Rainforest Habitats Globally

Background information;by edgardowelelo@yahoo.com, Master of the game

Twelve hours of reliable sunshine all year round and regular downpours of rain provide the tropical regions of our Planet Earth with perfect growing conditions. The result is rich RAINFOREST and a variety and complexity of life unmatched by any other habitat on Planet Earth. Tropical rainforests hold the greatest diversity of life of any environment on Planet Earth. The sheer numbers of species are extraordinary. One hectare are (2.47acres) of Malaysian rainforest was found to contain more than 180 different species of tree; in a similar area of deciduous temperate woodland, you would be lucky to find ten. So far, in the tiny CENTRAL AMERICAN COUNTRY OF PANAMA, more than 1500 species of butterfly have been found; in the whole of US, there is little more than half that number, while in the UK, there are only 56 native resident butterflies. In the Amazon River there are more than 3000 fish species – more species than in the whole of the NORTH ATLANTIC OCEAN. In fact, though the TROPICAL RAINFORESTS cover just 3 per cent of the Planet Earth’ surface, they are thought to contain more than 50 per cent of all the animals and plants described or yet to be described.

THE PERFECT GREEN HOUSE

Walking into a TROPICAL RAINFOREST for the first time can give you a physical shock. It is almost as if the HUMIDITY is punching you in the stomach Sweat pours off your skin and you feel completely submerged in the weight of the air. Sometimes the ground cover can be so thick that, with every forward step, the vegetation seems to be making a grab at your ankles. If you dare to sit down on the forest floor, you wonder if the fungus will have eaten the sodden clothes off your body by the time you move on. It is hardly surprising then that RAINFOREST can be one of the most demanding habitats to work in. But for the plants that dominate this sticky world, the conditions are perfect. The high input of energy from the SUN and the continuous supply of rainfall are the key reasons for the enormous wealth of plant life found In the TROPICAL RAINFOREST of the EQUATORIAL REGIONS. In these steamy hot house conditions, vegetation grows faster than anywhere else on our Planet Earth. The enormous quantity of RAIN that falls has also moulded the FORESTS in another way. No one who has ever been drenched by a tropical storm in a jungle can fail to be impressed by its power. It starts quietly as the first heavy drops drum on the leaves far above. But soon the drum roll builds to a roar and water comes pouring down from the canopy. This regular torrent leaches nutrients and minerals out of the ground and leaves RAINFOREST SOILS comparatively infertile. Yet it is this very shortage of soil nutrients and their patchy distribution that has encouraged competition and diversity among the plants. The other key to DIVERSITY is the massive three – dimensional structure of the rainforest. Beneath the canopy of the enormous trees, their  trunks and the trunks and branches of younger, shorter trees provide smaller plants such as climbing lianas and orchids with their own particular niches.  The tangled framework that results provides nooks and crannies and feeding opportunities for animals. Continuous sunshine is also crucial for DIVERSITY. Though the annual amount of sunlight at the equator is no more than that at the POLES, it is delivered in 12 – hour doses every day throughout the year. The Sun always rises around six in the morning and always sets around six in the evening. One moment you can be walking among bright shafts of warming sunlight’ streaming down from the canopy, and the next it feels as if someone has switched off a light. The familiar sounds of day time are instantly replaced with a new cacophony of night – time cicadas and courting frogs, and suddenly the forest becomes a far more frightening place to be in. For WILDLIFE, life in the TROPICS is comparatively easy. There are none of the seasonal extremes of climate experienced as you approach the POLES, and with no changing seasons to disturb their life – cycles, insects in particular have proliferated. This has driven further diversity among the plants on which so many of them feed. As plants have evolved various defenses, so the insects have changed their methods of attack, and the resulting arms races have further fuelled diversity. Similar arms races between predators and prey have encouraged enormous proliferation among the animals themselves. And with a relatively stable supply of suitable food, most species can develop and specialize further and further. But cooperation, too, has driven the diversification of species. The forest canopy is so thick that little wind is available to pollinate flowers or spread seeds. So plants have developed intimate relationships with animals, bribing them with nectar to carry pollen from flower to flower and fruit to disperse the resulting seeds. Such mutually beneficial relationships are particularly common and complex in RAINFORESTS. The final HOT HOUSE factor in this burgeoning of life is that the TROPICAL CLIMATE has, for the most part, remained unchanged over thousands of years, giving many RAINFOREST ECOSYSTEMS time to develop a complexity unmatched anywhere else.

