BBC State of the Planet – Is there a crisis

We live in extraordinary times, we’re surrounded by more species of animals and plants

than have probably existed at any one time in the history of the earth. For nearly 50 years

I’ve been lucky enough to spend my time travelling around the earth documenting those

animals and plants but it is now increasingly apparent that one species, our own, has

developed a unique ability of so altering its surroundings that it can destroy whole species

indeed whole environments.

How great is the damage we are actually doing to the world? Why is it that what we do

has such a destructive effect and how can we change what we do in order to ensure that

our children and grandchildren inherit as wonderful and as varied a world as we were

lucky enough to do. I'll be putting those questions to some of the worlds leading scientists

in order to discover the very important answers. I will be looking for clues all over the

world, some can be found on the savannahs of Africa others are to be sought under the

sea, we will visit our own past and consider our future and scientists will talk about their

own most recent research in order for us to understand the truth about the current state of

our planet. First we have to establish the facts about the scale of the damage we have

done to the earth so far.

40 years ago our curiosity about the worlds beyond our planet lead to one of the most

stupendous achievements in human history “we have ignition, sequence time, 5, 4, 3, 2, 1

we have lift off.” Paradoxically sending a rocket towards the moon made us aware in a

radical way of the true nature of the world it left behind. For most of human history our

world had seemed vast and its resources infinite but those men in space saw something

different “that is the most beautiful sight, what a view, its absolutely unreal, I have never

seen… all I can say is its spectacular”

The astronauts view made us realize more vividly that ever before that the earth is limited

in both its space and its resources. From that it follows that there will also be a limit on

the amount of life our planet can hold. Living creatures on this planet have always had to

endure natural catastrophe and change yet now there is a greater variety of life on earth

that there has ever been so change and damage are not necessarily destructive to life as a

whole and the view from space showed us why. Its because such damage even on a scale

that seems disastrous for those of us in the midst of it is usually local in extent. Indeed,

we now realize that such change is the spur that has created life’s richness by presenting

new opportunities and challenges to which animals and plants have responded. Life in

fact can recover from or adapt to even very great damage but today the damage inflicted

by humanity is global and it is taking place at a speed that is without precedent in the

whole three and a half billion years of the earth history.

To understand the scale of our impact on the rest of life we have to discover just how

great the diversity of life really is. For the past 500 years scientists and explorers have

travelled the world cataloguing its natural wonders. We can still see the biggest creature

that has ever lived, the blue whale, and the simplest, microscopic bacteria. On land, in the

air and under the sea we have discovered an astonishing variety of life forms. That work

is still going on giving us a better understanding of this astonishing variety of life, this

biodiversity. So how many different kinds of living things are there? Biologist, Sir Robert

May has made a special study of this question. Amazingly we don’t even know how

many distinct species have been named and recorded, for the major groups like the birds

and mammals, the furies and the featheries, we really do know but for most groups they

are on scattered records in different museums not yet co-ordinated into one computer

base. Best guess would be about one and a half million different plants, animals, fungi,

algae. This listing and cataloguing of the natural world has occupied the lives of many

experts and still does. A total of one and a half million species might seem to suggest that

we have discovered the majority of life forms on the planet, but that is not so, again and

again new discoveries make us aware of just how limited our knowledge really is. No

where demonstrates this better than the Savannah grasslands of east Africa. In this

environment as in many others it is the big mammals that have captured out attention.

They have become so famous owing to books television programs and safari holidays

that you might well think that they represent the majority of the animals here. The scale

of biodiversity on the African grasslands is a bit deceptive if you go out during the day

you are probably looking for spectacular animals like these elephants. You will also see a

few smaller things like butterflies and beetles and bugs but the overwhelming impression

you have of sheer mass of life is of herds of just a few kinds of big animals. The truth as

research has recently shown is quite different. For evidence of that just look in the grass.

This is a column of driver ants there ferocity so great and their appetite so huge that they

have given rise to all kinds of legends, stories about human beings and horses stumbling

into their paths and being striped to skeletons within minutes. These are perhaps a little

exaggerated but non the less the appetite of these ants is so huge that they will attack

anything that cant get out of their way. They prey mainly on other small animals and

move across the grasslands in columns that may contain 20 million individuals. So many

ants need vast quantities of prey, so their abundance is living proof that the savannas

team with smaller life. When scientists recently began to study these smaller creatures.

They found that 50% of the insects they were seeing were new to science. Simple

calculations suggest that driver ants alone consume more animal matter per year on the

grasslands than all the famous big predators put together. The reason why it is difficult to

appreciate the scale of biodiversity on the savannahs is that many of the creatures that

live here are both nocturnal and very very small. You get some impression of what they

are if you come out at night with a lamp like this. But to get an idea of the full range of

those creatures you have to use a light of a very special kind like this one. The bulb that is

illuminating this sheet produces a high proportion of ultra violet light and many night

flying insets find that absolutely irresistible. There are moths, small ones, big ones, here’s

a kind of silk moth, beetles, more moths a mantis, a great fat sausage fly, an ant lion lots

of tiny little insects I can hardly see what they are oh and mosquitoes. Recent work has

shown that there is a far greater variety of insect life on the savannahs than was

previously thought. There may not be as many species as are found in a tropical rainforest

but in terms of sheer quantity the savannahs are their equal.

It is in the famously rich rainforests of South America that research first revealed the

scale of our ignorance. If you walk slowly and look carefully in a rainforest like this one

in Ecuador you can find all kinds of small interesting creatures and that is how the first

explorers and naturalists worked and it is still possible to find new species that way. I

picked up this little stick insect from over there and in order to discover whether it is a

new species or not I will have to show it to an expert in stick insects and if he could not

match it exactly then he would describe it, give it a new name and I would have

discovered a new species. However, I can only search an area from the ground to a

couple of feet above my head but the trees here grow to over 100 feet tall. What might be

up there? Well birds and monkeys because I can see them from down here but what else

might there be? Until very recently that was a matter of pure speculation but then

Professor Terry Erwin invented a way of finding out. He decided that in order to discover

what actually lived in a canopy of a single tree or even a single branch he had to use a

machine known as an insecticide fogger. This was originally designed for mosquito

control but it can be used to sample other insect equally well. When we first started

fogging in Peru the results were just absolutely fantastic, we just never imagined we were

going to get so much. The fog, harmless to anything but insects drifts up into the canopy

and the insects drop down. The results of Terry Erwin’s early work dramatically altered

our estimates of how many animals there might be on this planet. This might seem a quite

drastic way of discovering what lives in the trees, however as well as providing

information that is important for conservation this work has also shown that insects

reproduce so fast here that within four months of a tree being fogged insects living in it

had returned to their previous numbers. From all of the studies I have made over the past

25 years and the little bit that we have been able to analyze in the laboratory it seems that

at least 80% of the species that we are getting out of the canopy are new species, new to

science and the reason that’s true is because the average size of a beetle is only 3 mm

long and so the small stuff hasn’t been studied. And its not just small things in rainforests

that are still being discovered. We are still finding things even among the primates,

among the mammals, our closest relatives. There are about half a dozen new species of

primate that have turned up this decade, small marmoset things. It really underlines what

we don’t know. Most of those small primates were found in the Amazon rainforest. Until

very recently European explorers could only penetrate any distance into these vast forests

by travelling up the rivers. Now however, using powerful machinery roads have been cut

though the forests that enable scientists to reach even the least known areas in their

search for biological gold, new species. And it is here that they discovered new

Marmosets. One way of enticing a primate to show itself is to play back the calls of a

closely related species. This can trick it in to thinking that its territory has been invaded

by rivals so it may emerge from the forest to investigate. In 1992 this technique revealed

a new species of marmoset in this area of Southern Brazil. Since that discovery no one

has been back again to look for it and until now it has never been filmed. This kind of

waiting game can go on for weeks or months usually without success. But there it is, the

call of a new species. This is the black faced marmoset. We have no idea how this animal

lives or what kind of social interactions take place in its groups. It has yet to be studied.

And as quickly as they appeared the black faced marmosets melt back again into the

forest. It is not just on land that the scale of recent discoveries have amazed scientist, the

oceans too have been found to contain a far greater diversity of life than was previously

thought. The sea covers two thirds of the planet. In some parts it is filled with a huge

range of species. The famous coral reefs which occupy a tiny fraction of the oceans are

probably its best known most closely studied habitat. Would it be fair to suggest that here

at least we have discover most of its inhabitants? Silvia Earle is an expert in marine

biology. Just as with what we have begun to understand about rainforests that there are

thousands perhaps millions of species that have yet to be discovered, described or even

named, so it is with coral reef systems that are enormously complex and diverse but

diverse on a scale that exceeds rainforest. If so much remains to be discovered even about

coral reefs which occupy the most shallow and accessible parts of the sea what about the

rest of it. The average depth is two and a half miles. The depth where the titanic rests, the

maximum depth is seven miles and we are still nibbling around the surface. Scuba divers

go to 100-150 feet/ 50m or so. We have a few submersibles that can go down to half the

oceans depth and one that has been to full ocean depth once but most of the ocean

remains a mystery. What does this tell us about the scale of discoveries still to be made in

the sea? The greatest era of discovery is just begun, with the oceans less than 5% have

really been looked at. Mapping has been done, we know where the valleys are, where the

mountains and plains and so on but who lives in the sea? What do we really know of how

the natural systems actually function? We are just beginning to understand the magnitude

of our ignorance. How little we know has been brought home to us in research in the deep

ocean where conditions are so severe that it was once thought that no life of any kind

could possibly exist. In fact there are great numbers of creatures in these ocean depths.

