 
down and boltom-up driving forces are not 
mutually exclusive, and this oversimplification 
ol ecological processes has distracted ecologists 
from close examination of complex food webs 
and the role predators have in ecosystem function. 
Trophic cascades, identified as the process bv 
which predators can influence other species 
beyond their prey, are introduced as the ‘holy 
grail' to understanding how ecosystems function 
and to predict their responses to system perturba¬ 
tions. This chapter sets the stage for evidence 
presented from aquatic, terrestrial, and general 
predation studies to shift paradigms to focus on 
the strong relationships within food webs that 
stabilize ecosystems and maintain diversity, 
largely tied to the function predators have in 
these systems. A major emphasis is placed on 
three-level trophic interactions, typically predator, 
prey, and producer, but with the recognition the 
chains within cascades may be two or potentially 
larger than three levels. 
Part one focuses on case studies in aquatic 
systems that provide supporting evidence of top 
predators affecting producers. The strongest 
forces of top predators are observed in whole- 
lake systems, and intertidal and benthic marine 
environments. Evidence for effects from top 
predators does exist for pelagic systems, but there 
is a general lack of studies focusing attention on 
top-dow n ellects of predators in oceanic systems 
relative to other aquatic ecosystems. Sea otters 
(Enhydra lutris ) influence sea urchins (Stronglyo- 
centrotus purpuratus) and kelp forests, -as well as 
the role of star fish (Pisaster ochraceiis) on 
species composition on rocky shores are examples 
of strong interactions where top-down forces 
influence the producer trophic level. Direct 
interactions of changes in population size were 
only one impact of top predators, but a secondary 
theme of indirect influences such as behavioral 
changes begins to emerge as an influence of 
higher trophic levels on their prey. 
Part two delves into case studies demonstrating 
the role of top predators on terrestrial ecosystems 
with a focus on impacts of herbivore-plant inter¬ 
actions, as well as influences of top predators 