THE RAIFOREST BELT

TROPICAL RAINFOREST is found, as its name suggests, between the TROPICS OF CANCER and CAPRICORN, wherever the annual rainfall is more than 2500 mm (98 inches) per year – an EQUATORIAL BELT that extends from QUEENSLAND in AUSTRALIA in the east to the vast RAINFORESTS of SOUTH AMERICA in the west. Up to 40 different types of RAIFOREST have been described, but they all fall into five (5) basic categories.

1. LOWLAND TROPICAL FOREST

The most extensive by far is the EVERGREEN LOWLAND TROPICAL FOREST, which occurs up to around 1000 m (3280 feet) and includes an unequalled abundance and variety of trees, including the giants so prized by loggers. The canopy often towers more than 45 m (150 feet) above the FOREST FLOOR, with occasional ‘emergents’ protruding to more than 60 m (200 feet). This is the classic jungle of the TARZAN MYTH, where constantly moist air encourages the climbing CREEPERS and LIANAS and a covering of EPIPHYTES in the canopy. It makes up the thirds of the total area of TROPICAL RAINFOREST and includes the vast river basins of the AMAZON and DRC RIVERS. It is also found in CENTRAL AMERICA, WEST AFRICA and various parts of SOUTHEAST ASIA, though here it has been broken up into fragments by extensive logging.

2. TROPICAL DECIDUOUS FOREST

Move a few degrees NORTH OR SOUTH of the EQUAOR, and the climate becomes more seasonal. Periods of heavy rain are interspersed with months of driver weather. Up to a third of the trees will shed their leaves  each year, and in the  ‘monsoon forests” of ASIA, the trees come into leaf with the onset of the monsoon season. There are few climbing plants and epiphytes, which need continuous moisture and cannot survive the drier spells. Though, INDONESIA still has reasonably large areas of TROPICAL DECIDUOUS RAINFOREST, elsewhere in ASIA, AFRICA and SOUTH AMERICA, most of it has been logged or cleared for farming.

 

3. FLOODED FOREST

Many of the GREAT TROPICAL RIVERS rise and fall throughout the year, flooding vast tracts of LOWLAND FOREST – known as SWAMP FOREST or FLOODED FOREST. The stresses of flooding cause the trees to be smaller than those of dry lowland forest, and the diversity of species is also lower. With the exception of stretches along the Fly and Sepik rivers in PAPUA NEW GUINEA, most of the swamp forest of SOUTHEAST ASIA has been cut down. But in SOUTH AMERICA, vast areas of flooded forest still remain. There are two distinct types. VARZEA is found on the floodplains of white – water rivers such as the AMAZON that are heavy with sediment washed down from the Andes. This sediment is trapped by the buttress roots of the trees and builds up as rich soil. Along the floodplains of the black – water rivers such as the RIO NEGRO is ipago forest. These rivers carry no sediment, and so no soil builds up. But in the dry season, when the water – level falls, beautiful banks of sand are exposed, out of which the trees grow – mainly PALMS but also giants such as KAPOKS, with their spectacular buttressed roots.

4. TROPICAL MOUNTAIN FOREST (MONTANE FOREST)

Climb up from the sticky humidity of the lowland forest floor and you enter a very different WORLD. With every hundred metres, the temperature drops about half a degree centigrade. Soon you leave behind the towering trees of the lowland forest, and the canopy height drops to 15 – 30 m (50 – 100 feet). Not only do the trees get shorter, but the leaves become smaller, too. Twisted, gnarled, multi – stemmed trunks replace the single, straight ones of the lowland forest, and when you get above 2000 m (6560 feet), the trees are barely taller than a man.