Some recently discovered are so strange that it can be difficult to see any relationship to

organisms that live in shallower water.

Even in the best known environments there are still discoveries to be made. Surprisingly

the greatest may come from underground. The top most layer of the land in many places

is of course soil. This is crucial because quite simple it is what most plants grow on and it

is vital to us as we plant our crops in it. We might think that it is just dead matter with a

few worms in it but actually it is full of the most extraordinary creatures. Beneath the

surface of the soil the abundance of life is breath taking. In this small patch just in front

of me there could well be 2000 different species a quarter of a million different

individuals. Most of them of course are very small. Some are microscopic but on their

own scale the drama of their worlds is just as great as you can find on the plains of East

Africa or the rainforests of South America. Here there are predators and prey just a few

millimetres long with their own complex systems of attack and defence. This world lies

directly beneath our feet but we know little more about it than we do the deepest depths

of the ocean. Nematode worms so small they can only be properly seen under the

microscope are armed with piercing weaponry and protected with amour. What is the

significance of all the small forms of life that are being constantly discovered these days?

Biologist Edward Wilson is an expert in biodiversity. What is important about bugs and

weeds is not just that they have most of the biodiversity around the world but that they

are the foundation of the ecosystem. If you were to remove all of the biggest animals, in

fact humanity is very much in the process of doing that, there would be important

changes in the forests and the grasslands and the other major habitats but they would

survive. If you removed all of the insects, however, probably the entire thing would

collapse. It is the little things that make the world work. Bacteria are among them; they

are also probably the most abundant but remain the least studied of all forms of life. If a

visitor from another planet were to analyze all the cells that make up my body he or she

would come to the conclusion that I am only 10% human. That is because 90% of the

living cells in my body are bacteria. Bacteria are the most numerous living organisms on

earth; they are also among the smallest. To understand just how small they are let me take

a perfectly clean pin and put it in this scanning electron microscope. At low

magnifications the pin seems perfectly clean, it is only when we zoom in and magnify it

to 10,000 times that the size of the bacteria becomes clear. Every living thing on the

planet depends on bacteria in one way or another but we still have no accurate idea of

how many kinds there are. Recently extraordinary discoveries deep below ground have

shown that all our previous estimates were far too low. These pumps in California are

pulling up oil from 1000 feet below the surface bring up evidence that there is life down

there as well, mostly in the form of bacteria. Indeed other evidence suggests that other

microscopic forms of life may exist two miles, three and a half kilometres below the

surface. Such bacteria may grow so slowly that an individual bacterium may only

reproduce once every 500 years. Among the most extraordinary claims for this new and

unexpected wealth of life deep below ground is that if one were able to gather it all

together then it would weigh more than all forms of life, animals and plants that live on

the surface. The discoveries are so new that we cannot yet be sure, and as for how may

different kinds of life there is down there we simply have no idea, all of which goes to

show that we still have a lot to learn about the planet on which we live. So what might be

the final total of all the different kinds of living organisms that presently exist on earth?

Different specialists in the field using different methods have produced estimates of the

number of species out there, plants animals, bacteria and other micro-organisms that fall

anywhere from shall we say 5 million up to as high as 100 million. Now that we

appreciate, if only roughly, how great life’s diversity really is we can begin to judge the

scale of threat it faces from human activities. The sad fact is that even though we have

only identified the minority of species even some of those we have named have already

become extinct, some so recently that we have their images on film. Including the

Tasmanian tiger and the Golden Toad. Many more are now so rare that there is real

danger that they too will be lost before long. To assess the rate at which species are now

disappearing we need to know a little more about the way such losses happen. What does

extinction actually mean? Nothing could illustrate it more dramatically than the sad and

infamous case of the Dodo. This is a kind of giant ground living pigeon; it was

discovered by Portuguese sailors at the beginning of the 16th century living on the island

of Mauritius. They didn’t think much of it, in fact they called it fat and lazy and stupid.

But that didn’t stop them clubbing it over the head in vast numbers and eating its flesh,

then they introduced pigs and monkeys which ate its eggs. By the mid 1600s the Dodo

was teetering on the brink of extinction. A few Dodos were captured and shipped back to

Europe as curiosities most of them died on the way. How long the last Dodo survived

alone on its island, we don’t know, it could have been hours days or even years. But

eventually that one also died and at that point the Dodo as a species was extinct. The

Dodo was particularly prone to extinction because it lived only on the relatively small

island of Mauritius. The process of extinction becomes more difficult to chart when the

species has a wider distribution.

In May 1980 Mount St Helens on the Pacific North West Coast of the United States

erupted. A huge area of the landscape was virtually scoured clean of life. In hours after

the eruption rocks and mud flows swept almost every living thing off the mountain

slopes. But within weeks life began slowly to return to the devastated landscape. The

scale of damage was astonishing; within minutes of the eruption beginning a superheated

blast of gas travelling at 500 mph had flattened 250 square miles of virgin forest. No

species was exterminated because there was none that were restricted to Mount St

Helens. Even though the blanket of ash looked so sterile some plants were able to grow in

it and soon the landscape was repopulated from the surrounding areas. Some

environmental losses however, though they look less dramatic are more permanent. In

recent times virtually the whole of Southern England was covered by woodland, a small

patch of which survives behind me. It was home to a great range of species of plants,

birds, insects and mammals. Now however most of that woodland has been felled in

favour of agriculture and fields like these are totally unsuitable for those woodland

species so they have disappeared. When the species disappears over a small part of its

range it is known as a local extinction. If you have too many local extinction s the

population level will fall dangerously low and then that species may be on the road to

total extinction. There comes a time in the life of a species when it has been reduced to a

point that it can’t be recovered even by strenuous efforts. A lot of species are in that

condition and ecologists call them the living dead. An animal that nearly became one of

the living dead still lives near the city of Rio de Janeiro in Brazil. In this area 90% of the

forest that once spread for 100s of miles along the coast has been lost. The remains have

been split up into small patches. One of the most famous inhabitants of this forest is the

beautiful Golden Lion Tamarind. It was in imminent danger of disappearing because it

had lost most of its home. At the last moment a major captive breeding program was

started and strict controls introduced to conserve the last remnants of its habitat so the

species may have been pulled back from the brink of extinction. Most living dead species

do not receive this kind of intensive help. One of the difficulties of measuring the current

rates of extinction is that animals classed as living dead may be doomed yet they can

hang on in slow decline for many years. John Lawton is a biologist who is specialized in

the study of animal populations. Some extinction is instantaneous, some will happen over

a 20 or 30 year time period when the population gets hit by a sudden extreme event and

some may take over 100 years as the last adults of a non-reproducing species finally dies

out. These estimates of extinction are bedevilled by the fact that it is very hard to be sure

that something has really gone. Several species that were thought for many years to have

been lost have reappeared. An example occurred recently in Australia. Brisbane museum

holds the preserved remains of many Australian mammals including three dried skins of a

small marsupial known as the mahogany glider. They were collected by a clergyman in

1886 at a place called mount Echu in Queensland, but they were never recorded again.

Was this animal extinct? That seemed very likely but then in 1989 some unidentified

mammal skins collected 15 years earlier were by chance re-examined and one was

recognized as a mahogany glider. The skins came from Barrats Lagoon near the

Queensland town of Tully. But even when the specimens were being collected their

environment was being destroyed. Surely the Mahogany Glider must now be extinct.

Then this stuffed animal was noticed in a house near Barrats Lagoon. The farmer who

had collected it thought it was a squirrel so he had had it mounted with a nut in its hand.

But it was a Mahogany Glider; the trail was obviously still warm. Eventually on the 5th of

December 1989, 103 years since it was last officially recorded the Mahogany Glider was

re-discovered alive at Barrats Lagoon. Today it has been provided with nest boxes but it

remains critically rare. Although mostly nocturnal individuals do appear during the day

and put on a stunning display of aerobatics gliding between the trees. There was great

excitement and not only among scientists that this beautiful creature was still around.

