[dramatic music] [water gushing] [enchanting music] [enchanting music continues] - In 1912, Sir Arthur Conan Doyle wrote this famous book, "The Lost World," an adventure into the past, filled with prehistoric monsters, a place that time forgot.

Hi, I'm George Page for "Nature".

"The Lost World" took readers to the mysterious, unexplored tepuis, plateau-topped mountains in Southern Venezuela.

Towering thousands of feet above the jungle floor, they stand separate from the world below, isolated and inaccessible.

This week we follow filmmaker Wolfgang Bayer, as he travels to Venezuela to bring back their real story.

Millions of years of isolation have made the tepuis mountaintop laboratories of evolution, and while we no longer expect to find dinosaurs, each tepui expedition has discovered new forms of life.

Imagine that.

We're still discovering new forms of life this late in the 20th century.

The tepuis represent a landlocked Galapagos, which we're just beginning to understand.

[stirring music] [wind howling] Deep in Southeastern Venezuela, in a region called the Gran Sabana, strange mountains rise from the jungle, giant columns of sandstone, jutting abruptly skyward from an emerald sea of rainforest.

[stirring music continues] Shrouded in mists, their summits are special worlds, mysteries of evolution.

Biological treasure islands distinct from the jungle below.

[stirring music continues] [stirring music continues] This landscape is one of the oldest on earth.

Long before the age of dinosaurs, before the continent split and the Atlantic Ocean was born, even before the first terrestrial life emerged from the sea, a massive sandstone plateau reached across this land for a thousand miles.

These mountains are all that remain.

Indian legends say that some are the ancient stumps of the trees of life, cut down in a harvest of greed for their fruit.

They're known by their Indian name, tepuis.

[wind rushing] It's been just over a hundred years since the first European naturalist stood here on the vast summit of Mount Roraima, one of the largest tepuis.

The craggy surface has weathered into fantastic shapes.

[wind rushing] [wind blowing] Cold winds and fogs play across its harsh expanse, replacing tropical sunlight with a chilly gloom.

[wind blowing] [stirring music] And in its eroded rock faces are the portraits of time.

[stirring music continues] This is the lost world Sir Arthur Conan Doyle populated with dinosaurs in his famous story.

It's not so far from the truth.

Strange and contradictory life forms, found nowhere else, flourish on these remote plateaus.

[playful music] [teeth chattering] [wings flapping] Many are completely new to science, and have yet to be identified.

[stirring music] There are more than 50 tepuis in Venezuela.

Most of them ascend from the plain of the Gran Sabana, a vast carpet of rainforest dotted with grassland.

[stirring music] [thunder rumbling] [water gushing] The tremendous power of water has carved and separated the plateaus, relentlessly working at the rock for hundreds of millions of years.

[stirring music] [waterfall gushing] Cutting vertical walls in the sandstone layers, the water exposes the past, opening up a record of one and a half billion years.

Eons of erosion have created an archipelago of distinct habitats, laboratories of evolution, where plants and animals have developed in response to a world much older than that of the Gran Sabana below.

[wind blowing] [wind blowing] These sedimentary sandstones are too ancient to contain fossils.

Nevertheless, history is written in their layers, and as erosion exposes the past, some surprises come to light.

Beautiful crystals, like these of pure quartz, gave rise to tales of fabulous jewels atop the tepuis, tales as yet unrealized.

[stirring music] [waterfall gushing] But the wealth of water pouring from the tepuis has created breathtaking beauty.

Angel Falls, descending 3,212 feet, the world's highest waterfall, surging from near the top of Auyan Tepui.

[waterfall gushing] Reports of such great wonders brought explorers and adventurers into this remote region.

The spectacular cataracts of the tepuis were photographed from the air by early pilots, but the first extensive exploration was begun by Captain Felix Cardona Puig in 1927.

Captain Cardona, initially an explorer, cataloged large numbers of previously undiscovered plants.

Pilot Jimmie Angel, pursuing stories of gold, attempted unsuccessfully to land his plane on Auyan Tepui in 1937.

He found no gold, but discovered the great waterfall which now bears his name.

The Phelps expeditions, begun in 1938, set out to explore many of the more remote tepuis.

