The Winnersof the Blue

2001

PlanetPrize

2001Blue

PlanetPrize

Lord (Robert) May of Oxford(Australia)

Dr. Norman(U.K.)

President

Honoraryof the Royal

Societyof London

Oxford

The

Earth

is

an

Visiting

Myers
Fellow,

Green

College,

University

aquatic

planet. We exist only because
we are blessed with life-giving water.
At the 2001
Awards
Ceremony,whichmarkedthe Blue
PlanetPrize's 10th anniversary,
we
explored the Earth's aquatic
nature in the opening film.
This film instills a sense of
appreciationof being on aplanet that is "a drop of waterin the galaxy."221

His Imperial
ceremony.
His Imperial

Highness

Prince Akishin

1congratulates

Highness

Prince Akishinoat thethe laureates.
Dr. Jiro Kondo, chairman of theSelection Committee,
describes
the Blue Planet Prize selection
process.

The prizewinners
from Foundation

receive their trophies and certificates
Chairman Hiromichi Seya.

Lord (Robert) May of Oxford

The Blue Planet

222

Prize Commemorativeof merit

Dr. Norman

Lectures.

Myers

John McCarthy, Ambassador of Australia to Japan(left), and Stephen Gomersall, Ambassador of theUnited Kingdom to Japan (right), congratulate thelaureates.

Profile

Lord (Robert) May of Oxford
Presidentof the Royal

Societyof London

EducationandAcademic

and

1936

Born

in January

in Australia.

1956

B. Sc., University

of Sydney.

1959

Ph.D.,

Physics,

1959-1961

Researcher,

1962-1972

Professor,

1973-1988

Professor,

1979

Fellow,

Royal

1980

WeldonMemorial

1984

MacArthur

1988-1995

Professor,

1991

LinneanMedal,

1991

Overseas

Member,Australian

1992

Inaugural

Christian

Marsh

1992

Foreign

1995

Frink

1995-2000

Chief Scientific Advisor, Government

1.996

Crafoord Prize in Biosciences,

1998

Balzan Prize awarded by the President

2000—

President,

Theoretical

Professional

Harvard

Activities

University

University,of Sydney.

U.S.A.

Physics,

University

of Sydney.

Biology,Princeton

University.

Societyof London.

Prize,

OxfordUniversity.

Award.
Imperial

Member,Medal,

College

Linneanand Oxford

UnitedKingdom.

Academyof Sciences.

Prize.

U.S. National

Zoological

University,

Society.

Academyof Science.

Society.

of the United Kingdom.

Royal Swedish Academyof Sciences.

of Italy.

Royal Society of London.

After pursuing research in theoretical physics at the University of Sydney, Lord (Robert) May
of Oxford shifted his focus to mathematical biology. He achieved a solid record of noteworthy• accomplishments at Princeton University in the United States before coming to his present postat Oxford University, where he is active as an influential, world-leading academic.
Applying mathematical concepts to biology, he studied the stability of animal populations in 1973, and discovered for the first time that when you increase the number of species,
even in complex animal societies, or add more interactions between species, the probability ofthe system becoming less stable was greater. Furthermore, he uncovered the fact that unidimensional nonlinear differential equations often exhibit dynamic states similar to those ofanimal populations, and founded the new field of "chaotic dynamics" in biology.
Lord May drew attention to the fact that if we wish to manage ecosystems—for example, if we wish to estimate the impact of human fishing on fishing grounds—that we must pay
attention to the characteristic changes in the populations. He also investigated how AIDS,

223

whichwas transmitted

lizinga combination

data required

to a differentof simplified

to formulate

In 1995, Lord

May

strategies.
Chiefof the Officeof Scienceof the Royal

Society224

modelswas appointed

President

preservation

as a result

preventativeand Headfor ecological

speciesanalytical

Scientificand Technology,

of London.

and action

Fromof environmental
and computer

Advisorand was honored
these elite positions,to curb various

urgentchange,simulations

spreads,uti-

to provide

theto the British
in 2000

with election

he continues

environmental

Governmentas

to counsel

problems.

EssayBiological
Past,

Diversity
Present,

in a Crowded
and Likely

World:

FutureLord (Robert) May of Oxford
February

2002

How much do we know about the diversity of organisms on our planet? First, estimates of thenumber of distinct species of plants, animals and fungi (eukaryotes) that have been named andrecorded—a simple, factual question, like how many books in the library catalogue—range
from 1.4 million to 1.8 million. Second, estimates of the total number of species present on
Earth today range over more than an order-of-magnitude, from a low of around 3 million, to ahigh of 30 million or possibly much more. And third, we have even less idea of the rates atwhich species may currently be going extinct as a result of habitat destruction, introduced
aliens, overexploitation and other consequences of human population growth.
Numbers of Species Today
The systematic naming and recording of species began relatively recently with Linneaus'canonical work, which in 1758 recognised some 9,000 species. Today, the total number of living species named and recorded is around 1.7 to 1.8 million. Amazingly, no centralised catalogue exists. Around one million of these are insects, of which an estimated 400,000 are beetles. And of these beetles, an estimated 40% are known from only one collecting site, andsometimes from only one specimen. So it is not surprising that there is a problem with synonymy (the same species unwittingly recorded under different names by different researchers).
Known rates of synonymy run, on average, around 20%. Recent mathematical studies, however, suggest that if these rates are the ones we know, the true rates are likely to be higher(Solow et al, 1995). My estimate is that we may have named and recorded around 1.5 million
species (May, 2000), but this number could be 10% higher or lower. To this total, we areadding around 13,000 new species each year. But at the same time, we are resolving synonymies, so that the net addition is around 10,000 new species each year (Hammond, 1995).
Some groups are much better known than others, reflecting patterns in the taxonomic
workforce, which derive from intellectual fashions rather than analytic assessments of priorities. Bird and mammal species are comparatively well documented; even though three to fivenew bird species and around 10 new mammal species are found each year, such numbers are
small fractions of the totals recorded in these classes (approximately 10,000 species of birds
and 4,000 of mammals). The roughly 270,000 recorded species of vascular plants probably
represent 90% or so of the true total. But comprehensive explorations of invertebrate groups225

in previously-unstudied places—tropical canopy insects; deep-sea benthic macrofauna;
fungi—typically find 20% to 50%, or even more, of the species are new to science.
Taxonomists are distributed roughly evenly between vertebrates, plants and invertebrates. But
there are roughly 10 plant species for each vertebrate animal species, and conservative estimates suggest around 100 insect species for each vertebrate one. Thus, current patterns ofknowledge reflect the fact that the average vertebrate species receives 10 times more taxonomic effort than the average plant species, and 100 times more than the average invertebrate(Gaston and May, 1992). This is a bad way to run a business.
The true total number of living species is very uncertain. My guesstimate is in the range
5 to 15 million with a favoured figure of perhaps 7 million (May, 2000). Dramatically higher
numbers have been proposed: 30-million insects on the basis of studies of beetles in tropical
canopies; tens of millions of benthic invertebrates on the basis of a deep-shelf transect off thenortheastern U.S.A.; 1.5-million fungi on the basis of scaling up the species ratio of fungi tovascular plants in Britain; and others. I am sceptical of all these estimates, but a true total anywhere in the range 3 to 100 million could turn out to be correct. The fact that reasonable estimates vary so widely says a lot about how little we know.
Understanding Diversity
The lack of systematic compilations of information about recorded species, much less about
the true species totals, greatly impedes our understanding of the causes of biological diversity
and of the likely consequences of its impending reduction.
Various patterns—some more general than others—have been tentatively documented.
None are fully understood (May, 1990, 1999; Wilson, 1992; Lawton, 1995).
(1) For most groups of organisms, there is a marked "latitudinal species diversity gradient." This is particularly notable for tree species, where the enormous diversity oftropical forests gives way to the almost monospecific conifer forests of northerly latitudes.

•(2) Other things being equal, there is a relation between a region's area and the numberof species found in it. A tenfold reduction in area (as when a reserve is establishedand its surroundings modified) roughly halves the number of species; more generally, S=cAz, where the constant c varies from group to group, and the exponent z is
usually in the range 0.2 to 0.3.
(3) There are broad trends in the relative abundances of species within a community or
ecosystem. In old-established communities, these patterns of species relative abundance tend to be more even (often described by a subset of lognormal distributions)than those for early successional or highly disturbed situations. These "canonical"
lognormal patterns can be interpreted as arising from the multiplicative interplay ofmany ecological and evolutionary factors, and the observed species-area relations
can be derived from them (under the additional assumption that total numbers of226

individuals scale roughly linearly with area).
(4) The numbers of species in different categories of physical size vary systematically.
For terrestrial animals, a decrease by a factor 10 in characteristic linear dimensions(or equivalently, a factor 1,000 in mass) roughly results in 100 times more species.
This rough rule holds down to size categories around a few millimetres; species
numbers fall away below this. What are the ecological or evolutionary origins of thisrough rule, which holds true over four or more orders-of-magnitude in characteristic lengths of animals on land and roughly similarly in the sea (Fenchel , 1993). To
what extent—and why—is the breakdown in this rule at small sizes real , and to what
extent may it be a consequence of less knowledge about smallerthings?

(5) Patterns in the relations between the body sizes and the geographical ranges of
species are only just beginning to receive systematic attention. It is possible thatgeographicalranges are typically more extensive for relatively large organisms andfor microorganisms (protozoa and below) than for mid-size organisms (insects). If
true, such patterns, which are entwined with the species-size effects of (4), are relevant, amongst other things, to possible range modifications associated with climatechange.
Extinction Rates
The history of life on Earth, written in the fossil record over the past 600-million years since
the Cambrian explosion in the diversity of multicellular organisms, is one of broadly increasing diversity, albeit with many fluctuations and punctuated by episodes of mass extinction . As
reviewed in more detail elsewhere (Sepkoski, 1992; May, 2000), the average lifespan of a
species in the fossil record, from origination to extinction, is typically a few million years (thatis, of the order 106 to 107 years). There is, however, much variation both within and amonggroups, and some groups have lifespans significantly longer or shorter than this. Comparing
this few-million-year average lifespan with the 600-million-year fossil record span , we might
estimate that 1% to 2% of all species ever to have lived are with us today . But, allowing for thefluctuating but steady—very roughly linear—average growth in species diversity since theCambrian, a better estimate might be 2% to 4%. And if we recognise that most of today's
species are terrestrial invertebrates (mainly insects), whose patterns of diversification beganaround 450-million years ago and whose average lifespan may be characteristically longer
than 10-million years, it could be that today's species represent more like 5% , or conceivably
even 10%, of those ever to have graced our planet.
Over the past century, rigorously documented extinctions in well-studied groups—primarily birds and mammals—have run around one species per year . Because tropical species
typically receive less attention, true extinction rates of birds and mammals are undoubtedly
higher. But even one per year among the roughly 14,000 species of birds and mammals translates to expected species' lifetimes, based on documented recent extinction rates , of around 104
years. Although seemingly long, this is shorter by a factor of order 10-2to 10-3than the back-227

ground averagelifespan of 106to 107years seen in the fossil record. That is, recent extinction
rates in well-documented groups have run one-hundred to one-thousand times faster than the
average background rates.
Looking toward the immediate future, four different approaches to estimating impending rates of extinction suggest species' life expectanciesof around a few hundred to one-thousand years. One of these approaches is based on the above-mentioned species-area relations,coupled with assessments of current rates of tropical deforestation or other habitat loss (iftropical forests are being lost at the rate of 1% to 2% each year, the species-area relation
implies this commits 0.25% to 0.5% of their speciesto extinction,which invertsto a rough estimate of species' lifetimes of roughly 200-400 years). Two other methods are based in different ways on the InternationalUnion for the Conservationof Nature's (IUCN) current catalogue
of "endangered" or "vulnerable" species. As reviewed elsewhere (May et al, 1995), one ofthese estimates the average rate at which species in better-studied groups (birds, mammals andpalm trees) are climbing the ladder of IUCN categories of endangerment. This suggests
expected species' lifetimes in the range 100 to 800 years in these groups. A more precise variant of this approachuses species-by-speciesassessmentsof extinctionprobability distributions
as functionsof time. Using 10 vertebrate groups (3, 4, 3 orders or families of reptiles, birds andmammals, respectively), Mace (1994) estimates average species' lifetimes in the range 100 to
1,000 years, and mainly in the 300- to 400-year range for mammals and birds. The fourth
method uses models for branching processes in phylogenetic trees, along with recent data forbird and mammal orders, to project averagetimes to extinctionwithin bird and mammal orders(McKinney, 1998). Under a range of assumptions about branching processes, these models
suggest species' lifetimes again of the order of a few hundred years (characteristically shorter
for mammalsthan birds). Thus, all four of these methods, each of which is unreliable in its own
distinctive way, agree in suggesting a further shortening of expected species' lifetimes toaround 102to 103years.
Such figures correspondto likely extinctionrates of a factor of ten thousand, give or takeat most an order of magnitude, above background over the next century or so. This represents
a sixth great wave of extinction, fully comparable with the Big Five mass extinctions of thegeologicalpast, but different in that it results from the activities of a single other species rather
than from external environmental changes.
As we face this future, we must ask: does it matter more if we lose 25% of all mammal
species than if we lose 25% of the vastly more numerous insect species? Or does it matter
equally? Or less? There is need not only for more taxonomic information, but also for a "calculus of biodiversity" based on this information. Such a calculus should, ideally, quantify thetaxonomic uniqueness, or amount of independent evolutionary history, inherent in individual
species(Vane-Wrightet al, 1991; Nee and May, 1997). I would like to see such quantification,
along with more explicit recognition of constraining political, economic and social realities,
replace emotion in assigning conservationpriorities and places on the Ark (although emotional
elements should, certainly, also be part of such a quantification). For further review andremarks on this topic, see May et al (1995).

228

Why Value Biological Diversity?
One argument for the preservation of biological diversity is narrowly utilitarian. It correctly
emphasises the benefits already derived from natural products, such as foods, medicines andso on. Currently, 25% of the drugs on the shelves in the pharmacy derive from a mere 120
species of plants. But, throughout the world, the traditional medicines of native peoples makeuse of around 25,000 species of plants (about 10% of the total number of plant species). We
have much to learn. More generally,as our understanding of the natural world advances, bothat the level of new species and at the level of the molecular machinery from which all organisms are self-assembled,the planet's genetic diversity is increasinglythe raw stuff from which
our future can be constructed. It seems a pity to be burning the books before we can read them,and before we can create wealth from the recipes on their pages.
Another class of arguments is more diffusely utilitarian. The interactions between biological and physical processes created and maintain the earth's biosphere as a place where life
can flourish. With impending changes in climate caused by the increasing scale of humanactivity,we should be worried about reductions in biological diversity,at least until we understand its role in maintaining the planet's life support systems. The first rule of intelligent tinkering is to keep all the pieces.
For me, however, a third class of argument is the most compelling. It is clearly set out
by the U.K. Government in This CommonInheritance (HMSO, 1990, ch 1.14). It is "the ethical imperative of stewardship ... we have a moral duty to look after our planet and hand it on
in good order to future generations."This argument is, however,easier to sustain for those privileged to live in affluent developed countries. Were I struggling to feed my fifth child in abject
poverty in some areas of the developingworld, I suspect I would find this ethical argument lesscompelling.
Conclusion
The previous century has seen more advances in our understanding of the natural world thanhas all previous human history. We have applied this scientific understanding to improve lives
in both developed

and developingof the unintended

adverse consequencesnificant is accelerating

countries. We are, however, now beginningloss of biologicalof well-intentioned

actions. Arguably

diversity. What happens

to realise somethe most sig-

to our world, and to us andthe creatures we share the world with, in the future depends on the actions we take now. As a
new century dawns, our greatest challenge remains to ensure that necessary increases in global
productivity are achieved in a sustainable and environmentallyfriendly way.
I believe these are matters of concern for all of us. But effective action must be based ongood scientific understanding
logical diversity.

of the underlying

causes, and likely consequences,of loss of bio-

References
Fenchel, T. "There are More Small than Large Species?" Oikos, 68 (1993), 375-378.
Gaston, K.J. and R.M. May. "The Taxonomy of Taxonomists." Nature, 356 (1992) , 281-281.
Hammond, P.M. "The Current Magnitude of Biodiversity." In Global Biodiversity Assessment . Ed. V.H. Heywood.
113-128. Cambridge: Cambridge Univ. Press, 1995.

229

HMSO. This CommonInheritance: Britain's EnvironmentStrategy. London: HMSO, 1992.
Lawton, J.H. "Population Dynamics Principles." In Extinction Rates. Ed. J.H. Lawton and R.M. May. 147-163.
Oxford University Press, 1995.
McKinney, M.L. "Branching Models Predict Loss of Many Bird and Mammal Orders within Centuries." Anim.
Consv., 1 (1998),159-164.
Mace, G.M. "An Investigation into Methods for Categorizing the Conservation Status of Species." In Large Scale
Ecologyand Conservation Biology.Ed. P.J. Edwards,R.M. May and N.R. Webb. 295-314. Oxford: Blackwell,
1994.
May, R.M. "How Many Species?" Phil. Trans. Roy. Soc., B330 (1990), 292-304.
May, R.M. "Unanswered Questions in Ecology." Phil. Trans. Roy. Soc., B354 (1999), 1951-1959.
May, R.M. "The Dimensions of Life on Earth." In Nature and Human Society: the Questfor a Sustainable World.
Washington, D.C.: National Academy of Sciences Press, 2000.
May, R.M., J.H. Lawton and N.E. Stork. "Assessing Extinction Rates." In Extinction Rates. Ed. J.H. Lawton and
R.M. May. 1-24. Oxford University Press: 1995.
Nee, S. and R.M. May. "Extinction and the Loss of Evolutionary History." Science, 278 (1997), 692-694.
Sepkoski, J.J. "Phylogenetic and Ecologic Patterns in the Phanerozoic History of Marine Biodiversity." In
Systematics,Ecology, and the Biodiversity Crisis. Ed. N. Eldredge. 77-100. New York: Columbia University
Press, 1992.
Solow, A.R., L.A. Mound and K.J. Gaston. "Estimating the Rate of Synonymy." Syst. Biol, 44 (1995), 93-96.
Vane-Wright,R.I., C.J. Humphries and P.H. Williams. "What to Protect: Systematics and the Agony of Choice."
Biol. Conserv., 55 (1991), 235-254.
Wilson, E.O. The Diversity of Life. Cambridge, Mass: Harvard University Press, 1992.

230

Lecture

Biological
Causes,Consequences,

Diversity:
and Conservation

Lord (Robert) May of Oxford
Introduction
I am honoured to receive the 2001 Blue Planet Prize. Also I am very aware that I receive
this prize as a symbolic representative of the large community of scientists, who in recent
years have greatly advanced our understanding of the causes and consequences of biologicaldiversity, and of growing threats to it. I especially commend the Asahi Glass Foundation forestablishing this Prize in recognition of the importance of environmental and conservation
science.
Properly to understand how today's rich and varied plant and animal life came to be
here, we need to answer underlying ecological questions. How does the structure of the webof interactions among species affect communities' ability to recover from disturbance or toresist invasion? What factors determine the observed variety of patterns of species abundance,of commonness and rarity? More generally, what determines species numbers in different
places? Above all, what are the various causes of observed extinctions, and to what extent are
extinction rates currently accelerating? In what follows, I will sketch answers to some of thesequestions, and also will indicate remaining areas of uncertainty.
Structure of Ecosystems
Earlier Ideas. Around 1970, the conventional wisdom—set out in textbooks, following the work of the pioneering ecologists, Charles Elton and Evelyn Hutchinson—was that"complex" communities (those with more species and/or richer webs of connections amongthem) were more "stable" (better able to resist or recover from disturbance, human-created or
natural). Comparing mathematical models for ecological communities with few species
against the corresponding models with many species, I showed there could be no such simple
and general rule; all things being equal, complex systems are likely to be more dynamicallyfragile. This and other related work was drawn together in the monograph Stability andComplexity in Model Ecosystems (1973, with a second edition in 1974). In 2001, Princeton
University Press reissued this book, with introductory "retrospective thoughts," in its
Landmarks in Biology series.
Ecosystem Stability and Complexity. I believe this work helped to refocus the agenda
for studies of the structure and function of ecosystems. For one thing, we have become more
careful about distinguishing the productivity of a community of interacting plants and animals,
as a whole, from the productivity and fluctuations in the individual populations that constitutethe community. Recent studies by Tilman et al (1996, 1998), Naeem and Li (1997) and others

231tend to bear out my earlier suggestions that increasing complexity or diversity, in the sense ofa larger number of constituent species in the community (larger "species richness"), tends tomake for greater stability in total productivity, but that individual species are liable to greaterfluctuations in abundance in such communities. For another thing, it has become clear that
increasing numbers of interactions among species in a foodweb (increasing "connectance")
does not automatically enhance ability to resist disturbance; instead, current efforts seek tounderstand the special kinds of interconnectedness among subsets of species that reconcile
complexity with stability in particular ecosystems (McCann et al, 1998).
A Contemporary Synthesis? More broadly, my own view is that, over evolutionary
time, ecosystems are in tension .between two opposing forces. On the one hand, evolution
tends to favour every opportunity, every niche, being exploited, making for increasing diversity over time. On the other hand, more species-rich communities in general are more dynamically fragile, tending to set limits to diversification. In relatively environmentally predictablesettings, such as tropical rainforests or some coral reefs, the trade-off between these two countervailing pressures is set at a point corresponding to more species-rich communities. In
harsher and less predictable environments, such as boreal forests or estuaries, the trade-off
results in relatively simpler communities. In both cases, the set point is determined by theacceptable average degree of fluctuation in individual populations, which is broadly similar—
over the long run—in all cases. As noted above, this cuts across the earlier conventional wisdom, but seems increasingly in accord with observations about levels of fluctuation in tropical communities, and in various field experiments.
Patterns in the Distribution and Abundance of Species
Species Relative Abundance. There are broad trends in the relative abundances of
species within a community or ecosystem. In old-established communities, these patterns ofspecies relative abundance tend to be more even (often described by a subset of lognormal distributions) than those for early successional or highly disturbed situations. Such "canonical"
lognormal patterns can be interpreted as arising from the multiplicative interplay of many ecological and evolutionary factors. These patterns have implications, amongst other things, forunderstanding the different kinds of "rarity" (Rabinowitz et al, 1986; Gaston, 1994); see Table
1. In particular, they imply that to be rare is by no means necessarily to be in danger of extinction. This latter point appears frequently to be misunderstood: for example, the current IUCNRed List of Threatened Plants (Walter and Gillett, 1997) unaccountably, and unlike the corresponding animal lists, treats all "rare" plants as threatened.

232

Table 1. The distribution of 160 plant species from the Biological Flora of the British Isles, classified into eightcategories according to geographicdistribution (wide or narrow), habitat specificity (broad or restricted), and local
abundance (somewhere large or everywhere small). We would recognise the circled category (wide distribution,broad range of habitats, locally abundant somewhere) as "common;" the other seven categories represent "sevenkinds of rarity" (after Rabinowitz et al, 1986).
Geographic
Local

population

size
habitat
Broad

Somewhere

large

Everywhere

small

58

NarrowWide
specificity

habitatBroad

Restricted2

distribution

specificity
Restricted

71

6

14

6

0

3

Species-Area Relations. Other things being equal, there is a relation between a region'sarea and the number of species found in it. A tenfold reduction in area (as when a reserve isestablished, and its surroundings modified) roughly halves the number of species. More generally,there is a power law relationship, S = cAz;here S denotes the number of species, A thearea, c is a constant which varies from group to group, and the exponent z is usually in therange 0.2-0.3. Figure 1 gives an illustrative example. Interestingly, this relation follows fromthe "canonical" lognormal distribution of species relative abundance mentioned above, combined with the additional assumption that total numbers of individuals scale roughly linearlywith area (for a recent review, see May and Stumpf, 2000). Given the shakiness of these theoretical assumptions, it is perhaps surprising that the species-area relationship is so widely
found in nature. It has important implications. In particular, we shall see below how it can beused to make tentativeprojections about future extinction rates.
200

100

50Long20control islands
exploded
volcanoes
tidal-wave-defaunated10-

isletsRitter

5-

2
0.001

0.01

0.1

10

100

1,000

10,000100,000

Area (km2)
Figure 1. An example of the relation between species number and island area in an archipelago: number of resident, nonmarine, lowland bird species Son islands in the Bismarck Archipelago, plotted as a function of island area
on a double logarithmic scale. The solid circles represent relatively undisturbed islands, and the straight line S=18.9 A 0.18was fitted by least-mean-squares through the points for the seven largest islands. The open circles referto the exploded volcanoes, Long and Ritter, where species number is still below equilibrium, especially on Ritter,because of incomplete regeneration of vegetation. The open triangles refer to coral islets inundated by the Ritter
tidal wave in 1888. (From Diamond, 1974).