This was a narrow escape. Is it something about which we should be greatly concerned,

haven’t such losses always been happening? Extinction is a natural event. These draws

and wracks at the Natural History museum in London are full of the fossilized remains of

creatures called ammonites. They first appeared about 250 million years ago. Over the

millennia some species died out other ones appeared. 65 million years ago all the

ammonites disappeared and with them went a great number of other species of animals

and plants. Such mass extinctions have happened 5 times in the history of our planet. The

question arises, are we ourselves on the verge of such an event? In some groups such as

the birds all recent extinctions have been recorded so we can estimate the rate at which

extinctions are happening and compare it with the past. There is absolutely no doubt in

my mind and in the mind of all my professional biological colleagues that the earth is

facing a massive extinction crisis. The extinction rate is at crisis proportions, perhaps 100

to 1000 times higher than before humanity came along. That’s the kind of acceleration in

extinction rate, 100 to 1000 fold that characterizes the lead in to the five great extinction

events on the fossil record. The last of those 5 great mass extinctions took place 65

million years ago when the dinosaurs disappeared. Studying that event reveals the scale

of loss that a mass extinction can inflict on life’s diversity. Palaeontologist Peter Ward

has made a study of these events. What we have got here on a beach in France is

evidence of one of the worlds mass extinctions. We had a global catastrophe and that

catastrophe is written in the rocks with this very thin layer through here. This is the end

of the age of dinosaurs, this is the start of the age of mammals, that differentiation is

deposited as this very thin band of strata, in that band of strata we have evidence of a

meteor impact. We had bits and pieces of Mexico which had been thrown into space,

come down, deposited on the deep sea bottom here in France. Age of dinosaur creatures

are found in the strata right up to this point and they suddenly go extinct. This mass

extinction was sudden it was catastrophic, it wiped out about 60-70% of all species on

Earth. Can we define such an event? Mass extinctions are very short intervals of time

when huge numbers of species go extinct. They are over say 1000s of years maybe 10 of

1000s of years when over half of the biodiversity then on earth goes extinct. And now

due to the spread of the human species over the Earth it seems we are on the verge of an

even more dramatic one. The difference from the last five great mass extinctions and the

6th which some scientists think we are on the verge of, is one of speed. Each of the last

took place over many thousands of years. The next, according to some predictions could

happen within 100. It will take a great deal of will power and economic strength if we are

to significantly reduce the damage we are doing to biodiversity. In order to decide if that

is worthwhile we must ask ourselves, does the disappearance of a species really matter. In

a very few cases the species that go extinct are likely to prove to be what we call

keystone species, that is, like the keystone of an arch if it is pulled out a lot of the

remaining structure changes and usually not for the good. It is often extremely difficult to

know before hand which species will be keystone species. Sea otters are a clear example.

They live off the Pacific coast of North America. In the Southern part of their range, a

huge sea weed the giant kelp grows up from the sea floor and creates a kind of

underwater forest. Many different animals depend on these kelp forests. They are the

spawning ground for fish. Seals live here as well and many smaller creatures such as

snails clams and urchins. Sea otters feed on these clams and urchins they bring them to

the surface and open them by smashing them on stones balanced on their stomachs.

During the 18th and 19th centuries sea otters were intensively hunted for their skins and

exterminated over huge areas. Their disappearance lead to dramatic changes in the

environment. The sea urchins with no sea otters to keep their numbers down increased

explosively. Urchins eat kelp and their vast numbers soon began to destroy the under

water forests. As the kelp disappeared so did all the animals that depended on it. What

was left was a bare sea bed carpeted with urchins. Species do not exist in isolation, they

are linked to one another in complex ways and when those links are cut a crisis may

result eventually hunting the otters was banned, they spread back into this area from

further a field and the kelp forests slowly recovered. Clearly many of the species on the

verge of extinction, when they are taken out are not going to cause the collapse of an

ecosystem. We should lament their passing for other reasons but there are many that

might cause serious repercussions and until we understand the whole process better, we

are rolling a dice, we are taking chances whenever we let a species go extinct. So how

would the loss of species and environments affect us? First of all if you want to be

completely practical there is the matter of wild species being an almost bottomless source

of new antibiotics and other pharmaceuticals yet to be discovered and developed, new

crops, new fibres and other new natural products, we are just getting underway the whole

effort to make use of biodiversity in this way. An example of a useful product from a

surprising source comes from Cape Cod in the United States. Horseshoe crabs are

collected here daily from the sea bed for their blood contains a substance that can save

human lives. The crabs are taken to a laboratory and here in what looks like a scene in a

science fiction film, they are restrained in racks and some of their blue blood is extracted

from them. One of the substances in the blood is used about the world to test if batches of

inoculants are healthy or contain lethal bacteria. The crabs are then released unharmed in

a part of the sea that will not be harvested again for a year. Clearly many individual

species can be of great use to us but are there benefits to be gained from conserving

natural environments? There is this whole matter of ecosystem services, you know an

ecosystem like the one we are sitting in here is doing a tremendous amount for humanity

it is creating soil, it is cleansing water, it is creating the very air we breathe and the

important thing is that it is doing it all for free. Many reasons given for preserving

biodiversity are selfish ones to do with our health and comfort but is there any other

reason that we should be concerned about the loss of species? It is a clear and ethical

argument, an argument of stewardship, an argument of handing on a world as rich as the

one we inherited and that is an argument we in the first world have the luxury to consider.

We would have a different perspective if we are struggling to get the next meal. It is an

extraordinary gift that our generation received, this natural heritage and to destroy a large

part of it just fundamentally seems wrong especially when you think of what we are

doing to future generations. Scientists have a word for an environment that has lost many

of its animals and plants, they call them, impoverished. Some of them may have lost

almost all of their species as has happened recently on many coral reefs. Other

environments may appear to be largely intact even though many of their original

inhabitants have become critically rare or lost altogether. Future losses could include

many smaller kinds of life yet to be discovered as well as some of the best known

animals on the planet. There is a spiritual value an aesthetical value a psychological

benefit for having a large diversity of life on earth we should not be removing it. I believe

it could conceivably be possible that in a few hundred years time we reduce that

dependence and we lived in an almost wholly science-fictiony artificial world, the world

of the cult movie blade runner. The question you have to ask is, do you want to live in

that world? The view the astronauts gave us when they looked back at Earth enabled us to

see more vividly than ever before, just how limited space is on this small planet for life.

We now know that we are seriously damaging biodiversity and there is the risk that the

world that we hand on to our next generation will be less rich, poorer in biodiversity than

the one we inherited. Why is it that the activities of our one species aimed at no more

than living in reasonable comfort and avoiding hunger should cause such devastation on

the rest of the natural world?

BBC State of the planet part 2 – Why is there a crisis?

65 million years ago an environmental catastrophe wiped out the dinosaurs and over half

of all of the other species then living on the planet. There is now strong evidence that

similar losses are about to happen again.

This is Hawaii, it is the most isolated group of islands on the planet. 2400 miles away

from the Californian coast. From the air it may look like an island paradise but the history

of its animals and plants since humanity first reached it 1700 years ago, is very alarming.

It can be seen as an example in miniature of what mankind has done to the planet as a

whole. In environmental terms it is tragically impoverished. Small islands are especially

vulnerable to the environmental changes that so often follow the arrival of humans.

Hawaii not so long ago had more unique kinds of plants and animals than any other group

of islands on earth. But this lush beauty is deceptive. These mountainous forests and

lowlands which once teamed with such unique species have today been emptied of their

biological riches. The islands give us all a dramatic warning of the level of losses that

could soon occurs right across the planet. 100s of species of both animals and plants have

disappeared since humanity first came to Hawaii and its now absolutely clear from

research that here on Hawaii and on other islands that when ever human beings settle on

an island great loss of species occurs. If we are to control our impact on the environment

it is absolutely essential that we should understand why this should be.

Across the world from the tropics to the ice caps we are surrounded by an extraordinary

variety of life. We have so far named one and a half million different species. There

could be as many as 100 million. This great abundance of life is known as biodiversity. It

is this richness that today is threatened as our species attempts to fulfil our biological

needs. In this program we will identify the five human activities that are causing such

destruction that it leads some experts to foresee a mass extinction of species during this

present century.

To begin with it may help to get an idea of the scale of environmental change necessary

to cause a massive global extinction of life. To do this we can look back 65 million years

to the last great wave of extinctions that left the dinosaurs as nothing more than fossils for

us to study and display. Many scientists believe that this event was due to the

environmental after effect of the collision with the earth and a 10 mile wide meteor

travelling at 25 thousand miles an hour. This was the equivalent to the simultaneous

detonation of 10,000 times the world’s total arsenal of nuclear warheads. Superheated

fragments of rock set half the worlds plants on fire. Dense clouds of dust blocked out the

sun for months on end sending temperatures plummeting in what had previously been a

largely tropical world. The rain that fell was acid and poisonous. The cumulative effect of

all that was the extinction of over 50% of all species on the planet. There is a place in

Arizona where a meteor only a fraction of the size of the one that is thought to have lead

to the disappearance of the dinosaurs has left its mark. On a global scale it is a mere pin

prick. But that mark is enormously impressive. Many are now suggesting that the impact

of our own species may represent for the rest of life on earth, the biological equivalent of

a modern meteor strike. It may seem somewhat fanciful to compare the effect that

humanity is having on biodiversity with the world wide catastrophe caused by a massive

meteor impact. There is a lot of evidence to show that we are on the very brink of an

extinction event. So the comparison is not without relevance. If we want to see what

humanity has done to its environment a very good place to start is where humanity itself

started, in Africa.

Here on the Savannas we can still see great herds of what scientists call mega fauna. The

big mammals. Why is it that if you want to see big herds of large mammals, you have to

come to Africa? Well the answer is pretty obvious, it is the only place where there are

such things. If you went anywhere else you would be in for a big disappointment. It

wasn’t always that way. 50,000 years ago there were big herds of big animals on every

continent on the planet except Antarctica and then around that time in a very short period,

those animals began to go extinct. At the same time human beings were beginning to

expand from the continent where they began in Africa right across the planet. Was that a

coincidence or was it the first evidence that human beings could have an effect on the rest

of the animals on Earth unlike that of any other species. In North America 2/3s of all big

mammal species were lost. What was it like there before that happened? Biologist Jared

Diamond has made a detailed survey of the mega fauna extinctions worldwide.