William and Kathy Phelps continued to work in the region until the 1960s, and the highest tepui, Pico Phelps, is named for them.

[waterfall gushing] [propellors whirring] Today, new explorers have taken up their work.

[stirring music] The tepuis are magnets for scientists studying the mysteries of evolution, their sheer sides divide them into distinct biological realms.

Each one is different.

Each one offers new species to discover, new clues to the development of life itself.

[stirring music] [propellors whirring] [stirring music] [propellors whirring] These explorers come with the questions of modern science, seeking new knowledge from these islands in time.

The tepui formations are anchored in the stable granite bedrock of the Guiana Shield, the massive continental core of South America.

Only a few degrees north of the equator, they have never been glaciated, never inundated by the rise and fall of prehistoric seas, never torn apart by the upheavals of mountain building.

[stirring music continues] [propellors whirring] They stand as a faithful record of a distant past, long vanished from most of the earth.

They are among the few places where terrestrial life may have existed without interruption since it began, some 400 million years ago.

[stirring music] [propellors whirring] [stirring music] [propellors whirring] This multinational team of scientists is conducting cooperative studies of tepui ecosystems.

By combining their individual research specialties, they're seeking to understand each tepui, and how together, the tepuis influence the environment of the region.

[engines roaring] [propellors whirring] The climate here is dramatically different from the tropical forest below.

Perpetual cloud cover brings mist and rain, and temperatures that drop to just above freezing.

Vegetation has developed in response to these conditions.

Lichens, more at home in the Arctic, cling to the bare rock.

[wind blowing] An opportunistic member of the blueberry family hangs in precarious determination.

[wind blowing] Here on Roraima, little soil has developed.

Located on the eastern edge of the Guiana Shield, it's constantly buffeted by the strong easterly trade winds.

[wind blowing] And it's not only plants that have to cope with the high winds.

The tiny Roraima toad, found only here, has developed an unusual method of locomotion.

Curling into a ball, it rolls over the rock.

[wind blowing] [wind blowing] An awkward walk is only preparation for a daredevil leap.

[wind blowing] [insects chirping] A crevasse sheltered from the wind is a garden spot compared to the forbidding surface above.

The many species endemic to the tepuis are still being discovered.

Some are early forms of modern species, stranded on these plateaus as the tepuis became progressively isolated.

[insects chirping] [water babbling] A quiet pond is home to an unidentified cricket.

[insects chirping] [birds tweeting] Conan Doyle may have exaggerated the size of the reptiles, but he was right in speculating that evolution had left behind some ancient relics of a younger planet.

[birds tweeting] [insects chirping] [water babbling] The rugged terrain provides an enormous variety of habitats, and each one remains a different and surprising world.

[wind blowing] [all speaking in foreign language] - [George] The scientists plan their fieldwork, mapping out a coordinated effort to maximize the effectiveness of their research.

[scientists speaking foreign language] - [George] Dr. Carlos Schubert is the paleo-ecologist.

[Schubert speaking foreign language] - [George] Dr. Otto Huber, the botanist.

[all speaking in foreign language] - [George] Dr. Stefan Gorzula and Dr. Henry Briceno are the zoologist and the geologist of the expedition.

[waterfall gushing] [waterfall gushing] They begin their research with the rocks themselves.

[hammer tapping] [waterfall gushing] Dr. Briceno studies the forces that created the tepuis, erosion and uplifting, as part of a new dynamic theory of the history of the Guiana Shield.

[waterfall gushing] - This is a good example of how water has been working its way down the crack, along the border of the tepui, eroding away the rock, and opening this wider, and taking all this sediment down to the Caroni basin.

So we have the force of tectonic pushing up, and erosion eroding away the sediment and trying to erode the whole thing, and make this flat.

So we have that balance between these two forces, one tectonic, and the other one, erosion.

[wind blowing] [footsteps pattering] - [George] As a paleo-ecologist, Dr. Schubert studies the history of these habitats, and how a community of plants becomes established.

- Algae are the first substrate, organic substrate, that forms in the little puddles on top of the rock.

As soon as this substrate forms, then lichens and other plants come in, and they begin to grow there, and begin to add to this substrate, until eventually, larger plants can come in and grow in this place, and actually form a community.