The vegetation changes to that more reminiscent of temperate regions. In the HIMALAYAS, for instance, you find the beautiful rhododendrons that were transplanted as to colder northern climes. Cold temperatures bring mist that engulfs the forest in twisting cloud. Light levels are reduced, and condensation makes the leaves constantly run with moisture. Many of the branches are covered with dripping lichens, the forest floor is a carpet of wet, spongy moss, and the canopy is fully of epiphytes –  orchids and bromeliads – enjoying the permanently moist air. You are now in cool, damp cloud forest – a blessed relief from the oppressive sanna of the lowland rainforest below. In SOUTHEAST ASIA, gibbons swing through the cloud forest branches and giant hornbills fly noisily across the steep valleys. In Central America, this is the world of hummingbirds and quetzals.

 

5. MANGROVE FOREST

Along sheltered TROPICAL SHORES grows a highly specialized type of RAINFOREST. Though MANGROVES are found as far north as 32 degrees, and even further in the SOUTHERN HEMISPHERE, the largest and most extensive mangrove forests are found alongside the EQUATORIAL RAIFOREST BELT. Mangroves are specially adapted for life in salty and tidal environments, with breathing roots that stick up out of the waterlogged mud into the air to absorb more oxygen. Of all the RAINFOREST HABITATS, this has to be the least welcoming. At high water, the thick, scrubby vegetation is hard to penetrate even in a canoe. .At low tide, you find yourself squelching through sticky mud. But it is this inaccessibility that makes MANGROVES so valuable for wildlife. The largest remaining MANGROVE FOREST in the east is found in the SUNDARBANS of the GANGES DELTA, where a healthy population of TIGERS still hides out. In the west, MANGROVE is still found along parts of WEST AFRICA, the coast of Central America and the CARIBBEAN ISLANDS – in Trinidad, for example, mangroves provide a safe night – time roost site for hundreds of bright red scarlet ibis. In most of Southeast Asia, though, mangrove forest has been scrubbed out to provide ponds for prawn – and fish – farms.

THE GIANTS

The RAINFOREST is essentially a gallery superstructure supported by trees. Each tree creates a framework for other plants and animals to live on and in. GIANT EMERGENTS – trees that emerge from the top of the CANOPY – can reach 60 m (200 feet) in height and 17 m (56 feet) in girth. But most manage a more modest 30 m (100 feet) in height. Rainforest trees are usually evergreen with the same simple design; tall, slender trunks and simple, branching, umbrella – shaped canopies. Their root systems tend to be shallow, and so the trunks require extra support from buttresses. These are provided by roots that grow above ground and extend upwards and outwards from the trunk as thin flanges. Unlike temperate trees, rainforest trees are able to grow all year round, and so they have no growth rings. Though they may live to be 1400 years old, they can take 60 years to reach maturity. Even then, a tree will not flower and produce fruit every year, rationing itself to every   three to ten years, perhaps taking turns with other trees to use the services of animal pollinators and dispersers.

GOING UP, GOING DOWN

Today a variety of specially designed hot – air balloons can carry you up and over the FOREST CANOPY. You can float just a few metres above the TREE TOPS with your feet literally dipping into the endless sea of green that forms the FOREST CANOPY. The trees arch into LEAF at this level, and their foliage is crowned with life. They provide a platform for EPIPHYTES and CLIMBERS that clamber through the countless umbrellas of LEAVES to bathe in the full glare of the SUN. This is the powerhouse of the forest. Light and heat are at their greatest – temperatures may reach 32°C (90°F) – and so most of the PHOTOSYNTHESIS  takes place here. Flowers and fruits abound, the canopy buzzes with insect life, and the network of branches provides aerial walkways for monkeys and squirrels. As plants scramble up towards the light, they tend to form layers of foliage. Each level filters out yet more light from the one from the one below, forms a barrier to warmth from the Sun and traps in moisture. The principle is the same in TEMPERATE FORESTS, but what makes TROPICAL FORESTS so different is the spectacular range of strata, the enormous number of plants within each and the huge differences in light levels.  It is a vast cathedral made up of many worlds, each with its own microclimate. To explore downwards, you need to take to ropes. Just below the CANOPY is an UNDERSTOREY of smaller or younger trees at different stages of growth, and passing through them, on their way up, are LIANAS and EPIPHYTES. Some of these will complete their LIFE – CYCLES halfway up, while others must climb to the very top. The smaller trees may spend many years here waiting in the wings for light and space. At this stage of their lives, they are shade tolerant and may grow very slowly. But when a fallen tree provides the opportunity to reach the sunlight, they will surge upwards to maturity. On the FOREST FLOOR, life is very different. Only 2 per cent of SUNLIGHT penetrates down here, temperatures reach just 28°C (82°F) and the humidity soars to 90 per cent. In the murky light, only shade – tolerant plants can survive. In some forests, the floor may be so dark that little survives. In others, where there is make space and shafts of light filter down through the foliage, the ground is a tangle of young trees, shrubs and lianas. This is particularly characteristic of MONSOON FORESTS in ASIA, which lose their leaves in the dry season, giving plants on the FLOOR a short chance to establish themselves before the gloom sets in again.

