It's a great pleasure to be here today, and it's also been a wonderful
pleasure over the last couple of years to work with Bayley and Joanna
on this project. It was quite bizarre for me. I guess it was about
three years ago when the phone rang and this person said, "I've been
reading your book and I'd like to make a film of it." I'm like, what?
And, in fact, once I got to meet Bayley, it was wonderful. It's moved
away from being about this book I wrote. So what I thought I'd do
today is actually start off with a section that ended up in the book.
Those of you who managed to see the film, realize that it had this
wonderful section shot in Venezuela and part of that segment actually
came from life. It was a trip I made to the grand savanna in Venezuela,
this wonderful area, that I wanted to visit, in part because I'd been
working in the Serengeti, a place which everybody sees as this fantastic
ecosystem-a pretty traditional ecosystem, because all the predators
are vertebrates, a comparatively minor group of species, eating other
vertebrates. The wonderful thing about the grand savanna in Venezuela
is that all the predators in that system, instead of being vertebrates,
are actually plants. So it's the complete opposite of the Serengeti.
Everywhere you wander around, you're treading on this carpet of predators.
So it's a wonderfully strange biological experience.
We also went there because I had had hopes that it would present a
wonderful opportunity to cross the grand savanna and then look out
across at the Amazon forest. I guess nearly everybody who went to
the tropics as an evolutionary biologist or as a behavioral biologist
in the '70s and the '60s went through this same road-to-Damascus process.
When you got there to study biology, you realized most of the things
you'd gone to study were disappearing. I very vividly remember waking
up—here's a beautiful little church on the edge of the grand
savanna which we'd got to in the middle of the night. We set up our
tents and woke up expecting to look across at unbroken Amazon forest.
But when you looked across it, it was beginning to disappear. It was
just little. There were big patches of it in the distance, but you
could see these little patches of agriculture, the fires where people
were burning. So we walked down there the next morning with Marguerita,
my post-doc, the person who you saw in the film yesterday, and visited
several of these people who were clearing land to grow manioc and
pineapples just to make their livelihood - a very sobering experience,
and one that's constantly repeated by anybody who goes to the tropics.
It becomes a theme of the movie that we can look at biodiversity.
It's still out there, providing these huge services. It's beyond our
scientific understanding as it stands at present, in part because
we wasted our scientific understanding on lots of things that were
problems that we could have solved later. But also just the sheer
scale of its destruction is so huge that we need to work more on it.
Whenever you work in the tropics, you constantly get the feeling that
it's just disappearing. This slide shows, probably one of the first
biological research stations set up in Trinidad by the grandfather
of 20th-century biological exploration in the tropics, William Beebee.
He set up the station up toward the end of his life, having worked
in Venezuela, the Galapagos, all over the world. You could go and
work there, as I did after visiting Venezuela. The characteristic
memory I have—this is the view out of my bedroom window there—is
that every morning I'd wake up to the sound of chain saws. People
just cutting the forest down and the forest disappearing. A very sobering
experience.
Finally, I worked in Madagascar for a short period. Each morning when
we went out to go wash in the street, the first people we'd meet were
these really wonderful people who came into the forest each day just
to cut out one particular variety of plant and turn it into plant
pot holders, which they'd sell for about five or 10 cents to people
visiting Madagascar to take back and put their plants in. Each day
they'd have to go further and further into the forest to collect these
plants. The species was just being removed from the forest one plant
at a time and turned into plant pot holders for people to put comparatively
common plants into. Very strange.
So what sort of message would we want to get across to our children?
(This is one of my children - you can tell various things are inheritable
in life.) If we want to educate people, and particularly children
- it's too late to educate many other people, but if we can educate
children, there's a hope that they can educate their parents - what
sort of message do we want to get across to them about biodiversity?
What sort of message would we want to put into a film about it? And
what sort of message would we want to put into museum exhibits, books
for children, etc.?
The rest of the talk deals with the current problems about biodiversity.
They tell us a lot about ourselves. We're a stupid species. We are,
in many ways, arrogantly stupid. But how can we possibly change that?
Could children get the message across to their parents that many of
the things we see, that we're doing, are really pretty stupid things?
Can we get parents to change their habits through their children?
And create, in the time that remains, a cohort of people who fully
realize the magnitude of the problem while there's just enough time
to do something about it?
In particular, it's important for people to realize that it's not
just a problem of the tropics. Actually, it's very much a problem
of the developed world. While those people cutting little patches
of manioc are making a small and apparently visible impact if you
go there, what's more insidious and has a larger impact is the huge
amounts of consumption on the part of people in the developed part
of the world. Every person in the United States has a bigger impact
on the environment than those people in Venezuela or Madagascar by
a factor of about 500. So we're much more to blame individually than
people in the developing world.