233

Numbers of Species in Relation to their Physical Sizes. The numbers of species ofanimals in different categories of physical size vary systematically. For terrestrial animals, a
decrease by a factor 10 in characteristic linear dimensions (or, equivalently, a factor 1,000 inmass) roughly results in 100 times more species (May, 1978); see .Figure 2. This rough ruleholds down to size categories around a few millimetres; species numbers fall away below this.
What are the ecological or evolutionary origins of this rough rule, which holds true over fouror more orders-of-magnitude in characteristic lengths of animals on land, and roughly similarly in the sea (Fenchel, 1993)? To what extent—and why—is the breakdown in this rule atsmall sizes real, and to what extent may it be a consequence of less knowledge about smaller
things?
10 6

10 5

10 4

10 3

10 2

10

1
.0005

.001

.005

.01

.05

.1

Body

Length

.5

1

5

10

(m)

Figure 2. A crude estimate of the distribution of all terrestrial animals categorized according to characteristic
length L . The dashed line indicates the relation S — L-2, as in Fig. 3 ( S = number of species). (After May, 1978)

Body Sizes and Geographical Ranges. Patterns in the relationsbetween the body sizes
and the geographicalranges of species are only just beginning to receive systematic attention.
It is possible that geographical ranges are typically more extensive for relatively large organisms and for microorganisms (protozoa and below) than for mid-size organisms (insects). If
true, such patterns—whichare entwined with the species-size effects mentioned immediately
above—arerelevant, amongst other things, to possiblerange modifications associated with climate change.

234

Patterns in Foodweb Structure. It has been strongly argued that each plant or animal
species in a foodweb typically is connected—eating or being eaten—with only 3 to 5 otherspecies. Why so roughly constant a number, and why so small? Also, the lengths of foodchains in such webs—the number of links connecting the primary producing plants, throughthe animals eating them, and those eating them, and so on, to the top predators— typically are
only 3 to 4 links long, with surprisingly little variation within and among foodwebs. Again,
why so roughly constant a rule, and why are chains so short? Although these important empirical patterns (Pimm et al, 1991) may in part be artifacts of the way humans gather and analysecomplicated data, there are important questions here. Various explanations currently contend:
efficiency of energy transfer from level to level within a foodchain; relations between the
dynamics of the system and its structure; evolutionary instability of excessively complex
chains; and others. But every explanation proposed so far has important weaknesses.
Connections Among Seemingly Different Questions. To illustrate how the above
questions are intimately entwined with seemingly simpler questions of how many species
there are on earth, consider the relation between foodweb patterns and global species numbers.
If we really had a fundamental understanding of how foodweb structure was determined byevolutionary and ecological factors in specific environments, we could predict the average
ratio between the number of animal species and the number of primary producing plant species
that ultimately sustain them, in foodwebs in particular environments, and thence the overall
global average such ratio. We can be fairly certain, to within 10% or so, that the global total ofplant species is around 300,000. So if we knew the animal/plant species ratio, we could assess
the total number of animal species, by this indirect argument based on understanding ecosystem structure. Unfortunately, we have no such understanding. Such rough empirical data as areavailable suggest that the animal/plant species ratio is around 10 in foodwebs, although withmuch variation from place to place. This very rough empirical estimate suggests a global totalof about 3-million animal species; we shall return to this below.
Dynamicsof Plant and Animal

Populations

Another, very different, strand of my work is ultimatelyof the surprisinglight it sheds on how populations

The Balance
assumeof Nature?

that population

Early work on "the balance of nature" implicitly

numbers

unless affected by environmental
and animal populations—foodritorial

considerations,themselves

dependwould be roughly
fluctuations.

tended tofrom year to year,

But the factors regulating

the densities of plant

infectious

diseases, nest sites or other ter-to operate in a nonlinearthat govern the possibleon population

becausesteady, unchanging

supplies, predators,

and many others—tendstrengths of the feedbacks

related to biodiversity,

can react to disturbance.

steady or "equilibrium"

size, so that if the population

way. That is, thepopulation

size

doubles, it does not simply

mean that per capita birth rates and death rates double; birth rates may fall, and death rates rise,
more than proportionately
does not necessarily

Chaos and Other
logical populations

or "linearly." This is what "nonlinear"

add up to four when the governing
Surprises.

may be regulated

The simplest nonlinear
by feedbackmeans. In effect, two plus two

mechanisms
equationsmechanisms

are nonlinear.
representing

how bio-can exhibit a bewildering,235

almost magical, array of behaviour. The simplest such equations, of the kind suggested by various people working on insect and on fish populations as descriptions of their systems, can—although purely deterministic, with no statistical elements—give rise not only to the expected
constant "equilibrium" solutions, but alternatively to stable and self-generated cycles of boom
and bust, or even more surprisingly, to apparently random fluctuations. For a population, suchas many temperate insects, with discrete non-overlapping generations (adults appearing eachyear, laying eggs to develop into next year's adults, then dying), a simple metaphor is Xt+i =rXt (1 - Xt ). Here Xt is the population in year t, scaled so that if X ever gets as large as 1, it
extinguishes itself, and r is its intrinsic growth rate at low density (when X is close to 0). As
can be verified by iterating this simple equation on a hand-held calculator, if r is between 1 and3, this equation describes a population that settles to a constant equilibrium value, as earlier
ecological intuition required. If r is above 3 but below about 3.57, we see self-sustained cycles.
For r bigger than 3.57, but below 4, there is "chaos," apparently random fluctuations, generated by this trivially simple deterministic equation. This behaviour is illustrated in Figure 3.

1 (a)

l

(b)

r =2.4 (stable point)

0

5

10

Generation

15

20

25

r =3.4 (stable cycles)

0

5

10

Generation

time, t

15

20

25

time, t1 (c)r =3.99 ("chaos")
0

5

10

Generation

15

20

25

Figure 3. Illustrating the behaviour of the equation
Xt+1= rXt (1-Xt ), for different values of r.

time, tGeneral Implicationsof Chaos. This observation, motivated by purely ecologicalquestions, was one of the strands that brought chaos centre stage across the sciences (May,
1974, 1976; the other strand was Lorenz's (1963) meteorological metaphor, based on a more
complicated set of three differential equations). The recognition that simple and fully deterministic rules or equations can generate dynamical patterns that are effectively indistinguishable from random noise has very deep implications for science. It effectively marks the end of236

the Newtonian dream that knowing the rules will enable prediction; predicting local weather
beyond about 10-15 days is not just a problem of computational power, but of the inherent
unpredictability of chaotic dynamical systems.
Ecological Implications of Chaos. The implications of cyclic and, even more, of
chaotic, dynamics for ecology are widespread. Often the "balance of nature" is disturbed byenvironmental fluctuations; this has long been recognised. But often the "balance of nature"
is inherently cyclic or irregularly fluctuating, driven by the nonlinear dynamics of its own regulatory mechanisms. We have yet fully to realise the implications of this work for understanding the causes and consequences of biological diversity (May, 1985).

Biodiversity
What is the State of our Knowledge? Against the background of ecological questions
sketched above, how well do we know the world of plants, animals and microorganismns withwhich we share this planet? The answer, by any one of a variety of objective measures, must
be: not very well. First, estimates of the number of species that have been named and recorded(a simple factual question, like how many books in the library catalogue) range from 1.4 million to 1.8 million. Second, estimates of the total number of species present on Earth today
range over more than an order-of-magnitude,from a low of around 3 million to a high of 30
million or possibly much more. And third, we have even less idea of the rates at which species
may currently be going extinct, as result of habitat destruction and other consequences ofhuman population growth.
Some Personal Estimates. In this brief overview, I outline my own best guess of theanswers to these three questions. For the number of distinct species named and recorded, Iemphasise the uncertainties caused by unresolved synonymies. For the likely total number ofliving species, I set out my reasons for leaning to the lower end of the range of published estimates. And for present and likely future extinctions, I sketch a relatively precise approach,based on comparative rates of extinction, which avoids some of the imprecisions inherent indealing with total number of species.
Numbers of Named Species: Background. The systematic naming and recording ofspecies began relatively recently, with Linneaus' standard work, which in 1758 recognised
some 9,000 species. Today the total number of living species named and recorded has been
estimated at around 1.7 to 1.8 million. Amazingly, no centralised catalogue exists. There aresynoptic and computerised catalogues for some better-known groups, most notably birds andmammals. But more than half (roughly 56%) of all named species are insects, and the majority of these are still on card catalogues in individual museums and other collections. By one
estimate, around 40% of all named beetle species are known from only one site, and manyfrom only one specimen. In short, the amount of taxonomic effort varies very widely fromgroup to group, with roughly one-third of all taxonomists working on vertebrates, anotherthird working on the 10-times more numerous plant species, and the remaining third working
on invertebrate animals, which outnumber vertebrate species by at least a factor of 100 (seeTable 2).

237

Table 2. The taxonomy of taxonomists: a rough estimate of the distribution of the taxonomic workforce amongbroad taxonomic groups, in Australia, U.S.A. and U.K. (after Gaston and May 1992).
Animals
PlantsVertebrates

Invertebrates

Approximate division of
workforce (%)

30

25

35

Estimated total numberof living species(Thousands)

300

45

3,000 +

Microorganisms

Fossils2-3

5

Numbers of Named Species: Problems. Hammond's (1995) assessment for the IUCNof the total number of distinct species that have been named and recorded emphasises theuncertainties caused by synonyms. His survey estimates that around 13,000 new species are
currently named each year, but current rates of resolving synonymies—the same species inadvertently given different names by different people in different collections—reduce this number to around 10,000 distinct new species added yearly to the known total. In effect, this corresponds to a synonymy rate of around 20% in named species, a figure elsewhere cited as
representative on more direct grounds (Solow et al, 1995). Of course, any such assessment ofknown synonymy rates must be a lower limit, with other synonyms yet to be uncovered or
accumulating in new work. Solow et al (1995) have made a start on this important problem,suggesting the true synonymy rate may be more like 40%.
Numbers of Named Species: A Current Estimate. Allowing for all this, my recent
assessment (May, 1999) is that the current global total of distinct eukaryotic species (broadly,plants, animals and fungi) that have been named and recorded is around 1.5 million. This islower than Hammond's (1995) 1.74 million, but is consistent with Wilson's (1988) estimate of
1.4 million ten years ago (augmented by 0.01 million each year for 10 years). See Table 3.
Table

Group
Protozoa

Numberof named,

distinct species of eukaryotes (in thousands)

Hammond (1995)
40
40
270

Algae
Plants
Fungi
Animals

70
1,320
45
25

Vertebrates
Nematodes
Molluscs
Arthropods

70
1,085

(crustaceans)(arachnids)(insects)(other)others
Total

238

3.

May (1999)
40
40
270
70
1,080
45
15
70
855

(40)
(75)
(950)
(20)

(40)
(75)
(720)
(20)

95

95

1,740

1,500

Total Number of Species Living Today. The true total of extant species, as distinct
from those we have named and recorded, is hugely uncertain. My recent assessment of the evidence and uncertainties led to a guess of around 7 million in total, with a plausible range of 5
to 15 million (May, 1999). This is lower than Hammond's (1995) guess of 12-million eukaryotic species, but higher than other estimates which are as low as 3 million or so species in total.
Estimates as low as 3 million, or as high as 100 million or more, can be defended. See Table
4.
Table

4.

Estimated total numbers of living species (in thousands)

Hammond (1995)
Group
Protozoa
Algae
Plants
Fungi
Animals
Verts
Nematodes
Molluscs
Arthropods(crust)(arachnids)(insects)

High

- low

200
1,000
500
2,700

-

60
150
300
200

100,000
55 -

3,000
50

1,000
200
100,000

100
100
2,400

-

Working
Figure
200
400
320
1,500
9,800
50
400
200

(200 - 75)(1,000 - 300)
(100,000 - 2,000)

others800

100,000

Total
Range•100
Plausible
range15
Best guess•7

•

200

-

3,500
- 3

million- 5

millionmillionMay (1999)
100
300
320
500
5,570
50
500

8,900

120
4,650

(150)
(750)
(8,000)

(150)
(500)
(4,000)250

250

12,2006,800

Total Number of Species: Further Comments. All such estimates are dominated by
insect totals. I favour an estimate of around 4-million insect species in total, partly based on themethods developed by Gaston and Hudson (1994). This is lower than Hammond's 8-million
insects species, but higher than other estimates of around 2 million, either of which could becorrect. My total also reflects a distrust of the dramatic upward revision of fungal species
numbers by Hawksworth (1991) and of marine macrofaunal species by Grassle and Maciolek(1992), amongst other things. For more detailed reviews of these hugely important issues, see
May (1990, 1994, 1999).
EXTINCTIONRATESThe Past. The history of life on Earth, written in the fossil record over the past 600-million years since the Cambrianbroadly increasing

explosion in the diversity of multicellular

diversity, albeit with many fluctuations

and punctuatedorganisms,

is one ofby episodes of mass

239

O

extinction; see Figure 4. As reviewed in more detail elsewhere (Sepkoski, 1992; May, 1999),
the average lifespan of a species in the fossil record, from origination to extinction, is typicallya few million years (that is, of the order 106 to 10' years); there is, however, much variation
both within and among groups, and some groups have lifespans significantly longer or shorter
than this; see Table 5. Comparing this few-million-year average lifespan with the 600-millionyear fossil record span, we might estimate that 1%-2% of all species ever to have lived are with
us today. But, allowing for the fluctuating but steady—very roughly linear—average growthin species diversity since the Cambrian, a better estimate might be 2%-4%. And if we recognise that most of today's species are terrestrial invertebrates (mainly insects), whose patternsof diversification began around 450-million-year ago and whose average lifespan may be characteristically longer than 10-million-year, it could be that today's species represent more like
5%, or conceivably even 10%, of those ever to have graced our planet.

800
5

1

600

2

3
4

400

200

0
v

600

S

e

500

D
400

C
300

P

Tr

J

200

K
100

T
0

Geologic time (106 years)
Figure 4. The history of the diversity of marine animal families, as shown by the fossil record over time. The
curve connects 77 discrete data points, each giving the total number of well-skeletonized families from a particular stratigraphic stage. The arrows indicate the Big Five episodes of mass extinction. The length of the various geological epochs are indicated on the time axis (V, Vendian; -E, Cambrian; 0, Ordovician; S, Silurian; D, Devonian;C, Carboniferous; P, Permian; Tr, Triassic; J, Jurassic; K, Cretaceous; T, Tertiary).

240

Table 5. Estimated lifespans, from origination to extinction, of various taxa in the fossil record (measured in millions of years). The first part of the Table is after May et al (1995), whereas the second part is a new compilation
by Robin Cocks (Natural History Museum, London).

TAXONPart I : Referencesin May et al (1995)

Raup (1978)
Valentine (1970)
Raup (1991)
Sepkoski (1992)
Simpson (1952)
Martin (1993)
Raup and Stanley (1978)
Van Valen (1973)
Van Valen (1973)
Van Valen (1973)
Raup and Stanley (1978)
Durham (1970)
Rickards (1977)

All invertebrates
Marine invertebrates
Marine animals
Marine animals
All fossil groups
Mammals
Cenzoic mammals
Diatoms
Dinoflagellates
Planktinic foraminifers
Cenozoic
bivalves
Echinoderms
Silurian graptolites

Part II : Information

Average lifespan(millionyears)

Date of estimate

compiled

Koren and Rickards (1996)
Davidek et al, in press
R. Cocks, pers. comm.
R. Cocks, pers. comm.
R. Cocks, pers. comm.
J.J. Hooker, pers. comm.
Budd et al, (1996)

ForamsCoccoliths

Buzas and Culver (1984)
J.R. Young, pers. comm.

Extinctions.

Over the past century,

studiedgroups—primarily

Becausetropicalspecies

typicallymammals

are undoubtedly

higher.

birds

and mammals

extinction
order
record.

rates,

10 -2 to 10
Thatone- thousand

birds

translatesof aroundandreceivelessto expectedattention,

species'than the backgroundaveragetimes faster

0.4
0.5
0.3 —1.00.5
3
0.2 —7(average 4)
14 —16c. 10

documented

lifespanrates in well-documented

than the averagebackgroundin well-species

per year.

aroundtrue

extinction

rates

the roughly

13,000lifetimes,

seemingly

extinctions

run

But even one per year among

Althoughextinction

0.2

rigorously

mammals—have

10 4 years.

is, recent

45*
0.5 — 5
1
1 —2
8
13
7
10
6
2
6 —7

by R. Cocks

Silurian graptolites
Cambrian trilobites
Brachiopods
Rodents
Perrissodactyls
Insectivores
Corals (tertiary-recent)

Recent

11*
5-10

based

long,

one

on documented

this is shorterof 10 6 to 10 ' years
groupsof birdshave

species

andofrecentby a factorofseen in the fossil

run one-hundred

torates.

241

Guesses About Tomorrow. Looking toward the immediate future, four different
approaches to estimating impending rates of extinction suggests species' life expectancies ofaround a few hundred to one-thousand years. One of these approaches is based on the abovementioned species-area relations, coupled with assessments of current rates of tropical deforestation or other habitat loss (if tropical forests are being lost at the rate of 1%-2% each year,
the species-area relation implies this commits 0.25%-0.5% of their species to extinction, which
inverts to a rough estimate of species' lifetimes .of roughly 200-400 years). Two other methods are based in different ways on the International Union for the Conservation of Nature's(IUCN's) current catalogue of "endangered" or "vulnerable" species. As reviewed elsewhere(May et al, 1995), one of these estimates the average rate at which species in better-studiedgroups (birds, mammals, palm trees) are climbing the ladder of IUCN categories of endangerment; this suggests expected species' lifetimes in the range 100 to 800 years in thesegroups. A more precise variant of this approach uses species-by-species assessments of extinction probability distributions as functions of time. Using 10 vertebrate groups (3, 4, 3 orders
or families of reptiles, birds and mammals, respectively), Mace (1994) estimates average
species' lifetimes in the range 100 to 1,000 years, and mainly in the 300- to 400- year range
for mammals and birds. The fourth method uses models for branching processes in phylogenetic trees, along with recent data for bird and mammal orders, to project average times toextinction within bird and mammal orders (McKinney, 1998); under a range of assumptions
about branching processes, these models suggest species' lifetimes again of the order of afew- hundred years (characteristically shorter for mammals than birds). Thus, all four of thesemethods, each of which is unreliable in its own distinctive way, agree in suggesting a further
shortening of expected species' lifetimes, to around 102 to 103 years.
The Sixth Wave of Extinction. Such figures correspond to likely extinction rates of afactor of ten thousand, give or take at most an order of magnitude, above background, over the
next century or so. This represents a sixth great wave of extinction, fully comparable with the
Big Five mass extinctions of the geological past, but different in that it results from the activities of a single other species rather than from external environmental changes.
A Calculus of Biodiversity? As we face this future, we must ask: does it matter more
if we lose 25% of all mammal species than if we lose 25% of the vastly more numerous insect
species? Or does it matter equally? Or less? There is need not only for more taxonomic information, but also for a "calculus of biodiversity" based on this information. Such a calculus
should, ideally, quantify the taxonomic uniqueness, or amount of independent evolutionary
history, inherent in individual species (Vane-Wright et al, 1991; Nee and May, 1997). I would
like to see such quantification, along with more explicit recognition of constraining political,
economic and social realities, replace emotion in assigning conservation priorities and placeson the Ark (although emotional elements should, certainly, also be part of such a quantification). For further review and remarks on this topic, see May et al (1995).
Why

Value

Biological

A Narrowly
diversity242

is narrowly

Diversity?

Utilitarian

Argument.

One argument

utilitarian.

It correctly

emphasises

for the preservation

the benefits

alreadyof biologicalderived

from

nat-

ural products, as foods, medicines and so on. Currently, 25% of the drugs on the shelves in thepharmacy derive from a mere 120 species of plants. But, throughout the world, the traditional
medicines of native peoples make use of around 25,000 species of plants (about 10% of thetotal number of plant species); we have much to learn. More generally, as our understandingof the natural world advances, both at the level of new species and at the level of the molecular machinery from which all organisms are self-assembled, the planet's genetic diversity is
increasingly the raw stuff from which our future can be constructed. It seems a pity to be burning the books before we can read them, and before we can create wealth from the recipes on
their pages.
A Broadly Utilitarian Argument. Another class of arguments is more diffusely utilitarian. The interactions between biological and physical processes created and maintain theearth's biosphere as a place where life can flourish. With impending changes in climate causedby the increasing scale of human activity, we should be worried about reductions in biologicaldiversity, at least until we understand its role in maintaining the planet's life support systems.
The first rule of intelligent tinkering is to keep all the pieces.
An Ethical Argument. For me, however, a third class of argument is the most compelling. It is clearly set out by the U.K. Government in This Common Inheritance (HMSO,
1990, ch 1.14): it is "the ethical imperative of stewardship ... we have a moral duty to look after
our planet and hand it on in good order to future generations."
Conclusion
The previous century has seen more advances in our understandingof the natural world

than has all previous human history. We have applied this scientific understanding
lives in both developed

and developing

some of the unintended

adverse consequences

significant

is the accelerating

to improvecountries. We are, however, now beginningloss of biologicalof well-intentioned

to realise

actions: arguably the mostdiversity. What happens to our world, and to

us and the creatures we share the world with, in the future depends on the actions we take now.
As a new century dawns, our greatest challenge remains to ensure that necessary

increases

inglobal productivity are achieved in a sustainable and environmentally friendly way.
I believe these are matters of concern for all of us. But effective action must be based ongood scientific understanding
logical diversity.

of the underlying

causes, and likely consequences,of loss of bio-

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Gaston, K.J. and E. Hudson. 1994. "Regional Patterns of Diversity and Estimates of Global Insect Species
Richness." Biodv. and Consv., 3, 493-500.
Gaston, K.J. and May, R.M. 1992. "The Taxonomy of Taxonomists." Nature, 356, 281-282.
Grassle, J.F. and N.J. Maciolek. 1992. "Deep-Sea Species Richness: Regional and Local Diversity Estimates from
Quantitative Bottom Samples." Amer. Natur. 139, 313-341.
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McKinney, M.L. 1998. "Branching Models Predict Loss of Many Bird and Mammal Orders within Centuries."
Anim.Consv., 1, 159-164.
Mace, G.M. 1994. "An Investigation into Methods for Categorizing the Conservation Status of Species." In Large
Scale Ecology and Conservation Biology (eds. P.J. Edwards, R.M. May and N.R. Webb). 295-314. Blackwell;
Oxford.
May, R.M. 1973. Stability and Complexityin Model Ecosystems.Princeton University Press; Princeton, N.J.
May, R.M. 1974."Biological Populations with Nonoverlapping Generations:Stable Points, Stable Cycles, Chaos."
Science, 186, 645-647.
May, R.M. 1976. "Simple Mathematical Models with Very Complicated Dynamics." Nature, 262, 459-467.
May, R.M. 1978. "The Dynamics and Diversity of Insect Faunas." In Diversity of Insect Faunas (eds. L.A. Moundand N. Waloff). 188-204. Blackwell; Oxford.
May, R.M. 1985. "When Two and Two Do Not Make Four: Nonlinear Phenomena in Ecology." The Croonian
Lecture. Proc. Roy. Soc., B228, 241-266.
May, R.M. 1990. "How Many Species?" Phil. Trans. Roy. Soc., B330, 292-304.
May, R.M. 1994. "Conceptual Aspects of the Quantification of the Extent of Biological Diversity." Phil. Trans.
Roy. Soc., B345, 13-20.
May, R.M. 1999." The Dimensions of Life on Earth." In Nature and Human Society. National Academy of
Sciences Press; Washington, DC.
May, R.M.,J.H. Lawton, and N.E. Stork, 1995."Assessing Extinction Rates." In ExtinctionRates (eds. J.H. Lawton
and R.M. May). 1-24. Oxford University Press; Oxford.
May, R.M. and M.P.H. Stumpf, 2000. "Species Area Relations in Tropical Forests." Science, 290, 2084-2086.
Naeem, S. and S. Li, 1997. "Biodiversity Enhances Ecosystem Reliability." Nature, 390, 507-509.
Nee, S. and R.M. May. 1997. "Extinction and the Loss of Evolutionary History." Science, 278, 692-694.
Pimm, S.L., J.H. Lawton, and J.E. Cohen, 1991." Food Web Patterns and their Consequences." Nature, 350,
660-674.
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Soule). 182-204. Sinauer; Sunderland, Mass.
Sepkoski, J.J. 1992. "Phylogenetic and Ecologic Patterns in Phanerozoic History of Marine Biodiversity." In
Systematics,Ecology, and the BiodiversityCrisis (ed. N. Eldredge). 77-1000. Columbia University; New York.
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Ecological Consequence? "Nature, 151, 277-282.
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Choice." Biol. Conserv., 55, 235-254.
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244

