Commemorative Lecture By Prof. Stuart L. Pimm for 2019 International Cosmos Prize
November 13, 2019; The University of Tokyo
I am greatly honored to have won this year’s the Internationaltion got that number from me and I want to talk about where that

Cosmos Prize. I am greatly honored to see so many students in thenumber comes from, how I got it, and what we can do about it.

audience. I love teaching. I am just very happy that you are here.

So, first, I want to talk about why we should care, why should be

The idea of the International Cosmos Prize is to seek the harmoni-concerned about the loss of biodiversity.

ous coexistence between nature and human kind. I think that is thegreatest challenge of our century, a century which young ladies andI think there are three broad explanations. One of them is an

gentlemen you are going to live through most of it. Some of you

ethical concern. That is what sort of a planet are we going to give

may live through all of it. Because if we do not ensure the harmoni-

to our children and our grandchildren. Are we going to give themous coexistence of nature and human kind we will leave to our chil-an inheritance that is rich in species such as tropical forests, suchdren and grandchildren a very damaged planet. I want to address a

as coral reefs and are we going to show them a place that is beauti-

part of that coexistence, the part of coexistence that deals with the

ful and wonderful. There is another aspect to the fact that we areloss of species, the loss of biological diversity. Because extinction isdestroying nature. When we hear about the loss of forests from say

permanent we cannot bring species back. So, what we drive species

the Amazon, we don’t always realize that people live there that theto extinction we are changing the planet forever.

Amazon is full of people, full of people some of whom don’t wear
any clothes. So, I have had to adjust my slide because of young

So, what do we know about the current extinction crisis?

people present. We have a responsibility to nature to indigenous

It’s already high — 1000 times higher than it should be

people and that I think is an ethical responsibility. The Catholic
Pope a couple of years ago came out with a very important document and then cyclical in which he said, we have no right, we haveno right to destroy the planet because of what that does to future
generations.
The second is, it’s a matter of esthetics, it’s a matter about culture, about heritage and just two examples. The last time I was inJapan was in January and when I came people asked me where I
wanted to go and I said, I wanted to go to Hokkaido in January.
They asked because January is famously cold and the answer was

Now, if we were to ask how fast species are going to extinct you

yes because I wanted to see these birds called the Japanese crane.

would hear from Al Gore in the movie Inconvenient Truth that

But there are parts of our heritage too. This is one of a famous set

they are going extinct a thousand times faster than they should beof wood cuts, the 36 views of Mount Fuji and I love the fact thatand I am very proud of the fact that this woman demonstrating inseveral people are trying to estimate the side of a tree by putting

England, held up a sign showing extinction rate up a thousand fold.

their arms around it and it’s too big. This tree is so large that you

My work has never been featured in the demonstration before andcan’t put several people’s arms around it. So, what are we doing to

I was very proud. The fact is that both Al Gore and this demonstra-

our forests? Have we destroyed our forests, are we keeping them as

International Cosmos Prize for 2019

part of our heritage.

talk about the extinction rate being a thousand times higher than it
should be. What’s wrong with simply talking about how many spe-

Economics is an important reason for serving biodiversity too.

cies are going extinct per day? Why can’t we say something simple

Many poor people around the world like these fishermen on thelike three species of extinction per day? Well, the problem is wecoast of Goa in India depend upon the diversity of the oceans for

don’t have a very good idea about how many species are on. And sotheir food. We depend upon a whole variety of different animals

I want to address four questions.

and plants for our survival. So, we destroy the oceans, if we destroy

1. How many species there are and how many we don’t know?

the land, we’re destroying something that is valuable to us. We also

2. How fast are those species going extinct?

value nature and we go and see it, we go and visit it. Tourism, eco-

3. What are we doing to protect them?

tourism is a very, very important industry. It’s worth 100s of billions

4. And how can we do better?

of dollars. And African countries get most of their money, some ofSpecies in the wild

them from tourists.
The species can be interesting and important in other ways too.
These are cone shells. Sometimes people pick up these beautiful
shells on the beach and stick them in their pockets. That can be avery dangerous thing to do because these cone shells surprisingly
feed on fish. I know what you are thinking. How can a snail thatmoves very slowly feed on the fish that swims very quickly? The
answer is the snail has a poison dart that if it shoots at the cone shelland then it reels the fish in… I think you will nightmares thinking
about that tonight. Why is that important? It’s important because