Here around us in Los Angles, the mega fauna that went extinct consisted largely of

mammals there were camels, we had a lion here. If we had been standing here 14

thousand years ago it would have looked like the Serengeti plains with Lions and

Cheetahs and Elephants. Could the hunting of big mammals by those ancestral humans

really have played a role in their disappearance? The one correlation around the world is

that the mega faunal extinctions happened whenever humans arrived in the area. Arriving

in Australia 40,000 years ago in the Americas 13,000 years ago, in New Zealand 1000

years ago that I think is enough to convict humans.

There are still a few kinds of big mammals left in North America such as these carefully

protected bison on the plains of South Dakota. These are big animals and potentially very

dangerous which is why I must stay in a car if I approach them as closely as this. These

however, are small compared to some of the huge animals that roamed these plains.

There was the mammoth, the size of the African Elephant, Sabor tooth cats, a ground

sloth weighing 3 tonnes, a beaver the size of a bear. And that raises the question of how

humans, on foot, armed with nothing more than bows and arrows and spears could hunt

such monsters so successfully that they contributed significantly to their extinction.

Surprisingly the answer is to be found back in Africa by investigating why big animals

did not die out here despite this being the very place where humans developed their

hunting skills. The big animals of Africa had been evolving along with humans for 5

million years as humans started out as ineffective hunters and gradually evolved to be

effective hunters so the animals of Africa had a long time to learn fear of humans

whereas unfortunately the big animals around us here in Los Angeles were the best

professional big game hunters that there have ever been in human history. None of the

big animals outside Africa had ever seen human beings before and didn’t recognise them

as predators so instead of being fierce they probably appeared almost tame, as a

consequence they were easy to hunt. But that is not all, Human beings are what

biologist’s call, switching predators.

John Lawton is an expert in the study of animal populations. A switching predator is a

predator with a variety of prey available to it, able to attack a wide array of prey items so

that if one prey gets rare it can switch to an alternative kind of prey, that way it can work

its way through a smorgasbord of prey items sustaining its population on whatever

happens to be common at the time.

To get an idea of how a switching predator like those early humans can have such a

damaging effect of species we can look at a modern story involving another rather

surprising switching predator from Europe. In the mid 1970s 5 hedgehogs were taken

from the Scottish mainland where they are common and released as garden pets on the

island of South Ewest off the west coast. It is an island too remote for the hedgehog ever

to have reached by itself. They and their descendants took to living in old rabbit burrows.

The island turned out to be an almost perfect place for hedgehogs with no predators to

control their numbers. Being a switching predator the hedgehog will feed on anything of

the right size that it can find. Slugs, snails and worms are among its favourites and their

hugely abundant in the damp climate here. So well did the island suit the hedge hog that

those five have given rise to around 10,000 hedgehogs. Originally other animals also

benefited from the lack of predators, the dunlin had always nested here successfully for

although it lays its eggs on the ground there is nothing here to take them. But the

hedgehog changed all that, in the way of a switching predator it is always looking for

new kinds of food. It turns out the hedgehogs will happily switch from slugs and worms

to Dunlin eggs. This switch led to a drastic collapse in the Dunlins breeding success.

Unfortunately the story doesn’t end there, at low tide South Ewest is connected to other

islands by sand bars, hedgehogs can simply walk from one island to another devastating

the populations of breeding birds as they go. Some islands that are not naturally

connected by sand bars have now been joined by causeways and then the hedgehogs do

not even have to wait for low tide.

Humans are no ordinary switching predator. The loss of the mega fauna was just the first

sign that they can kill their prey at a faster rate than their prey can reproduce. Over

harvesting of both animals and plants is the first in the fives ways in which we are

affecting the diversity of life on earth. As the growing human population devises ever

more efficient technology its ability to over harvest becomes ever greater. Trees illustrate

this tendency only too clearly. If we cut them down faster than they can grow then a

forest will inevitably get smaller or disappear altogether. The natural processes of

regeneration will no longer be sufficient to maintain them. This over harvesting will

inevitably affect all the species that interact with trees or depend upon them. Today trees

are being harvested 10 times faster than they are being replaced with new growth. The

sea is being over harvested too.70% of the major fish species are being removed at a rate

at or above the rate at which they can reproduce. Sylvier Earle is an expert in marine

biology. We are getting too good at removing wildlife from the sea. Fish have no escape

any more. Perhaps there was a time 50 years ago certainly 100 years ago when our

numbers were smaller and our ability to capture wildlife in the sea was less sophisticated

than now but with acoustic methods we can find ever last tuna, every last squid, every

last shrimp in the sea. This kind of use of technology is wonderful in some respects but

terrible in others because it is encouraging us to just take too much out of the natural

systems. Recent figure suggest that each year up to half of the planets new plants and a

large proportion of animals too is harvested for the use of one species, our own.

The second way in which human activities are changing the diversity of life also began,

like over harvesting, when humans spread across the globe. This is the damage that is

caused when animals are introduced into places where they have never lived before.

Australia is famous for the number of alien species that have gained a foot hold on its

land, often to the determent of its native species. A dramatic example is the European

rabbit. Without their natural predators and diseases rabbit populations in Australia

sometimes explode. These rabbits can graze bare 100s of square miles of grassland

affecting everything else that lives there. Overgrazing eventually affects the rabbits too

and they die of starvation by the million. However alien species cause the most damage

on small oceanic islands and no where more so than on Hawaii. Here one alien

introduction after another has driven many native species to extinction. When you arrive

on Hawaii it looks wonderful, it is a tropical paradise and what most tourists don’t realize

is that almost everything they see there in the lowlands is introduced and there is

essentially no native birds and very little native vegetation. Many of those that remain

have now become isolated on mountain tops by this tide of introduced animals and

plants. Hawaii once had about 100 species of bird that were found no where else on earth.

More than half have gone forever and many of those that survive are critically

endangered. Snails better than any other Hawaiian animal illustrate how one introduction

after another can devastate local wildlife. Millions of years ago a small number of snails

arrived here on floating vegetation. From them 1000 other species evolved all unique to

Hawaii. Today only a small fraction of these still survive. Some that produce these

colourful shells are now so rare that their total world population number less than 10

individuals. These huge collections of Hawaiian snails are a product of a collecting craze

in the late 19th century. Many of them will never be seen again, they’re extinct. Some of

those were driven onto extinction by the sheer intensity with which they were collected

others undoubtedly had their population sizes reduced. But the final blow that drove so

many of Hawaii’s snails to extinction was the introduction of alien species. The rat was

just one of the more damaging arrivals eating its way through the great populations of

ground living snails and doing considerable damage to those that lived up in the trees.

Things became worse with the introduction of pigs and goats which damaged or

destroyed the plants on which the snails lived and so caused many extinctions. But this

was not all. Alien snails now appeared. These are giant West African snails and they

were introduced into Hawaii about a century ago because some people thought they were

particularly delicious to eat. Unfortunately snails as big as this have pretty good appetites

themselves and before long they were out of control and chewing up peoples gardens and

so it was decided to try and control them by introducing killer snails, including this one

from Florida. Unfortunately nobody though to check whether the introduced cannibal

snails would prefer the giant West Africans or the native Hawaiians. In the event they

chose the Hawaiian snails and so another series of extinctions began in Hawaii. These

killer snails glide over branches looking for the trails left by the native species they track

them down and then they eat them. Killer snails are now moving across Hawaii at a rate

of 1 km a year destroying native snail populations as they go. One might question

whether the disappearance of a range of species of snails in Hawaii really matters. After

all there have been no ecological consequences or damage as far as we know. It could be

that we won’t be aware of any damage for some time to come but even if there is none,

surely it is sad indeed that our descendants will inherit a world that is more impoverished

than the one we inherited. The introduction of alien species which we often make so

thoughtlessly is the second in which we are damaging life’s diversity.

The third and the most damaging of all is the destruction of habitats. There is a very clear

example of habitat destruction in South Africa this is Cape Town. Surrounding the city

on this tiny corner of the African continent is a habitat known by the Afrikaans name of

fynbos. It is one of the most remarkable plant communities on earth with a higher

concentration of species than even the Amazon rainforests of South America. It is what

scientists call a biological hot spot. There are over 5 and a half thousand plants growing

here that are found no where else on the planet. It is a remarkable place too because some

of the plants here have ranges so small that the entire world population may be crammed

into an area the size of a football field . This peculiarity, sadly, provides a clear

demonstration in miniature of habitat destruction.40% of the original area of fynbos have

been destroyed by human activities such as agriculture and the spread of the city. Clearly

if a plant has a world range of only a few 100 square meters and that area is destroyed

then the plant will become extinct. It’s a simple idea, take away the home of a species

and that species vanishes. That is habitat destruction. And the damage may not stop there.

Other plants or animals may also use that patch of land or depend on that rare plant so

they too will be affected even if their range is larger than the area destroyed. We

ourselves are not immune from the effects of habitat destruction. There is a startling

example of how that can happen in the United States. This is Charko canyon in the state

of New Mexico. It is part of a desert that covers 100s of square miles. When the first

European travellers reached here on horseback about 350 years ago they found very little

water, hardly any trees to provide fuel for fires or timber for housing and a soil that was

very very infertile. The place seemed virtually uninhabitable and then they entered this

canyon and were greeted by the most extraordinary sight. This is the settlement of Puebo

Bonito and it is just one of a number of structures in this desert. They were built about

1000 years ago by the Anazarzi Indians and they were abandoned a mere 300 years later.