Major Publications
Lord (Robert) May of Oxford
Books
May, R.M. Stability and Complexityin Model Ecosystems. Princeton: Princeton Univ. Press, 1973.
— . Stability and Complexityin Model Ecosystems. Second Edition. Princeton: Princeton Univ. Press,
1974. Re-issued in the Princeton Landmarks in Biology series with a new Introduction, 2001, xi–xxxiv.
May, R.M., ed. Theoretical Ecology: Principles and Applications. Oxford: Blackwell Scientific
Publications, and Philadelphia: Saunders, 1976.
—.Theoretical Ecology: Principles and Applications. Second Edition. Oxford: Blackwell Scientific
Publications, and Sunderland, Mass.: Sinauer, 1981. (Translated into German, 1982. Translated
into Chinese, 1983.)
Anderson, R.M. and R.M. May, ed. Population Biology of Infectious Diseases. Berlin and N.Y.:
Springer Verlag, 1982.
May, R.M., ed. Exploitation of Marine Communities.Berlin and N.Y.: Springer Verlag, 1984.
Roughgarden, J., R.M. May and S.A. Levin, ed. Perspectives in Ecological Theory. Princeton:
Princeton Univ. Press, 1989.
Hassell, M.P. and R.M. May, ed. Population Regulation and Dynamics. London: The Royal Society,and Cambridge: Cambridge Univ. Press, 1990.
Anderson, R.M. and R.M. May. Infectious Diseases of Humans: Dynamics and Control. Oxford:
Oxford Univ. Press, 1991.
Anderson, R.M. and R.M. May. Infectious Diseases of Humans: Dynamics and Control. Oxford:
Oxford Univ. Press, 1991. Second printing with minor revisions in paperback, 1992.
Beddington, J.R., D.H. Cushing, R.M. May and J.H. Steele, ed. Generalizing across Marine andTerrestrial Ecology. London: The Royal Society, 1994.
Edwards, P.J., R.M. May and N.R. Webb, ed. Large-Scale Ecology and Conservation Biology.Oxford:
Blackwell Scientific Publications, 1994.
Grenfell, B. and R.M. May and H. Tong, ed. Chaos and Forecasting. London: The Royal Society(Single Issue of Philosophical Transactions, 348, No. 1688), 1994,323-514. [Also published byWorld Scientific Publishing, Singapore, 1995.]
Lawton, J.H. and R.M. May, ed. Extinction Rates. Oxford: Oxford Univ. Press, 1995.
Magurran, A.E. and R.M. May, ed. Evolution of Biological Diversity. Oxford: Oxford Univ. Press,
1999.
Nowak, M.A. and R.M. May. VirusDynamics: Mathematical Principles of Immunologyand Virology.
Oxford: Oxford Univ. Press, 2000.

Chapters in Books
May, R.M. "Ecosystems: The First Three Billion Years and the Next Fifty Years." In Brain Mechanism
and the Control of Behaviour. Ed. Messell and S.T. Butler. 65-119. Sydney: Shakespeare Head
Press, 1972.
—. "Stability in Model Ecosystems." In Proc. of the Ecological Societyof Australia, 6,18-56.1971.
—. "Ecosystems Pattern in Randomly Fluctuating Environments." In Progress in Theoretical Biology.
Ed. R. Rosen and F. Snell. Vol. III, 1-50. N.Y.: Academic Press, 1974.
—. "General Introduction."In Ecological Stability. Ed. M.B. Usher and M. Williamson. 1-14. London:
Chapman and Hall. 1974.
— . "How Many Species: Some Mathematical Aspects of the Dynamics of Populations." In Some

245

Mathematical Problems in Biology, Vol. 6. Ed. J. Cowan. 64-98. Providence, R.I.: American
Mathematical Society, 1974.
- . May, R.M. "Patterns of Species Abundance and Diversity." In Ecology and Evolution ofCommunities.Ed. J. Diamond and M. Cody. 81-120. Cambridge,Mass.: Harvard Univ. Press, 1975.
- . May, R.M. "Stability in Ecosystems: Some Comments." In UnifyingConcepts in Ecology. Plenary
session reports at the First International Congress on Ecology. Ed. W.H. van Dobben and R.H.
Lowe-McConnell. 161-168. The Hague: W. Junk Pubs, 1975.
- . "Mathematical Aspects of the Dynamics of Animal Populations." In Studies in Mathematical
Biology,MAA Studies in Mathematics, No. 15-16. Ed. S.L. Levin. 317-366. Washington, D.C.:
Mathematical Association of America, 1978.
- . "Mathematical Models and Ecology: Past and Future." In The Changing Scenes in the Natural
Sciences, 1776-1976. Ed. C.E. Goulden. 189-201. Philadelphia: Academy of Natural Sciences,1977.
- . "Factors Controlling the Stability and Breakdown of Ecosystems." In The Breakdown and
Restoration of Ecosystems. Ed. M.W. Holdgate and M.J. Woodman. 11-25. N.Y.: Plenum Press,
1978.
- . "The Dynamics and Diversity of Insect Faunas." In Diversityof Insect Faunas. Ed. L.A. Mound and
N. Waloff. 188-204. Oxford: Blackwell Scientific Publications, 1978.
- . "The Structure and Dynamics of Ecological Communities." In Population Dynamics. Ed. R.M.
Anderson,B.D. Turner and L.R. Taylor. 385-407. Oxford: Blackwell ScientificPublications, 1979.
Aron, J.L. and R.M. May. "The Population Dynamics of Malaria." In Population Dynamics ofInfectiousDiseases. Ed. R.M. Anderson. 139-179. London: Chapman and Hall, 1982.
May, R.M. "Mathematical Models in Whaling and Fisheries Management." In Some Mathematical
Questions in Biology, Vol. 13. Ed. G.F. Oster. 1-64. Providence, R.I: American MathematicalSociety, 1980.
- . "The Dynamics of Natural and Managed Populations." In Mathematical Theory of the Dynamics ofPopulations II. Ed. R.W. Hiorns and D. Cooke. 5-29. N.Y.: Academic Press, 1981.
- . "Modelling Recolonisation by Neotropical Migrants in Habitats with Changing Patch Structure,with Notes on the Age Structure of Populations." In Forest Island Dynamics in Man-DominatedLandscapes, Vol. 41. Ed. R.L. Burgess and D.N. Sharpe. In Springer-Verlag Series on EcologicalStudies.207-213. N.Y.: Springer Verlag, 1981.
- . "Population Biology of Parasitic Infections." In The Current Status and Future of Parasitology. Ed.
K. S. Warren and E. F. Purcell. 208-235. N.Y.: Josiah Macy, Jr., Foundation, 1981.
May, R.M. and J.R. Beddington. "Notes on Some Topics in Theoretical Ecology, in Relation to theManagement of Locally Abundant Populations of Mammals." In Problems in Management ofLocally Abundant WildMammals. Ed. P.A. Jewell and S.J. Holt. 205-216. N.Y.: Academic Press,
1982.
Martin,R.D. and R.M. May. "Outward Signs of Breeding." In Evolution Now:'A Centuryafter Darwin.
Ed. J. Maynard Smith. 234-239. London: Macmillan, 1982.
May, R.M. and R.M. Anderson. "Parasite-HostCoevolution." In Coevolution.Ed. D.J. Futuyma and M.
Slatkin. 186-206. Sunderland, Mass.: Sinauer, 1983.
May, R.M. "Nonlinear Problems in Ecology and Resource Management." In Chaotic Behaviour of
Deterministic Systems. Ed. G. looss, R.H.G. Heileman and Stora. 389-439. Amsterdam: NorthHolland Publishing, 1983.
- . "Parasitism: Ecology and Population Biology." In Tropical and Geographical Medicine. Ed. K.S.
Warren and A.A.F. Mahmoud. 152-166. N.Y.: McGraw-Hill, 1984.
- . "Creation, Evolution, and High School Texts." In Science and Creationism. Ed. A. Montagu.
306-310. Oxford: Oxford Univ. Press, 1984.
- . "Adaptations,Constraints and Patterns of Evolutions."In Evolution: Essays inAppreciation of John

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Maynard Smith. Ed. D.J. Greenwood, M. Slatkin and P.H. Harvey. 107-116. Cambridge:
Cambridge Univ. Press, 1984.
-. May, R .M. "An Overview: Real and Apparent Patterns in Community Structure." In EcologicalCommunitiesConceptual Issues and the Evidence. Ed. D.R. Strong, D. Simberloff,L.G. Abele andA.B. Thistle. 1-16. Princeton: Princeton Univ. Press, 1984.
May, R.M. and D.I. Rubenstein. "Mammalian Reproductive Strategies." In Reproduction in Mammals,Vol. 4. Ed. C.R. Austin and R.V. Short. 1-23. Cambridge: Cambridge Univ. Press, 1985.
Hassell, M.P. and R.M. May. "From Individual Behaviour to Population Dynamics." In Behavioural
Ecology. Ed. R. Sibly and R. Smith. 3-32. Oxford: Blackwell Scientific Publications, 1985.
May, R.M. "Host-Parasite Associations: Their Population Biology and Population Genetics." In
Ecology and Genetics of Host-Parasite Interactions. Ed. D. Rollinson and R.M. Anderson.
243-262. N.Y.: Academic Press, 1985.
-. "Population Dynamics." In The Study of Populations. Ed. H. Messel. 1-44 (4 chaps). Sydney:
Pergamon Press, 1985.
- . "Ecology of Insect-Pathogen Interactions,and Some Possible Applications." In Ecological Theory
and Integrated Pest Management.Ed. M. Kogan. 185-201. N.Y.: John Wiley & Sons, 1986.
Dobson, A.P. and R.M. May. "Patterns of Invasions by Pathogens and Parasites." In Ecological
Biological Invasions of North America and Hawaii. Ed. H.A Mooney and J.A. Drake. 58-76. N.Y.:
Springer Velag, 1986.
May, R.M. "Experimental Control of Malaria in West Africa." In Ecological Knowledge andEnvironmental Problem-Solving: Concepts and Case Studies (NAS Committee on Applications of
Ecological Theory to Environmental Problems). 191-203. Washington, D.C.: National Academy
Press, 1986.
Dobson, A.P. and R.M. May. "Population Dynamics and the Rate of Evolution of Pesticide Resistance."
In Pesticide Resistance: Strategies and Tacticsfor Management (NAS.Committee on Strategies for
the Management of Pesticide Resistance Pest Populations). 170-193. Washington, D.C.: National
Academy Press. 1986.
-. "Disease and Conservation." In Conservation Biology: The Science of Scarcity and Diversity. Ed.
M.E. Soule. 345-365. Sunderland, Mass.: Sinauer, 1986.
May. R.M. "Population Biology of Microparasitic Infections." In Mathematical Ecology: An
Introduction. Ed. T.G. Hallam and S.A. Levin. 405-442. N.Y.: Springer Verlag, 1986.
Dobson, A.P. and R.M. May. "The Effects of Parasites on Fish Populations: Theoretical Aspects." In
Parasitology Quo Vadit? Ed. N.J. Howell. 363-370. Canberra: Australian Academy of Science,
1986.
May, R.M. "Mathematical Models in Ecology: The Dynamics of Surprise." In Highlights in Science.
Ed. H. Messel. 88-128. Sydney: Pergamon Press, 1987.
-. "Prolog." In Size-Structured Populations . Ed. B. Ebenman and L. Persson. 1-3. Berlin: SpringVerlag, 1988.
May, R.M., R.M. Anderson and A.M. Johnson. "Patterns of Infectiousness and the Transmission of
HIV-1." In AIDS 1988: AAAS Symposia Papers. Ed. R. Kulstad. 75-83. Washington, D.C.:
American Association for the Advancement of Science, 1988.
Hassell, M.P. and R.M. May. "The Population Biology of Host-Parasite and Host-Parasitoid
Associations." In Perspectives in Ecological Theory. Ed. J. Roughgarden, R.M. May and A. Levin.
319-347. Princeton: Princeton Univ. Press, 1989.
May, R.M. "How Many Species?" In The Fragile Environment: The Darwin College Lectures. Ed. L.E.
Friday and R.A. Laskey. 61-81. Cambridge: Cambridge Univ. Press, 1989. (Reprinted in Italian as"Il Fragile Ambiente" by Edizioni Dedalo, 1991.)- . "Levels of Organization in Ecology." In Ecological Concepts.British Ecological Society's Jubilee
Symposium. Ed. J.M. Cherrett. 339-363. Oxford: Blackwell Scientific Publications, 1989.

247

- . "Parasitism: Ecology and Population Biology.". In Tropical and Geographical Medicine, 2nd
Edition. Ed. K.S. Warren and A.A.F. Mahmoud. 130-145. N.Y.: McGraw-Hill, 1989.
Anderson, R.M. and R.M. May. "Complex Dynamical Behaviour in the Interaction between HIV andthe Immune System." In Cell to Cell Signalling. Ed. A. Goldbeter. 335-349. London: Academic
Press, 1989.
May, R.M., R.M. Anderson and A.R. McLean. "Possible Demographic Consequences of HIV/AIDS
Epidemics: II, Assuming HIV Infection Does Not Necessarily Lead to AIDS." In Mathematical
Approaches to Problems in Resource Management and Epidemiology. Lecture Notes in
Biomathematics, Vol. 81. Ed. C. Castillo-Chauvez, S.A. Levin and C.A. Shoemaker. 220-245.
N.Y.: Springer Verlag, 1989.
May, R.M. and R.M. Anderson. "Heterogenities, Cofactors and Other Aspects of the Transmission
Dynamics of HIV/AIDS." In Current Topicsin AIDS,Vol. 2. Ed. M.S. Gottlieb, et al. 33-67. N.Y.:
John Wiley & Sons, 1989.
- . "The Transmission Dynamics of Human Immunodeficiency Virus." In Applied Mathematical
Ecology (Biomathematics, Vol. 18). Ed. S.A. Levin, T.G. Hallam and L. Gross. 263-311. N.Y.:
Springer Verlag, 1989.
May, R.M. and T.R.E. Southwood."Introduction."In Living in a Patchy Environment.Ed. B. Shorrocks
and I.R. Swingland. 1-22. Oxford: Oxford Univ. Press, 1990.
May, R.M. "Population Biology and Population Genetics of Plant-Pathogen Associations." In Pests,
Pathogens and Plant Communities.Ed. J.J. Burdon and S.R. Leather. 309-325. Oxford: Blackwell
Scientific Publications, 1990.
Dobson, A.P. and R.M. May. "Parasites, Cuckoos, and Avian Population Dynamics." In Bird
Population Studies. Ed. C.M. Perrins, J.D. Lebreton and G.J.M. Hirons. 391-412. Oxford: Oxford
Univ. Press, 1991.
May, R.M. "The Dynamics and Genetics of Host-Parasite Associations." In Parasite-Host
Associations: Coexistence or Conflict? Ed. C.A. Toft, A. Aeschlimann and L. Bolis. 102-128.
Oxford: Oxford Univ. Press, 1991.
- . "How Many Species on Earth Today? And Tomorrow? How Do We Manage the Ark?" Chap.
2,3,4. In Living with the Environment. Ed. L.E. Cram and D.D. Millar. 8-35. Sydney & Oxford:
Pergamon, 1991.
- . "The Role of Ecological Theory in Planning Re-Introduction of Endangered Species." In Beyond
Captive Breeding: Re-Introducing Endangered Mammals to the Wild.Ed. J.H.W. Gipps. 145-163.
Oxford: Oxford Univ. Press, 1991.
May, R.M., S. Nee and C.H. Watts. "Could IntraspecificBrood Parasitism Cause Population Cycles?"In Acta XX Congressus Internationalis Ornithologici, Vol. II. Ed. B.D. Bell, et al. 1012-1022.
Wellington, NZ: NZ Ornithological Congress Trust Board, 1991.
May, R.M. "Past Efforts and Future Prospects towards Understanding How Many Species There Are."In Biodiversityand Global Change. Ed. O.T. Solbrig, H.M. van Emden and P.G.W.J. van Oordt.
71-81. Paris: International Union of Biological Sciences, 1992.
May, R.M. and Watts, C.H. "The Dynamics of Predator-Prey and Resource-Harvester Systems." InNatural Enemies: The Population Biology of Predators, Parasites and Diseases. Ed. M.J. Crawley.
431-457. Oxford: Blackwell Scientific Publications, 1992.
Futuyma, D.J. and R.M. May. "The Coevolution of Plant-Insect and Host-Parasite Relationships." In
Genes in Ecology. Ed. R.J. Berry, T.J. Crawford and G.M. Hewitt. 139-166. Oxford: Blackwell
Scientific Publications, 1992.
May, R.M. "The Chaotic Rhythms of Life." In The New.Scientist Guide to Chaos. Ed. N. Hall. 82-95.
London: Penguin Books, 1991. (Published in the USA as Exploring Chaos. N.Y.: Norton, 1993.)- . "The Modern Biologist's View of Nature." In The Concept of Nature. Ed. J. Torrance. 167-182.
Oxford: Oxford Univ. Press, 1993.

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- . "Ecology and Evolution of Host-Virus Associations." In Emerging Viruses.Ed. S.S. Morse. 58-68.
Oxford: Oxford Univ. Press, 1993.
Holton, D. and R.M. May, "Chaos and One-DimensionalMaps (Ch. 5); Models of Chaos from Natural
Selection (Ch. 6); Distinguishing Chaos from Noise (Ch. 7); The Chaos of Disease Response andCompetition (Ch. 8)." In The Nature of Chaos. Ed. T. Mullin. 95-200. Oxford: Oxford Univ. Press,
1993.
May, R.M. "Biological Diversity: Britain's Traditions and Their Implications." In Action for
Biodiversityin the UK.Ed. F.J. Wright, C.A. Galbraith and R. Bendall. 16-20. Peterborough: JNCC
Publications Branch, 1993.
- . "Global Change: The Need and Concern for Collecting and Preserving." In Proc. of theInternational Symposium and First World Congress on the Preservation and Conservation of
Natural Collections, Vol. 3. Ed. C.L. Rose, S.L. Williams and J. Gisbert. 35-42. Madrid: Spanish
Ministry of Culture, 1993.
- . "The Effects of Spatial Scale on Ecological Questions and Answers." In Large-Scale Ecology andConservation Biology. Ed. P.J. Edwards, R.M. May and N.R. Webb. 1-17. Oxford: Blackwell
Scientific Publications, 1994.
Jones, T.M., M.P. Hassell and R.M. May. "Population Dynamics of Host-Parasitoid Interactions." In
Parasitoid CommunityEcology.Ed. A. Hawkins and W. Sheenhan. 371-394. Oxford: Oxford Univ.
Press, 1994.
May, R.M. "Changing Diseases in Changing Environments." In Health and the Environment. Ed. B.
Cartledge. 151-171. Oxford: Oxford Univ. Press, 1994.
May, R.M., J.H. Lawton and N.E. Stork. "Assessing Extinction Rates." In Extinction Rates. Ed. J.H.
Lawton and R.M. May. 1-24. Oxford: Oxford Univ. Press, 1995.
Nee, S., E.C. Holmes, R.M. May and P.H. Harvey. "Estimating Extinction from MolecularPhylogenies." In Extinction Rates. Ed. J.H. Lawton and R.M. May. 164-182. Oxford: Oxford Univ.
Press, 1995.
May, R.M. "Spatial Chaos and Its Role in Ecology and Evolution." In Frontiers in Mathematical
Biology (Lecture Notes in Biomathematics, Vol. 100). Ed. S.A. Levin. 326-344. N.Y.: SpringerVerlag, 1995.
May, R.M., S. Bohoeffer and M.A. Nowak. "Spatial Games and Evolution of Cooperation." In
Advances in Artificial Life.Ed. F. Moran, A. Moreno, J.J. Merelo and P. Chacon. 749-759. Berlin:
Springer-Verlag, 1995.
- . "Fractals, Chaos and Strange Attractors (from programme notes for Stoppard's play, Arcadia)." InThe Faber Book of Science. Ed. J. Carey. 495-504. London: Faber & Faber, 1995.
- . "The Co-Evolutionary Dynamics of Viruses and Their Hosts." In Molecular Basis of Virus
Evolution. Ed. A. Gibbs, C.H. Calisher and F. Garcia-Arenal. 192-212. Cambridge: Cambridge
Univ. Press, 1995.
- . "Introduction." In Aspects of the Genesis and Maintenance of Biological Diversity. Ed. M.A.
Hochberg, J. Clobert and R. Barbault. 1-13. Oxford: Oxford Univ. Press, 1996.
Nee, S., May, R.M. and M.P. Hassell. "Two Species Metapopulation Models." In Metapopulation
Biology: Ecology, Genetics and Evolution. Ed. I Hanski and M. Gilpin. 123-147. USA.: Academic
Press, 1997.
May, R.M. "Introductory and Concluding Remarks." In Multitrophic Interactions in Terrestrial
Systems. Ed. A.C. Gange and V.K. Brown. 305-306,419-421. Oxford: Blackwell Science
Publications, 1997.
- . Foreword in The Role of Genetics in Conserving Small Populations. Ed. T.E. Tew, T.J. Crawford,
J.W. Spencer, D.P. Stevens, M.B. Usher and J. Warren. 5-6. Hertford: Stephen Austin & Sons (forJNCC), 1997.
- . "Life Science." In Science and Society, a JSPS-UK Research Council Symposium 1995.129-130.

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Northampton: Pilkington Press, 1997.
-. "The Fractal Frontiers of Science." In Nurturing Creativity in Research: Ideas as the Foundationsof Innovation. Ed. P.M. Shearmur, C.B. Osmond and P. Pockley. 136-142. Canberra: Australian
National Univ. Press, 1997.
Ferguson, N.M., R.M. May and R.M. Anderson. "Measles: Persistence and Synchronicity in Disease
Dynamics." In Spatial Ecology: The Role of Space in Population Dynamics and InterspecificInteractions. Ed. D. Tilman and P. Kareiva. 137-157. Princeton: Princeton Univ. Press, 1997.
May, R.M. "Levels of Organization in Ecological Systems." In The Limits of Reductionism in Biology.
Ed. G.R. Bock and J.A. Goode. 193-202. Chichester: John Wiley & Sons, 1998.
- . "Ecology in Practice." In Ecology: Theoriesand Applications. Ed. P. Stiling. 470-471. New Jersey:
Prentice Hall, 1998.
- . "The European Dimension of the UK Science Base: Patterns and Policies." In Science Funding, The
European Dimension. 61-66. Discussion Meeting of The Royal Society, 17 March, 1998.
May, R.M. and K. Tregonning. "Global Conservation and UK Government Policy." In Conservation ina Changing World. Ed. G.M. Mace, A. Balmford and J.R. Ginsberg. 287-301. Cambridge:
Cambridge Univ. Press, 1998.
May, R.M. "What We Do and Do Not Know about the Diversity of Life on Earth." In Perspectives in
Ecology. Ed. A. Farina. 33-40. Leiden, NL: Backhuys Pubs., 1998.
- . "Are We Getting Better at Exploiting Our Scientific and Innovative Capability?" In RSA on Design
and Innovation, 97-113. Aldershot: Gower, 1999.
- . "Conservation:Dealing withExtinction." In Imagine Tomorrow's World. Ed. J.A. McNeely.57-68.
Gland, Switzerland: The International Union for Conservation of Nature (IUCN), 1999.
- . "Science Advice, Social Responsibility and Policy-Making." In Science, Technology and Social
Responsibility.Ed. L. Wolpert. 91-95. London: The Royal Society, 1999.
- . "The Dimensions of Life on Earth." In Nature and Human Society, The Questfor a Sustainable
World. Ed. P.H. Raven. 30-45. Washington,D.C.: US National Academy Press, 2000.
May, R.M. and R. Pitts. "Communicating the Sciencebehind Global Environmental Change Issues." InThe Daily Globe Environmental Change, the Public and the Media. Ed. J. Smith. 15-25. London:
Earthscan Pubs., 2000.
May, R.M. "The Scientific Approach to Complex Systems." In World Conferenceon Science. Ed. A.M.
Cetto. 63-65. UNESCO, 2000.