Species in museums known to science
Described first decade

Described second decade
Described third decade
Described fourth decade

A simple idea: more unknown species, the more described per decade

We can model this and predict how many species
remain to be described. It’s a great idea…
And it fails badlythat poison paralyses the fish. It dulls the nerves. And the poison
from cone shells are used as medicine for people who are termi-

Well, we have scientific names for about 2 million species. But

nally ill with cancer that cannot be helped by the normal kind of

the idea is that there are many, many more species for which we dopainkillers and that cone shell painkiller gives people a substantial

not have scientific names. And I want to suggest a way of estimat-amount of relief from pain. It’s an example of how we use biodiver-ing how many species there are. Supposing that there is a magicalsity in our medicines.

kingdom where there are many species of unicorns as yet unknown
to science and we enter this magical kingdom and we begin to

Finally, nature does a lot of things that we call ecosystem servic-

describe those species of unicorns by collecting them and putting

es. When we burn the Amazon, we put carbon dioxide into the at-them in a museum. So, in the first decade, we might describe quite

mosphere. We warm the atmosphere and we know that the tropicala lot of unicorns. In the second decade, we describe fewer because

storms, the typhoons, the hurricanes are becoming more powerful

there were fewer ones that we haven’t already described. I think you

and more damaging over time and that destroys people’s lives andget the idea. As time goes on there were fewer species that are un-their homes. Protecting nature is good economic sense.

known and so the rate of species description goes down. The more
we know the fewer that are unknown and the harder it is to findSo, with that I want to go back to why Al Gore and other people

new ones. It’s a great idea and it fails badly.

International Cosmos Prize for 2019

I have to say with great respect is his Imperial Majesty the Emperor
Gobiidae fish

Consider gobies.
These are the numbers of species
described every ten years
they are increasing, not decreasing

Emeritus who is one of the world’s leading experts on gobies andis responsible for describing many of them. He is a legend in mycommunity and not just because he is your Emperor Emeritus but
vis-à-vis contribution to taxonomy. So, when we wish the Emperor
Emeritus a very long life many of my colleagues do so hoping that
he would describe more new species of gobies. The fact is the number of goby species described is not going down. So, we have no
way of estimating when we are going to run out of new gobies. We
have no idea how many species of gobies there are.
We can do this kind of calculation for other species. We have apretty good idea of how many species of vertebrates there are, how

Gobiidae fish

But, there are now moretaxonomists describing them

many birds, how many mammals, how many amphibians. When
we do this for plants we think there is probably about 15% more
plant species out there than we know. But for many other species
for insects, for fungi, for many organisms, we simply don’t know
how many species there are. So, it doesn’t make any sense to say
we think three species are going extinct today when we really don’tknow whether there are 2 million species or 8 million species or 30
million species.

And there is an example of this. I want to show you why. This isa group of fish called gobies. They are group of marine fishes. And
if you look at the number of species of gobies that are describedevery year, the number of gobies is increasing not decreasing. We
seemed to have more and more kinds of gobies every year. From
one year to the next we know more and more not fewer and fewer
new ones. There seems to be an unlimited number of gobies out
there. Well, part of that is due to the fact that we have more people
describing gobies now. Taxonomists, people who do goby descrip-

Extinction is a death rate
for species, rather than individuals

tions. That number is going up, so more taxonomists, more gobies.
So, perhaps the number of species divided by the number of tax-

We can, however, calculate a death rate for species in much theonomists is going down. And the answer is it isn’t. And the culprit

same way that we can calculate the death rate for people. The typi-International Cosmos Prize for 2019

cal human death rate is about 8 people per 1000 per year. I want toassure you that nobody has ever died during one of my seminars.
I would be very concerned if I bored you young men and womenand you die during my seminar you may go to sleep but I promise
you won’t dies. On the other hand, there were clearly times in our
history when we have had wars and the death rates have been veryhigh. What’s happening in nature is we are declaring war on species. And extinction is a death rate but it’s for species rather than
individuals. I am not going to explain the slide in any great detail