In time, they will get larger and larger.

The process will accelerate because of the larger organic deposition, and they will eventually coalesce, and form the forest that we see covering the tepuis to a large extent.

[insects chirping] - [George] Schubert and his assistant take samples of peat moss.

They look for the deepest deposits, and use radiocarbon dating to determine the age of the sample.

[both speaking in foreign language] - [George] The earliest deposits found are only 8,000 years old, roughly coinciding with the end of the last ice age.

Schubert hypothesizes that during the ice ages, the tepuis became so cold and dry, that soil-forming processes stopped, plants migrated to lower elevations and then back again, as the climate changed.

While many of these species are ancient, their communities actually may be surprisingly young.

Dr. Otto Huber studies the distribution of the unique vegetation.

- The tepuis in Guiana are characterized that each of them has a different vegetation and different flora, and long time this has believed to be due to the fact that all of the tepuis were so isolated from each other, and from the surrounding lowlands.

[birds tweeting] - [George] But Huber is discovering that the tepuis' isolation is not so complete as was once thought.

Although many species are endemic, the tepuis also share many species in common.

They even show similarity to vegetation in the Andes, and as far away as Mount Kilimanjaro in Africa.

The key to life on the tepuis is not just their isolation, but also their climate and altitude.

[birds tweeting] - I think we have started to demonstrate in the last years with our research, that this static view, this view of things that would never change in time, is probably wrong.

Enormous number of different ecosystems, and the long time at their disposal to evolve in each single niche, have altered, even to a young and dynamic flora to speciate, to open up like a fan, in millions of different life forms and adaptations.

[enchanting music] [birds tweeting] - [George] These environments offer few nutrients, and some plants have found animal protein an excellent source of vital nitrogen.

This sundew, endemic to the region, uses sticky glands to trap an insect, which will later be digested and absorbed.

The beautiful blossom of the sun pitcher.

Unwary insects are attracted to the nectaries in the cupped leaves, but this genus, found only in the tepuis, is too primitive to excrete digestive enzymes.

It relies on bacteria to break down its prey.

Mosquito larvae, however, thrive in the tiny nutrient-rich pools.

They will hatch to fly out of this insect trap.

[stirring music] [birds tweeting] [stirring music] [birds tweeting] Dr. Stefan Gorzula, zoologist.

- We've spent five years exploring around about 40 tepuis in Southeastern Venezuela.

We've lived months up on the tepuis over this period.

We've now got a very good impression of what the tepui fauna is composed of, which is basically small rodents, the occasional opportunistic species like possums, coatimundis, small reptiles such as lizards, snakes, and amphibians.

These are ecosystems which have very low fertility.

The growth rate of the plants, everything is in a very, very slow turnover, and just doesn't give nutrients that would support large mammals like deer, peccaries, and large predators.

- [George] Each expedition offers the chance to find an animal no one else has ever seen.

[wind blowing softly] [grass crunching underfoot] - [Dr. Gorzula] Tubular bromeliads are quite often very abundant on tepuis, and each one of them has a nice little micro-habitat, with a water reserve in the base which frogs can hide in.

So one of the sampling methods that one uses on tepuis is to walk along looking into bromeliad tubes.

And if there are any frogs inside, one can see them immediately before they drop down into the... And try and hide themselves in the water.

- [George] Gorzula has discovered more than 25 new vertebrate species, including this little frog, named Stefania in his honor.

- [Dr. Gorzula] Most species have got breeding strategies where they lay a very few large eggs, with enough yolk so that the frog can develop completely within the egg, without having a free-living tadpole stage.

Stefania carries the eggs for the whole period of their development on her back.

- [George] Collecting animals isn't always so easy.

Some creatures make it a contest.

[rocks clattering] [footsteps pattering] [stirring synth music] [stirring music continues] [stirring music continues] [footsteps pattering] [stirring music continues] [rock scraping] [ominous music] [lizards rustling] And there's always one that gets away.

[stirring music] [wind howling] Compiling a complete zoological record on the rugged surface of the tepui entails exploring all its hiding places.

The many caves may be explored at night.

Daytime offers no advantage here.

[wind howling] [water babbling] [stirring music] The sound of the water rushing through these caves often makes too much noise to hear a creature move.