  THE RUSH FOR LIGHT

IN a VIOLENT TROPICAL STORM, a tree crashes to the ground and perhaps more than a thousand years of interdependent plant and animal life comes to an end. And as the tree falls, it may bring other trees with it, creating a small clearing and bringing the sudden gift of light. Almost overnight, humidity plunges, temperatures rocket and even nutrients in the soil change. But though the stable environment of the FOREST FLOOR has been shattered, the transformation is one that is vital for the regeneration and diversity of the forest. All over the forest floor, seeds have been waiting for such a moment, some for many years. Large seeds, typical of primary forest trees of the AMAZON, are designed to live off their reserves while establishing themselves slowly in the shade and then bursting into accelerated growth as soon as light appears. In this new, dynamic environment, competition is intense. Within days, animals moving into the cleaning will have brought yet more seeds with them. A race is on to get a foothold before the dense ceiling of vegetation closes over again. Saplings already present respond to increased light by putting on a spurt of growth towards the CANOPY. The young jungle grows quickly. In less than ten years, it may not have the same height as the original forest, but it will already have the same leaf coverage.

THE CLIMBERS

In a WORLD dominated by TALL TREES, it might seem impossible for any other plant life to penetrate this tight – knit community. Yet there are some that do so with such skill that they are able to make their way to the FOREST CANOPY. There are several ways to succeed at winding and grasping your way to the top. Some CLIMBERS such as RATTANS use thorns and brute force to get there, hooking onto the surrounding vegetation and reaching up to 200 m (655 feet). PITCHER PLANTS also climb like this, using special whip – like extensions of their leaves to lash onto vegetation. These same leaves can turn into the pitchers – traps that catch and drown found such as insects and even reptiles and small mammals in a digestive broth.  Other plants such as lianas tether themselves by growing tendrils that sprout from their leaves or stems and act as guy ropes. These tendrils have evolved to reach away from light, waving around into the gloom in search of something to lash onto. When they brush against another plant, they are stimulated to curl and grasp with lightning speed. The tendrils of a tropical American gourd, for instance will curl within 20 seconds of contract and can coil around its support within 4 minutes. Some climbing plants use CLASPING ROOTS to anchor themselves as they climb. These special sideways – growing roots develop adhesive hairs when they make contact with the surface. (Ivy works like this, and anyone who has had to pull it from a wall will know just how strong a group these roots can exert. Plants that use clasping roots may lose their ground – feeding roots and finish high up in the CANOPY, dependent on their side roots to keep them alive.

GARDENS IN THE AIR

Gaining access to LIGHT without investing in long stems or roots is a popular strategy, and RAINFOREST TREES are often festooned with exotic gardens of orchids, cacti, aroids and bromeliads. These plants are EPIPHYTES and they make a living by setting up camp high on the bark of tree branches.  Many lichens, mosses and ferns have evolved to do this. They are not parasitic, since their roots do not penetrate the bark for food, but their roots may absorb moisture from the air as well as their surroundings. Epiphytes do especially well in the moist conditions of the cloud forest, where they may form thick mats along the high branches of the CANOPY. Little pools of water form in the bromeliads, providing high – altitude homes for frogs. In fact, whole communities of small animals can live permanently in these gardens in the air. Many epiphytes form associations with ANTS – the INDONESIAN Myrmecodia echinata develops tuber – like lower parts that are inhabited by ants, whose activities release nutrients used by both plant and ants. The epiphytic way of life is highly successful, and a quarter of all plant species in lowland forest are epiphytes. They are so numerous that, in places, their leaf output may be greater than that of the tree they are growing on. In one tree crown alone, their weight may reach several tons.