Ever since they were discovered the same questions have been asked about them. Why

should the Anazarzi build their cities in a desert and why should their civilization be

abandoned a mere 300 years later? We now know the answers to those questions and they

still retain the power to shock as they’re as relevant to our civilization as they are to that

of the Anazarzi 1000 years ago. Pueblo Bonito was five stories high the tallest building in

North America until the advent of steel sky scrapers in the late 19th century. About

215,000 wooden beams were used in the buildings that ones stood in the canyon. It’s not

just a question of why the Anazarzi lived here, but how. Where did they find the timber

for their construction work and fuel for their fires? There are signs of fields and irrigation

systems round here but the water table is well below the surface and the Anazarzi didn’t

have pumps to raise it. It required an inspired piece of detection work to solve the

mystery of Charku canyon and rather surprisingly the key to it was a little mammal called

the pack rat. The pack rat is nocturnal and very shy. Just to see it we have to use a

sensitive night vision camera. They live in burrows, at night they emerge to collect sticks,

pine needles and pretty much anything else they can carry which they deposit on a mound

on top of their burrow. This mound is their toilet area. Such middens may be used

continuously for over 100 years before being abandoned. Over the years the nitrogen in

their droppings crystallises and their middens solidify and can survive for thousands of

years in this hot dry climate. Fossil middens are like time capsules. They carry an

accurate record of the plant life at the time that the midden was created. Scientists have

analysed the contents of 52 such middens which between them covered a period of

10,000 years. What they found was a revelation. By dissolving the crystallised nitrogen

and studying the plant remains the history of a civilization was unravelled. It was

discovered that when the Anazarza first arrived in Charka canyon the area was woods

with pinion and ponderosa pines. These trees were cut down for fire wood and building

materials. When the canyon had been cleared of all its trees the Anazarzi built roads to

bring timber back from up to 70 miles away in the mountains but by then the damage had

already been done. This is one of the few trees still standing. It seems that the destruction

of the trees combined with an ill timed period of drought caused the water table to drop

below the level of the irrigation systems in the fields until they could no longer produce

crops. The land became the desert that we know today and the Anazarzi were forced to

leave. The collapse of this civilization is in itself an alarming story but Chaku canyon was

by no means unique. There are dozens of examples, there were collapses in the fertile

crescent on East Riload at Ankoa What in the Indas vally and great Zimbabwe, in Greece

in the mississipi valley, it goes on and on and on. The destruction of habitats is doing

more damage to biodiversity around the world than any other human activity. As our

population increases and we cover more of the earth’s surface with our buildings and our

cultivated fields we will inevitably loose more wild habitat.

The damage we have inflicted on the world environments have lead many to question

whether the human species is deliberately destructive. Edward Wilson is a biologist that

has made a special study on the effect of human behaviour on the rest of life. I think it

would be a grave injustice to speak of the human species in some sense evil even though

we are destroying the environment so efficiently at the present time. Basically that’s not

our intent, it never was. It was very natural in fact it was necessary for survival for the

ancestral human being to throw everything they had against the wilderness in an attempt

to conker it, to utilize it. That is the nature of human kind, to expand the population, to

gain security to control, to alter and for millions of years that paid off without undue

damage. Then what happened was as we developed a modern industrial capacity then the

techno-scientific capacity to eliminate entire habitats quickly and efficiently. We

succeeded too well. At long last we broke nature and almost too late we are waking up to

the fact that we’ve over done it and we are destroying the very foundation of the

environment on which humanity was built. Habitat destruction is the third way in which

humans are damaging life’s diversity.

A process called islandisation is the fourth. When we destroy habitats we tend to leave

undisturbed pockets. Whenever you fly over any bit of the globe now you can see what

we are doing to it. Basically the process can be thought of as one of islandisation. Islands

of undisturbed habitat in a sea of totally modified habitat. What happens to habitats that

have been cut up and reduced to islands. To answer that a huge and ingenious experiment

was set up in the rainforests of Brazil by conservation biologist, Tom Lovejoy. Well

basically its like you have this carpet of green forest and you took a cookie cutter and put

it down in a few places and cut away all the forests around the cookie cutter and you are

left with these green patches of forest. Although the cleared areas have now begun to

grow back the re-growth consists of just a few weedy species so the islands of rainforest

like this dark green rectangular patch still remain isolated. It was found that these islands

of forest changed from the centre to the edge. The nearer the margins the more species

will have gone. Species are continuing to disappear 20 years later because of changed

conditions or because the islands are simply not big enough to sustain their populations.

The results were usually the same whether in an experimental island or in an area of

forest bisected by nothing more than a road. One clear example of the effects of

islandisation that has been studied here involves a group of birds that habitually follow

the swarms of army ants. Studies have been made to discover whether these ant birds will

fly from one patch of forest to another. Antbirds rely for their food on the army ants

which range over the forest floor hunting insects. The antbirds follow them picking off

whatever insets they can. A colony of ants needs a large area of forest to provide it with

enough insects. If an island of forest is not big enough then the ants will simply leave and

cross to another one. This presents a problem for the ant birds. They are psychologically

adapted to staying in dark shady forest and they simply will not go out in the open. They

are unable to follow an army ant colony if it leaves a fragment. If they are then left in the

fragment they will starve and die. One species after another will be lost where ever you

create an island in any kind of habitat. You are going through a simplification of an

ecosystem an impoverishment of the number of species. So in the end you end up with

something which is quite less than what you started out with. Islandisation is happening

more and more around the world, even nature reserves are islands. The smaller an island

the more vulnerable its inhabitants and a large species may need very big islands indeed.

There is a small but clear example on the chalk grasslands which once extended right

along the whole length of the downs of Southern England. Changes in agricultural

practises here have had a dramatic effect on this little insect. Like many animals and

plants the silver spotted skipper butterfly is very particular about where it lives. In

England it can only survive where the grass is very well grazed as it is here on box hill in

Surry. That grazing keeps the grass very short and allows a full range of down land

flowers to bloom. More importantly for the butterfly it also creates areas of bear earth

where there is no grass and no flowers. These bare patches of earth are crucial to it

because they warm up very quickly in the sun. The butterflies bask on them and so raise

their body temperature. Only when they have done that can they fly away and lay their

eggs on the surrounding grass. The silver spotted skipper’s home has now been reduced

to a number of small grassland islands. They wont fly more than a short distance over

unsuitable ground so don’t move from one island to another. Each butterfly population is

now isolated from the others a typical consequence of islandisation. If a bad season or

disease eliminates one colony that area cannot be naturally restocked from elsewhere.

The danger for species living in isolated populations is that one after another those

populations may die out. If nothing is done to save them then before long the species has

disappeared over quite a wide area and if its range was not large to start with quite soon it

becomes totally extinct. The piece meal destruction of populations caused by

islandisation of habitats is the 4th way in which humans are effecting the environment.

The 5th way is pollution. There is pollution in many parts of the world. Its damage to the

habitat may be great but often it is only local. There is one kind of pollution however that

could have world wide consequences. That is the global warming that results in the

human activities that pump carbon dioxide into the atmosphere. Carbon dioxide is a green

house gas that is to say, it traps the suns heat. The more carbon dioxide there is in the

atmosphere the warmer it becomes. Stephen Schneider is a scientist who has studied

both climate change and its effects on the natural world. It is absolutely certain that

humans, when they use the atmosphere as a free sewer and we dump our smoke stacks

and our tail pipes in it and we chop down our trees and we have cement plants, are adding

to that envelope of green house gasses. It is virtually certain that that traps enough heat to

make a significant difference. There’s probably damages already, we know that sea levels

now are probably 10-20 cms higher than they were. That mountain glaciers are melting.

That there is probably a little added intensity to hurricanes so it is already possible to

argue plausibly that we have started to crank up the stress in terms of added droughts and

floods and so forth. Global warming has occurred naturally many times before. You can

see the effect on animals and plants of just one such happening if you go a few miles out

to sea and back in time by 10,000 years. I’m in a fishing boat in the North Sea just off the

Dutch coast and we are trawling at a depth of about 30 m 90 feet for mussels. Sometimes

the nets bring up more than mussels, they bring up vivid evidence of an ancient global

warming. Starfish, razor shells, star fish, now that’s more like it, that is a bit of bone, and

a huge bone too, that would have been an articulating surface like that. That looks like a

tooth, that’s a tooth of a small horse but this is nothing compared with what has been got

out of this particular sea. Over here, all these have come out from just here. A tusk, a

mammoth tusk, and this is the joints from the top of the shoulder also from a mammoth.

And this perhaps is the most convincing of all, no one could have doubts that this is very

strange, this is a mammoths tooth. These are its roots and this is the substantial body of

the tooth that was in the jaw and this was the grinding surface. A spectacular

demonstration that 9, 10, 11 thousand years ago, this patch of the sea was dry land with

mammoth wandering over it. That global warming lead to a great rise in sea levels which

drowned much low lying land and changed the characters of many areas by altering

weather patterns. Finding the bones of a great land animals like a mammoth underneath

the sea makes it perfectly clear that global warming can bring about great profound

changes in the distributions of animals and plants and equally obviously and future global

warming is likely to do the same. When it happens temperatures change all over the

planet as we can se on this thermal image. This is a problem for many animals and plants

because most can only live within a very limited temperature range so if climate changes

they must move to keep pace of it. For example when the climate warmed after the last

ice age, oak forest moved north or south to keep up with their shifting temperature zones.