Gorzula watches for the reflections of his spotlight in a pair of eyes.

[stirring music continues] [water babbling] When he finds a specimen, the light blinds it long enough for him to grab it.

[stirring music continues] [water babbling] [wind howling] Most creatures that make their home on a tepui are small and difficult to spot, but some actually seek out the scientists.

[pan clattering] [possum snarls] - We've made a very interesting discovery.

This is an endemic subspecies of a possum, and the best way to sample them, is to hang up three-day-old salami, and wait for them to come into camp.

This species occurs from Chile in the lowlands, Argentina in the lowlands, as you go further north, they're found at very high altitudes up into the Andes of Venezuela.

And there's also this endemic subspecies in the tepuis.

See the rather beautiful face, beautiful markings, compared to the ordinary lowlander possum.

[footsteps pattering] Well, there you go.

Can tell your friends about the good salami.

[grass rustling] [waterfall gushing] - [George] Great torrents of water link the tepuis to the lowlands.

The rainy season lasts most of the year, producing a seemingly inexhaustible supply of water.

[water gushing rapidly] [waterfall gushing heavily] [water gushing stronger] [river gushing] Bit by bit, water is carrying the tepuis away, depositing their sediments downstream.

In this region, the streams drain into the Rio Caroni, a major tributary of the Orinoco.

[waterfall gushing] [waterfall gushing] [waterfall gushing] [waterfall gushing] The tremendous volume and force of this water has given Venezuela an important source of energy, hydroelectric power.

[waterfall gushing] [waterfall gushing] Guri Dam, one of the biggest hydroelectric power plants in the world.

EDELCA, Venezuela's power conglomerate, completed its construction in 1986, and it now produces energy equivalent to an annual consumption of 85 million barrels of oil.

[water gushing heavily] [water gushing heavily] Its turbine generators supply Caracas, a city of more than three million, with 90% of its electrical power.

[traffic humming] [horns honking] [birds tweeting] The reservoir of the Guri Dam, covering 1700 square miles, is the ultimate destination of the water and sediment from the tepuis.

[water babbling] As it was filled, vast areas of forest were drowned, displacing many animals.

Islands of trees remain on patches of higher ground, supplying food and shelter for their remaining inhabitants.

[birds tweeting] But these islands are too small to support many animals for long.

Most, like these howler monkeys, will soon have to swim to new forest.

[leaves rustling] [birds tweeting] The loss of this forest was part of the trade-off for a relatively clean source of power.

70% of Venezuela's electricity already comes from hydroelectric power, and the Guri plant is not yet working at full capacity.

[water babbling] [birds tweeting] But destruction of the rainforest has an ironic cost.

These forests are the very source of the constant rains that power the dam.

[wind blowing] [water babbling] [birds tweeting] The tepuis serve to concentrate the rainfall into the many streams which feed the vast reservoir.

[birds tweeting] [water babbling] Lowland tapirs swim through the still waters, feeding on aquatic plants.

They're jungle cousins to their closest living relatives, the horse and the rhinoceros.

[water babbling] [birds tweeting] [water splashing] Collared peccaries grazing by the water's edge, roam in gregarious groups of a dozen or more.

[water babbling] [peccaries grunting] [birds tweeting] Dense foliage provides protective shelter for the shy and reclusive, and a fitting backdrop for the more flamboyant.

[birds tweeting] The toucan.

These birds prefer the high treetops, and use their enormous bills to reach berries and seeds on the outer branches.

Brilliant macaws and parrots fill the forest with sound and color, in sharp contrast to the silent world of the tepuis.

[birds tweeting] The capuchin monkeys, alert and inquisitive, are the first to sense danger.

[fire crackling] The rainforest is burning, and like the flood, it's not an accident.

The fires have been set deliberately to clear the forest.

[fire crackling] [wind blowing] Large areas of the Gran Sabana are being stripped of their trees to make way for agriculture.

These old weathered soils are extremely low in nutrients, and the ash from burned trees produces enough added fertility to allow a few years of meager farming.

[birds tweeting] [birds tweeting] What was once a carpet of deep green jungle, is becoming a mosaic of forest and grassland.

