All language subtitles for BBC.Secrets.of.our.Living.Planet.1of4.The.Emerald.Band.XviD.AC3.MVGroup.org.eng

Ten million species live on planet Earth,

Each one is remarkable-

But none can survive on its own-

All life depends upon connections.

Unexpected, invariably complex,

beautiful relationships between
millions of plants and animals.

Starting in ourjungles-

Wow!

It's a different world.

Why do jungles have more animals
and plants than anywhere else?

And why can't this mighty brazil nut tree
survive without an orchid

and this nimble little rodent?

Connections like these
form the planet's great ecosystems-

They're vital for all life-

I want to show you our world
as you've never seen it before.

(DISTANT BIRD AND ANIMAL CALLS)

Central America-

The narrow isthmus of land
joining two vast continents-

This is Pipeline Road in Panama.

Named because it runs alongside
an old pipeline that was put in

during the Second World War
to get oil from the Pacific

through to the Atlantic 0cean.

And it cuts through some of the most
pristine rainforest in this part

of Central America, and I have to
tell you that amongst birdwatchers,

this is a hallowed place.

It's world famous.

(FAINT BIRDS0NG
AND GENTLE HUM 0F CRICKETS)

Semiplumbeous hawk-

Green honeycreeper-

Blue-crowned motmot-

Black-tailed trogon-

I've been out here since first thing
this morning, that's about five hours,

and during the course of that time,

I've seen or heard
75 different species of bird.

Some of them
are quite tricky to identify -

1've just got glimpses through the trees,

If I was to stay out here all day

and work really hard,

I might see as many
as 200 different species.

During Christmas of 1 989, a party
from the Audubon Society came here

and recorded no fewer
than 357 different types of birds.

It was a new world record,
set in this area of rainforest in Panama.

To put that in context,

the most anyone has ever seen in Britain
in a single day is just 1 43-

And it's not just birds-

1n this tiny reserve,
there are twice as many mammal species

as there are in the whole of the UK,

three times more butterflies
and 1 3 times as many frogs-

Perhaps this astonishing diversity
is shown best

by the richness of these superb birds,

(L0UD VIBRATING)

Hummingbirds are nectar feeders

so they find these dishes
of sugar solution irresistible-

But it's not just the individuals
that are so dazzling,

it's the sheer variety-

Blue-chested hummingbird-

Long-billed hermit-

Violet sabrewing-

Black-throated mango-

And white-necked jacobin-

There are 59 different species
of hummingbird in Panama's jungles,

The almost bewildering variety of life
that you find in rainforests

is exhibited by almost every animal
and plant group that lives there,

and it's the same in rainforests
all over the planet.

It's the remarkable thing
that sets them apart

from the rest of our
terrestrial ecosystem,

and it's a profound example
of what we call biodiversity.

The number of different living things
in a given area at a given time.

The big question is why?

And it's a question that's been
vexing scientists for decades.

Why are there so many different
living things in the rainforest?

1n Asia, rainforests cover
hundreds of islands -

some small, some vast-

New Guinea,

Java, Sumatra-

Amongst them,
some of the remotest places on the planet,

Across the 1ndian Ocean, Africa
and the rainforests of the Congo Basin-

Further west still
and we reach the Americas,

home to the Amazon rainforest,

the largest unbroken expanse of trees
in the tropics-

Together, these jungles form
an emerald band that circles our globe,

(CLAP 0F THUNDER)

Here on the equator,
there are virtually no seasons-

1t's hot and wet all year round-

Humidity barely drops below 9O%---

---and the sunlight is more intense
than anywhere else on the planet,

day in and day out-

All of this rain and all of this sun

results in a phenomenon
on a scale unseen anywhere else-

It's happening here, in these leaves,
in all of these billions of leaves.

And even if you're a really hard-nosed
biologist, really pragmatic about life,

it's nothing short of miraculous.

1t's the chemical process
of photosynthesis-

What plants are doing is combining
two very abundant ingredients -

carbon dioxide in the air, and water,

Two ingredients that are
almost impossible to combine-

If we take carbon dioxide and water
and mix them together,

even under great pressure,
all we get is fizzy water.

0n the other hand,
when plants mix carbon dioxide and water,

they get something else.

They get food.

They get sugar.

More of these sugars are produced
in a given area of rainforest

than in any other habitat
because of the sheer quantities

of water and solar energy-

1n fact, the energy captured
by rainforests in one year alone

could power the UK
for over a million years-

All of that energy

is turned into food,

quite literally out of thin air.