How does an oak forest move? The answer is, very slowly by having its seeds transported

by animals. In the autumn squirrels and Jays bury acorns as food stores for the winter

months but they forget where many of them are and those acorns will germinate. When

global warming happens acorns buried in the north of the forest will grow where those to

the South will die. And so a forest slowly creeps north. This process took thousands of

years but today it seems that global warming is happening faster than ever before. Its not

like it was when the ice age ended, you know 15,10, 12 thousand years ago and the trees

marched north, marched in the sense that the seeds spread and the animals literally flew

and walked, now we are saying, go ahead and redo that not in 1000 years or 5000 years

like in history but go ahead and do that in a century and do it when you have to cross

factories, farms and urban settlements and all the human disturbance and its that

combination of factors the disturbance combined with the climate change that makes

most of us in environmental science very concerned about the ability of the earth to

support anywhere near the current level of biodiversity in the next century.

So these are the 5 ways in which we are damaging the planet. Over harvesting,

introducing alien species, destroying the places where species live, creating small areas of

habitat and finally by polluting the atmosphere. Change in itself is not necessarily

destructive when it happens slowly. However these five factors are all happening at

unprecedented speed. It seems that the reasons behind the loss of species today make the

impending change unique amongst the great waves of mass extinction that have

happened so far. Scientist Sir Robert May is a leading authority on the current biological

crisis. The dinosaurs were probably done in through an asteroid impact. An external

environmental impact. What we are seeing at the moment is something unique in the

history of life, a single species, us, sequestering to our use for example a quarter to a half

of all the plant material that grows on the earth in any one year. Our activities are creating

the conditions that are driving this 6th great wave of extinction, the wave on whose tip we

stand. It is both literally the best of times and the worst of times. There has never been a

more exciting time to be alive when we are beginning to actually read the book of life

itself and we have the potential to apply that understanding for good stewardship and

husbandry of this marvellous world that we are heir to. Or we can just thoughtlessly bend

it for creating more bits of garbage to amuse ourselves. I don’t think that there is going to

be some major environmental catastrophe some major Armageddon, the world isn’t going

to stop tomorrow, the world will simple become a grotty less interesting place. If you like

rats and cats and house finches and a few things like this and you would like to see them

everywhere you go then biotic impoverishment is for you but if you or your descendants

would like to live in an interesting world in which there is richness of life, variety of life

and wild environments full of surprises and aesthetic delight then conservation of

biodiversity is for you. My belief is that given enough education, enough awareness,

enough sensitivity to the problems presented to them people have the capacity to do

amazing things and change their attitude.

We began our investigation in Hawaii, the very image of a tropical paradise. The

vulnerability of its native animals and plants has much to do with the fact that they

evolved on islands but none the less their fate should be taken as a warning. We now

understand which of humans activities inflicts the greatest damage on the diversity of

animals and plants on the planet. That knowledge is going to be crucial if we are going to

meet the great challenge of the next century. How to provide a good living standard for

the ever growing number of human beings without inflicting a grave impoverishment on

the planet.

State of the planet 3 – The Future of Life

This is Nairobi National Park. Ten years ago Black Rhino were being poached quicker

than they were reproducing, it seems certain they were doomed to extinction, yet here

they are. How has that happened? Well it has happened because one species, ourselves,

decided it could happen and should happen. Today we have the ability to make a

difference and what the human species does to the planet over the next 50 to 100 years

will determine the future of all life on Earth.

In the case of the Rhino we may have saved the species but not necessarily its habitat.

This city was once far away, but over recent years its grown so much its now hard against

the park fence. It’s a scene that has been repeated over and over again across the planet.

The rhino is just one of the more obvious endangered species but if things go on as they

are its likely that over half of all species will become seriously endangered or extinct

within the next 100 years. As the human species increases in numbers so do inevitably

the demands that it makes on the Earth and the other creatures that live there. Somehow,

we must find ways of reducing the pressures we are putting on the planet. In only too

many places our interests and those of wildlife seem to be in direct conflict. Rwanda in

Africa is one such place. There the Verunga Mountains are home of one of the

charismatic of all species, the Mountain Gorilla. Just over 20 years ago, I went to Rwanda

to see them myself as part of a documentary that we were making. Then it was

comparatively easy to see Gorillas in the wild in their very rough country, and even to

interact with them.

And so if ever there was a possibility of escaping the human condition and living

imaginatively (mmmggggmmm), in another creature’s world it must be with a Gorilla.

There were only about 240 of them in the Verunga Mountains at that time. This friendly

youngster was known as Pablo, but he and his family were in real danger. Part of their

Forest was being felled for farms, and they were being killed by poachers. It was only

when their plight was brought to international attention in the 70’s, that things began to

change. Park guards supported by conservation charities reduced poaching and so many

tourists paid to come and see the Gorillas that the government recognized officially that

these magnificent animals were a major economic asset.

But during the 1990’s another much bigger tragedy started to unfold. Rwanda was

devastated by civil war and genocide. Immense refugee camps formed on the slopes of

the mountains where the Gorillas lived. Humanitarian aid provided food but not the fuel

to cook it, so the people took that from the forests. They had no choice. What had been

lush mountain vegetation where the Gorillas came to forage became a wasteland. Some

of the Gorillas were killed, but despite the shooting and the reduction in the size of their

forest, the Gorilla community survived. Pablo is now fully grown. Miraculously he and

his family came through the turmoil relatively unscathed, but there are still dangers in

this forest. This Gorilla lost its hand in a poacher’s snare. Even so, the Verunga

population has begun to increase. At the last count there were 320, what future do they

have? Ian Redmond is a biologist who has being studying and working to protect the

Gorillas for over 20 years. “Now that those Gorillas are seen as an economic resource,

then the quality of lives of all the people associated with the park is going to be increased

by the fact that there are still Mountain Gorillas there. And more important, the Gorillas

are part of the ecosystem of those mountains and that’s one of the most densely populated

parts of Africa most people are farmers, they depend on the rainfall that those mountains

generate and they depend on the streams that flow out of those mountains which wouldn’t

flow year round if the forest was gone. So you have got to save the forest which means

you need the animals in the forest which means the people around that forest can benefit

from it.” Its not just in developing countries that humans and wildlife can be at odds, that

could also happen in prosperous parts of the world.

The state of Oregon in the north-west of the United States still has vast wilderness areas,

but even here there is a species that has been threatened with extinction. This time it’s a

bird, the Northern Spotted Owl. Its diet is quite varied for an Owl. Frogs, lizards even

insects, but it relies mainly on small rodents. One pair of Spotted Owls needs around 8

km2 of old growth forest in which to catch enough prey to feed themselves and their

chicks. But part of this territory in recent decades has become a major centre for logging.

When the forest is cleared the Owl can no longer hunt and it takes about 60 to 100 years

for an area to recover sufficiently for the Owl to return. Around 60% of its former habitat

has now been lost. The timber industry here is big, powerful and very important. If it

were to go entirely over 30,000 jobs and millions of dollars of revenue will be lost. Its

hardly surprising that the issue caused bitter divisions among the people of the area,

many of whom couldn’t accept that they should lose their jobs just because of a bird. But

fundamentally the argument was not just about a bird, but about the whole complex

community of animals and plants living in these magnificent forests and eventually it was

decided that logging should be restricted. However, shutting off large areas of land to

protect wildlife and finding local people new jobs is not always an option. Elsewhere

there may not be enough space to give each its own territory.

In Africa in Kenya’s Shimba hills there is such a problem. What was once wild bush is

gradually being taken over by farms. The area, however, is particularly rich in animals

such as Elephant and also contains a great range of plants. Within the Shimba Hills

Reserve, there is an area of 35 km2 containing a once migratory population of 500 or so

elephants, this has been fenced off to protect growing numbers of farms from crop

raiding by Elephants. Fortunately, closed reserves may be beset by many problems and

this area has one, too many Elephants. Elephants may push over trees to get to the leaves

of the higher branches, but with so many animals restricted to this small area there is a

risk, that the carefully protected environment will be severely damaged. So a solution has

to be found. In this case around 30 of the worst offenders are tracked by helicopter,

tranquilized to be moved elsewhere. Even so this solution is only temporary because the

population that remains is still too large, it does however buy time until a more long term

solution can be found. This is a dangerous procedure that can only be tackled by

specialists such as the Kenya Wildlife Service. Paula Kahumbu is their scientific advisor.

“This is a particularly difficult area to work in because it is forest and bush land. We have

a team from the Kenya Wildlife Service which includes our chief vet and his veterinary

assistants, um, and the capture team with all the equipment. We are planning to move 30

bulls, so it is one of our biggest operations that we have ever conducted. This may be a

distressingly undignified procedure, but its the only way to translocate an Elephant. The

Elephants will go to Tsavo East National Park, 200 km away. It’s a much larger reserve

less densely populated by Elephants. But is there a danger of having increasing numbers

of small isolated patches of natural environment. “I do think it will happen more and

more. We’ve been, um, unable to stop the fragmentation of these habitats all across

Africa, um, in Kenya it is particularly bad because our protected areas only cover 7.9 %

of the total landscape.” But more small reserves may require evermore damage limitation

exercises like this. Even small areas of natural habitat may contain thousands of animal

and plant species, they may be smaller and less glamorous than Elephants but equally

important for the health of the area. Over several weeks 28 elephants were translocated.