ArticlesMay, R.M. "Stability in Multispecies Community Models." Math. Biosc., 12 (1971), 59-79.
Kramer, N.F. and R.M. May. "Interspecific Competition, Predation and Species Diversity: A
Comment." J. Theor. Biol., 34 (1972), 289-293.
-. "What is the Chance that a Large Complex System will be Stable?" Nature, 238 (1972), 413-414.
-. "Limit Cycles in Prey-Predator Communities." Science, 177 (1972), 900-902.
May, R.M. and R.H. MacArthur. "Niche Overlap as a Function of Environmental Variability." Proc.
Nat. Acad. Scis., 69 (1972), 1109-1113.
May, R.M. "Time-Delay Versus Stability in Population Models with Two and Three Trophic Levels."
Ecology, 54 (1973), 315-325.
Hassell, M.P. and R.M. May. "Stability in Insect Host-Parasite Models." J. Anim. Ecol., 42 (1973),
693-726.
May, R.M. "On Relationships between Various Types of Population Models." Amer. Naturl., 107(1973), 46-57.
- . "Mass and Energy Flow in Closed Ecosystems: A Comment." J. Theor. Biol., 39 (1973), 155-163.
- . "Qualitative Stability in Model Ecosystems." Ecology, 54 (1973), 638-641.

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—. "Stable Limit Cycles in Predator-Prey Populations: A Comment ." Science, 181 (1973), 1074.
— . "Stability in Randomly Fluctuating versus Deterministic Environments." Amer. Naturl., 107 (1973),
621-650.
— . "On the Theory of Niche Overlap." Theor. Pop. Biol., 5 (1974), 297-332.
Hassell, M.P. and R.M. May. "Aggregation of Predators and Insect Parasites and its Effect on Stability."
J. Anim. Ecol., 43 (1974), 567-594.
May, R.M., G.R. Conway, M.P. Hassell and T.R.E. Southwood. "Time Delays, Density Dependence
and Single-Species Oscillations." J. Anim. Ecol., 43 (1974), 747-770.
Southwood, T.R.E., R.M. May, M.P. Hassell and G.R. Conway. "Ecological Strategies and Population
Parameters." Amer. Naturl., 108 (1974), 791-804.
May, R.M. "Biological Populations with Nonoverlapping Generations: Stable Points, Stable Cycles,
Chaos." Science, 186 (1974), 645-647.
May, R.M. and W.J. Leonard. "Nonlinear Aspects of Competition between Three Species." SIAM J.
AppL Math. 29 (1975), 243-253.
May, R.M. "Some Notes on Estimating the Competition Matrix." Ecology, 56 (1975), 737-741.
— . "Biological Populations Obeying Difference Equations: Stable Points, Stable Cycles, and Chaos."J. Theor. Biol., 51 (1975), 511-524.
May, R.M., J.A. Endler and R.E. McMurtrie. "Gene Frequency Clines in the Presence of Selection
Opposed by Gene Flow." Amer. Naturl., 109 (1975), 659-676.
May, R.M. "Change in Gene Frequency under Selection in a Finite Population: A Comment." Theor.
Pop. Biol., 7 (1975), 208-211.
Beddington, J.R. and R.M. May. "Time Delays are Not Necessarily Destabilising." Math. Biosc., 27(1975), 109-117.
May, R.M. "A Note on Random Sets Mosaics." J. Math. Biol., 2 (1975), 351-357.
May, R.M. and G.F. Oster. "Bifurcations and Dynamic Complexity in Simple Ecological Models."Amer. Naturl., 110 (1976), 573-599.
Hassell, M.P., J.H. Lawton and R.M May. "Patterns of Dynamical Behaviour in Single-Species
Populations." J. Anim. Ecol., 45 (1976), 471-486.
Levin, S.A. and R.M. May. "A Note on Difference-Delay Equations." Theor. Pop. Biol., 9 (1976),
178-187.
May, R.M. "Estimating: A Pedagogical Note." Amer. Naturl., 110 (1976), 496-499.
— . "Simple Mathematical Models with Very Complicated Dynamics." Nature, 262 (1976), 459-467.
[Reprinted:(i) Hungarian translation, published by Hungarian Academy of Sciences, Alkalmazott Matematikai
Lapok, 8 (1982), 427-446.
(ii) In Chaos. Ed. Hao Bai-Lin. Singapore: World Scientific Publishing, 1984.
(iii) In Univ. in Chaos. Ed. P. Cvitanovic. Bristol: Adam Hilger, 1984.
(iv) In Chaos, Vol. II. Ed. Hao Bai-Lin. Singapore: World Scientific Publishing, 1990.]
Diamond, J.R. and R.M. May. "Species' Turnover Rates on Islands: Dependence on Census Interval."
Science, 197 (1977), 266-270.
Beddington, J.R. and R.M. May. "Harvesting Natural Populations in a Randomly Fluctuating
Environment." Science, 197 (1977), 463-465.
May, R.M. "Togetherness among Schistosomes: Its Effect on the Dynamics of the Infection." Math.
Biosc., 35 (1977), 301-343.
Hamilton, W.D. and R.M. May. "Dispersal in Stable Habitats." Nature, 269 (1977), 578-581.
Godley, W. and R.M. May. "The Macroeconomic Implications of Devaluation and Import Restriction."
Econ. Pol. Rev., 3 (1977), 32-42.
May, R.M. "Dynamical Aspects of Host-Parasite Associations: Crofton's Model Revisited." Parasitol.,75 (1977), 259-276.

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—. "Thresholds and Breakpoints: Ecosystemswith a Multiplicityof Stable States." Nature, 269 (1977),
471-477.
Bradley, D.J. and R.M. May. "Consequences of Helminth Aggregation for the Dynamics ofSchistosomiasis." Trans. Roy. Soc. Trop. Med. & Hyg., 72 (1978), 262-273.
Anderson, R.M. and R.M. May. "Regulation and Stability of Host-Parasite Population Interactions: (I)Regulatory Processes." J. Anim. Ecol., 47 (1978), 219-247.
May, R.M. and R.M. Anderson. "Regulation and Stability of Host-ParasitePopulation Interactions: (II)Destabilising Processes." J. Anim. Ecol., 47 (1978), 249-267.
May, R.M. "Host-Parasitoid Systems in Patchy Environments: A Phenomenological Model." J. Anim.
Ecol., 47 (1978), 833-844.
—. "Evolution of Ecological Systems." Sci. Amer., 239 (1978), 160-175.
May, R.M., J.R. Beddington, J.W. Horwood and J.G. Shepherd. "Exploiting Natural Populations in an
Uncertain World." Math. Biosci., 42 (1978), 219-252.
May, R.M. "Bifurcations and Dynamic Complexity in Ecological Models." Annals NYAcad. Scis., 316(1979), 517-529.
May. R.M. "Simple Models for Single Populations:An Annotated Bibliography." Firtchritte der Zool.,
25 (1979), 95-107.
Anderson, R.M. and R.M. May. "Prevalence of Schistosome Infections within Molluscan Populations:Observed Patterns and Theoretical Predictions." Parasitol., 79 (1979), 63-94.
May, R.M., J.R. Beddington, C.W. Clark, S.J. Holt and R.M. Anderson. "Laws, Management ofMultispecies Fisheries." Science, 205 (1979), 267-277.
Anderson, R.M. and R.M. May. "Population Biology of Infectious Diseases: Part I." Nature, 280(1979), 361-367.
May, R.M. and Anderson, R.M. "Population Biology of Infectious Diseases: Part II." Nature, 280(1979), 455-461.
Beddington, J.R. and R.M. May. "A Possible Model for the Effect of Adult Sex Ratio and Density on
the Fecundity of Sperm Whales." Reports of the International Whaling Commission,Special Issue
2 (1980), 75-76. [Also issued as SC/S30/ 4 (1977).]
May, R.M. and J.R. Beddington. "The Effect of Adult Sex Ratio and Density on the Fecundity of Sperm
Whales." Reports of the International Whaling Commission, Special Issue 2 (1980), 213-217. [Also issued as SC/S78/14 (1978).]
Comins, H.N., W.D. Hamilton and R.M. May. "Evolutionary Stable Dispersal Strategies." J. Theor.
Biol., 82 (1980), 205-230.
Beddington, J.R. and R.M. May. "Maximum Sustainable Yield in Systems Subject to Harvesting at
More Than One Trophic Level." Math. Biosc., 51 (1980), 261-281.
Anderson, R.M. and R.M. May. "InfectiousDiseases and Population Cycles of Forest Insects." Science,
210 (1980), 658-661.
May, R.M. and G.F. Oster. "Period Doubling and the Onset of Turbulence: An Analytic Estimate of the
Feigenbaum Ratio." Phys. Letts., A 78 (1980), 1-3.
May, R.M. and M.P. Hassell. "The Dynamics of Multi-Parasitoid-Host Interactions." Amer. Naturl.,
117 (1981), 234-261.
May, R.M. "Nonlinear Phenomena in Ecology and Epidemiology."Annals NYAcad. Scis., 357 (1981),
267-281.
Anderson, R.M. and R.M. May. "The Population Dynamics of Microparasites and Their Invertebrate
Hosts." Phil. Trans. Roy. Soc. B., 291 (1981), 451-524.
Anderson, R.M., H.C. Jackson, R.M. May and A.M. Smith. "Population Dynamics of Fox Rabies in
Europe." Nature, 289 (1981), 765-771.
Bonner, J.T. and R.M. May. "Introduction." To Charles Darwin, The Descent of Man. (First Edition,1871).vii—xii. Paperback reprint, Princeton: Princeton Univ. Press, 1981.

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May, R.M. "The Role of Theory in Ecology." Amer. Zool., 21 (1981), 903-910.
May, R.M., M.P. Hassell, R.M. Anderson and D.W. Tonkyn. "Density Dependence in Host-Parasitoid
Models." J. Anim. Ecol., 50 (1981), 855-865.
Anderson, R.M. and R.M. May. "Directly Transmitted Infectious Diseases: Control by Vaccination."
Science, 215 (1982), 1053-1060.
[Also circulated, in an expanded form, as Report ICCET Series E, No. 2 (1981), by the Imperial College
Centre for Environmental Technology.]—. "The Control of Communicable Diseases by Age-Specific Immunisation Schedules ." Lancet, 16
January (1982), 160.
"Coevolution of Hosts and Parasites." Parasitol., 85 (1982), 411-426.
Beddington, J.R. and R.M. May. "Multispecies Harvesting in Natural Ecosystems." Sci. Amer., 247(1982), 60-69.
Anderson, R.M. and R.M. May. "The Population Dynamics and Control of Human Helminth
Infections." Nature, 297 (1982), 557-563.
— . "Vaccination and Herd Immunity." Lancet, 3 April (1982), 807.
— . "The Logic of Vaccination." New Sci., 96 (1982), 410-415.
May, R.M. "Parasitic Infections as Regulators of Animal Populations." Amer. Sci., 71 (1983), 36-45.
— . "Vaccination against Rubella and Measles: Quantitative Evaluation of Different Policies." J.
Hygiene, 90 (1983), 259-325.
Hassell, M.P., J.K. Waage and R.M. May. "Variable Parasitoid Sex Ratios and Their Effect on HostParasitoid Dynamics." J. Anim. Ecol., 52 (1983), 889-904.
Harvey, P.H., R.K. Colwell, J.W. Silvertown and R.M. May. "Null Models in Ecology." Ann. Rev.
Ecol., Sys., 14 (1983), 189-211.
May, R.M. and R.M. Anderson. "Epidemiology and Genetics in the Coevolution of Parasites andHosts." Proc. Roy. Soc. B., 219 (1983), 281-313. [Reprinted in Mathematical Genetics Ed. W.F.
Bodmer and J.F.C. Kingman. 61-93. London: The Royal Society, 1983.]
Ehrlich, P.R., R.M. May, N. Myers, et al. "Long-Term Biological Consequences of Nuclear War."
Science, 222 (1983), 1293-1300.
Anderson, R.M. and R.M. May. "Two-Stage Vaccination Programme against Rubella." Lancet, 17
December, 1983.1416-1417.
May, R.M. and R.M. Anderson. "Spatial Heterogeneity and the Design of Immunisation Programmes."
Math. Biosc., 72 (1984), 83-111.
Anderson, R.M., B.T. Grenfell and R.M. May. "Oscillatory Fluctuations in the Incidence of Infectious
Disease and the Impact of Vaccination: Time Series Analysis." J. Hygiene, 93 (1984), 587-608.
May, R.M. "Regulation of Populations with Non-Overlapping Generations by Microparasites: A Purely
Chaotic System." Amer. Naturl., 125 (1985), 573-584.
Ives, A.R. and R.M. May. "Competition within and between Species in a Patchy Environment:
Relations between Microscopic and Macroscopic Models." J. Theor. Biol., 115 (1985), 65-92.
Anderson, R.M. and R.M. May. "Spatial, Temporal, and Genetic Heterogeneity in Host Populations andthe Design of Immunization Programmes." IMA J. Maths. Appl. in Med. & Biol., 1(1985), 233-266.
May, R.M. and S.K. Robinson. "Population Dynamics of Avian Brood Parasitism." Amer. Naturl., 126(1985), 475-494.
May, R.M. "Ecological Aspects of Disease and Human Populations."Amer. Zool., 25 (1985), 441-450.
Anderson R.M. and R.M. May. "Age-Related Changes in the Rate of Disease Transmission:
Implications for the Design of Vaccination Programmes." J. Hygiene, 94 (1985), 365-436.
—. "Herd Immunity to Helminth Infection and Implications for Parasite Control ." Nature, 315 (1985),
493-496.
— . "Helminth Infections of Humans: Mathematical Models, Population Dynamics and Control."Advances in Parasitol., 24 (1985), 1-104.

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May, R.M. and R.M. Anderson. "Endemic Infections in Growing Populations." Math. Biosc., 76(1985), 1-16.
Anderson, R.M. and R.M. May. "Vaccination and Herd Immunity to Infectious Diseases." Nature, 318(1985), 323-329.
May, R.M. and J. Seger. "Ideas in Ecology: Yesterday and Tomorrow." Amer. Sci., 74 (1986), 256-267.
Hassell, M.P. and R.M. May. "Generalist and Specialist Natural Enemies in Insect Predator-Prey
Interactions." J. Anim. Ecol., 55 (1986), 923-940.
Anderson, R.M., J.A. Crombie and R.M. May. "Predisposition to Helminth Infection in Man." Nature,
320 (1986), 195-196.
May, R.M. "When Two and Two Do Not Make Four: NonlinearPhenomena in Ecology." The Croonian
Lecture, 1985. Proc. Roy. Soc. B., 228 (1986), 241-266.
Anderson, R.M. and R.M. May. "The Invasion, Persistence and Spread of Infectious Diseases within
Animal and Plant Communities." Proc. Roy. Soc. B., 314 (1986), 533-570.
Anderson, R.M., R.M. May, G.F. Medley and A. Johnson. "A Preliminary Study of the Transmission
Dynamics of the Human Immunodeficiency Virus (HIV), the Causative Agent of AIDS." IMA J.
Maths. Appi. in Med. & Biol., 3 (1986), 229-263.
May, R.M. "The Search for Patterns in the Balance of Nature: Advances and Retreats." The Robert H.
MacArthur Award Lecture, 1985. Ecology, 67 (1986), 1115-1126.
May, R.M. and R.M. Anderson. "Transmission Dynamics of HIV Infection." Nature, 326 (1987),
137-142.
Anderson, R.M. and R.M. May. "Plotting the Spread of AIDS." New Sci., 26 March (1987), 54-59.
Crawley, M.J. and R.M. May. "Population Dynamics and Plant Community Structure: Competition
between Annuals and Perennials." J. Theor. Biol., 125 (1987), 475-489.
May, R.M. "Epidemiology of AIDS." Family Health International (Special Issue), (1987), 4-5.
—. "Chaos and the Dynamics of Biological Populations." Proc. Roy. Soc., A 413 (1987), 27-44.
[Reprintedin Dynamical Chaos. Ed. M.V. Berry, I.C. Percival and N.O. Weiss. 27-44. London: The
Royal Society, 1987.]—. "Nonlinearities and Complex Behaviour in Simple Ecological and Epidemiological Models." Ann.
NY Acad. Scis., 504 (1987), 1-15. [Reprinted in Perspectives in Biological Dynamics andTheoreticalMedicine. Ed. S.H. Koslow, A.J. Mandell and F. Shlesinger. 1-15. N.Y.: Ann.NYAcad.
Scis., 1987.]—. May, R.M. "Chaos and the Dynamics of Biological Populations."Nuclear Physics B. (Proc. Suppl.),2 (1987), 225-246. [Reprinted in Chaos 87: International Conferences on the Physics of Chaos andSystemsFar from Equilibrium. Ed. M. Duong—Van. 225-246. Amsterdam, 1987.]
May, R.M. and M.P. Hassell. "Population Dynamics and Biological Control." Phil. Trans. Roy. Soc. B.,
318 (1988), 129-169. [Reprinted in Biological Control of Pests, Pathogens and Weeds:
Developmentand Prospects. Ed. R.K.S.Wood and M.J. Way. 19-59. London: The Royal Society.]
Anderson, R.M., R.M. May and A.R. McLean. "Possible Demographic Consequences of AIDS in
Developing Countries." Nature, 332 (1988), 228-233.
May. R.M. "Conservation and Disease." Consv.Biol., 2 (1988), 28-30.
Anderson, R.M. and R.M. May. "Epidemiological Parameters of HIV Transmission." Nature, 333(1988), 514-518.
Hassell, M.P. and R.M. May. "Spatial Heterogeneity and the Dynamics of Parasitoid-Host Systems."
Annales Zoologici Fennici, 25 (1988), 55-61.
May, R.M. "How Many Species are There on Earth?" Science, 241 (1988), 1441-1449. [Reprinted in
Biological Systems.Ed. B.R. Jasny and D.E. Koshland. 245-260. Washington, D.C.: AAAS, 1990.]
May, R.M., R.M. Anderson and A.R. McLean. "Possible Demographic Consequences of HIV/AIDS
Epidemics:I, Assuming HIV Infection Always Leads to AIDS." Math. Biosc., 90 (1988), 475-505.
[Reprinted in Nonlinearity in Biology and Medicine. Ed. A.S. Perelson, B. Goldstein, M. Dembo254

and J.A. Jacquez. 475-505. N.Y.: Elsevier, 1988.]
May, R.M. and R.M. Anderson. "The Transmission Dynamics of Human Immunodeficiency Virus(HIV)." Phil. Trans. Roy. Soc. B., 321 (1988), 565-607. [Reprinted in The Epidemiology andEcology of Infectious Disease Agents. Ed. R.M. Anderson and J.M. Thresh. 239-281. London: The
Royal.Society, 1988.]
Hassell, M.P., J. Latto and R.M. May. "Seeing the Wood for the Trees: Detecting Density Dependence
from Existing Life-Table Studies." J. Anim.Ecol., 58 (1989), 883-892.
May, R.M., R.M. Anderson and S.M. Blower. "The Epidemiology and Transmission Dynamics of
HIV/AIDS." Daedalus, 118 (2) (1989), 163-201. [Reprinted in Living with AIDS. Ed. R.S.
Graubard. 163-202. Cambridge, Mass.: MIT Press, 1989.]
Anderson, R.M., R.M. May and S. Gupta. "Non-Linear Phenomena in Host-Parasite Interactions."
Parasitol, 99 (1989), S59—S79.
May, R.M. "The Chaotic Rhythms of Life." New Sci. (1989), 37-41. [Reprintedin Chaos. Ed. N. Hall.
82-95. London: Penguin, 1991.]
Anderson, R.M., T.G. Ng, M.C. Boily and R.M. May. "The Influence of Different Sexual-Contact
Patterns between Age Classes on the Predicted Demographic Impact of AIDS in Developing
Countries." Ann. NYAcad. Scis., 569 (1989), 240-274.
[Reprinted in Biomedical Science and the Third World: Under The Volcano. Ed. B.R. Bloom andA. Cerami. 240-274. N.Y.: NYAcad. of Scs., 1989.]
Gupta, S., R.M. Anderson and R.M. May. "Networks of Sexual Contacts: Implications for the Patternof Spread of HIV." AIDS, 3 (1989), 807-817.
Pacala, S.W., M.P. Hassell and R.M. May. "Host-Parasitoid Associations in Patchy Environments."
Nature, 344 (1990), 150-153.
Sugihara, G. and R.M. May. "Applications of Fractals in Ecology." TREE, 5 (1990), 79-86.
Anderson R.M. and R.M. May. "Modern Vaccines: Immunisation and Herd Immunity." Lancet, 335(1990), 641-645. [Reprinted in Modern Vaccines. Ed. E.R. Moxon. 24-33. London: Edward
Arnold, 1990.]
Sugihara, G. and R.M. May. "Nonlinear Forecasting as a Way of Distinguishing Chaos from
Measurement Error in Time Series." Nature, 344 (1990), 734-741.
Hochberg, M.E., M.P. Hassell and R.M. May. "The Dynamics of Host-Parasitoid-Pathogen
Interactions." Amer. Naturl., 135 (1990), 74-94.
May, R.M. and R.M. Anderson. "Parasite-Host Coevolution." Parasitol., 100 (1990), S89—S101.
May, R.M. "How Many Species?" Phil. Trans. Roy. Soc. B., 330 (1990), 293-304.
Sugihara, G., B. Grenfell and R.M. May. "DistinguishingError from Chaos in Ecological Time Series."
Phil. Trans. Roy. Soc. B., 330 (1990), 235-251.
Nowak, M.A., R.M. May and R.M. Anderson. "The Evolutionary Dynamics of HIV-1 Quasispeciesand
the Development of Immunodeficiency Disease." AIDS,4 (1990), 1095-1103.
Nee, S., P.H. Harvey and R.M. May. "Lifting the Veil on Abundance Patterns." Proc. Roy. Soc. B., 243(1991), 161-163.
Blower, S.M., D. Hanel, H. Dowlatabadi, R.M. Anderson and R.M. May. "Drugs, Sex and HIV: A
Mathematical Model for N.Y. City." Phil. Trans. Roy. Soc. B., 321 (1991), 171-187.
Basson, M., J.R. Beddington, R.M. May. "An Assessment of the Maximum Sustainable Yield of Ivory
from Elephant Populations." Math. Biosc., 104 (1991), 73-95.
Anderson, R.M., S. Gupta and R.M. May. "Potential of Community-Wide Chemotherapy or
Immunotherapy to Control the Spread of HIV-1." Nature, 350 (1991), 356-359.
May, R.M. "Le Chaos en Biologie." La Recherche, 232 (1991), 588-599.
Pagel, M.D., R.M. May and A.R. Collie. "Ecological Aspects of the Geographical Distribution andDiversity of Mammalian Species."Amer. Naturl., 137 (1991), 791-815.
Nowak, M.A. and R.M. May. "Mathematical Biology of HIV Infections: Antigenic Variation and255