It's a bit like the botanical equivalent
of turning water into wine.

Photosynthesis might explain
why there's so much life here-

But it doesn't explain why there are
so many differenttypes of life-

There's one very special animal
that 1'd like you to meet-

She's a leafcutter ant,
and she's an ant with a challenge-

You see, her problem is that
she can't digest leaves on her own-

She needs to take them back to her nest,

But what possible effect could a tiny pest
like her have on this immense forest?

There are plenty of plant pests
in temperate forests,

but there's one crucial difference.

Temperate forests have winters

and each winter, the cold
kills off creatures like the ants

and they have to rebuild their colonies
and start from scratch each spring.

But here in the rainforest,
there is no winter

and as a consequence, the plants here
are under almost relentless attack.

Our ant is just one worker
among thousands in a single colony-

Each ant deposits her leaf fragment
deep within the nest-

There it will be composted and turned
into a fungal food for the whole colony,

Added together, the impact of all of these
thousands of ants is enormous-

It's relatively easy to work out
just how much these ants are harvesting.

We know there's around a hundred thousand
in every nest, and scientists counted

the number of journeys they made every day
carrying pieces of leaf.

37 4,200.

They also measured the leaf area -

the total being carried each day
by the ants - 1 1 square metres.

Multiply that up and during the course of
a year, it adds up to 3,855 square metres

and that is 20%/ of the leaf cover

that's produced here
in the area of the forest

where these little guys are foraging.

That's one fifth of all of the leaves here
destroyed by nothing more than ants-

And that's just the ants-

Grasshoppers, caterpillars,
slugs and snails---

everything seems to be
eating its greens here-

Wherever you look in the forest,
it's almost impossible to find a leaf

that hasn't been attacked by pests-

The simple fact that there's no winter

to kill off these pests
is a huge problem for plants-

So to stand any chance of survival,

every single plant
in the rainforest is armed-

And many are filled with toxic chemicals
which render them inedible-

All of this has had a profound effect

on the evolution of
the animals that live here-

Take a closer look at these creatures-
What do you notice?

Many of them are plain weird-

They're unlike anything else-

And one of the strangest of all
is found here in Latin America-

Here it is, and what an amazing animal.

Really charming as well.

But if we take a closer look at it,
you can see exactly what I mean by weird.

This is a female three-toed sloth-

And she's embarking on a 2O-metre
vertical climb to find food-

She is charming, but she's also
quite unlike any other animal-

So why is she so weird?

Well, it's a direct result of
a very peculiar diet-

You see, she is a very fussy eater-

Feeding on only one or two trees,
the leaves of which are tough

and full of toxins-

But her gut has evolved to host bacteria
which are specially equipped to break down

these otherwise inedible leaves-

1t's a slow process-

Digesting this salad can take weeks-

She gets so little energy from this diet

that she's forced
to keep her movement to a minimum-

She's almost become
part of the forest furniture-

So much so that other creatures
have started to move in-

She's the ideal home
for a colony of sloth moths-

The way she looks, the way she eats
and the way she moves are all a result

of having to overcome
heavily defended leaves,

and that is why sloths are so weird -

they're specialists-

1n order to survive in a rainforest,
you need to be a specialist-

There are no jack of all trades here-

The battle between plants
and animals goes on every day

and it's this battle that creates
the jungle's biodiversity-

Let me show you what 1 mean,
with one of the most toxic plants of all-

This a passion flower vine and its leaves
are laced with a pretty toxic defence.

Cyanogenic glycoside molecules, and when
they break down, they form cyanide.

As you might imagine, it works wonders

because cyanide is every bit as dangerous
to insects as it is to us humans.

Well, that is to the majority of insects,
but not all of them.

These are caterpillars from a species
of butterfly called Heliconius doris-

They have evolved
a unique internal body chemistry,

to do what few other creatures can -

counteract the plant's deadly cyanide-

They even incorporate the poison
into their own bodies-

And after metamorphosing
into the adult butterfly,

their bright colours
advertise their toxicity-

Very clever-

As one of the few animals
that can eat these leaves,

they have this food source
pretty much all to themselves-

But the downside is,
they can't eat anything else-

They are wedded to this vine-

The adult butterflies
will not lay their eggs on anything else-

But of course, plants evolve too-

This is a different species
of passion flower vine.

It grows in exactly the same patch
of rainforest as the first.