So what are the benefits of concentrating great effort and expense on just a few of the

largest species? An expert in African conservation is Walter Lusigi. Although we must

use a single species as a flagship but we must always remember that the species survive

within an ecological system and they are related to their surrounding environment and

protecting that species means protecting that whole environment for it to be able to

survive. But to conserve an elephant on its own, that does not work.

We now know that many of the reserves created in the past are too small. One way to

deal with that is to join them up. Across Africa there are several hundred protected areas

and national parks. At the moment they are isolated from one another. Here in Southern

Africa where Zimbabwe, Mozambique and South Africa meet their borders are being

opened up to connect existing parks so that wildlife can migrate between them as they

once did. There is now a plan to link this huge area with other reserves across southern

Africa. Its known as the peace parks initiative and its headed by zoologist John Hanks.

We stress three important things about the peace parks the first is of course the role that

these larger areas play in the conservation of global biological diversity. The second is

that peace parks really do promote a culture of peace and that is something Africa needs

and the third things we stress about all of this is bringing in the local people as partners so

they benefit from it. That hasn’t always been the case. This is all that is left of one of the

villages belonging to the Makaleki people after they were forcibly removed to make way

for the Kruger National park 3 decades ago. 30 years on the Makaleki have achieved

something unique. They appealed to the law and won back their land, now they have

decided to manage it to encourage wildlife. They hope that in the next few years such a

wild and beautiful area as this, if properly conserved will attract tourists and bring money

and jobs. So both people and wildlife will benefit. Trying to get across the message that

biological diversity is not just a bunch of conservationists saying we’ve got to conserve

these spectacular mammals because we like to look at them. We are talking about quality

of life, we are talking about human survival and we are talking about the commercial

value of a range of species that really can make a difference to communities living in

some of these marginal areas

Conservation tends to focus on protected areas and protected areas are fine as an absolute

bottom line but they are not enough so we have to develop methods of living in amongst

nature not separating humans from nature and all those projects where communities

benefit from wildlife and from natural resources in a sustainable way are the way

forwards.

Enabling both wildlife and people to live alongside one another appears to be working in

parts of Africa but in many densely populated countries places where wildlife can

flourish are now only tiny patches. This is Eastern England, part of Cambridgeshire. Over

the past 50 years pasture and woodlands highlighted here in green have been greatly

reduced and it now has some of the largest fields in the country. This has had a

considerable effect on many species. Bats can live for up to 25 years so many individual

bats in Cambridgeshire have had to make major adjustments to their lives in order to

survive. They feed on moths and are able to detect them by listening for the sound of

beating wings. One bat may catch up to 20 moths a night. Bats depend upon hedgerows

for their food, insects, and for shelter but hedgerows are extremely important from

another point of view. They act as corridors between the bats roost and the woodlands in

which they feed. After the Second World War new agricultural machinery was

introduced that needed big fields. So hedgerows were torn up and with them went many

of the bats highways and feeding grounds. It takes only a few minutes to rip up a

hedgerow. But over a century for a hedgerow to build-up a richly varied population of

animals and plants. This may be a rather odd and special example but in fact corridors

can be crucially important for animals both small and big. We now recognize the

importance of hedgerows and other wild habitats and laws have been passed to protect

them even in the overcrowded English landscape.

The natural environment can be destroyed in less obvious ways by alien species that have

infiltrated some of our seemingly unspoilt wildernesses. This is the Snowdonia national

park. Set aside as a national treasure and protected for its wonderful landscape and its

wildlife and the public appreciation. This welsh park has one of the highest

concentrations of different mosses in the country. It is also a place where Rhododendrons

in flower bring vivid colour to whole hill sides. But rhododendrons are not native to this

part of the world. They were introduced to Britain 200 years ago as an ornamental shrub

for gardens originally from Spain and Portugal and then from the Himalayas. They like

high rainfall and humidity with an acid soil and in these conditions they thrive.

Rhododendrons combine the characters of beauty and the beast. Here they grow into a

great wall of foliage 20 to 30 feet high. Nothing grows beneath them, the ground is

absolutely bear, they simply take over from native species. Removing them is a very big

job, but you might think that was the end of the matter. Not so. The reason that nothing

else grows here is not just because of the lack of light. Rhododendrons like many plants

rely for their nourishment on a partnership between their roots and a fungus. The fungus

that grows on rhododendrons produces a chemical that is highly toxic to anything other

than rhododendrons. So the plain fact of the matter is that this soil is poisoned and dead.

Not only that but most British mammals birds and insects that tried to live here would

also be poisoned. The park is getting rid of the rhododendron but it is a massive task.

Once you have cleared an area you cant immediately plant it with native species because

the rhododendron fungus remains poisonous for up to 7 years. The only thing that can

come back into the soil at that time is more rhododendrons. The rhododendron is the most

widespread invasive plant in Britain. What may appear to be a harmless and pretty shrub

is in fact and implacable invader that exterminates everything in its way. Biologist

Edward Wilson is an expert in plant and animal communities. A growing problem for

biodiversity world wide is the problem of invasive species. We are just also waking up to

the fact that due to the increased commerce all around the world quarantine systems of

many countries are weak and more and more species are getting introduced to places

where they are not native. And a small percentage of those species become destructive to

the environment and also economically. How do we prevent aliens taking over new

territories? Biologist Sir Robert May has a solution. Some of the answers for invasive

species the answer is just tighter regulation but that gets harder and harder in a more and

more crowded world with more movement. The root of the problem is that we ourselves

have become incessant intercontinental travellers. Each year there are around 8 million

commercial flights. As our technology makes the world a smaller place and as it becomes

easier for us to move around it also becomes easier for animals and plants to do so. Each

year around 10 million reptiles 3 million captive wild birds, 30,000 monkeys and apes

and many other species are transported around the world, some legally and some not.

There are regulations trying to control their movement. Customs officers working for

CITES, the convention on international trade of endangered species are responsible for

monitoring the movement of endangered wildlife. Here at London’s Heathrow airport

they check to see if a cargo is legal. None of these are endangered are they, no none of

this lot, there’s a bag down there. Detecting the import of species that are endangered or

potentially invasive is a tough and skilled job. Last year customs officials made over

30,000 seizures of cites listed plants and animals illegally entering the UK. Its an old

controlled one isn’t it , Berchelli. These are just some of the illegally exported animals

products, ivory and skin, feet, fur, coral, that have been confiscated here in London’s

Heathrow airport. As creatures like these become rarer in the wild so the value of their

products increases and the price on their heads goes up.

If you over harvest a species taking away more than can be replaced by natural

reproduction then that species is heading for disaster. That is happening in the West

African forest. Many monkeys apes and other animals are already threatened by loss of

habitat but in the last 10 years new threats appeared, the commercial bush meat trade.

Meat from wild animals, bush meat has always been part of the staple diet of people who

live in the forests. As the population grows and people move increasingly into towns they

all still want their traditional bush meat and commercial hunters supply it. It is a multi

million dollar business, the selling of bush meat but great apes have such slow

reproductive cycles that losing a part of a group can have a huge effect and populations

are declining

Taking too much out of the wild to sustain the human population isn’t something that just

happens in less developed countries. Across the globe forests are being cut down faster

than they can regenerate and stocks of fish are being plundered so heavily that whole

populations are being exterminated. The obvious way to prevent over harvesting is to

bring in regulations to control the amount we take from the wild. Whales have been

hunted for centuries but the introduction of explosive harpoons and electronic techniques

for finding the animals have reduced many species to dangerously low numbers. At the

height of the hunt 50,000 whales were being killed each year. One species, the grey

whale, was reduced to a few hundred individuals. Then an international ban on

commercial whaling was introduced and some species were rescued from the brink of

extinction but now after 14 years that ban maybe lifted. Over harvesting is a particular

concern of biologist John Lawton. I believe that it will be in the interests and it is in the

interests of rich developed nations to help developing nations move to more sustainable

development to pay for the protection of forests, to pay for the protection of wildlife and

so on and that is exactly what has happened in the far distant corner of Indonesia in the

Arfat mountains of Western New Guinea. Birdwing butterflies live here. They are among

the largest butterflies in the world with a wing span of up to a foot across. Ever since they

were first seen by Europeans they have been highly prized by collectors. The forests are

also home to the Moylay people. They earnt money by catching and selling butterflies

which fetched big prices around the world. So many of the birdwings were being taken

that their numbers fell dangerously low. Now with the aid of a conservation organization

the Moylay are being encouraged to harvest the butterflies in a different way. Inggris

Wonggor and other men in his village recognize that the bird wings rely on one particular

vine Alestolocia. They plant it in special gardens on the edge of the forest. Wild

butterflies come to lay their eggs in these gardens and then fly off. Caterpillars hatch

from the eggs, feed on the Alestilocia leaves and eventually turn into pupae. A few days

before the adults emerge the pupae and taken down to the nearest town a days walk away.

Here there is a butterfly co-operative that helps the villagers get the best price from the

world market. Inggris is paid 5000 rupear, just less than one dollar for each butterfly

pupae that he brings in. The co-operative has special temperature controlled rooms.

Where the adults emerge without any problems. The butterflies are killed packed and sent

to collectors around the world. The income from the butterfly co-operative is the only

source of income for most villagers like Inggris Wonggor. The environment is very

important to us, if the forest is devastated; it means no butterflies so we can get nothing.