Diversity Threshold." Math. Biosc., 106 (1991), 1-22.
Anderson, R.M., R.M. May, M.C. Boily, G.P. Garnett and J.T. Rowley. "The Spread of HIV-1 in
Africa: Sexual Contact Patterns and the Predicted Demographic Impact of AIDS." Nature, 352(1991), 581-589.
May, R.M. "El Caos en Biologia." Mundo Cientifico, 115 (1991), 746-754.
Hassell, M.P., R.M. May, S.W. Pacala and P.L. Chesson. "The Persistence of Host-Parasitoid
Associationsin Patchy Environments. I. A General Criterion." Amer. Naturl., 138 (1991), 568-583.
Nowak, M.A., R.M. Anderson, R.M. May, et al. "Antigenic Diversity Thresholds and the Developmentof AIDS." Science, 254 (1991), 963-969.
Hassell, M.P., H.N. Comins and R.M. May. "Spatial Structure and Chaos in Insect Population
Dynamics." Nature, 353 (1991), 255-258.
Nee, S., R.D. Gregory and R.M. May. "Core and Satellite Species: Theory and Artifacts." OIKOS, 62(1991), 83-87.
May, R.M. and G. Sugihara. "How Predictable is Chaos?" Nature (Sci. Corresp.), 355 (1992), 26.
Watts, C.H. and R.M. May. "The Influence of Concurrent Partnerships on the Dynamics of
HIV/AIDS." Math. Biosc., 108 (1992), 89-104.
Nee, S. and R.M. May. "Dynamics of Metapopulations: Habitat Destruction and Competitive
Coexistence." J. Anim. Ecol., 61 (1992), 37-40.
Gaston, K.J. and R.M. May. "Taxonomy of Taxonomists." Nature, 356 (1992), 281-282. [Reprintedin
Italian: Sapere, No. 59,14-16 (1993).]
May, R.M. "Concluding Discussion on the Meeting on Chaos." J. Roy. Stats. Soc. B., 54 (1992),
451-452.
— . "Density Dependent Populations." Nature (Sci. Corresp.), 356 (1992), 391-392.
Anderson, R.M. and R.M. May. "Understanding the AIDS Pandemic." Sci. Amer., 266 (1992), 58-66.
Anderson, R.M., R.M. May, T.W. Ng and J.T. Rowley. "Age-Dependent Choice of Sexual Partners andthe Transmission Dynamics of HIV in Sub-Saharan Africa." Phil. Trans. Roy. Soc. B., 336 (1992),
135-155.
May, R.M. "0 Fragile Equilibrio da Vida." Ciencia Hoje, 14 (1992), 18-25.
McLean, A.R. and R.M. May. "Understanding the Immune System: The Role of Mathematical
Models." J. NIH Res., 4 (1992), 101-103.
Nowak, M.A. and R.M. May. "Coexistence and Competition in HIV Infections." J. Theor. Biol., 159(1992), 329-342.
May, R.M. "How Many Species Inhabit the Earth?" Sci. Amer., 267 (1992), 42-48.
Comins, H.N., M.P. Hassell and R.M. May. "The Spatial Dynamics of Host-Parasitoid Systems." J.
Anim.Ecol., 61 (1992), 735-748.
Nowak, M.A. and R.M. May. "Evolutionary Games and Spatial Chaos." Nature, 359 (1992), 826-829.
May, R.M. "Marine Species Richness." Nature (Sci. Corresp.), 361 (1993), 598.
Nee, S. and R.M. May. "Population-LevelConsequences of ConspecificBrood Parasitism in Birds andInsects." J. Theor. Biol., 161 (1993), 95-109.
Gupta, S., R.M. Anderson and R.M. May. "Mathematical Models and the Design of Public Health
Policy: HIV and Antiviral Therapy." SIAMReview,35 (1993), 1-16.
Agur, Z., Y.L. Danon, R.M. Anderson, L. Cojocaru and R.M. May. "Measles Immunization Strategies
for an Epidemiologically Heterogeneous Population: The Israeli Study." Proc. R. Soc. B., 252(1993), 81-84.
Nowak, M. and R.M. May. "AIDS Pathogenesis: Mathematical Models of HIV and SINTInfections."
AIDS, 7 (Suppl 1: 92/93 Year in Review), (1993), S3—S18.
—. "The Spatial Dilemmas of Evolution." Intl. J. Bifurcation & Chaos, 3 (1993), 35-78.
Smith, F., R.M. May, R. Pellew, T.H. Johnson and K.S. Walter. "Estimating Extinction Rates." Nature(Sci. Corresp.), 364 (1993), 494-496.

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May, R.M. "Dinamiche Caotiche e Ritmi Biologici." Sfera, 36 (Special issue on "Caos e complessita"),(1993), 48-51.
May R.M. and M.E.J. Woolhouse. "Biased Sex Ratios and Parasite Mating Probabilities." Parasitol.,107 (1993), 287-295.
Smith, F., R.M. May, R. Pellew, T.H. Johnson and K.S. Walter. "How Much Do We Know about theCurrent Extinction Rate?" TREE, 8 (1993), 375-378.
May, R.M. "Biological Diversity: Differences between Land and Sea." Phil. Trans. Roy. Soc. B., 343(1994), 105-111.
Nowak, M.A. and R.M. May. "Superinfection and the Evolution of Parasite Virulence." Proc. Roy. Soc.
B., 55 (1994), 81-89.
Smith, F.D.M., R.M. May and P.H. Harvey. "Geographical Ranges of Australian Mammals." J. Anim.
Ecol., 63 (1994), 441-450.
Nee, S. and R.M. May. "Habitat Destruction and the Dynamics of Metapopulations: Reply to Aldaz."
J. Anim. Ecol., 63 (1994), 494.
Heywood, V.H., G.M. Mace, R.M. May and S.N. Stuart. "Uncertainties in Extinction Rates." Nature(Sci. Corresp.), 368 (1994), 105.
Nowak, M.A., S. Bonhoeffer and R.M. May. "More Spatial Games." Intn. J. Bifurcation & Chaos, 4(1994), 33-56.
Nee, S., E.C. Holmes, R.M. May and P.H. Harvey. "Extinction Rates Can be Estimated from MolecularPhylogenies." Phil. Trans. Roy. Soc. B., 344 (1994), 77-82.
S. Nee, R.M. May and P.H. Harvey. "The ReconstructedEvolutionary Process." Phil. Trans. Roy. Soc.
B., 344 (1994), 305-311.
Nowak, M.A., S. Bonhoeffer and R.M. May. "Spatial Games and the Maintenance of Cooperation."
Proc. Natl. Acad. Sci., 91 (1994), 4877-4881.
Hassell, M.P., H.N. Comins and R.M. May. "Species Coexistence and Self-Organizing Spatial
Dynamics." Nature, 370 (1994), 290-292.
May, R.M. "Conceptual Aspects of the Quantification of the Extent of Biological Diversity." Phil.
Trans. Roy. Soc. B., 345 (1994), 13-20. [Reprinted in Biodiversity: Measurement and Estimation.
Ed. D.L. Hawksworth. 13-20. London: Chapman & Hall, 1995.]
Lenski, R.E. and R.M. May. "The Evolution of Virulence in Parasites and Pathogens: Reconciliation
between Two Competing Hypotheses." J. Theor. Biol., 169 (1994), 253-265.
May, R.M. "Graeme Caughley and the Emerging Science of Conservation Biology." TREE, 9 (1994),
368-369.
— . "Ecological Science and the Management of Protected Areas." Biod. & Consv., 3 (1994), 437-448.
Tillman,D., R.M. May, C.L. Lehman and M.A. Nowak. "Habitat Destruction and the Extinction Debt."
Nature, 371 (1994), 65-66.
May, R.M. and M.A. Nowak, "Superinfection, Metapopulation Dynamics, and the Evolution ofDiversity." J. Theor. Biol., 170 (1994), 95-114.
Antia, R., B.R. Levin and R.M. May. "Within-Host Population Dynamics and the Evolution and
Maintenance of Microparasite Virulence." Am. Nat., 144 (1994), 457-472.
Harvey, P.H., R.M. May and S. Nee. "Phylogenies without Fossils." Evolution, 48 (1994), 523-529.
May, R.M. "Disease and the Abundance and Distribution of Bird Populations: A Summary." Ibis, 137(1995), S85-586.
Nowak, M.A., R.M. May and K. Sigmund. "The Arithmetics of Mutual Help." Sci. Amer., 272 (1995),
76-81.
Lipsitch, M., M.A. Nowak, D. Ebert and R.M. May. "The Population Dynamics of Vertically andHorizontally Transmitted Parasites." Proc. R. Soc. B., 260 (1995), 321-327.
Nowak, M.A., R.M. May, R.E. Phillips, et al. "Antigenic Oscillations and Shifting Immunodominancein HIV-1 Infections." Nature, 375 (1995), 606-611.

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May, R.M. "Necessity and Chance: Deterministic Chaos in Ecology and Evolution." Bull.Amer. Math.
Soc., 32 (1995), 291-308.
Nowak, M.A., R.M. May and K. Sigmund. "Immune Responses against Multiple Epitopes." J. Theor.
Biol., 175 (1995), 325-353.
May, R.M. and M.A. Nowak. "Coinfection and the Evolution of Parasite Virulence." Proc. Roy. Soc.
B., 261 (1995), 209-215.
Hassell, M.P., O.Miramontes, R. Rohani and R.M. May. "Appropriate Formulations for Dispersal in
Spatially Structured Models: Comments on Bascompte & Sole." J. Anim. Ecol., 64 (1995),
662-664.
May, R.M. "Science and Everyday Life." Editorial in Science, 269 (1995), 1199.
Anderson, R.M., R.M. May and S. Gupta. "Genetic Heterogeneity in Helminths." Parasitol., 111(1995), 537-538.
Bonhoeffer, S., A.V.M. Herz, M.C. Boerlijst, S. Nee, M.A. Nowak and R.M. May. "Explaining`LinguisticFeatures' of Noncoding DNA ." Science, 271 (1996), 14-15.
—. "No Signs of Hidden Language in Noncoding DNA." Phys. Rev. Letters, 76 (1996), 1977.
Nowak, M.A., S. Bonhoeffer and R.M. May. "Robustness of Cooperation." Nature, 379 (1996),
125-126.
Sheill, D. and R.M. May. "Mortality and Recruitment Rate Evaluations in Heterogeneous Tropical
Forests." J. Ecol., 84 (1996), 91-100.
Gupta, S., M.C.J. Maiden, I.M. Feavers, S. Nee, R.M. May and R.M. Anderson. "The Maintenance ofStrain Structure in Populations of Recombining Infectious Agents." Nature Medicine, 2 (1996),
437-442.
Lloyd, A.L. and R.M. May. "Spatial Heterogeneity in Epidemic Models." J. Theor. Biol., 179 (1996),
1-11.
Tilman, D. and R.M. May. "Species Fragmentation or Area Loss?" Nature (Sci Corresp.), 382 (1996),
215-216.
Herz, A.V.M., S. Bonhoeffer, R.M. Anderson, R.M. May and M.A. Nowak. "Viral Dynamics In Vivo:
Limitationson Estimates of IntracellularDelay and Virus Decay." Proc. Natl. Acad. Sci., 93 (1996),
7247-7251.
Rohani, P., R.M. May and M.P. Hassell. "Metapopulations and Equilibrium Stability: the Effects of
Spatial Structure." J. Theor. Biol., 181 (1996), 97-109.
Nowak, M.A., R.M. Anderson, M.C. Boerlijst, S. Bonhoeffer and R.M. May. "HIV-1 Evolution and
Disease Progression." Science, 274 (1996), 1008-1011.
Anderson, R.M. and R.M. May. "The Population Biology of the Interaction between HIV-1 and HIV2: Coexistenceor Competitive Exclusion?" AIDS, 10 (1996), 1663-1673.
Stone, L., G. Landau and R.M. May. "DetectingTime's Arrow: A Method for Identifying Nonlinearity
and Deterministic Chaos in Time-Series Data." Proc. R. Soc. B., 263 (1996), 1509-1513.
Klenerman,P., R.E. Phillips, R.M. May, et al. "Cytotoxic T-Lymphocytes and Viral Turnover in HIV1 Infection." Proc. Natl. Acad. Sci., USA, 93 (1996), 15323-15328.
May, R.M., D.J. Stekel and M.A. Nowak. "Antigenic Diversity Thresholds and Hazard Functions."
Math. Biosci., 139 (1997), 59-68.
May, R.M. "The Scientific Wealth of Nations." Science, 275 (1997), 793-796.
Nowak, M.A., S. Bonhoeffer, G.M. Shaw and R.M. May. "Anti-Viral Drug Treatment: Dynamics ofResistancein Free Virus and Infected Cell Populations." J. Theor. Biol., 184 (1997), 203-217.
—. "Scientific Advance Thrives on Openness." Nature (Sci. Cones.), 389 (1997), 11.
—. "Science by the Country." Science (Letters), 276 (1997), 882-885.
Nee, S. and R.M. May. "Extinction and the Loss of Evolutionary History." Science, 278 (1997),
692-694.
Bonhoeffer, S., R.M. May, G.M Shaw and M.A. Nowak. "Virus Dynamics and Drug Therapy." PNAS,

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94 (1997), 6971-6976.
May, R.M. "Kyoto and Beyond." Science (Editorial), 278 (1997), 1691.
Nowak, M.A., D.C. Krakauer, A. Klug and R.M. May. "Prion Infection Dynamics ." Integrative
Biology, 1 (1998), 3-15.
May, R.M. "The Scientific Investments of Nations." Science, 281 (1998), 49-51 .
—. "A Note of Climate Change ." Cosmos, 8 (1998), 47-51.
May, R.M. and S.C. Sarson. "Revealing the Hidden Costs of Research." Nature, 398 (1999) , 457-459.
Lloyd, A.L. and R.M. May. "Synchronicity, Chaos and Population Cycles: Spatial Coherence in an
Uncertain World." TREE, 14 (1999), 417-418.
May, R.M. "Science, Politics and Public Opinion: Tackling 'The Modern Dilemma:' The Wooldridge
Lecture." The Veterinary Record, 145 (1999), 411-412.
•—. "Unanswered Questions in Ecology ." Phil. Trans. R. Soc. Lond. B., 354 (1999), 1951-1959.
—. "Simple Rules with Complex Dynamics ." Science, 287 (2000), 601-602.
Wodarz, D., R.M. May and M.A. Nowak. "The Role of Antigen-Independent Persistence of Memory
Cytotoxic T Lymphocytes." International Immunology, 12, No. 4 (2000), 467-477 .
Mace, G.M., May, R.M. and 13 others. "Duplicating Conservation Efforts." Nature (Sci . Cones.), 290(2000), 714-715.
—. "Relation between Diversity and Stability in the Real World ." Science (Sci. Cones.), 290 (2000),714-715.
May, R.M. and M.P.H. Stumpf. "Species-Area Relations in Tropical Forests." Science, 290 (2000) ,2084-2086.
May, R.M. "Biotechnology: The Challenges." In J. Biolaw & Bus., Special Supplement (2000), 90-93 .
— . "Science and Society." Science, 292 (2001), 1021.
—. "The Science of Climate Change ." Science, 292 (2001), 261.
Lloyd, A.L. and R.M. May. "How Viruses Spread among Computers and People." Science, 292 (2001) ,1316-1317.
May, R.M. "Risk and Uncertainty." Nature, 411 (2001), 891.
May, R.M., S. Gupta and A.R. McLean. "Infectious Disease Dynamics: What Characterizes a
Successful Invader?" Phil. Trans. R. Soc. Lond. B., 356 (2001), 901-910.

259

Profile

Dr. Norman
Honorary

Visiting

Fellow , Green

College,

Myers

OxfordEducation

and Academic

1934

Born

in August

1958

B.A.,

Oxford1958-1965

District

Officer,

1963

Master's

Degree,Oxford1966-1969

Freelance

writer,photographer

1970-1972

Attended

the University

1973

Ph.D., University of California, Berkeley.
Research projects for the U.S. National Academy of Sciences, the Royal Society
in the United Kingdom, the Soviet Academy of Sciences, NASA, the WorldBank,
United Nations agencies, the OECD, WWF, and many other bodies.
Honorary Visiting Fellow, Green College, Oxford University.
Gold Medal, World Wildlife Fund.
Gold Medal, New York Zoological Society.
Special Achievement Award, Sierra Club.
Distinguished Achievement Award, Society for Conservation Biology.
Fellow, World Academy of Art and Sciences.
Volvo Environment Prize.
Member, U.S. National Academy of Sciences.
Sasakawa Prize, United Nations Environment Programme.
Appointed by Queen Elizabeth to the Order of St. Michael and St. George "ForServices to the Global Environment."
Ambassador,World Wide Fund for Nature/U.K.

1972—

1983
1986
1987
1987
1989
1992
1994
1995
1997
2000

To this day, Dr. Myers
commissioned
tionalin the United

chant for presenting
Althoughof approximately

gestions

260

were

Administration;Highand lecturerof California,

research

one per year, Dr. Myersat the tremendous

in Kenya.

of anyproblems

professor

singleaheadorganization,

on behalf

at Harvard,of many

Oxfordof the rest of the world.

calculated

that it was more likely

out that the deforestation

by manyotheris his pen-

up to the 1970s to be proceeding

rate of 75,000

beinginterna-and manyof his research

was thought

he pointed

with skepticism

wildlife.

One of the characteristics

new topics

of species

on African

independent

as a visiting

the world.

1970s,

TeacherBerkeley.

serving

and analyzing

SchoolUniversity.

into environmental

the extinction

greeted

Kingdom.

researcharoundof one per day. In the late
was proceeding

Kenya

has pursued

while

universities

Activities

University.

to conductorganizations

high-profile

and Professional

University

squarekilometers

occurringof tropicalcorrect

at a rate
rainforests

per year. Theseat first, but he was proved

at a rate

new sug-by the facts,

including analysis of satellite images.
In the late 1980s, he advocated the "hotspot" approach as the best way to conserve thespecies that were in the most trouble. This approach concentrates efforts on those areas withlarge concentrations of species facing extinction. This approach has been adopted by manyenvironmental conservation organizations as a policy for conserving biodiversity.
Dr. Myers, who is well versed in both the natural and social sciences, has also led theworld in analyzing such topics as environmental refugees and perverse subsidies. In addition
to authoring several hundred scholarly articles, he continues to make a major contribution toprogress toward a sustainablefuture for all through other publications and public appearances.

261

EssayOur Environmental
Dr. Norman

Myers

December

The present
we camegenerationout of our caves,throughmass extinctiona hostof othereconomies
humanstandsat a vital turning

2001

point

in humanentiresegments

of our planetaryof species,

tropicaldeforestation,

environmental

are ultimately

activities.

Futureproblems.

dependent

By safeguarding

These

history.
ecosystem

facedesertification,

are economicon the environmental

our environments,

For the first time since

problems
resource

terminal

global

as wellbase

we are safeguarding

threatwarming

that

and

since

our

supportsallour daily well-being

too.
Shall we not say, then,enterprise

when

this outsizethat we are a privileged

we have opportunity

challenge,

we shall surely

Indeed,we are a uniquegeneration.

becausethe environmental

that comes

earn the thanks

No generation

problems

our descendants

will have nothingthem.

It is up to us alone.

Fortunately,

to surmountthis exceptionally
our environmentaltion they deserve.

In fact,

I consider

years.

ing supplied

This is research,moreover,generosityof today.

challenge,

No generation

if we do not overcome

with the disasterdreamsthe prob-that we passarises.

In this essay, I proposeWhat

are the two mostimportantattention

throughto themthat I could not undertakeof the Blue Planettime?

more can we dothat we give greaterthat do not generally

on tobeforeto live at this unprecedented

a key question

two aspects

they

I shall plan to give priority

by the financial

context,

difficulties?

of our challenge;

comingbeyondcreative

aspects

future.

those

with

into the future.

a similar

we still have time to get on top of these problems

tion to two salient

mentalmatchedbecauseIf we succeed

generations

us has ever faced

left but to cope

they get on top of us. Are we not fortunate
Withinto live at a stage in the humanand our world?

of numerous

beforehave not remotely

after us will ever face such a challenge,lems,

generation

to save both our Earthreceivefactors
my researchatten-

the atten-

in our environefforts

in theif it were not for the fund-Prize.

1. The Future
We all spend a lot of the present thinking about the future. Business leaders focus on the next
quarterly sales statement. Bankers fixate on the year-end returns on investment. Politicians arepreoccupied with the next election. Citizens ponder all kinds of concerns, from next week tonext year, to retirement time.
Whatever our situation and whatever our time horizon, we all "discount" the future. For
each and every one of us, one dollar today is worth more than one dollar tomorrow. But consider: a sum of $100 in fifty years discounted at an annual rate of 10% (a frequent rate as dic-262

tated by capital markets) is worth less than $1 today. Given the same discount rate of 10%, acost of $100 billion accruing in 100 years' time (through global warming for example) will
have a present value of hardly more than $7 million. With a more modest discount rate of 5%,
a cost of $1 billion in 100 years' time will have a present value of only $87 million. Conversely,
an investment of $1 today (to counter global warming for instance) will, with a 5% discountrate, be worth almost $18,000 in 200 years' time, and with a 10% discount rate it will be worth$190 million.
The clincher factor is that a discount rate of 10% implies there is no future worth bothering about beyond seven years. Thus, the iron rule of the investment market.
Equally to the point, if the most valuable forest on Earth cannot make its "investment in
the future" in less than seven years (most trees in the forest won't produce new adult trees in'less than 10 years, more likely 20 years or more), it makes commercial sense for a logger tochop the whole lot down straight away and put the earnings into the stock market with its
greater and quicker profit. It is financially rational, too, for a corporation to pursue activities
with revenues of $1 million this year even though it recognizes that in fifty years' time these
activities will entrain environmental costs—such as writing off a potentially renewable
resource—of $100 million.
Thus arises the apparent shortsightednessof investors, if not their outright indifference
to the future. It is not that they are truly shortsighted, rather they play by the rules of the marketplace as laid down by society. If society does not like the outcome, it is up to society tochange the rules rather than shout foul at the investor (as is the inclination of certain environmentalists).
Within this framework,consider one particular environmentalproblem, the mass extinction that is overtaking the planet's species. This biotic crisis threatens not only to eliminate
large numbers of species (conceivablytens of thousands per year already), but to reduce evolution's capacity to generate replacement species. This "end to birth" phase looks likely toendure for fully five million years and possibly several times longer. Just five-million years—
a period twenty times longer than humans have been humans—makes it impossible for us topostulate any realistic discount rate at all.
Moreover,the number of people affected withinjust five-million years could be as manyas 500 trillion, or 10,000 times more people than have ever existed. (Just one trillion is a large
number; figure out the length of time made up of one trillion seconds.) The "decision" on mass
extinction being taken by the present generation—to allow it to proceed virtually unrestricted—will be far and away the biggest decision ever taken on the unconsulted behalf offuture generations. In certain respects it will surely surpass all such past decisions combined.
In this situation, are discount rates of any use at all?
This throws a new perspective on what is known as "intergenerational equity" orjustice
to future generations. The best books on this issue speak of no more than a dozen generations(300 years) ahead, beyond which the future is ostensibly unknowable and of scant practicalinterest anyway. While there is much uncertainty about what species are "good for," we are
effectively saying we are completely certain that 200,000 future generations during those fivemillion years will not be unduly disadvantagedthrough the mass extinction we are precipitat-263

ing today. Yet our scientific understanding indicates the opposite is the case.
In any case, can we really envisage so many generations ahead? That is, can we identify with them, can we sense how they will cope with their future world, and imagine what willbe their hopes and experiences?I must confess that I myself, for all my professional analysisof the future, cannot personallyreach out in my mind beyond just a few generations. I hope one
day to see some grandchildren, and I speculate on what sort of children they will eventually
produce in turn. But five generationsahead is the best I can manage, try as I might. At the sametime, I have to admit that my affluentlifestyle is surely serving to impose injury,howeverunintentionally,on the future world way beyond five generations, worth 125 years. Global warming, for instance, will degrade the planet for many hundreds of years.
Bottom line: we need a device in addition to discount rates to reflect our evaluations of
the future. In fact, to reflect those evaluations that truly count. Relying on the supposed preferences of the marketplace means we would not bother in the least to safeguard the planet's
forests, its oceans, its atmosphere or its ozone layer, let alone its climate. But because we do
not have an economic alternative to conventionaldiscounting, the case for forests, et cetera,
tends to fail by default.
2. Environmental

Surprises

Ahead

Despite our inability to value the future in any way that makes sense in the long run, we should
assume that the future will feature a host of surprises.