And were it to arm itself

with exactly the same cocktail of cyanide
as that first plant

then clearly it wouldn't be able
to protect itself

from these Heliconius doris caterpillars,
so it doesn't do that.

It's changed very subtly the type of
compounds that it's got in the leaves

that produce the cyanide.

And as a consequence of that,
it's totally toxic

to this species of caterpillar.

A victory for the vine, perhaps?

Except this is a never-ending battle-

Another species of butterfly has evolved-

One that can cope
with the different toxins-

1ntroducing Heliconius cydno-

1ts wing patterning is a little different
to that of doris-

But the most important changes
are internal-

Because each of these butterfly species

has evolved to be able to eat
a different type of vine-

The battle between plant defence
and caterpillar attack never stops-

The result?

A proliferation of species
of both vine and butterfly-

1n fact, each species of plant and tree
in the rainforest

has ended up with its own
specialised pests-

1t's become an evolutionary arms race-

Just as pest pressure
is driving the diversity of trees,

the diversity of trees
is driving the diversity of tree pests.

And it's not just the pests,
it's their predators too.

Animals like this praying mantis
are continually evolving

to try and outwit those pests,

which, in turn, are continually evolving
to try and outwit the mantis.

If conditions in the forest here
remain stable,

and new species have time to evolve,
one thing is for certain.

This rainforest will become
a whirlpool of biodiversity.

Now, it's easy for us to think
of biodiversity as a wonderful thing-

But the pressures
that create this biodiversity

make the rainforest
a very dangerous place-

Especially when it comes to the survival
of the forest's youngest inhabitants-

Let's think about it
from the plant's point of view-

I've collected about
1 5 different types of tree seed here,

all of which have come from
this small patch of forest behind me.

Now, imagine that each of these seeds
represents a tree-

And imagine that the forest
was made up of a single species-

Like this one,
that the locals call prischaco-

What you'd have is a monoculture-

But in the pest-infested rainforest,
this doesn't happen-

And here's why-

You see, imagine you're a seedling
trying to germinate and grow here.

We know that each of these tree species

has a highly specialised set of herbivores
which attack it.

So this one will be accessible to all
of the herbivores living on these trees.

Not a good situation at all.

But what if you were a different species
of tree germinating here?

Then you wouldn't be susceptible
to this particular set of herbivores,

and that would confer
a real advantage to you.

Then there's a far greater chance that
it would prosper through to maturity,

that it would survive. And in fact...

...if another tree species
were to grow here,

it too would enjoy the same advantages.

Reduced susceptibility
to this type of herbivore attack.

The strategy spreads like wildfire
through the forest.

What we end up seeing...

...is a complete mosaic of species.

A seedling is far more likely to survive
if it germinates in isolation,

far away from the parent tree,
surrounded by different tree species-

So how do plants get their precious seeds
away to safety,

away fromtheir set of voracious pests?

To find the answer,
1'm going to the jungles of Borneo-

Home to some of the largest animals
in any rainforest-

1n the Kinabatangan river,
a group of pygmy elephants-

Among the herd is a baby,
born only a few weeks ago-

Nearby, in the Sepilok sanctuary,
this young orang-utan is just days old-

They don't know it, but these youngsters
are incredibly important-

Because not only are both species rare,

but both will play a crucial role
in this ecosystem-

0rang-utans.

Absolutely extraordinary animals.

So easy to see why we generate
so much affection for them.

And when you look into their eyes,

it's like a reflection
in a not-so-distant mirror.

But there is another reason why we should
value both orang-utans and elephants-

If you're a tree, seed dispersal and
germination is a pretty risky business.

After all, you're covered with pests,
all of which want to gobble up those seeds

or snap up any tasty
germinating seedling.

Your only chance is to get your seeds
as far away from yourself

and those pests as possible.

The question is, how do you do it?

There's a clue.

This young orang-utan will grow to be
the heaviest arboreal animal in the world-

And this pygmy elephant
will grow to be nearly three metres tall-

By most standards, that's not pygmy-

They both face the same problem---

---how to find enough food-

The solution, as the baby is starting to
realise, is that they never stop moving-

She will have to work hard
to keep up with the herd-

You see, these elephants
are on the lookout for fruit-

Overhead, orang-utans search for fruit
in the canopy-

And thanks to their agility,
they can reach almost all of it-

But for the young elephant,

even low-hanging fruit
can be just out of reach-

Her mother shows her how to get them-

But what's important here is that
this elephant can smell some fruit

from well over a kilometre away-

And there are some plant species here

that have specifically evolved
to attract elephants-

For instance, this jackfruit is so large
that nothing else can really deal with it-