The project also helps wild butterflies. Not all the pupae in the gardens are collected a

significant proportion hatch there and the adults fly off into the forest where they

replenish the original population. Both the people and the butterflies in these mountains

now have a more secure future. There is another strange and romantic species that has

found a market internationally; you can find examples of it if you know where to look in

Chinese communities all over the world. Including London’s China Town. At least 50

different countries are involved in the trade for sea horses. Some are caught for keeping

in aquaria or curios but many like these dried ones are for use in traditional medicine.

World wide up to 20 million seahorses are caught each year and the demand for them

seems to be limitless needless to say this is having a dramatic effect on some local sea

horse populations. In the Philippians there are some local peoples who depend upon sea

horse trade for their living. So there a conservation program has been started. Which tries

to ensure that there needs as well as those of the sea horses are being considered. Most of

the sea horses are gathered at night. They rely for their defence on camouflage but these

divers are very skilled at spotting them among the coral and the seaweed. Few escape

their practiced eye. Sea horses are more prone to the dangers of over harvesting than most

species of fish because of the extraordinary way in which they breed. Instead of laying

several thousand eggs like many fish seahorses produce only a few hundred. Incredibly it

is the male that becomes pregnant and gives birth to the young alive. Males and females

form bonds for life so if one of them is taken the other may not find another mate for a

long time. But commonly both partners are caught as they tend to live close to one

another. In this village a new method of seahorse fishing has been introduced thanks to

the support of an international conservation group organized by a marine biologist, Dr

Amanda Vincent. Project seahorse is trying to ensure the long term persistence of healthy

seahorse populations healthy populations of their relatives and healthy habitats in which

sea horses live. We are doing this in a way that respects human needs and we are also

very focused on education. The fishermen bring their catches to a local buyer in the

village. On a good night a man can reckon to earn a couple of dollars. The seahorses will

be dried and sent abroad. Careful reports are made on what was caught so the effects on

the population can be monitored. Scholarships have been set up for local students who

help with the record taking. With this information the harvesting of seahorses can be

properly planned to prevent the over fishing of any one area and to conserve a healthy

breeding population. The villagers still go out fishing for seahorses but the project is

helping them to make a better living through associated crafts and some tourism. Now a

chain of carefully guarded sanctuaries has been created where the seahorses can breed in

safety. Both the seahorse and the birdwing butterfly projects are concerned with

sustainability. That means not taking too much out of the wild so that species of animals

and plants will continue to flourish. If you do take too much of course then those

populations can decline dangerously sometimes beyond recovery and then there is

nothing for anyone to take out now or in the future.

Protecting a population from overexploitation is essential but even that may not be

enough if another threat to their environment is not tackled quickly. That threat comes

from pollution. Pollution is often localized and even sometimes reversible. One kind is

not reversible. The continuous release of carbon dioxide and other green house gasses

into the earth’s atmosphere. This has a long term effect on the earth’s temperature.

Stephen Schneider is a climatologist. The world is going to warm up 1 to 5 degrees in the

next century, one being mild, 5 being catastrophic. Not very satisfying but we have to tell

the truth and the truth is it is very likely something significant will happen but it gets

much more complicated. The big problems occur when the warming gets to several

degrees because that starts to be the number where some species really want to move 100

to 1000s of kilometres and it is going to be very difficult for those migrations to take

place across the factories, freeways and urban settlements of the world at the rates at

which climate could change. Is there any real evidence that species might be able to move

in this way? Here in Kings Canyon and California’s Sierra Nevada, there is proof and it

comes in the form of a butterfly called Edith’s checker spot. Like most butterflies this

species is very sensitive to changes in temperature and climate. It is at its most

vulnerable, not when it flies as an adult but when it feeds as a caterpillar. It lays its eggs

in summer, when the caterpillars hatch out they feed on a particular plant, figwort, as they

prepare to hibernate until the next spring but if spring comes too early due to climate

change then the plants flower and die before the caterpillars have a chance to eat them.

Studies going back as far as 20 years have shown that in order to survive the species has

gradually moved its range further up the mountains to get to the cooler temperatures

where the plants put out their leaves at the right time for the caterpillars to feed. It has

been found that the butterflies have extended their range northward by 200 km.

The earth has gone through many changes in temperatures and climate in its history but

now conditions are changing at such speed that some species will have to move really

rapidly. So what happens if they cant do so. These are the Maldives islands in the Indian

Ocean. They have one of the least polluted habitats on the planet. Their spectacular reefs

make them one of the top spots for divers. Although coral reefs occupy less than 1% of

the vast space taken up by the oceans they support 25% of all species of marine fish.

Corals are extremely sensitive to changes in water temperature. This is what on of the

many coral reefs in the area usually looks like but during the month of April 1998 it

suddenly changed. The whole reef turned white, exposing its naked skeleton the majority

of the tiny coral polyps that had built these structures had been killed by a rise in the

water temperature of just 1 degree centigrade. Marine biologists believe this to have been

caused by a fluctuation in the earth’s climate known as El Nino combined with the

beginnings of global warming. 18 months later this is what the same reef looked like,

between 80 and 90% of the corals were dead their skeletons covered with brown slime. It

may be decades before the reefs of the Maldives are re-colonised. 10% of the world’s

coral reefs were severely damaged during this one episode when the ocean temperatures

for a short time changed. We know from fossil evidence from earlier mass extinctions

like the one during which the dinosaurs disappeared. Many coral species also vanished

probably as a result in a change in temperature. So what can be done about global

warming? The solution to global warming is more sustainable energy sources so that we

are not burning past fossil fuels and releasing green house gasses it is also having fewer

people and more efficient energy and having less patterns of consumption. All the

problems we have recognized so far are being made greater by the increase in human

population. 100 years ago the worlds population was around 2 billion people today it

stands at just over 6 billion, that’s six thousand million, and the last thousand million was

added in the last 12 years. Ian Diamond is a demographer studying population growth. If

we don’t see increases of the use of family planning and declines in child bearing as we

have started to see in many parts of the world in the last few years then we will have

much much bigger populations that 9 or 10 billion. In the long term into the 22 century

the world’s population will flatten out at around 11 billion. What does that mean for the

future of the planet? As far as food is concerned agricultural technologists say that crop

yields could be improved significantly to sustain around 11 billion people. But if 6 billion

people are already damaging the planet and its biological diversity a population of 11

billion would put intense pressure on global resources far beyond anything we have yet

witnessed. Are we content that that should happen? We understand what the problems are

and what we can do about them and we have the ability to minimize the damage to

biodiversity but how many species can we afford to loose during this immense increase in

the human population without seriously compromising the future. Conservation of

biodiversity will depend on how we scale down our excesses in consumption but if things

are decidedly done on a political level on a local level at the governmental level to be

able to address this problem head on without political excuses and different people

getting excuses then I think we have a chance. If we don’t take those measures then we

risk loosing up to 50% of all species on earth among them would be some of the most

well known but also there would be many others which haven’t been discovered yet.

We all like to save biodiversity and the environment but preservation of the creation as it

were, we have to learn a new ethic that allows us to care as much about the Brazilian

rainforest as our own local reserve and to think beyond a few years or a generation, to

future generations and what it is we would like to leave to them.

A warning of what the future could old can be seen on one of the most remote places on

earth a tiny island in the middle of the Pacific Ocean two and a half thousand miles from

anywhere. This is Easter Island and these astonishing stone sculptures are vivid evidence

of the technological and artistic skills of the people who once lived here. How did they

survive with hardly any large animals to provide them with meat, there are very few

different kinds of plants. There are no trees to provide timber with which to build houses

or ocean going canoes. In terms of human survival this island is very baron indeed. Easter

Island was not always like this. 1500 years ago when the first Polynesians settlers landed

here they found a miniature world that had ample resources to sustain them. They lived

well, erected their spectacular monuments and over the centuries their population grew to

around 20,000. So what went wrong? These are the remains of an early Easter Islanders

house and from excavations from the refuse dumps and around the kitchen we can get a

pretty good idea of what they had for meat. There was a lot of fish and there was also

shellfish and rats and chickens and there was a lot of pollen grains too and that tells us

what kind of trees there were on the island, there were a lot of then. About 500 years ago

things changed. This fish almost disappear from the diet and changes in the pollen and

the reduction in its quantity give us the reason why. Almost the last of the trees had been

felled by them, so the islanders no longer had timber to build sea going canoes and at

about the same time the carving of the great stone statures came to an end. Without wood

to make canoes the people couldn’t leave their shores, even to fish. Starvation threatened,

warfare broke out between rival clans as they fought over the remaining food and the

remaining productive soil. The old culture that had sustained them was abandoned and

the statues toppled. What had been a rich fertile world in miniature had become a barren

desert.

It seems that we will have to make further changes in our behaviour and attitude if we are

not to inflict lasting damage on the other animals and plants with which we share this

planet. We ourselves as a species may well survive come what may but it could also be

that unless we change we like the ancient Easter Islanders will be condemning

generations to come to live in a poorer and impoverished world. The future of life on

earth depends on our ability to take action. Many individuals are doing what they can.

But real success can only come if there is a change in our societies and our economics

and in our politics. I have been lucky in my life time to see some of the greatest

spectacles the natural world has to offer, surely we have a responsibility to leave for

future generations a planet that is healthy and inhabitable by all species