[birds tweeting] The burning has been going on for hundreds of years.

The Pemon Indians have used fire to clear the land since they came to the Gran Sabana some 500 years ago.

Their origins are not known for certain, but they are not forest people.

They rely on farming.

[fire crackling] Years ago, their numbers were small, and their fires scattered, but their growing population has increased the need for land.

They set fire to the grass in an attempt to revitalize a pasture.

[fire crackling] [fire crackling] [fire crackling] The burning, however, does not go unchecked.

[siren wailing] EDELCA has established two full-time firefighting companies to combat the flames with modern technology.

Controlling the fires is essential in protecting their enormous investment in the Guri Dam.

[sirens wailing] [engines roaring] [propellors whirring] If the forest is destroyed, erosion from exposed soil will increase the sediment content in the Caroni River, sediments that would threaten the lifespan of the turbines at the plant.

[firefighters speaking foreign language] [propellors whirring] [fire crackling] [engines roaring] [propellors whirring] [fire crackling] [spades patting fire down] [propellors whirring] [fire crackling] [spades patting fire down] [firefighters speaking foreign language] [propellors whirring] [fire crackling] The helicopter creates a wind, to turn the fire back on itself.

[propellors whirring] [engines roaring] The loss of the rainforest threatens to alter the amount of rainfall on the high plateaus.

Indirectly, the fires here in the Gran Sabana, could destroy the fragile ecosystems of the tepuis.

[somber music] [somber music continues] The effects of the fire are being studied by soil ecologist, Dr. Horst Fölster.

- In this fire area of 1940, the forest was destroyed completely, and a regrowth started.

In this 50 years, it has not reached more height than we see here, but there's eight meters, and the young secondary trees are continuously dying.

A sign of very low vitality of the vegetation, very low growth, and an indicator also of the irreversible breakdown of an original forest vegetation.

[soil rustling] [insects chirping] - [George] The power company tries to discourage the burning, but the Indians' traditions are very strong.

[wind blowing] [leaves rustling] [tool chopping] The staple crops are bananas and yuca root, a thick tuber which is pulped and pressed to remove the poisonous yari juice, and then later baked into loaves and other products.

It's meager fare, but it's all the land will produce.

[ground rustling] [tools chopping] - The Sabana is burned regularly.

Every year, or every second year, and with each burning there's a lot of nutrients.

Nutrients go up there, or they're washed down.

So what results in the soil, is a very low quantity of nutrients.

The vegetation is a result of this extremely low fertility of the soil.

The grasses are extremely poor, have a very low digestibility, so the carrying capacity for wildlife or cattle is extremely low.

One can say that practically this Sabana grassland is without wildlife or economic use.

- [George] It may look like ideal grazing country, but the cattle can only eat tender new growth.

The food value in the grass is so poor, that each cow needs more than 20 acres to sustain it.

[cows grunting] Agriculture is undermining the critical equilibrium between the forest and the soil.

The crops are failing, and the forest may never regenerate.

[wind blowing] [birds tweeting] One of the very few creatures that can live in the infertile grasslands, is the termite.

[birds tweeting] Colonies dig hole after hole deep into the earth, but soon they too exhaust the nutrients in the soil.

The colony moves on, leaving the plain dotted with defunct mounds.

[wind blowing] The forests of the Gran Sabana are shrinking, and a desert of sterile grassland is taking their place.

[birds tweeting] But even more devastating than the spread of grassland, is gold fever, and the mining scars that gash the land.

[engines rumbling] [water spraying] High pressure hoses scour the sediment, causing unprecedented erosion.

[mud squelching] [water spraying] Mercury is used to separate the gold from the sediment.

Inevitably, the tainted sludge finds its way into the streams.

[water babbling] As mining drains vast amounts of water from the rivers, the banks are left high and dry.

[water babbling] Fish three feet long were once pulled from this river.

Now, this is a typical day's catch.

[fisherman speaking foreign language] [singing in foreign language] [cheerful music] - [George] The miners come into the towns that spring up around the strike, to trade their gold for cash.

[cheerful music from radio] It may be their only source of income, but it comes at a great price.

[engine rasping] Pollution from mining sludge, and increased erosion, threaten the valuable water supply of the region.