[problem with slide projector] The moment you blame the U.S., all
the technology breaks down. We are not paranoid.
Eleanor: You should mention that the plant in Madagascar is
usually 50 to 100 years old.
Andy: That's right. The plants that they're using in Madagascar,
that they cut down three or four of a day, those plants are usually
50 to 100 years old. They're not going to come back next year.
I guess what's happened is the bulb has blown - again emphasizing
our reliance on technology. Steve Schneider, whom I've worked with
on a couple of things, has a wonderful line that he uses on such occasions.
He says, "It's amazing what we spend our money on." He adds, "There
are people out there who believe that we can put a system up in the
air to stop incoming missiles and that we'll be safe while dependent
on that technology. Yet you try to give a talk and of course this
light blows, and you realize just how worrying it is to be dependent
on that technology."
I'm going to talk about the different things that are causing biodiversity
to disappear. We can divide those up into four or five categories,
some of which Joel and Eleanor have already mentioned and that I know
Ross will talk about as well. If we look back historically, we can
see that the things that have caused quite a lot of extinctions over
the past four or five hundred years have to do with human over-exploitation
of species and loss of habitat. If we continue to look at what's causing
threats to species, if we were to do a survey of endangered species
in the United States today, we'd find that the major reason why species
are threatened or endangered is loss of habitat, which is the major
threat to all the species in the United States currently listed as
threatened or endangered. For 80% of those species, that threat is
due to loss of their habitat, mainly due to conversion to agriculture,
but also conversion into shopping malls, etc.
The next major threat is one that affects about 50% of endangered
and threatened species in the United States, and that seems to affect
similar numbers of species across the world, and that's the introduction
of alien species from elsewhere. This is not only worrying because
it's affecting about half our nation's species, but also because it's
the fastest growing class of threat. And those alien species aren't
little green men from outer space. There probably aren't any little
green men from outer space. They're things like plants that have been
moved between different parts of the world.
Another major threat continues to be human over-exploitation. If we
look at all the world's fisheries, they're in a really pathetic state.
Although you'd think we'd be able to manage something that both creates
jobs and creates food - most of the world's protein comes from fish—our
inability to manage fisheries effectively, mainly driven by greed,
has led to their over-exploitation.
[back to slides] So I was going to say, what could we give as examples?
First of all, let's look at fish. This is a fish species you'll probably
never see sitting on your plate of sushi. You won't even see it out
in the wild. This is the Rio Grande bloodnose shiner. It's gone extinct.
If you look at the number of extinctions of species of fish in each
decade, you'll notice two patterns. One, initially, here in the United
States we lose two or three species of native fish each decade to
extinction. Second, the rate at which the U.S. has been losing fish
species has been increasing. So the extinction rate's increasing and
these are fish that are irreplaceable. We haven't yet got all the
data for the '80s or the '90s because looking for something as it
gets rarer and rarer is a hard thing to do.
It seems thast cross-breeding with introduced species accounts for
about 30% of the disappearance of native species, and over-exploitation
accounts for about 15%. These seem to be the evil quartet of reasons
why most biodiversity is threatened. We look at fish. Fish and chips
in England has been completely replaced by Indian food as the traditional
food, in part because there are just no fish left. It's too expensive
to go out and have fish and chips anymore. It's not the cheap source
of food it used to be. The world's fisheries have been massively over-exploited.
A wonderful example of that comes from a fishery in Pavlof Bay, Alaska.
These are three pictures taken on roughly the same fishing boat at
10-year time intervals. The bottom one is from when the fishery opened
in the 1960s or early 1970s. We then go into the 1980s. Notice there
are very few large fish by then. By the time we come into the 1990s,
it's all tiny little fish. You may be able to chop it up and make
it into some elegant little piece of sushi, but that fish is going
to be eaten before it's ever had a chance to reproduce. So as long-term,
stable management of the fishery, it's a completely useless way to
do it. Yet the demands to keep the fishery open to maintain people's
jobs mean that it will continue to be over-exploited. If you look
at all of the world's fisheries, there are now no examples of a sustainably
managed fishery.
The same thing applies to other species we might exploit. This is
a species you have effectively no chance of seeing in the wild. This
is a snow leopard. You've got a good chance of seeing it in two places
in New York. You can go up to the Bronx Zoo and see a snow leopard,
but you're more likely to see it in another form: it's been caught
by the wildlife trade and converted into a coat for some bimbo to
wear walking down Fifth Avenue. But it takes about six to 10 of those
snow leopards to make one coat. For other small cats, it takes up
to 30 or 40. Which is the better use of it as a biological resource?
To have it out there as something that nobody sees, but you know it's
out there, or to glorify somebody?