Most protected areas are in “wild places”

but what it shows is that the death rates of species run at the rate of
between 50 and 500 extinctions per million species per year. Take amillion species, look at them for a year, you would expect between
50 and 500 dying. That’s what we are doing to nature and the question is how much higher is that than we would expect?
Well, one way to compare that is to look at the fossil record. It’s
actually quite hard to interpret the fossil record. So, what I want totalk about is how fast species are born, how fast are species createdduring the process of speciation, during the process of evolution?
And we can get that number by looking at molecular phylogenies.
You look at the DNA of species and you see how similar they are
and you can work out how quickly species are formed during evolution from this molecular phylogenetic tree. We know for example
that we human split from chimpanzees about 6 million years ago.
For this particular group of orchids, we have a very, very detailed
description of how fast these species are being formed. And thenumber that comes out of that in this particular case is 0.26 new
species per species per million species per year. That’s the birthrate.
The death rate you may recall was between 50 and 500. And it’sthat difference between how fast species are dying and how fast they
are born that leads to that conclusion that we are driving species toextinction a thousand times faster than they should go extinct. We
need to know that number because it’s a measure of what we are doing to the planet. We need to know that number so we can measure
whether we are reducing the species extinction rate.

In short, that’s the impact we are having on the planet, driving
species to extinction a thousand times faster than they are being
created. What are we going to do about it? What are we doing toprotect species? Well, the answer is that over the last 30 years or
so, we have – we the global community have protected a lot moreof the planet by creating national parks and other protected areas.
This map shows in green where the protected areas are and it showsin yellow where the wilderness is and by wilderness I mean places
where few people live, few people live in the boreal forests, few
people live in the Arctic, few people live in the Sahara. And as you
can see most of the green areas are in wilderness, most protectedareas are in the places where there were few people. One questionof course is should we protect more of them. This is a politically
relevant question. Next year in China the various nations of theworld will come together to talk about the future and biodiversity
at the convention on biological diversity. They meet regularly. Thisis the 15th meeting and they will plan an agenda for political action
for the next decade. Do we want to protect more of the wild places
or do we want something else?
The problem with many of the wild places is that they have very
few species in them. That photograph is of a huge national park. It’sa million square kilometers in the north of Greenland. I took that

International Cosmos Prize for 2019

photograph myself. I am very pleased with myself for doing that.

land, 13% is protected. What species occur in that 13%? Let’s take

When you fly from the United States to China, you go straight

this hypothetical insect, this bug. Supposing it has a large geograph-over the top. You go to north, right over the North Pole and comeical range what would we expected? By chance we would expect

down the other side. So, that was taken from an airplane. I have nothat 13% of its geographical range shown in that black outline theintention of going to Northern Greenland. It’s far too cold for me.

13% might be on the protected area and perhaps 50% of it could

It’s a big national park but it doesn’t do much for species. There

be in wilderness.

were not many things if any that live in such a remote place. So,
protecting more remote places is not going to enable us to protect
more biological diversity.

~13%

~50%
~13%

~50%

The null hypothesis: what fraction of species
ranges are in protected areas and wilderness?
The null hypothesis: what fraction of species
ranges are in protected areas and wilderness?

Now, let’s go back to my mythical kingdom of unicorns. I haveshown six species of unicorn. Perhaps one of those unicorns would
be in the protected area, two in wilderness, three in other places, but again on average 13% of the ranges of unicorns would beprotected, 50% would be in wilderness. That’s what we expect bychance, technically under what we call the null hypothesis.

~13%

~50%

The null hypothesis: what fraction of species
ranges are in protected areas and wilderness?

So, let’s look at how well protected areas are doing to preserve
species. Thirteen percent of the land, this is the ice-free part of theInternational Cosmos Prize for 2019

Range size in km2

Average percentage of range protectedwith small ranges.

~13%

~50%
~50% expected forprotected and wildareas

In short, we’ve done abetter job than many think!
~13% expected forprotected areas

This is about what we expect

Average percentage of range protected
Range size in km2

Let’s look at some examples. The animal at the top left is calleda Skywalker gibbon named after Luke Skywalker from Star Wars.
If you see in the latest episode of Star Wars, we have Luke with his~50% expected forprotected and wild
areas

hood up. So, this is named after him, the Luke Skywalker gibbon.
The bottom left is a very special humming bird. The frog at thebottom right is called a poison dart frog. Indigenous people takethe darts they are going to use to hunt and they rub them on the~13% expected forprotected areas

Surprisingly, for species withsmall ranges, this is very muchbetter than what we expect!

skin of the frog. The frog skin is poisonous, so when they have theirblow guns and shoot a dart at a bird it poisons the bird, it falls to
the ground and they get a meal. The fact is that all four of these
species have small geographical ranges but we have done a goodSo, let’s look at what we have achieved globally. For species with

job in protecting them. In short, we have done reasonably well. We

large geographical ranges more than the million square kilometersneed to do better but we are doing better than many people expect.