His huge gut will take a couple of days
to digest that meal,

by which time he may have travelled
over ten kilometres-

Between them, the orang-utan
and the elephant

disperse thousands of species of fruit-

Not only will the seeds be supplied
with ready-made fertilizer,

they will germinate safely away
from the threat of attack

from the mother tree's pests-

Rainforests,
more than any other ecosystem,

rely on animals to spread their seeds
over large distances-

But paradoxically,
this has created a nightmare-

1t's not often you get the chance
to walk 3O metres up in the treetops-

This canopy walkway certainly gives
a unique perspective

on the diversity of the rainforest.

It's been built in Sabah in Borneo.

Look at this!

Wow!

There's no doubt that there is
a huge range of species here.

But the flipside is that
in any given area,

there aren't that many individuals
of each of those species.

This tree is just coming into flower.

But the thing is,
if I look around the forest here,

I can't see another of these trees.

No.

And this is bound to present a challenge
when it comes to sex, to pollination.

But it's a challenge
that nature has risen to.

The simple problem is, how do you
cross-pollinate to fertilize your seeds

if you're all alone?

The methods British trees might use
won't work here-

Below the canopy,
there's virtually no wind-

And relying on a general pollinator,
such as a honeybee,

is a bit like posting a letter
without an address-

1t might have collected your pollen,

but it's just as likely to deposit it
on the wrong flowers-

No, what's required in the rainforest
is special delivery-

The nectar in these long flowers
is out of the reach of most animals-

Because these petals have evolved in
harmony with a very specific pollinator---

---a sunbird-

With his long bill, he can reach
the nectar deep within the flower-

And he needs to getthis nectar because
he's evolved to feed on little else-

And critically,
when he's had his fill here,

he'll have to find another tree
with the same type of flowers-

1f you're a tree in a rainforest,
this relationship is ideal-

For plants, specialist pollinators
act as a form of insurance policy.

You see, these animals have evolved
to feed on yourflowers

and only your flowers.

So once they've visited you, no matter
how far away your nearest neighbour is,

they'll get there and effect pollination.

And this is typical.

Many of the trees and plants out here
will have specialist pollinators.

And because
there are thousands of species,

this in turn means that there are
a vast array of these types of animal.

The final leg of my journey
takes me to Amazonian Peru-

Now we know why jungles
are so productive,

so diverse,

1 want to see
how the whole ecosystem fits together-

There's one series
of remarkable relationships

that even in this distant rainforest
involves me and you-

Now, you may not know what this is.

But I'm certain you know what this is.

This is a brazil nut.

And this is a brazil nut pod.

So inside here are about 20 of these.

Come down here.

Because quite naturally,
this has come from a brazil nut tree.

And here is that tree.

What a thing!

It's magnificent.

Each huge seed pod
takes 1 2 months to grow-

And this mighty tree
owes its entire existence

to connections that have taken science
years to uncover-

0ne of the most intricate relationships
takes place up there.

I think I've got it.

It's difficult to say, it's so high up.

Now, that is it, that's it.

Yeah.

Well, after a bit of a climb,
here's the plant that I was looking for,

and saw from all the way down there
on the ground.

It's an orchid.

This little orchid is absolutely essential
to the brazil nut-

1n fact, if you've ever eaten one
yourself,

then you owe a debt of gratitude
to these flowers-

The story of why the brazil nut
needs the orchid is extraordinary.

It's so wonderful,
it's almost beyond belief.

And through unravelling that story,
we can understand some astonishing things.

(SAWING)

1t starts with those
amazing-looking seed pods-

How on Earth do they get dispersed?

They're not only very heavy,
they're unbelievably tough-

1 want to try a little experiment
to find out-

All 1 need is some fishing line
and some little pink flags-

1 know this might seem a bit odd, but
trust me, this is cutting-edge ecology-

It's all primed and ready for action,

but there are none of the animals
around at the moment.

So I'm going to put this down here,

wait for them to sniff it out,
and be patient.

Given their size,
you might expect something large-

But the animal that can handle it
is actually rather small-

1t's a rodent called an agouti-

She may look insignificant,

but her actions have a very significant
impact on this rainforest-

She specialises in eating
tough seeds and nuts-

Thanks to her teeth,
which work like chisels-

So this is how they're meant to be opened!