Pollution and pesticides are also a major and increasing threat. We
know this from studies of birds of prey, from eggshell collections
in museums, some of which were put together by Ian Newton who looked
at thickness indices for eggshells of birds of prey from the end of
the 18th century into the 19th century. DDT started being used in
Britain in the 1940s. The eggshells get thinner. The birds of prey
more or less disappeared. All the tasks they were doing in the countryside,
weren't taken up by somebody else. They just disappeared. Eventually,
the use of DDT was banned, and the shells began to thicken. First,
all the birds of prey disappeared, and then once we get to the 1980s,
they begin to come back. The museum collections allowed us to look
back historically and see what happened there.
We have a wonderful false sense of confidence that we've cured the
problem. If you actually look at the rate at which we're putting new
chemical substances out into the environment, it's now higher by a
factor of five than it was in the 1960s, when we started to think
about banning DDT. We naïvely believe none of these chemicals
will have any environmental downside. Pretty naïve.
Chemicals are not the only things we throw out into the environment.
We tend to throw lots of our garbage out there. But we also throw
things out that we think are doing some good, such as nitrogen and
phosphorous. Although the bicycle is fairly disfiguring, the old motor
bike is fairly disfiguring, all this additional green algae is probably
having a much more detrimental effect. That's a consequence of us
applying nitrogen and phosphorous to agriculture to increase its productivity.
Because of the amounts we apply, about 80% of it runs off and goes
into river systems and eventually into the sea, where it causes a
few very competitive species to out-compete everybody else. It causes
algal blooms. If you go down to the Gulf of Mexico, there will be
an algal bloom there annually that's now bigger than New Jersey. It
creates a dead zone under which nothing grows. The single species
of algae forming the mat of algae blocks the light for everything
else. Those dead zones are now appearing throughout the world's oceans
wherever we get significant amounts of runoff of nitrogen and phosphorous.
They completely disrupt many in-shore systems.
The fourth thing I wanted to talk about was invasive species. We all
know stories of things like the starlings introduced by some nutter
into Central Park because he thought that every bird mentioned in
Shakespeare should be present in Central Park. Starlings and house
sparrows introduced in the early part of last century rapidly spread
and colonized. They have displaced some native species, but they're
not the most worrying sort of alien species. It's usually invasive
plants that are the problem.
This is what California should look like. The state's native plant—the
California poppy—usually looks like this. But there are no native
plant species in this photograph which was taken at Point Lobos. Closer
to the shore, there are almost no native plant species present. It's
all invasive species, in this case from South Africa. This is in a
nature reserve, with invasive plants just completely taking over the
natural habitat. If you look at a map of California, the proportion
of plant species in each county in California that are not native
species is as high as 20% in those bright-red counties. It's only
in the high-mountain counties that there are no alien plant species,
or their presence is less than 5%. These alien plant species are taking
over much of the U.S. We have this impression from Hollywood that
we should worry about aliens from outer space. That's a pathetically
naïve worry. We should be much more worried about alien species
that just come in from other continents. They're arriving at a very
rapid rate, and they're doing much more damage. If you go to Oregon,
again, it's impossible to see, other than a few dotted trees, a native
plant in this entire picture. It has all been taken over by introduced
grass species from Asia, which aren't very good grazing forage, and
which change the fire frequency in the ecosystem and completely transform
the whole landscape. So this gives you an indication of the rate at
which these plant species can spread: between 1900 and 1930, they
just spread out completely, removing grazing land from productivity.
I was going to wind up by talking about loss of habitat, which is
still the biggest problem. Habitat is converted - here going back
to Venezuela - to make small farms. In New Jersey, it's converted
to make shopping malls. In other parts of the world, it's converted
to make other types of agriculture land. It's the biggest threat to
biodiversity. It's quite easy to think that we could make some simple
cost-benefit analysis. How much benefit can we get from the increased
agricultural productivity compared to the loss of biodiversity? But
first, we have no real way yet of estimating the economic losses as
species go extinct, because we forget about the services they provide
- pollination, clean air, etc. Secondly, we always na•vely assume
that this land will last as agricultural space forever. That's very
naïve. Most of the land we're now currently converting for agriculture
will only last for two or three years because it's on degraded land.
One of the real ironies of the biodiversity crisis is that the lands
we're converting at the moment are relatively poor for agriculture
- they'll only last for short periods of time - but they're very rich
in biodiversity, because often slightly lower-quality soils support
high levels of biodiversity. In the past, we converted land that was
relatively rich in potential for agriculture and that supported relatively
lower levels of biodiversity. As we have more and more people to feed,
we convert more and more land, but that land lasts for shorter and
shorter periods of time, and that raises the demand to convert more
and more land. This means that the time scale on which we expect the
remaining biodiversity to last is going to be increasingly short.
So the time we have in which to do something about it is, realistically,
the lifespan of the children we're educating now. That's why meetings
like this are so important.