Yet we supposethat surprises

are anunusual, if not a rare, phenomenon. We should start to wrap our minds around the idea of a"surprise –rich" future, however, since surprises are likely to become ever more frequent within
our lifetimes. They could also become the most significant single factor in the lives of businesspeople,

politiciansand, in fact, every single citizen.

Environmentalists

view surprises in the technicaltinuity arises when somethingsuddenly happens

sense of "discontinuities."

to mark a profoundA discon-change from the way

things have been. For instance, when water cools, it eventually, and without warning, turns
from a liquid to a solid, ice—all in a moment. It is the same when it heats and turns into a gas:steam. If you, the reader, are still puzzled, consider that we all have had first-handof an absolute discontinuity,a related discontinuity

and one of a profoundly

experience

personal sort: when we were born. And

awaits us at the end.

We are acquainted with all kinds of other discontinuities. In the economic field, there's
been the end of Japan's "bubble economy" in 1989, the abrupt emergence of OPEC, "Black
Wednesday"on the U.S. Stock Exchange,

These crashes constantly

take economists

entirely outside the establishedapartheid,264

said, economists

have pre-recall the fall of the Berlin Wall and the end ofplus the peaceful break-up

tion of the Philippines, South Korea, Argentina
Suharto regime in Indonesia.
In the environmental

in Asian financial markets.

by surprise, as if crashes, however often repeated, lie

order of things. As is sometimes

dicted six of the last three recessions.
In terms of political discontinuities,
South Africa's

and the recent upheavalsof Czechoslovakia

and the democratisa-

and Brazil. Also the peaceful collapse of thearena, we should anticipatea host of discontinuities

ahead.

The

future certainly will not be a simple extension of the past in light of the expanding niche ofhumankind and its multifarious activities. It behooves come to us to grips with the idea of discontinuities so that they won't take us so much by surprise. Why do they ever take us by surprise? Well, because environmental problems are often problems of which we have scarcely
thought.
These surprise phenomena deserve priority attention. Yet science has hardly touched onthem. For the most part, they remain black holes of research. Among environmental discontinuities of the recent past—phenomena that should give us a clue about potential future
events—are the "bleaching" of coral reefs with extensive morbidity and mortality throughout
coral communities; mass mortality of dolphins and seals; phytoplankton blooms; cancer epizootics in marine turtles and fish; population declines among birds, especially North Americanand European migrants; and fast-growing die-offs of frogs among other amphibians in many
parts of the world.
Still other environmental instances include the abrupt emergence of acid rain and theAntarctic ozone hole, likewise the collapse of the Peruvian anchovy fishery in the 1970s andthe New England cod fishery in the early 1990s. Broadly viewed as environmental issues, too,are population surprises, notably the sudden soaring of population growth rates in one hundred
countries during the 1960s, followed by steep plunges in a few countries in recent times. Whowould have supposed that Iran, a fundamentalist Islamic state and as chauvinistic as theycome, would need only 14 years to bring down its population growth rate from over 3%, to just
1% per year?
All these events have been unpredictable—or at least they have exceeded our present
capacity to predict them. Entirely predictable is our readiness to be caught unawares time after
time. We profess to have been surprised by the eruption of AIDS, yet the truly surprising thingis that we were surprised. It was surely inevitable that as huge numbers of people pressed
deeper and deeper into tropical forests with their huge reservoirs of new pathogens, one would
eventually make the leap from wild animals into humans, whereupon the pathogen would finditself in a bacterium's paradise, with human hosts travelling far and wide across landscapes
local and global. As humans invade one "foreign" ecosystem after another, should we notanticipate a whole series of disease disasters?
All this raises a key question that should be at the top of any research agenda for environmentalists, also for economists and political analysts. What surprises should we anticipate
for the foreseeable future. Hence, what can we do about them? What if China were to break
up into half-a-dozen "Chinas," a not-impossible prospect? Think of the earthquake effects it
would generate for global geopolitics. Or consider Saudi Arabia, only semi-stable at best with
its lavish, untaxed and oil-subsidized lifestyles becoming unaffordable. What if its autocratic
regime were to be undermined by educated princes returning from Harvard and Oxford universities, plus equally educated princesses told they must wear the veil, not drive a car and submit to numerous other restrictions? Were the Saudi regime to collapse or to be despatched bya coup, there would be a swift and sharp rise in oil prices, the spot market leaping to at least$50 per barrel, conceivably $75, not impossibly, $100.
Still more seismic would be some environmental discontinuities, especially climate

265changes. In the tropical Atlantic, water temperature can grow warmer and warmer withoutcausing severe storms, but once it passes 28 degrees Celsius it starts to generate hurricanes.
Even though the increase is merely incremental, it is enough to trigger a discontinuity of
exceptional impact. What if, as is all too possible, Caribbean hurricanes no longer bypass
Miami, but one of them were to land on top of the city? The damages could easily exceed $100
billion, whereupon the discontinuity would immediately become economic as much as environmental.
Still more to the point, a globally warmed world could melt enough of the Greenland
icecap to dislocatethe currents of the North Atlantic.Result, the Gulf Stream could shift southwards and leave Britain turned into anotherIceland. While this could not happen overnight,theprehistoricrecord shows it could occur in just a decade or two—lightning speed in terms of theeconomic traumas implied.
Giventhe many future global upheavals likely in a world with pressures from unprecedented growth in human numbers and human activities, we can surely expect that environmental changes will emerge faster,larger and more intense. In turn, these will entrain abundantdiscontinuities of both economic and political kinds, also social and cultural kinds, all arriving at once and making for super discontinuities.There could well be one discontinuity series
after another,or rather sideby sidewith each other, overtakingus at acceleratingpace, and producing fundamental shifts in global systems of every sort from grand-scale ecosystems tonation states; in fact, the entire human enterprise.
Whether it will precipitate a shift in our understanding is debatable. Thus far, we have. a scant idea of what discontinuitieslie ahead, nor are we likely to know until they start to happen (if then). The expert in greatest demand will be the specialist in surprises. The secret is tospot those trends that are headed for terminal decline after long build-up of adverse forces bubbling away beneath the surface.
Reader, why not take a moment to try your hand at becoming such an expert—by looking beyond the headlines to seek out the true news. Attempt, in other words, a discontinuity inyour own manner of thinking.

266

Lecture

Exploring

The Frontiersof Environmental

Dr. Norman

Science

Myers

I am deeply grateful to the Asahi Glass Foundation for awarding me this prestigious
prize. There are two particular reasons why I feel so appreciative. First, I pursue environmental science in a way different from most of my colleagues around the world. I work on my own
as an independent scientist,which is a form of career not usually recognized by a major award.
Secondly,you have selected me for work that spans a range of environmental fields: biodiversity, evolution,forests, eco-agriculture,environmental security, population, resource economics and sustainable development. My research is interdisciplinary,spanning both the life sciences and the social sciences. The environmental challenge covers a host of factors withmultiple interactions and as such it requires interdisciplinary science. In fact, I specialize inbeing a generalist, which, like my independent status, is different from what most scientists
do—and hence it too is rarely recognized through a top-rank prize. Your award will send astrong message to start-out environmental scientists that they may well be applauded if they
pursue an independentor an interdisciplinarycareer, preferably both.
Let me illustrate with some examples of my environmental research—examples that
also illustrate how I have attempted to explore some frontiers of environmental science. In thislatter respect too, I sometimes depart from mainstream science. Whereas many scientists concentrate on supplying new answers to established questions, I also prefer to ask if we are raising all the right questions in the first place.
1. Mass Extinctionof Species

In 1971, I started to demonstrate that we are into the opening phase of a mass extinctionof species. Far from accepting the conventional estimate that species were disappearing at a
rate of one per year—a view long establishedments—I

calculated

that the extinction

among scientists, conservationists

and govern-

rate was at least one species per day, possibly manytimes more. At first my findings were dismissed

as exaggerated,but they were eventually

proved correct by other scientists' analyses. I have subsequently refined my assessment several times, always with the same conclusion: that we are starting to witness the greatest depletion of life's abundance
65-million

and variety since the demise of the dinosaurs

years ago. Thereis much evidence,

and associatedalbeit less than conclusive,

speciesthat we could

already be losing tens of thousandsof species every year, and at a rate at least one-thousand

times greater than the "background"

rate of the prehistoricpast.

2. Tropical Deforestation
In 1978, I undertook a U.S. National Academy of Sciences project to investigate the true
rate of tropical deforestation. Using remote sensing data, I demonstrated that the rate was at267

least 2.5 times greater than had been conventionally supposed, and a rate that was accelerating rapidly. Since tropical forests contain the majority of Earth's species and were being
depleted faster than any other ecological zone, I identified the forests as the main locus of themass extinction underway. While my deforestation findings were viewed in some quarters as
alarmist, they were subsequently confirmed by other scientists' surveys. I convened a United
Nations conference to get the issue established on political agendas. In 1989,I undertook a follow-up assessment that supported my earlier projections of deforestation.
3. The Hamburger Connection
Also on the deforestation front, I started in the early 1980s to show that the overall
problem was not limited to tropical forest countries. It could also originate in developed countries through, for example, their marketplace demand for artificially cheap beef as epitomized
through "the hamburger connection" between North America and Central America, and "thecassava connection" between Europe and Southeast Asia. In the first instance, the beef wasraised on forestlands converted into pasture, and in the second instance, the cassava, being arich livestock feed for cattle in Europe, was grown on plantations established by clearing tropical forests. This time I ran into trouble from a hamburger corporation that threatened me witha lawsuit for damages totalling $3 million.
I subsequently documented North/South linkages of similar sort with respect to desertification in the Sahel through European governments' support of export crops, such as groundnuts and cotton, and with respect to desertification in Southern Africa by virtue of beef subsidies from the European Community. The upshot in all these cases was that environmental
degradation was caused by marketplace demand from countries way beyond the horizon from
where the degradation occurred. It was a case of looking beyond symptoms of problems tosources of problems—a more productive way to tackle environmental challenges in their fullscope.

4. The Triage Concept for Threatened Species
Also in the early 1980s, I broached the concept of "triage" with respect to threatened
species. The concept postulates that since we have far too few conservation resources to assist
all species under threat, we are obliged to choose (whether deliberately or not) between
species: some warrant our support, others cannot. While the choice is rarely made in systematic fashion, it is effectively and increasingly made as an in-built determinant of our savespecies efforts. Hence there is a premium on making conservation decisions by design rather
than by default. Americans have assigned $15 million to saving a single species, the California
condor, whereas the same sum could go far to preserve 200 threatened mollusc species in theMississippi River system—yet the implicit trade-off has hardly been addressed.
I devised a series of evaluatory criteria by which we can make selectivejudgements forand against particular species, and do it in informed and methodical fashion. These criteria
were based on biological, ecological, genetic, evolutionary, economic, aesthetic and ethicalfactors. My analyses were eventuallyadopted as an operational principle by a number of conservation organizations.

268

Much the same analysis applies of course to entire ecosystems and even biomes. Should
we not be making a super priority of tropical forests (even if that is to the detriment of otherbiomes) on the grounds that the forests feature the great majority of extinctions both present
and prospective? These are very hard decisions,demanding the best scientific insights we canmobilize.
5. Tropical Forests and Climate
In the mid-1980s, I synthesized data from the main sectors of the humid tropics to showthat contrary to much conventional thinking, tropical forests can indeed influence climate,whether at local, national, regional or even global levels. The forests manifest their influence
through disruption of rainfall regimes, increase in the albedo effect, and buildup of greenhouse gases in the atmosphere. More importantly, I evaluated the biomass dynamics of tropical forests with respect to their carbon sinks, concluding that despite established thinking(again), tropical forests play a pivotal role in the global carbon budget insofar as they containfully one-fifth of all carbon held in the planet's plants and soils. When the forests are burned,
they release their carbon, contributing very roughly one-quarter of carbon dioxide build-up in
the global atmosphere. I subsequently developed these findings via the Intergovernmental
Panel on Climate Change into a mode to mitigate global warming through enhanced forest
conservation and reforestation.

6. Economic Value of Species and Genetic Resources
Also in the mid-1980s, I returned to species, assessing the economic values of their
genetic resources and with particular respect to sectors such as medicine, agriculture, industry
and energy.I calculated that, for instance, the two anti-cancer drugs from the rosy periwinkle
generated commercial sales of $200 million per year worldwide, while economic values interms of the 70,000 working lives saved each year were worth several times more. I further
estimated that the commercial value of all plant-derived pharmaceuticals was at least $40 billion per year,yet we enjoyed their benefits after scientists had conducted intensive assessmentof only one plant species in one hundred.
This was the first occasion of demonstrating the capacity of species to exert their financial strength in the marketplace. The findings proved offensiveto certain colleagues, some ofwhom protested that my research was "evil" on the grounds that any species, being unique, isbeyond value by definition. Fortunately, the analytic methodology was accepted by the World
Health Organization.
7. Environmental

Security

Also in the mid-1980s,

I broached

an entirely new field: the environmental

to security issues. I was struck by the Gorbachev
so much nuclear missiles

but ozone-layer

warning that the threat from the skies was notdepletionand global warming.

Middle East leaders that a basic source of the Israel/ArabI had heard fromconflict was not oil but another liq-

uid, water. There were many other potential water conflicts, for instance between
Ethiopiadimensionover the River Nile. By 2025, there could be three-billion

peopleEgypt andsuffering

water

269

shortages,

the bulk of themsharing

Increasing

Water

Developing

Countries

internationalriver basins.

Shortages
with

Water

Shortages,

1990

and

2025

501
per

to 1700 cubic
meterspersonannually

500
per

cubic
personmetersor lessannually

Population

Reports

1990

2025

Green,C.P.

The Environment

Centerfor Communication
Data sources:
Falkenmark

andPopulation

Growth:Programs,
Population
1991, United Nations

There are still further illustrations
deforestationand fuelwood

itary confrontation.

Decadefor Action,

Information
Program,
1989, World Resources

Population

Reports,

M-10.

Johns

Hopkins

May 1992.
Institute 1990.

of environmental

security,

notablydesertification,shortages, all with scope for civil strife, outright violence

I persuaded

the World Commission

on Environment

and mil-and Development,amember of which was the Japanese Foreign Minister Mr. Saburo Okita, that its report should
include a chapter on these new threats to security. I produced
tion and conflict, examining

population

follow-up

analyseson popula-pressures as a cause of violence in Rwanda, for exam-ple. The overall rationale has been adopted as the underpinningsof security appraisals by
nations such as the United States, the United Kingdom, Norway, India and Australia. In 1997,
I briefed

a conferenceat the Pentagon

in Washington,

D.C., attended

not only by military

experts but by leaders from the White House, the U.S. State Department
Security Council. As a result of this conference,with environmental

there is now a Pentagon

and the National
department

dealingsecurity.

8. Environmental Refugees
As a subset of Environmental Security, I have investigated the emergent problem ofenvironmental refugees. These are people who feel driven from their homelands for environmental reasons such as soil erosion, water shortages,desertificationand fuelwood deficits, plus
associated factors, such as population pressures. In the mid-1990s, I calculated that theserefugees numbered 25 million, a total greater than all other forms of refugees put together.
Their number may well double by 2010, and even reach 200 million in a global warmed world.
This is an entirely new phenomenon, with major policy implications for the global community.

270

currentsea

50 cm sea

PEOPLE AT RISKIN A GLOBALLY-WARMEDWORLDCountry/Region

Millions at risk

China

77

Bangladesh

28

India

23

Egypt

15

Island States

1

Drought

60

Total

areas

2.0-2.5

level

level rise

m sea

l0

level

rise

25

50 km

204

9. Biodiversity Hotspots
In the late 1980s, I returned to species questions. I developedthe concept of "biodiversity hotspots," these being areas that feature exceptionalconcentrations of endemic species inhabitats subject to exceptional threat of destruction. Through follow-up analyses in conjunction with Conservation International in Washington,D.C., I have found that over two-fifth ofEarth's plant species and over one-third of vertebrate species (except fish) are confined to 25
localities that make up just 1.4percent of Earth's land surface, these being localities where thespecies face severe threat of extinction. The 25 hotspots are so environmentallydegraded thatthey have lost at least 70 percent, often 90 percent, of their original vegetation, and look likely,
in the absence of expanded conservation efforts, to lose much of the rest within a few decades.
The hotspotsanalysis has pointed the way to "silver bullet" responseson the part of conservation planners. This contrasts with the scattergun approach of traditional practice that hasoften sought to be many things to many threatened species, and through insufficient funds has
ended up by failing to be much to most such species. The hotspots strategy has been adopted
by the World Bank, the Global EnvironmentFacility, the MacArthur Foundation,Conservation
International, and several other front-rank organizations in the conservation arena.

271

Biodiversity

Mediterra neanr
Basin

California
Floristic
Province

Caribbean

Mesoamerica

Polynesia/
Micronesia

Hotspots

C hoco/—Darlen/Western
EcuadorCentralChileropicalAndes,

Brazil's
CerradoEasternArc
and Coastal
Fores
ts of
riya
W. FAfrican
orest

Polynesia/
Micronesia

G
Western
hats andSri Lanka
S und al an dBrazil's
Atlantic
ForestSucc ulent
Karoo
Cape Floristic
Province

Madagascar

Woltn

New
aledonia

Southwest'
Australia.

New ZealandBecause of the cost-effective nature of the hotspots strategy, the amount invested in
hotspots has topped $600 million in 10 years, the largest sum ever assigned to a single conservation strategy. All 25 hotspots could be safeguarded for only $500 million per year, a tiny
fraction of what governments, international agencies and citizen groups currently spend onconservation. The sum of $500 million is only twice as much as the Pathfinder mission toMars, justified largely on biodiversity grounds, vis-à-vis the search for extraterrestrial life. To
put it in further perspective,the sum is equivalentto one-twentieth of what Europeans spend
on ice cream each year.Were we to preserve the 25 hotspots, we would likely reduce the mass
extinction by at least one-third. No other strategy available could accomplish so much for solittle.
10. Future Evolution
I have also examined the future course of evolution. In the early 1980s, I began to raisequestions about what the current biotic crisis would do to basic evolutionary processes, suchas speciation, origination and adaptive radiation. I concluded that the crisis would not only
eliminate large numbers of species, but, still more significantly, it would deplete the capacityof evolution to generate replacement species within a recovery phase of 5-10 million years (theusual period following the five mass extinctions of the prehistoric past). The crisis would havethis depletive effect by degrading, if not destroying, tropical forests and wetlands that in theprehistoric past have served as the main "powerhouses" of evolution, supplying the bulk of
replacement species following mass extinctions. That is to say, the present crisis would
severely curtail evolution's capacity to make good the losses of the current mass extinction:"Death is one thing, an end to birth is something else."
In short, we look set to impoverish the planet for a period at least twenty times longer
than humans have been humans. The number of future people affected could, in principle, be
as many as 10,000 times more than have existed to date. The implicit "decision" we are taking
today—through our lack of sufficient action and through its impact on the unconsulted behalf

272

Tof futurealmostgenerations—isentirely

disregarded

time by the scientificthroughsurelythe biggest

by the public

community

the U.S. National

through

Academydecisionin the wholeof humanand its politicalleaders.

an international

conference

history,

It was tackled

yet it isfor the firstthat I organizedin 1999of Sciences.

11. Perverse Subsidies
In the late 1990s, I took a further look at some sources of environmental problems, as
opposed to the symptoms of problems that often attract more attention. I analysed those subsidies that exert adverse impact on, not only our environments, but our economies as well.
Leading categories include agriculture,fossil fuels, road transportation, water, forests and fisheries. These "perverse" subsides amount to around $2 trillion a year worldwide, hence they
have marked capacity to distort our economies in addition to inflicting grandscale injuries on
our environments. On both counts, they foster unsustainable development. Ironically the totalof $2 trillion is 3.5 times higher than the Rio Earth Summit's budget for sustainable development—a sum that governments dismissed as quite unavailable.
"PERVERSE"SUBSIDIES (billion $s per year)

Perverse
subsidies
are those which are harmful
to both the environment
and the economy.
Over-productive

agriculture510

energy300

Fossil fuels/nuclear
Road transportation

780

Mis-use and over-use
Over-harvestingOver-logging
Total

of waterof fisheriesof forests

230
25
92
1,950

By definition, these are funds going to support unsustainable development.
Contrast the Rio Earth Summit budget for sustainable development,$600 billion per year.

Were the perverse subsidies to be phased out, there would be a double dividend. Firstly,
the savings would enable governments to revise their fiscal priorities by, for example, cancelling their budget deficits at a stroke and markedly increasing their health and education outlays. Secondly, there would be an end to government support (unwitting as it is) for environmental degradation. In fact, reduction of perverse subsidies would do more for both ourenvironmentsand our economies than any other single measure.
There are sizeable political obstacles to cancelling the subsidies. In Washington, D.C.,
the Congress is subject to special interests' lobbying to the extent of $100 million a month.
Fortunately,a number of countries have demonstrated that the political obstacles can be overcome. New Zealand, a nation more dependent on agriculture than any other developed nation,
has got rid of virtually all its agri-subsidies. Several other nations have slashed their subsidies
in the other four sectors. Meantime, a typical American taxpayer funds the subsidies with
$2,000 per year, then pays out another $1,000 through environmental repair costs.

273

12. Sustainable

Agriculture

I have examined
decades,the challenge

plus the associatedthis is not a new issue,
cultureis ever-morevery muchsuccessfulbuild into their calculus
term agriculture,alone

climateit throughthe contrary.
as witness
declinesoil erosion,by half withinsustainable

But many

declining

through

outputexperts

grain

water

deficits,

two

Of course

assert that conventional

prices.

of the environmental

the coming

agriculture.

Unfortunately,

agri-

they do notresources

underpinninglong-

and pollutionof several

sorts, letchange.
thedepletive

for the World

were to be factored
for adoption

foodof doing

the parallel

notably

I assessed
appraisals

of increasing

challenge

Food Summit

in, grain pricesof sustainable

13. Food and Hunger
Followingfood prospects

impactof thein 1996. I showed

would

agriculture

over-loadedthat if thesesurely be soaring

via an Evergreen

in Sub-Saharanresource

throughenvironmental

and thus sending

policyproblems

urgentmessages

Revolution.

Africamy 24 years of living in Sub-SaharanAfrica, I have recently

for the region. Since 1960, and as per-capita

many people have become steadily hungrier. I have calculated
now malnourished,base

twice as many as officially estimated.

food production

assessedthehas declined,that two out of three people are

Yet governments

and development

agencies seem largely indifferent to the adverse trend; their implicit response,by virtue of theirlack of sufficientindefinitely.

action, is to suppose it can be allowed to keep on decliningOfcourse this is the opposite of what they intend, but their record implies as much.

SUB-SAHARAN
Total

peoplemalnourished

two-thirds

Total

today

of the regionalon verge

receivingof starvation

less thanIf malnutrition

local

faminelikelyto die ....

minimumto spread

5% of 130 million

recent

400 million

100 millionof daily

growing
population,
thenof starvationin 2010 ....

If only....

population

....

75%

continues

AFRICA

total

among

caloriesaon verge
130 million

die, as in the case ofdisasters,

then

total
6.5 million

I have demonstrated that the downward spiral cannot long continue before people cease
to grow more hungry. They will start to die, and in unprecedently large numbers. (This is not
to ignore that in certain countries the overwhelming source of mortality will lie with AIDS—a disease that is potentiated by malnutrition, and vice versa.) Fortunately, there are vigorous
and urgent initiatives available to raise food output and to slow population growth, both possible as witness the efforts of a few enlightened countries, whereupon the region could become
self-sufficient in food within two decades.