That nut is packed full
of energy and nutrients-

After all, it contains everything you need
to start growing a brazil nut tree-

And what happens next
is the bit that 1'm really interested in-

Because there are so many nuts in the pod,

she can't eat all of them in one go-

She's saving the rest for later-

The question is,
where is she going to put them?

And look at that-

She's even putting every leaf back
exactly where she found it-

Each nut is being carefully carried away
to a different hiding place-

As far as she is concerned,
this is the ideal place for a larder-

And by complete coincidence,
as far as the tree is concerned,

this is the ideal place
for its seed to germinate-

Here is one of our marked nuts.

And the mother tree is hundreds of metres
through there.

So the tree, a plant, has managed to get
a mammal to bury its seeds

with just as much care
as a really good gardener.

It's one of those magical
rainforest relationships.

And the best thing about it is that
she has no idea how important she is-

The agouti is the only animal

that can disperse the seeds
of the brazil nut tree,

so the brazil nut tree
is completely reliant on the agouti.

It's a case of what we call
species specific dependency.

0ff it goes to bury one of the nuts.

And you know, I can guarantee that every
brazil nut that you've ever cracked open

has come from a tree
that was planted by one of these animals.

That's fantastic.

You've got to admit, ecology is fantastic.

1t's clear why the brazil nut tree
needs an agouti-

But how does the orchid that 1 found
fit into our story?

Like many flowers,
it uses pollinating insects, bees-

1n fact, these orchids use a very special
group of bees called Euglossine,

or orchid bees-

And more specifically,
they have to be males-

Unlike most bees, which are after nectar,

this one is after something
quite different-

He's after perfume-

He collects a waxy secretion
by rubbing his legs all over the flower-

And in doing so, pollinates that flower-

Collecting this perfume is so important
to a male orchid bee

that it may fly miles all over the forest
in search of it-

The reason that he's collecting scent

is that the males compete with one another
using smell.

They have a sort of a scent-off.

The one with the best bouquet of perfumes
gets the right to mate with the females.

But what has all of this got to do
with our story of brazil nut trees

and agoutis?

0nly the male orchid bees
pollinate the orchids.

To reduce competition between the sexes,

the males and females
have evolved different niches.

It's another example
of the extreme diversification

that takes place here in the rainforest.

So the females pollinate
a completely different species.

A very, very much larger one.

The one that I'm sat on.

The brazil nut tree.

Once a year,
the tips of the brazil nut tree branches

are adorned with large white flowers-

They attract insects
from all over the forest-

1ncluding the much larger
female orchid bees-

The nectar is hidden beneath
a special petal-

And the female orchid bees are one
of the few insects that are big enough

and strong enough to open the flowers-

This smaller bee, on the other hand,

simply doesn't have the strength
to open it-

This selective door policy is the tree's
way of ensuring that it will only be used

by insects which are guaranteed to visit
other brazil nut tree blooms

and then pollinate them-

The intricate relationship between
the male orchid bee and the flowers

is the reason that brazil nut trees
like this one

can only grow
in intact rainforest ecosystems.

Now, the brazil nut tree needs the agouti,

way down there, to disperse the seeds.

The agouti needs the female orchid bee
up here to pollinate the flowers

so those seeds are produced
in the first place.

The female orchid bee needs the male,

which in turn needs those orchid flowers.

That's why the brazil nut
needs the orchid.

You just couldn't make it up, could you?

This wonderfully complex web
of connections has all come about

due to the sheer biodiversity
of rainforests-

And understanding it reveals the
natural world in a very different light-

Animals don't simply live in forests-

They are the forests-

And forests without orang-utans
and elephants are broken ecosystems-

We might want to save rainforests
for the elephants,

when, really, we should be saving
the elephants for the forest-

We've been motivated
by what an orang-utan looks like-

We should be motivated by what it does-

Stretched out around me is the most
complex ecosystem on our planet,

home to millions of different species.

And whilst there's wonder in the detail
of their individual lives,

nothing competes with the sheer beauty
of the bigger picture.

The dynamic, functional,
living, breathing rainforest.

For me, science is the art
of understanding truth and beauty.

Well, here's the beauty.

And we've seen just a little of its truth.

If you'd like to know more about the
fascinating web of links between species,

the 0pen University has produced some
material both to inform and inspire you.

For your free copy, or to find out more
about 0pen University programmes, ring...

0r go to the website...

And then follow the links
to 0pen University.

And join me next time,

when 1'll be travelling to some
of the world's greatest grasslands-