or more, we have actually protected species just as well as we would
expect. About 13% of these species are protected and close to half

The question is what should we do next, can we do better? Well,of their ranges are in wilderness. So, that’s good. That’s not better

we currently have internationally agreed targets that suggest we

than we expect. It’s about what we expect. The very surprising thingneed to protect 17%. But my good friend E. O. Wilson who is also

is what happens when we look at species with small geographicalthe International Cosmos Prize winner suggested that we want toranges. These are important because species with small geographicalprotect half of earth. What worries me about that is that if we ask

ranges are much more likely to be threatened with extinction thanthe politicians to protect half of earth they will give us more places

species with large geographical ranges. It’s easier for us to destroy

like Northern Greenland, the middle of the Gobi desert of China,

a species with a tiny range than to destroy a species with a large

the middle of the Arctic, places that will not protect a lot of biodi-

range. And we have done really rather well of protecting species

versity. When E. O. Wilson on the right and I on the left discuss

International Cosmos Prize for 2019these issues, we realize that we need to be careful for what we ask.

what we call strategic maps. They tell us where in the world we need

We need more protected areas but we need them to be in sensible

to act but they don’t tell us exactly how to act. For that we needplaces, places that will protect biodiversity not just remote places

tactical maps. This one and I will explain those on the project pages

that are politically convenient.

for each of the various places where Saving Nature works.

So, how can we do better? How can we maximize the efficiency

What I suggested here is that there are key areas around theof the protected areas that we have established? For that, I want

world where species are at considerable risk of extinction. It’s true

to introduce you to the work I do for a non profit organization I

for the oceans too. The areas south of Japan, Okinawa and further

direct called Saving Nature. We can map out the distribution ofsouth are a marine area that has high concentrations of species atmany species now in considerable detail. These are birds and theyrisk. In other words, we don’t have to save all of the planet to saveshow that the warm, wet tropics are where most of the species are;all the species but we do have to focus on efforts on critical places.

mammals show broadly similar pattern. These are places with the

And those places we can identify using the maps we showed you

greatest concentration of species and it’s likely to be true for most

but then we need to move to maps like this one which I will explain

species. Amphibians, for example, show a similar pattern while wein a moment which give us a tactical approach to deciding exactly

have less detailed data for plants it’s almost certainly true for them

what we need to do next.

too. But just looking at species it’s not sufficient. We need to dig
deeper.

If we look at Brazil and I am going to use Brazil as my example.
The species at risk in South America are concentrated in two areas

Let’s look again at the distribution of bird species. In the Ama-on the Northern Andes of Columbia and in the southeast of Brazil.

zon, there are the greatest numbers of species. But if we look at

Brazil has two rain forests; the well-known one of the Amazon andwhere species have smaller than the median range size, those dis-the much less well known one of the coastal forests. It’s where there

tributions are profoundly different. They concentrate in Central

are large numbers of threatened species both of birds, mammals

America and then the Northern Andes and in places like the coastal

and amphibians. We can see why when we look at satellite images.

forests of Brazil. That’s important because species with small ranges

That’s a series of satellite images that’s about 500 kilometers fromare much more vulnerable to extinction than species with large

east to west and you can see that lot of the forest has been cleared.

ranges. So, let’s take world tour where threatened species are. Our

There are not a lot of forests remaining. That big bluish area in thefirst office in Northern Andes and Saving Nature is involved in sev-

middle is a city of Rio de Janeiro.

eral projects in Columbia and Ecuador where the habitat destruction combined with the high numbers of small range species means

Let’s take a closer look. When you zoom in on that area, youthat there are a lot of species of list of extinction. Our second area

see that there is a forest but lot of that forest is in very small pieces,of concern is in Coastal Brazil. Again lots of habitat concentrationsin fragments. And taking those small fragments away you see thatof small range species means that there are worrying numbers of

there is a substantial amount of forests in small fragments. Now

threatened birds and mammals and amphibians and likely many

we know scientifically a lot about what happens to species in frag-other species in these forests. The final area where Saving Naturements.

works is in tropical Asia. We have three areas of interests, the Western Ghats of India, Assam up in the Northeast on the borders with
China, and Leuser Ecosystem of northern Sumatra. These maps are