274

14. New Consumers
Seventeen developing and three transition nations now feature over one-billion people
with enough household income to enjoy meat every day and to buy cars in fast-growing numbers. Already they possess purchasing power matching that of the United States. Their numbers may well increase by half by 2010, and their purchasing power by still more. Theirstrongly meat-based diet entails environmental problems in that the meat is often raised on
grain, which overloads croplands and diverts much water in countries with water shortages.
The new consumers possess 125-million cars or 22 percent of the global fleet, and by 2010 the
total could jump to 300-million cars or 38 percent. Cars not only cause much local pollution,
but are the fastest growing source of carbon dioxide emissions, which contribute roughly halfof global warming processes.

NEW

CONSUMERS

Total new consumers today:
1.07 billion(300 million in China, 140 million in India)
and with collective purchasing powerof PPP$6.1 trillion,
almost equivalent to the United States

NEW

CONSUMERS'

CARS(millions)

Total
1999

Projected
2010

20 New Consumer
countries

125

230

United

162

185

525

800

World

StatesCars are the fastest-growing
source of CO2 emissions—already 15% of all energy-related
emissions worldwide.

Of course, these people should be enabled to enjoy their new found affluence,provided
they do not impose undue environmental and hence economic harm at both local and international levels. Hopefully, the new consumers can learn from the mistakes, also the positive
experiences, of the long affluent nations in order that their environmental impacts remain
acceptable. Hopefully too, the rich-world consumers can be persuaded to adopt less environmentally harmful lifestyles, which could then serve as models for the new consumers. Thereis much scope for "Factor Four" and even "Factor Ten" reductions in energy use, greater recycling of materials, enhanced pollution controls and other forms of waste management, in fact,
resource conservation all round.
15. Environmental Surprises
I suspect that my main scientific contribution may eventually prove to be my research
into environmental problems that hitherto remain unknown, or at least unrecognized . At the1972 Stockholm Conference on the Human Environment, there was no mention of what havesubsequently come to be acknowledged as front-rank problems: mass extinction of species ,
tropical deforestation, desertification, ozone-layer depletion, and climate change. With 20/20
hindsight (that exact science), we can now see that with greater inclination to raise new questions, scientists could have identified some of these problems ahead of time, and thus moved275

to forestall them. I believe that the biggest environmental problems ahead could well be ones
we have not even thought of as yet—but that we could pinpoint with a more expansive
approach to research agendas.
Many "environmental surprises" are likely to arise in the form of what are technicallyknown as discontinuities, or non-linear switches in patterns and processes, often brought about
by synergized interactions between two or more environmental problems. The stock example
of a discontinuity lies with water, which can suddenly turn from a liquid into either a solid ora gas. Environmental discontinuities have included deforestation-derived declines in tropicalrainfall, ozone-layer depletion and global warming. In the biodiversity field, there have been
abrupt mass mortalities of dolphins and seals, phytoplankton blooms, cancer epizootics infish, bleaching of coral reefs, and the precipitous decline of Peru's anchoveta fishery andamphibians worldwide. We have also witnessed many synergized interactions, such as acidrain and wild fires in conjunction with over-heavy logging of tropical forests.
Both discontinuities and synergisms are recognized by scientists to be among the mostimportant phenomena in nature, and they are likely to become more frequent in a world ofincreasing environmental pressures among other problems (economic, social, political). Yet
they receive only a fraction of the research attention they deserve, despite ground-breaking
research such as my colleague Professor May has cited with respect to chaos theory and related
issues. I plan to use part of the Blue Planet funds to press ahead with research on the issue fromthe standpoint of intersectoral linkages with their many policy implications. Fortunately, there
can be positive discontinuities in the policy arena, generating reinforced leverage and multiplier effects, as witness the Ozone Layer Treaty, the plunge in birth rates in several countries,
and the start on slashing perverse subsidies.

Schematic
sensitivity,

276

expected

Sensitivesoils

Present

Present

emissions

Potential

map showing regions that currently have acidification

problems,

future emissions

might becomeand population

density, acidification

problemproblem

areas
areas

and regions where, based on soil
severe in the future

These 15 issues are what I regard as my main research products. They began in the early
1970s when I was still a student at the University of California and I raised the warning about
the mass extinction of species underway. That was also the time of the Stockholm Conference
on the Human Environment, and as noted above, I was struck that the participants made no
mention of mass extinction as a major environmental problem. Nobody had thought to ask if
it was a problem at all, even though if it had been recognized we could have done more to
reduce its ultimate scope.
Nor did the scientists at Stockholm mention any of several other issues (listed above)that subsequently came to be recognized as front-rank environmental problems. All of them
could, with a modicum of readiness to look beyond conventional thinking, have been brought
to the urgent attention of political leaders. It was this that persuaded me that the best scientificcareer I could follow would be, not so much to generate new answers to recognized questions,but to ask if we are raising all the right questions in the first place. It is an unusual form ofcareer—and in retrospect the most stimulating I could have chosen. What a rewarding life it
has been: wandering around on the horizons of environmental science, seeking one new question after another—and doing it at a time when environmental science is needed in its fullscope if it is to support our Earth and our world.

Conclusion
In summary,there have been three dimensions to my professional career. I haveworked
as independent scientist.I have practised interdisciplinary science. I have preferred to identify
new questions. None of these fits the usual mould of science. This returns me to the main reason why I am specially pleased to be selected for your Blue Planet Prize. Youhave recognizeda scientist who has long stood apart from mainstream science. I hope this helps you to understand how much I welcome your gesture. Moreover,through your award you have set me freefinancially to tackle those environmental questions that I consider most important. I can now
set out on what I hope will be the most productive phase of my entire career.
I also like to think you have selected me not just as an environmental scientist but as anenvironmental activist. Right from my start in 1970, I have made it a rule to take my researchfindings and policy recommendations to governments, international agencies and politicalleaders in dozens of countries. I have pressed the environmental cause with prime ministers
and presidents on four continents, with the head of the World Bank and United Nations agencies, and with corporate chiefs in many lands, including Japan. In addition, I have publicized
the environment on television and radio and through newspapers and magazines. I haveaddressed 5,000 people in London and I have sat down in front of bulldozers in Australia. I
hope that, through your selection of me for your Prize, you are encouraging more scientists tojump into the public arena and alert the world to our environmentalproblems—and our opportunities. These voices are sorely needed.
A Concluding
tory. Entire segments

Comment.

We live at an altogetherof our planetary

ecosystem

unprecedented

face terminal

time in human his-threat throughdeforestation,277

desertification,global warming and a host of other environmental problems. This prompts anoverriding thought. Are we not a privileged generation to live at a time when we have opportunity to save both our Earth and our world? No generation in the past has enjoyed such an
opportunity,since the problems were not there. No generation in the future will enjoy the same
opportunity,because if we do not get on top of the problems before they get on top of us, ourdescendants will have nothing left to do but to pick up the pieces we pass on to them. We are
fortunate indeed to live at a time of such a once-and-for-all challenge. It is a super-size challenge, and if we measure up to it, we shall surely feel five metres tall. Above all, we shall earn
the thanks of numerous generations to come.

278

Major Publications
Dr. Norman Myers
Books
Myers, N. The Long African Day. N.Y. and London: MacMillan, 1972. (Three printings).
- . The SinkingArk. N.Y. and Oxford: Pergamon Press, 1979. (Three printings, four translations).
-. Conversion of Tropical Moist Forests (Report to National Academy of Sciences). Washington,
D.C.: National Research Council, 1980.
- . A Wealthof WildSpecies.Boulder, Colorado: Westview Press, 1983. (Four book clubs and two science awards).
-.The Primary Source: Tropical Forests and Our Future. N.Y. and London: Norton, 1984. (Second
edition, 1985. Third enlarged edition, 1992).
- . The Gaia Atlas of Planet Management. London: Doubleday, and N.Y.: Pan Books, 1984. (Twelvetranslations. Fully revised and expanded edition, 1993.)
Myers, N., D.O. Hall and N.S. Margaris, ed. Economicsof EcosystemManagement. Dordrecht: W. Junk
Publishers, 1985.
Myers, N. The Gaia Atlas of Future Worlds: Challenge and Opportunity in an Age of Change. N.Y.:
Doubleday, and London: Robertson McCarta, 1990.
- . Population, Resources and the Environment: The Critical Challenges. N.Y.: United Nations
Population Fund, 1991. (French and Spanish translations).
Myers, N., ed. Tropical Forests and Climate. Dordrecht: Kluwer Academic Publishers, 1992.
-. The Environmental Basis of Political Stability. N.Y.: Norton, and Washington, D.C.: Island Press,
1993; Ultimate Security, 1996. (Chinese translation.Shanghai: Shanghai Publishing House, 2001.)
Myers, N. and Julian Simon. Scarcity or Abundance: A Debate on the Environment. N.Y.: Norton,
1994. (Italian translation, 1995).
Myers, N. and J. Kent. Environmental Exodus: An Emergent Crisis in the Global Arena. Washington,
D.C.: The Climate Institute, 1995. (Italian translation, 1999).
-. Perverse Subsidies. Winnipeg, Canada: International Institute for Sustainable Development, 1998.
Myers, N., R.A. Mittermeier,P.R. Gil and C.G. Mittermeier.BiodiversityHotspots. Monterrey,Mexico:
CEMEX Publishers, 1999. (Distributed outside Mexico by Univ. of Chicago Press).
Myers, N. Towards a New Greenprint for Business and Society. Tokyo, Japan: Tachibana Publishing,
1999. (In Japanese. Korean translation, 2000).
Myers, N. and J. Kent. Perverse Subsidies: How Tax Dollars. Can Undercut the Environment and theEconomy.Washington, D.C.: Island Press, 2001.
-. One Billion New Consumers: The Influence of Affluence.2002. (In prep.)

Refereed publications
Myers, N. "Wildlife and Development in Uganda." Bioscience, 21 (1971), 1071-5.
- . "National Parks in Savannah Africa." Science, 173 (1972), 1255-63.
-. "A Preliminary Appraisal of the Ecological and Socioeconomic Consequences of a Proposed
Tourist Development of Kenya's South Coast." Report to World Bank, Nairobi, Kenya. 1972.
- . "The Masai: Modernizing the Myth." Association of Pacific Coast Geographers Yearbook, 35(1973), 147-164.
- . "The Spotted Cats: In Danger-or in Danger of Danger?" In The World's Cats, Ecology andConservation. Vol. I. Ed. R.L. Eaton. 276-320. Winston, Oregon: World Wildlife Safari, 1973.
-. "Status of the Leopard and Cheetah in Africa and of the Jaguar and Ocelot in the Amazon." In Catsof the World.Ed. N. Sitwell. 16-27. London: Tom Stacey, 1973.

279

- . "National Parks and Land-Use Planning." Ekistics, 36/214 (1973), 223-229.
"Leopard and Cheetah in Ethiopia." Oryx, 12 (2) (1973), 197-205.
- . "The Ecologic-Socioeconomic Interface of Wildlife Conservation in Emergent Africa: Lakes
Nakuru and Naivasha in Kenya." J. Environmental Economics and Management, 1 (1974),
319-334.
- . "Institutional Inputs for Cheetah Conservation in Africa." Transactions of 39th North American
Wildlife and Natural Resources Conference, 1974,323-328.
- . "The Whaling Controversy." American Scientist, 63 (4) (1975), 448-455.
- . "The Tourist as an Agent for Development and Wildlife Conservation: The Case of Kenya." Intl. J.
Social Economics, 2 (1) (1975), 26-42. .
- . "The Cheetah Acinonyx Jubatus in Africa." IUCN Monograph No. 4. Morges, Switzerland: IUCN,
1975.
- . "An Expanded Approach to the Problem of Disappearing Species." Science, 193 (1976), 198-202.
- . "China's Approach to Environmental Conservation." Environmental Affairs, 5 (1) (1976), 33-63.
- . "The Leopard Panthera Pardus in Africa." IUCN Monograph No. 5. Morges, Switzerland: IUCN,
1976.
- . "The Cheetah in Africa under Threat." EnvironmentalAffairs, 5 (4) (1977), 617-647.
- . "The Cheetah's Relationships to the Spotted Hyena: Some Implications for a Threatened Species."
In Proceedings of the 1975 Predator Symposium(American Society of Mammalogists). Ed. R.H.
Phillips and C. Jonkel. (1977) 191-200.
- . "Discounting and Depletion: The Case of Tropical Moist Forests." Futures, 9 (6) (1977), 502-509.
- . "Wildlife of Savannah and Grasslands: A Common Heritage of the Global Community." In
Proceedings of Earthcare Conference. Ed. E. Schofield. 385-409. Boulder, Colorado: Westview
Press, 1978.
- . "What Use is Wildlife?" Earthscan Briefing Document 11. London: Earthscan, 1978.
- . "The Global Problem of Tropical Deforestation." Keynote paper in Proceedings of U.S. Strategy
Conference on Tropical Deforestation. 19-22. Washington, D.C.: Department of State, 1978.
- . "Institutional Inputs for Conservation of the World's Cats." The World's Cats, 3 (1978), 74-76.
- . "The Sinking Ark." Oxford and N.Y.: Pergamon Press, 1979. (Third printing, 1983. Translations infour languages.)- . "Tropical Biomass Systems." In Future Sources of Organic Raw Materials. Ed. L.E. St.-Pierre and
G.R. Brown. 343-354. N.Y.: Pergamon Press, 1980.
- . "Bio-Energy for Kenya: Some Technical Possibilities."In Energy and Environment in East Africa.
250-258. Nairobi, Kenya: United Nations Environment Programme, 1980.
- . "Present Status and Future Prospects of Tropical Moist Forests." Environmental Conservation, 7/2(1980), 101-114.
- . "Playing God to Save Diversity." TechnologyReview, 82/5 (1980), 62-63.
- . "Multinational Timber Corporations and Tropical Forests." N.Y.: Council for Economic Priorities,
1980.
- . "Bailing Out the Ark." Bioscience, 30/8 (1980), 553-556.
- . "What Future for Amazonia?" Americas, 32/10 (1980), 18-25.
- . "The Problem of Disappearing Species: What Can Be Done?" Ambio, 9/5 (1980), 229-235.
- . "Conversion of Tropical Moist Forests" (Report to National Academy of Sciences). Washington,
D.C.: National Research Council, 1980.
- . "The Exhausted Earth." Foreign Policy, 42 (1981), 141-155.
- . "The Hamburger Connection: How Central America's Forests Become North America's
Hamburgers." Ambio, 10/1 (1981), 3-8.
- . "Conservation Needs and Opportunities in Tropical Moist Forests." In The Biological Aspects ofRare Plant Conservation. Ed. H. Synge. 141-154. Chichester, U.K.: John Wiley, 1981.

280

—. "Corn Genes and Big Dollars." TechnologyReview, 84/2 (1981), 8-9,64.
—. "Conserving Marine Genetic Resources in Protected Areas." In Conserving the Natural Heritage of
Latin America and the Caribbean. 42-51. Gland, Switzerland: IUCN, 1981.
— . "The Leopard in Africa: Biological and Cultural Realities." Intl. J. for Study of Animal Problems,
2/1 (1981), 5-6.
— . "Corporate Destruction of Tropical Forests." Business and SocietyReview, 39 (1981), 9-13.
— . "Tropical Forests as Sources of Pharmaceuticals and Industrial Products." Tropical Silviculture.
InternationalUnion of Forest Research Organizations, 4 (1981), 1-6.
— . "Non-Market Values of Tropical Forests: Species." In Benchmark Papers in Tropical Ecology.Ed.
C.F. Jordan. N.Y.: Academic Press, 1981.
—. "Deforestation in the Tropics: Who Gains, Who Loses?" Studies In Third World Societies, 13(1982), 1-24.
—. "Conversion Rates in Tropical Moist Forests." In Tropical Rain Forest Ecosystems.Ed. F.B. Golley,
H. Lieth and M.J.A. Werger. 289-300. Amsterdam, Netherlands: Elsevier Publishing, 1982.
— . "Conservation of Rain Forestsfor ScientificResearch, for Wildlife Conservation,and for Recreation
and Tourism." In Tropical Rain Forest Ecosystems.Ed. F.B. Golley, H. Lieth and M.J.A. Werger.
325-334. Amsterdam, Netherlands: Elsevier Publishing, 1982.
Myers, N. and Dorothy M. Myers. "From the 'Duck Pond' to the Global Commons: Increasing
Awareness of the Supranational Nature of Emerging Environmental Issues." Ambio, 11/4 (1982),
195-201.
Myers, N. "Room in the Ark?" Bulletin of the AtomicScientists, 38/9 (1982), 44-48.
— . "The Theory of Pleistocene Forest Refugia and Its Implications for Conservation in Africa andOther Parts of the Tropics." In The Biological Model of Diversification in the Tropics. Ed. G.T.
Prance. 658-672. N.Y.: Columbia Univ. Press, 1982.
—. "The Carbon Dioxide Connection." J. Social and Biological Structures, 6 (1983), 17-28.
—. "Tropical Moist Forests: Over-Exploited and Under-Utilized?" Forest Ecology and Management,
6 (1983), 59-79.
Myers, N. and E.S. Ayensu. "Reduction of Biological Diversity and Species Loss."Ambio, 12/2 (1983),
72-74.
Myers, N. and Dorothy M. Myers. "How the Global Community Can Respond to International
Environmental Problems." Ambio, 12/1 (1983), 20-26.
Myers, N. "Depletion of Tropical Moist Forests: A Comparative Review of Rates and Causes in theThree Main Regions." Acta Amazonica, 12/4(1983), 745-758.
— . "A Priority-Ranking Strategy for Threatened Species?" The Environmentalist, 3 (1983), 97-120.
Myers, N., Paul R. Ehrlich and 18 others. "Long-Term Biological Consequences of Nuclear War."
Science, 222 (1983), 1293-1300.
Myers, N. "The Tropical Forest Issue." In Resource Management and Environmental Planning 4. Ed.
T. O'Riordan and R.K. Turner. 1-28.1983.
—. "A Wealth of Wild Species." Boulder, Colorado: Westview Press, 1983. Accepted as a Sciencebook and a quality paperback of the Book of the Month Club, also by the Library of Science Book
Club, the Natural Science Book Club, and the British Good Book Guide.
—. "Wild Genetic Resources." Impact of Science on Society (UNESCO), 34/4 (1984), 327-334.
—. "Genetic Resources in Jeopardy." Ambio, 13/3(1984), 171-174.
—. "Problems and Opportunities in Habitat Conservation." In Conservation of Threatened Natural
Habitats. Ed. A.V. Hall. 1-15. Pretoria: South African National Scientific Programmes, 1984.
— . "The Eternal Values of the Parks Movement and the Monday Morning World." In National Parks,
Conservation and Development.Ed. J.A. McNeely and K.R. Miller. The Role of ProtectedAreas in
Sustaining Society: 656-660. Washington, D.C.: Smithsonian Institution, 1984.
Myers, N., D.O. Hall and N.S. Margaris, ed. "Economics of Ecosystem Management." The Hague,281

Netherlands: W. Junk Publisher, 1985.
Myers, N., K.R. Miller and five others. "Issues in the Preservation of Biological Diversity." In The
Global Possible. Ed. R. Repetto. Resources, Development and the New Century: 337-362. New
Haven, Connecticut: Yale Univ. Press, 1985.
Myers, N., J.M. Melillo and three others. "A Comparison of Recent Estimates of Disturbance inTropical Forests." Environmental Conservation, 12 (1985), 37-40.
Myers, N., R.A. Houghtonand six others. "Net Flux of Carbon Dioxide from Tropical Forests in 1980."
Nature, 316 (1985), 617-620.
Myers, N. "Causes of Loss of Biological Diversity." Washington, D.C.: Office of Technology
Assessment, U.S. Congress, 1985.
- . "TropicalDeforestation and Species Extinctions.""The Latest News." Futures, 17 (1985), 451-463.
- . "Forests and Environment." In Managing Global Issues. Ed. J.T. Kikhonen. 88-97. Finland: Univ.
of Helsinki Press, 1985.
- . "The Global Possible: What Can Be Gained?" In The Global Possible. Ed. R. Repetto. Resources,
Development and the New Century: 477-490. New Haven, Connecticut: Yale Univ. Press, 1985.
Myers, N., D.O. Hall and N.S. Margaris, ed. "Economics of Ecosystem Management." Dordrecht,
Netherlands: W. Junk Publishers, 1985.
Myers, N., "The End of the Lines." Natural History, 94 (1985), 2,5,12.
- . "Environmental Repercussions of Deforestation in the Himalayas." J. World Forest Resource
Management, 2 (1986), 63-72.
- . "Tropical Forests: An Overview Assessment, With Impacts on Extinctions." In Conservation
Biology: Science of Scarcity and Diversity.Ed. M.E. Soule. 394 1109.Sunderland, Massachusetts:
Sinauer, 1986.
- . "Forestland Farming in Western Amazonia: Stable and Sustainable." Forest Ecology andManagement, 15 (1986), 81-93.
- . "Biological Resources of the Tropics." In Conservation for Productive Agriculture. Ed. V.L.
Chopra and T.N. Khoshoo. 1-10. New Delhi, India: Indian Council of Agricultural Research, 1986.
- . "Long-Term Impacts of a Nuclear Exchange on the Biosphere in Britain." In Civil Survival:
101-126. Oxford: Blackwell Books, 1986.
Myers, N., J. Molofsky and C.A.S. Hall. "A Comparison of Tropical Forest Surveys." Carbon Dioxide
Program. Washington, D.C.: Department of Energy, 1986.
Myers, N. "Tree Crop-Based Agroecosystems in Java." Forest Ecology and Management, 17 (1986),
1-12.
- . "Economics and Ecology in the InternationalArena: The Phenomenon of LinkedLinkages." Ambio,
15 (1986), 296-300.
-. "The Environmental Dimension to Security Issues." The Environmentalist, 6 (1986), 251-256.
- . "Monitoring of Tropical Forests: The Role of Remote Sensing." Bilbao, Panama: Smithsonian
Tropical Research Institute, 1986.
-. "Tackling Mass Extinction of Species: A Great Creative Challenge ." Albright Lecture inConservation.Berkeley, California: Univ. of California, 1987.
-. "Not Far Afield: U.S. Interests and the Global Environment." Washington, D.C.: World Resources
Institute, 1987.
Myers, N. and R. Tucker. "Deforestation in Central America: Spanish Legacy and North American
Consumers." Environmental Review, 11 (1) (1987), 55-71.
Myers, N. "Tropical Forests: Patterns of Depletion." In Tropical Rain Forests and WorldAtmosphere.
Ed. G.T. Prance. 9-22. Boulder, Colorado: Westview Press, 1987.
-. "Trends in the Destruction of Rain Forests." In Conservation in the Tropical Rain Forests. Ed.
C.W. Marsh and R.A. Mittermeier. 3-20. N.Y.: Alan R. Liss, 1987.
- . "The Extinction Spasm Impending: Synergisms at Work." Conservation Biology, 1 (1) (1987),282

14-21.
- . "Linking Environment and Security. " Bulletin of the Atomic Scientists, 4 (8) (1987), 46-47.
- . "Conservation of Africa's Cats: Problems and Opportunities." In Cats of the World.Ed. S.D. Miller
and D.D. Everett. Biology, Conservation and Management. 437-446. Washington, D.C.: National
Wildlife Federation, 1987.
Myers, N., R.A. Houghton and 10 others. "The Flux of Carbon from Terrestrial Ecosystems to the
Atmosphere in 1980 Due to Changes in Land Use: Geographic Distribution of the Global Flux."
Tellus, 39B (1987), 122-139.
Myers, N. "Emergent Aspects of the Environment: A Creative Challenge." The Environmentalist, 7 (3)(1987), 163-174.
- . "Nature Conservationat a Global Level: The Scientific Issues." Inaugural Lecture for new Chair andVisiting Professorship.Netherlands: Univ. of Utrecht, 1987.
Myers, N. and J.J. Kozub. "Land and Water Resources Management."Economic DevelopmentInstitute.
Washington, D.C.: World Bank, 1987.
Myers, N. "Policy Issues for Environment and Development." New Economics, 1 (1987), 7-8.
- . "Nuclear Winter in the Third World." In On the Brink: Nuclear Proliferation and the Third World.
Ed. P. Worsley. 237-242. London: Third World Publications, 1987.
-. "Population , Environment and Conflict." Environmental Conservation, 14 (1) (1987), 15-22.
(Award for best paper of the year).
- . "New Foods and Innovative Agriculture." In The Right to Food: Technology, Policy and Third
WorldAgriculture. Ed. P. Ehrensaft and F. Knelman.43-54. Montreal, Canada: Pharmi-Libri,1988.
-. "The EnvironmentalBasis of SustainableDevelopment." Annals of Regional Science (Specialissue
on Environmental Management and Economic Development), 21 (1988), 33-43.
-. "Tropical Deforestation and Remote Sensing." Forest Ecology and Management, 23 (1988),
215-225.
- . "Tropical Forests: Much More than Stocks of Wood." J. Tropical Ecology, 4 (2) (1988), 208-220.
-. "Tropical Moist Forests and Their Species: Going, Going...?" In BioDiversity. Ed. E.O. Wilson.
28-35. Washington, D.C.: Academy Press, 1988.
- . "Philippines: Forestry, Fisheries and Agricultural Resource Management." Washington, D.C.:
World Bank, 1988.
- . "Draining the Gene Pool: The Causes and Consequences of Genetic Erosion." In Seeds andSovereignty.Ed. J. Kloppenberg. Debate Over the Use and Control of Plant Genetic Resources.
90-113. Durham, North Carolina: Duke Univ. Press, 1988.
- . "Tropical Forests: A Storehouse for Human Welfare." In Tropical Rainforests, Diversity andConservation. Ed. F. Almeda and C.M. Pringle. 13-27. San Francisco: California Academy of
Sciences, 1988.
- . "Threatened Species: "Hot-Spots" in Tropical Forests." The Environmentalist, 8 (1981), 20.
- . "Tropical Forest Species: Going, Going, Going." ScientificAmerican, 259 (1988), 132.
- . "Natural Resource Systems and Human Exploitation Systems: Physiobiotic and Ecological
Linkages." Washington, D.C.: World Bank, 1988.
- . "Environmental Degradation and Some Economic Consequences in the Philippines."
Environmental Conservation, 15 (1988), 205-214.
- . "Environmental Challenges: More Government or Better Governance?" Ambio, 17 (1988),
411-414.
- . "Writing Off the Environment." In The Business of Savingthe World. Ed. J. Elkington, T. Burke and
J. Hailes. 190-192. London: Routledge Publishers, 1988.
- . "Extinction Rates Past and Present." Bioscience, 39 (1989), 39-41.
- . "Tropical Deforestation and Climatic Change." Environmental Conservation, 15 (1989), 293-298.
- . "The GreenhouseEffect: A Tropical Forestry Response." Biomass, 18 (1989), 73-78.