EDELCA has entered the battle to preserve the water, and protect the forest, the source of the precious rains.

[raindrops pattering] [stirring music] [raindrops pattering] [stirring music] [raindrops pattering] [stirring music] United by the water they share, the forest and the tepuis create a regional system of climate and hydrology.

In order to learn how to manage these ecosystems to maintain the water resources, the power company is funding the research Dr. Huber and the others are conducting on the plateaus.

[birds tweeting] [grass crunching underfoot] - [Huber] The phase of exploration that we started in '83, should also signify a step forward in research on tepuis.

This implies that we do not so much collecting, either zoological, or botanical, or geological.

We are more interested in studying the ecosystems, the tepui ecosystems as a whole, how they work, why are they there, what is their role in the regional or super-regional management plans.

- [George] One of the least explored and most beautiful of the tepuis is Chimanta.

It's also one of the largest, covering 150 square miles.

[birds tweeting] [birds tweeting] The mists envelop Chimanta's unique assemblage of life.

[birds tweeting] The golden-throated hummingbird, endemic to Chimanta.

It fluffs its feathers to keep warm in the early morning sun.

Indulging in a breakfast of nectar will serve to pollinate the plant.

[birds tweeting] [wings flapping] [tendrils rustling] Flying insects are less common in these high altitudes than in the forests below.

Their role as pollinators is all the more critical to the plant life here.

[birds tweeting] [tendrils rustling] [bee buzzing] In the mists, a spider's web catches more dew than prey, but even a drop of water is a starting place for life.

[birds tweeting] [water babbling] The large Chimantea plant closely resembles the form of the Rosetta tree in the high Andes, a similarity which may point to convergent evolutionary patterns in the different mountains.

[birds tweeting] [grass rustling] Dr. Glenda Medina, ornithologist, sets a mist net to ensnare birds without harming them.

[birds tweeting] - To me, to study birds in the tepuis, is only an instrument to understand how the whole ecosystem works, and in a way, having an ornithologist in a group that is formed with geologists, or this zoologist, and botanists, each one is contributing to understanding how this ecosystem works, and how to manage the ecosystem to preserve it.

[birds tweeting] - [George] Her net has entangled a diglossa, one of the highly specialized birds of the tepuis.

[birds tweeting] [birds tweeting] [bird screeches] [wings flapping] A nectar feeder, it's called the great flower piercer, because it uses the hook on its beak to pierce the base of the flower.

Until the diglossa developed this strategy, only a hummingbird could drink nectar from a flower like this.

[birds tweeting] [birds tweeting] Dr. Huber carefully prepares a specimen of Chimantea mirabilis for later study.

[birds tweeting] [paper rustling] [paper rustling] [birds tweeting] [package rustling] At the national herbarium in Caracas, Dr. Julian Steyermark catalogs and analyzes the samples.

Steyermark has cataloged more types of plants than anyone else in history.

At last count, more than 132,000 specimens.

He made his first trip to the tepuis during World War II, looking for quinine to treat soldiers suffering from malaria.

He discovered instead, an untouched wealth of plants on the high plateaus, including the genus Chimantea, and hundreds of new species.

[paper rustling] [diagrams rustling] [stirring music] [birds tweeting] There will be more discoveries from the tepuis for years to come.

[stirring music] [birds tweeting] New research just being proposed will examine the genetic makeup of tepui plants and animals.

Learning how life forms here are related, will help scientists unravel the history of their isolation.

[brooding music] [birds tweeting] [brooding music] [birds tweeting] And some of them are living fossils, that will connect this continent to other continents, and the great movements of the earth.

[brooding music] [wind blowing] [brooding music] [wind blowing] These strange remote summits are among those rare places that still may be essentially as they were when they were formed.

They hold many clues to the great scheme of evolution.

[brooding music continues] [brooding music continues] Already we have learned that isolation is never quite complete.

The tepuis are vitally connected to the world around them.

Never again can they be called "the lost world".

[brooding music continues] [brooding music continues] [brooding music continues] [brooding music continues] [brooding music continues] [brooding music continues] [brooding music continues] [brooding music continues] [wind blowing] [stirring music] [stirring music continues] [stirring music continues] [stirring music continues]