International Cosmos Prize for 2019

The problem
with fragments

That’s what it looks like from a helicopter. When you look overWhen we go to this map, what we have done here is to create athis landscape, you see that there are some forests remaining but it’s

map of where the forest cover is. Everything that is covered is forest

mostly in small fragments.

but we have covered it by the number of threatened species that occur there. We call this a tactical map because it immediately shows
us two things that the greatest numbers of species of risk are in thisarea to the east near the União Biological Reserve and that that area
like much of the rest of area is in forest fragments.
There is a long-term study done by my colleague Tom Lovejoy
that looks at what happens to species in fragments. Using an areathat was going to be deforested, Professor Lovejoy set up a seriesof experimental forest fragments. One hectare, 10 hectares or 100
hectares and followed how long it look for the species to disappear

S.L. Pimm and C. N. Jenkins Scientific
American September 2005

from them. The simple conclusion from this is that small fragments
lose more species and they lose them more quickly that you need tocreate forest areas of at least 10,000 hectares to have a good chanceof keeping all of your species. That’s practically very useful information. It means that you need to reconnect fragments to create
an area of sufficient size if you are going to prevent species going
extinct.

International Cosmos Prize for 2019

We will identify the places where the greatest number of species is at risk of extinction and when we do that we often find they
are in very fragmented landscapes. They are not in large areas ofcontinuous forest like the Amazon but they are in the biodiversity
forest spots and those places have already lost a lot of their habitats.
A good example of this is in the forest to the east of the city of Riode Janeiro in coastal Brazil. This map shows the fragment and thenumber of threatened species that they contain. We have not justmerely destroyed so much of the world’s tropical forests what wehave left behind is in tatters, in fragments. And those fragments areoften too small for species to maintain viable populations. There arejust aren’t enough males to go around for the females and females to
go around for the males. And of all the places, of all the fragments
one that I thought was particularly tragic was the one immediately
behind me. This is the União Biological Reserve in coastal Brazil,
about 100 miles east of the city of Rio de Janeiro because in thisisolated patch of forests are a whole load of species on the brink ofextinction, the most charismatic of which is a beautiful little monkey called the golden lion tamarin. And the golden lion tamarinsin that fragment could not go forth and multiply into the forestover there because there was the cattle pasture behind me. When I
saw that cattle pasture for the first time about 8 years ago, a cattle
pasture just like the one I am standing in I thought it has to go. So,
we have made it go away.
This is a restored forest. They help raised money for my friends
at the Associação Mico-Leão-Dourado, the Golden Lion TamarinSo, this is what that area looked like 10 years ago that’s what it

Association. They have planted this forest and it now connects thatlooked like 4 years ago. When I visited this spot this year, I couldn’t

once isolated fragment to forest in the União Biological Reserve totake that photograph because the area is now completely forested.

a much larger area of forest over in this direction. It’s what we call

We used children to plant the trees. Great thing about children isa biological corridor and it means that the golden lion tamarins

they are closer to the ground and they work for free. The importantthat were once imprisoned in this forest island, this forest fragment

thing is that we use local people because it’s their decision. We can’tbehind me can now cross through these small but growing trees andcome in and tell them what to do. What we can do is work withgo and find new habitats, new homes, new places for their tamarin

our local partners to find solutions that work for them. The trees

families.

are grown by women in the local community who collect the seeds
and they will the plants. They are planted by the local community
and we have created jobs to the local community, a pride in the fact

International Cosmos Prize for 2019that they have this very interesting species which is beginning to
attract tourists.

“The Harmonious
Coexistence between
Nature and Mankind”
requires we reduce thecurrent extinction rate.

Good science and commitment to local
communities shows we can achieve that.

The story that I have told you ends with planting a tree. It began
by looking at a global phenomenon. I hope I made the connection.
We are driving species to extinction a thousand times faster thanwe should. We don’t even have the names of most species but weare losing something that is of extraordinary value to us. To ensure
the harmonious connection of nature and human kind, we need toslow that extinction rate down. We know that there were criticalplaces in the Americas, in Africa, and Asia were species extinctions
are concentrated. We need to protect more of the planet and weneed to do that in a smart way to protect the places of matter and
we need to reconnect nature. We need to heal nature. With goodscience and commitment to local communities, we can do this. We
can ensure a harmonious connection between nature and humankind. Thank you so much for the honor of inviting me here today.
Thank you.

International Cosmos Prize for 2019