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- . "Environment and Security." Foreign Policy, 74 (1989),23-41.
- . "Loss of Biological Diversity and Its Potential Impact on Agriculture and Food Production." In
Food and Natural Resources. Ed. D. Pimentel and C. Hall. 49-67. N.Y.: Academic Press, 1989.
- . "Tropical Forestsand the Botanists Community." In Proc. of the XIVthIntl. Botanical Congress.Ed.
W. Greuter and B. Zimmer. 291-300. Koenigstein, Germany: Koeltz Scientific Books, 1989.
- . "The Future of Forests." In The Fragile Environment. Ed. L. Friday and R.A. Laskey. 22-40.
Cambridge, U.K.: Cambridge Univ. Press, 1989.
- . "Environmental Security: The Case of South Asia." Intl. Environmental Affairs, 1(1989), 138-154.
- . "A Mass Extinction Episode Ahead of Us: Predictable or Preventable?" In Conservation for the
Twenty-First Century.Ed.D. Western and M. Pearl. 42-49. Oxford: Oxford Univ. Press, 1989.
- . "Ecology of the Amazonian Rainforest." In Land Use Options for Amazonia Rainforests. Ed. C.
Johnson, R. Knowles and M. Colchester. 9-12. Oxford: Oxford Univ. Press, 1989.
- . "The Environmental Basis of Sustainable Development." In Environmental Management andEconomic Development. Ed. G. Schramm and J.J. Warford. 57-68. Baltimore, Maryland: Johns
Hopkins Univ. Press, 1989.
- . "Synergistic Interactions and Environment." Bioscience, 39 (1989), 506.
- . "Nuclear Winter: Potential Biospheric Impacts in Britain." Ambio, 18 (1989), 449-453.
- . "Tropical Deforestation and Climatic Change." In Climate and Geo-Sciences: A Challenge for
Science and Society in the 21st Century. Ed. A. Berger, S.H. Schneider and J.C.L. Duplessy.
341-354. Dordrecht, Netherlands: Kluwer Academic Publishers, 1989.
- . "Population Growth, Environmental Decline and Security Issues in Sub-Saharan Africa." In
Environmental Stress and Security. Ed. A. Hjort of Ornas and M.A.M. Salih. 211-231. Uppsala,Sweden: ScandinavianInstitute of African Studies, 1989.
- . "Tropical Forests and Gaia." Forestry for Sustainable Development Program, College of Natural
Resources, St. Paul, Minnesota: Univ. of Minnesota, 1989.
- . "Tropical Forests for Sustainable Development." Forestry for Sustainable Development Program,College of Natural Resources. St. Paul, Minnesota: Univ. of Minnesota, 1989.
- . "Sustainable Development: The Role of NGOs." Forestry for Sustainable Development Program,College of Natural Resources. St. Paul, Minnesota: Univ. of Minnesota, 1989.
- . "Milieuconflikten Bedreigen Wereldvrede." Wetenschap und Samenleving, 41 (5) (1989), 5-11.
- . "Natural Resource-BasedExport Initiativesin Central America and the Caribbean." Commissionfor
the Study of International Migration and Cooperative Economic Development. Washington, D.C.:
U.S. Congress, 1990.
- . "Economic Evaluation of Genetic Resources in Tropical Forests." Allgemeine Forst Zeitschriftfur
Waldwirtschaft und Umweldtvorsorge,1-2 (1990), 12-13.
- . "Environment and Security: The Emergent Linkages." National Forum, 70 (1990), 30-31.
-. "Tropical Forests." In Global Warming.Ed. J. Leggett. 372-399. Oxford: Oxford Univ. Press, 1990
- . "Mass Extinctions: What Can the Past Tell Us about the Present and Future?" Global and Planetary
Change, 82 (1990), 175-185.
Myers, N. and D.W. Pearce. "Economic Values and the Environment of Amazonia." In The Future of
Amazonia. Ed. D. Goodman and A. Hall. 383-404. London: Macmillan Press, 1990.
Myers, N. "The Coming Challenge of Mass Extinction." In Valuing Special Plants and Rare Species.
Ed. R.P. Cote. 5-14. Nova Scotia, Canada: Dalhousie Univ. Press, 1990.
-. "Environmental Science and the Policy Interface: Facing Up to the Lack of Interface." In
Sustainable Development, Science and Policy. 513-521. Oslo, Norway: Norwegian ResearchCouncil for Science and the Humanities, 1990.
- . "The Biodiversity Challenge: Expanded Hot Spots Analysis." The Environmentalist, 10 (1990),
243-256.
- . "The World's Forests and Human Populations: The Environmental interface." In Resources,284

Environment, Population: Present Knowledge, Future Options, Population and. Development
Review.Ed. K. Davis and M.S. Bernstam. (Special Supplement) 16 (1991), 233-247.
-. "Man's Future Needs the Beasts." In Man and Beast. Ed. M. Robinson. 319-329. Washington,
D.C.: The Smithsonian Press, 1991.
- . "BiologicalDiversity and Global Security."In Ecology, Economics,Ethics-The Broken Circle.Ed.
F. Bormann and S.R. Kellert. 11-25. New Haven, Connecticut: Yale Univ. Press, 1991.
Myers, N., ed. "Tropical Forests: Present Status and Future Outlook." In Climatic Change (special
issue on Tropical Forests and Climate), 19 (1-2) (1991), 3-32.
Goreau, T.J. and N. Myers, ed. "Tropical Forests and the Greenhouse Effect: A Management
Response." In Climatic Change (Special issue on Tropical Forests and Climate), 19 (1-2) (1991),
215-226.
Myers, N. "Tropical Deforestation: the Latest Situation." BioScience,41 (1991), 282.
- . "Biologists as Policymakers?" Environmental Conservation, 18 (1991), 6.
-. "Population, Resources and the Environment: The Critical Challenges." N.Y.: United Nations
Population Fund, 1991. (French and Spanish translations.)- . "Population/EnvironmentLinkages: Discontinuities Ahead?" Ambio, 21 (1992), 116-118.
- . "Tropical Forests: The Policy Challenge." The Environmentalist, 12 (1992), 15-27.
-. "The Anatomy of Environmental Action: The Case of Tropical Deforestation." In The International
Politics of the Environment. Ed. A. Hurrell and B. Kingsbury. 430-454. Oxford: Oxford Univ.
Press, 1992.
-. "Synergisms: Joint Effects of Climate Change and Other Forms of Habitat Destruction." In Global
Warming and Biological Diversity. Ed. R.L. Peters and T.E. Lovejoy. 344-354. New Haven,
Connecticut:Yale Univ. Press, 1992.
-. "The Environmental Consequencesfor the European Community of Population Factors Worldwide
and within the Community." Brussels, Belgium: The European Commission, 1992.
Myers, N., ed. "Tropical Forests and Climate." Dordrecht, Netherlands: Kluwer Academic Publishers,
1992.
-. "Environment and Development: The Question of Linkages." BioScience, 43 (5) (1993), 302-309.
-. "Questions of Mass Extinction." Biodiversityand Conservation, 2 (1993), 2-17.
"Biodiversity and the Precautionary Principle." Ambio, 22 (2-3) (1993), 74-79.
- . "Tropical Forests: The Main Deforestation Fronts." Environmental Conservation, 20 (1) (1993),
9-16.
-. "Population, Environment and Development." Environmental Conservation, 20 (3) (1993), 1-12.
- . "Environmental Refugees: How Many Ahead?" BioScience,43 (11) (1993), 752-761.
-. "Sharing the Earth with Whales." In The Last Extinction.Ed. L. Kaufman and K. Mallory. 179-194.
Cambridge,Massachusetts: MIT Press, 1993.
- . "Globale Umwelt Kooperation." In Jahrbuch Okologie.Ed. G. Altner, B. Mettler-Meibom, U.E.
Simonis and E.U. von Weizsacker. 186-193. Munchen, Germany: Verlag CH Beck, 1993.
Myers, N., P.R. Ehrlich and A.H. Ehrlich. "The Human Population Problem: As Explosive as Ever?"In Survivingwith the Biosphere. Ed. N. Polunin and J.H. Burnett. 270-281. Edinburgh: Edinburgh
Univ. Press, 1994.
Myers, N. "Sub-Saharan Africa and Carrying Capacity." Environmental Awareness, 16 (1994),
125-135.
- . "Protected Areas-Protected from a Greater What?" Biodiversity and Conservation, 3 (1994),
411-418.
- . "We Do Not Want To Become Extinct: The Question of Human Survival." In Biodiversity andLandscapes, A Paradox of Humanity. Ed. K.C. Kim and R.D. Weaver. 133-150. N.Y.: Cambridge
Univ. Press, 1994.
- . "Global Biodiversity II: Losses." In Principles of Conservation Biology. Ed. G.K. Meffe and C.R.

285

Carroll. 110-140. Sunderland, Massachusetts: Sinauer, 1994.
- . "Population Growth as a Factor Leading to Conflict over Land and Other Natural Resources." In
Environmentand Population Change. Ed. B. Zaba. 101-114. London: Ordina Editions, 1994.
- . "Global Population and Emergent Pressures." In Population and Global Security. Ed. N. Polunin
and M. Nazim. 17-48. Geneva, Switzerland: The Foundation for Environmental Conservation,
1994.
- . "Tropical Deforestation: Rates and Patterns." In The Causes of Tropical Deforestation. Ed. K.
Brown and D.W. Pearce. 27-40. London: Univ. College London Press, 1994.
- . "Population Summit: Guest Editorial." Environmental Conservation, 20 (1994), 291-292.
- . "Population and the Environment: The Vital Linkages." In Population, Environment andDevelopment.55-63. N.Y.: United Nations, 1994.
- . "Future Operational Monitoring of Tropical Forests: An Alert Strategy." ISPRA Joint ResearchCentre. Varese, Italy: Commission of the European Community, 1994.
- . "The World's Forests: Need for a Policy Appraisal." Science, 268 (1995), 823-824.
- . "Environmental Unknowns." Science, 269 (1995), 358-360.
- . "Tropical Deforestation: Population, Poverty and Biodiversity." In The Ecology and Economics ofBiodiversity Decline, The Forces Driving Global Change. Ed. T. Swanson. 111-122. U.K.:
Cambridge Univ. Press, 1995.
- . "Population and Biodiversity." Ambio, 24 (1) (1995), 56-57.
"Biodiversity." Environmental Awareness, 18 (1995), 51-60.
- . "Economics of the Environment: A Seismic Shift in Thinking." Ecological Economics, 15 (2)(1995), 125-128.
- . "Global Population Growth as a Source of Conflict." Center for International Studies, Pittsburgh,
Pennsylvania: Univ. of Pittsburgh, 1995.
Myers, N. and J. Kent. "EnvironmentalExodus: An Emergent Crisis in the Global Arena." Washington,
D.C.: The Climate Institute, 1995.
Myers, N. "The Rich Diversity of Biodiversity Issues." In BiodiversityII: Understanding and Protecting
Our Natural Resources. Ed. M.L. Reaka-Kudla, D.W. Wilson and E.O. Wilson. 125-138.
Washington, D.C.: National Academy Press, 1996.
- . "Extinctionand Biodiversity."In The Physical Geography of Africa. Ed. W.M. Adams, A.S. Goudie
and A. Orme. 356-366. Oxford: Oxford Univ. Press, 1996.
- . "Environmental Services of Biodiversity." Proc. of U.S.National Academy of Sciences, 93 (1996),
2764-2769.
- . "The Biodiversity Crisis and the Future of Evolution." The Environmentalist, 16 (1996), 37-47.
- . "Global Population Growth." In Global Security Beyond 2000. Ed. W. Burros. 25-26. Center forWest European Studies. Pittsburgh, Pennsylvania: Univ. of Pittsburgh, 1996.
Myers, N., ed. "Biodiversity: Environmental Discontinuities and Ecological Synergisms." Biodiversity
and Conservation (Specialissue on Discontinuities and Synergisms), 5 (1996), 1025-1034.
- . "The World's Forests: Problemsand Potentials." Environmental Conservation, 23 (1996), 156-168.
- . "Development, Environment and Health: What Else We Should Know." Environment andDevelopmentEconomics, 2 (1) (1997), 367-371.
- . "Biodiversity' s Genetic Library." In Nature's Services: Societal Dependence on Natural
Ecosystems.Ed. G.C. Daily. 255-273. Washington, D.C.: Island Press, 1997.
- . "The World's Forests and Their Ecosystem Services." In Nature's Services: Societal Dependence
on Natural Ecosystems.Ed. G.C. Daily. 215-235. Washington, D.C.: Island Press, 1997.
- . "Consumption: Challenge to Sustainable Development." Science, 276 (1997), 53-57.
- . "Consumption in Relation to Population, Environment and Development." The Environmentalist,
17 (1997), 33-44.
- . "Marine Fisheries: Two Macro-Constraints." Environment and Development Economics, 2 (1)286(1997), 88-93.
- . "Mass Extinction and Evolution." Science, 278 (1997), 597-598.
- . "Environmental Refugees." Population and Environment, 18 (5) (1997), 509-524.
- . "Perverse Subsidies: Their Nature and Extent." Chicago, Illinois: Research Report for the
MacArthur Foundation, 1997.
- . "Our Forestry Prospect: The Past Recycled or a Surprise-Rich Future?" The Environmentalist, 17(1997), 233-247.
- . "Global Biodiversity II: Losses and Threats." In Principles of Conservation Biology. Ed. G.K.
Meffe and C.R. Carroll. 123-158. Sunderland, Massachusetts: Sinauer, 1997.
- . "The Population/Environment Predicament: Even More Urgent than Supposed." Politics and theLife Sciences, 16 (2) (1997), 211-213.
- . "The Biodiversity Challenge." In The Human Impact Reader. Ed. A. Goudie. 432-446. Oxford:
BlacYwellAcademic Publishers, 1997.
- . "Global Survival: A Convergence of Faith and . Science?" In Ethics and Values-A Global
Perspective. Ed. I. Serageldin and J. Martin-Brown. 22-25. Washington, D.C.: World Bank, 1997
- . "Emergent Issues of Environmental Economics: What We Should be Analysing Closely But
Haven't Thought Enough About." Intl. J. Social Economics, 25 (6/8) (1998), 1271-1278.
- . "Global Population and Emergent Pressures." In Environmental Challenges II: Population and
Global Security.Revised and updated edition. Ed. N. Polunin. 17-46. Cambridge,U.K.: Cambridge
Univ. Press, 1998.
- . "Global Conservation Priorities and Future Investment Policies." In Conservation in a Changing
World: Integrating Processes into Priorities for Action. Ed. G.M. Mace, A. Balmford and J.R.
Ginsberg. 273-285. Cambridge, U.K.: Cambridge Univ. Press, 1998.
-. "Disappearing Species: Problems and Opportunities." In Proc. of the Royal Institution of GreatBritain, 69 (1998), 169-194. Oxford: Oxford Univ. Press.
- . "An Age of Environmental Opportunity." In Revelation and the Environment.Ed. S. Hobson and J.
Lubchenco.AD 95-1995.58-61. London: World Scientific Publishers, 1998.
Myers, N. and J. Kent. "Perverse Subsidies: Tax $s Undercutting Our Economies and Environments
Alike."Winnipeg, Canada: InternationalInstitutefor SustainableDevelopment, 1998. (Italiantranslation, Rome: Edizione Ambiente.)
Myers, N., R.A. Mittermeier, et al. "Biodiversity Hotspots: A Focused, Species-Based Approach toConservationPriorities." Conservation Biology, 12 (3) (1998), 516-520.
Myers, N. "Lifting the Veil on Perverse Subsidies."Nature, 392 (1998), 327-328.
- . "Natural Resources Conservation and Enhancement: Components of Ecotechnology." In
Ecotechnology and Shaping the Future. Ed. M.S. Swaminathan. 21-24. Chennai, India: Madras
Editorial Services, 1998.
- . "Population: Some Overlooked Issues." The Environmentalist, 18 (1998), 135-138.
- . "What's This Biodiversity and What's It Done for Us Today?" In Scientists on Biodiversity.Ed. L.
Kobner, J.E.S. Sokolow, F.T. Grifo and S. Simpson. 5-8. N.Y.: American Museum of Natural
History, 1998.
- . "The Next Green Revolution: Its Environmental Underpinnings." Current Science, 76 (4) (1999),507-513.
- . "Saving Biodiversity and Saving the Biosphere." In The Living Planet in Crisis. Ed. J. Cracraft andF. Grifo. 237-254. N.Y.: Columbia Univ. Press, 1999.
- . "Population, Gender, Environment and Food Security." In Malthus and Mendel: Population,
Science and Sustainable Food Security. Ed. M.S. Swarninathan. 69-74. Chennai, India: Madras
Editorial Services, 1999.
- . "Esodo Ambientale: Popoli in Fuga da Terre Difficili." Milan, Italy: Edizioni Ambiente, 1999.
- . "Population Dynamics and Food Security." In Food Security: New Solutionsfor the 21st Century.

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Ed. A.E. el Oebeid, S.R. Johnson, H.H. Jensen and L.C. Smith. 176-208. Ames, Iowa: Iowa State
Univ. Press, 1999.
— . "Environmental Scientists:Advocates as Well?" Environmental Conservation, 26 (1999), 163-165.
Myers, N., R.A. Mittermeier, P.R. Gil and C.G. Mittermeier. "Hotspots: Earth's Biologically Richestand Most Endangered Terrestrial Ecoregions." Monterrey, Mexico: CEMEX, Conservation
International and Agrupacion Sierre Madre, 1999. Outside Mexico, Chicago, Illinois: Univ. of
Chicago Press.
Myers, N. "Perverse Subsidies." President's Lecture to the Royal Society of Arts, London. RSAJ., 3-4(1999), 85-91.
Myers, N. and J. Kent. "Food and Hunger in Sub-Saharan Africa." Washington, D.C.: Report to theWinslow Foundation, 2000.
Myers, N., R.A. Mittermeier, C.G. Mittermeier, G.A.B. da Fonseca and J. Kent. "Biodiversity forConservation Priorities." Nature, 403 (2000), 853-858.
Myers, N. "Sustainable Consumption." Editorial in Science, 287 (2000), 2419.
— . "The Meaning of Biodiversity Loss." In Nature and Human Society: The Quest for a Sustainable
World. Ed. P.H. Raven. 63-70. Washington, D.C.: National Academy Press, 2000.
— . "The New Millennium: An Ecology and an Economy of Hope." Current Science, 78 (2000),686-693.
— . "Sustainable Consumption: The Meta-Problem." In Towards Sustainable Consumption: A
European Perspective. Ed. R.B. Heap and J. Kent. 5-15. London: The Royal Society, 2000.
—. "Subsidies are "Perverse." World Water Watch, 1 (1) (2000), 42-43.
—. "The Management and Repercussions of Nuclear Power." Oxon., U.K: The Ditchley Foundation,
Enstone, 2000.
—. "The Century Ahead: Ever-Greater Problems or Ever-Wider Opportunities?" United Nations
Chronicle, 3 (2000), 8-11.
—. "What's This Biodiversity and What's It Done for Us Today?" In The Biodiversity Crisis: Losing
What Counts.Ed. M.J. Novacek. 22-62. N.Y.: The New Press, 2001.
Myers, N. and J. Kent. "Food and Hunger in Sub-SaharanAfrica." The Environmentalist, 21 (1) (2001),
41-69.
— . "Biodiversity and Water Subsidies." Zeist, Netherlands: WWF International, 2001.
Myers, N. "Hotspots." Encyclopedia of Biodiversity, Vol. 3,371-381. Washington, D.C.: Academic
Press, 2001.
Myers, N. and A. Knoll. "The Biotic Crisis and the Future of Evolution." Proc. of National Academy of
Sciences, USA,98 (10) (2001), 5389-5392.
Myers, N. and J. Kent. "New Consumers:The Influence of Affluence." Washington, D.C.: Report to theWinslow Foundation, 2001.
Myers, N. "The World's Forests." In A Survey of Sustainable Development: Social and Economic
Dimensions. Ed. J.M. Harris, T.A. Wise, K.P. Gallagher and N.R. Goodwin. Washington, D.C.:
Island Press, 2001.
—. "The Biodiversity Outlook: Endangered Species and Endangered Ideas." In Social Order andEndangered Species Preservation. Ed. J.F. Shogren and J. Tschirart. N.Y.: Cambridge Univ. Press,
2001. (In press)— . "Environmental Refugees." Encyclopedia of Global Environmental Change, Vol. 3. Chichester,
U.K.: John Wiley, 2001. (In press)— . "Environmental Refugees: Our Latest Understanding." Philosophical Transactions of the Royal
SocietyB., 2001. (In press)
Myers, N. and S.L. Pimm, et al. "Can We Defy Nature's End?" Science, 2001. (In press).
Myers, N. "Sustainable Development: Tackling Problems—Or Sources of Problems?" In Proc. of
UnitedNations Univ. Conference. Ed. J. von Ginkel. Sep. 3-4, Tokyo, Japan: 2001. (In press).

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—. "Mediterranean-Climate Regions: Glowing Hotspots of Diversity ." J. Mediterranean Ecology,
2002. (In press)"Biodiversity and Biodepletion: The Need for a Paradigm Shift." In Protecting the Protected:
Managing Biodiversity for Sustainability. Ed. S. Stoll and T. O'Riordan. Cambridge, U.K.:
Cambridge Univ. Press, 2002. (In press).
Also

more

than

150 book reviewsin journals such as Nature,

BioScience,

AmericanScientist

andQuarterly Review of Biology.

289