JUNGLE WARFARE

Plants not only create a dense, towering rainforest structure, they also produce vast quantities of edible food – LEAVES. A square metre (11 square feet) of LOWLAND RAIN FOREST can produce a massive 11 square metres ( more than 13 square yards) of leaves. RAINFOREST TREES have evolved ingenious defences to avoid being stripped bare, but leaves are too valuable a source of food for animals not to fight for. In a battle that  has raged for millions of years, both sides have gained and lost ground, producing extraordinary strategies along the way.

DIGESTIVE PROBLEMS.

PLANTS have one great advantage; their leaves are made of cellulose, which is difficult to digest. Some animals such as CATERPILLARS have got around this by breaking down the tough cell walls with relentless chewing. Large leaf – eaters, though, would find the amount of chewing necessary to get enough energy from the food impossible. Instead, they have added cellulose – digesting bacterial to their gut floras to do the job for them. But bacteria are not fast workers. Leaves digested in this fashion travel slowly through the gut, and as a consequence many large leaf – eaters, such as South American howler monkeys, are heavy and slow.  Others, such as proboscis monkeys from the flooded forests and mangroves of Borneo, have large pot bellies in which they ferment their intake of tough leaves and seeds. Hardly any birds are leaf eaters, as the fermenting process    would make them too heavy and slow to fly. A few, however, have persevered with this system of digesting cellulose, the most famous of which is the HOATZN of SOUTH AMERICA. This bird keeps a colony of cellulose digesting bacteria in its enlarged oesophagus and crop, rather like the fermentation system in a cow’s stomach. Perhaps not surprisingly, since the leaves it eats take almost two days to move through its body, the HOATZIN produces characteristic manure – like smell, giving it the nickname of STINKBIRD. The leafcutter ants of Central and South America have become fungus farmers in their battle with plants. In their underground nests, they chew their leaf booty into a pulp and then add fungus spores, harvesting the fungus that subsequently grows.

PAINFUL AND STICKY ENDS

Being made of indigestible cellulose gives plants a ready – made deterrent, but they have also evolved other weapons. Many are armed with vicious prickles, spines and thorns to keep marauders at bay, while others use chemical warfare against the relentless army of chewers. The array of toxins and deterrents that RAIFOREST    PLANTS have come up with is more proof of their extraordinary resourcefulness. Some use substances that trap or disable leaf – eaters. As soon as it is punctured, whether on its trunk or a leaf, the Brazilian rubber tree produces a sticky liquid, familiar to us as latex – the raw material for rubber. It is not only toxic but also oxidizes on exposure to air to form thick glue that gums up the mouthparts of insects. But some insects have managed to foil the defence, disarming the tree by punching small holes in the leaf around the bit they are eating or by severing the main latex duct.

CHEMICAL MANIPULATION

Many RAINFOREST PLANTS have resorted to even more ingenious ways of using chemicals. For instance, some mimic the juvenile hormones of their attackers to trick them into arrested development, forcing them to live out their lives as larvae, unable to reproduce. Others disrupt the various stages development so that insects metamorphose into disfigured adults. Plants can even change the fertility of grazing mammals, producing oestrogen mimics that interfere with their fertility. In some cases, the chemicals used are powerful toxins that kill humans; strychnine and cyanide are common in RAINFOREST PLANTS. Yet the ingenuity of insects to outwit even these powerful deterrents is equally remarkable. In the chemical arms race, insects have evolved a battery of powerful enzymes to break down poisons, and for every plant poison, there is least one leaf eater – that can detoxify it. Some insects are even able to use plant poisons against their own enemies. Caterpillars of the huge birdwing butterflies  of PAPUA NEW GUINEA feed on poisonous lianas and store the toxins, using them through to adulthood, displaying a vivid, colourful warning pattern, signaling to predators that they are toxic. More bizarrely, aphids that feed on plants from the Asclepiadacea family use the plants’ toxins to drug the spiders that eat them. The psychoactive properties of the toxins cause the spiders to spin crazy, disrupted webs. Other insects have a more personal use for their sequestered poisons – male danaid butterflies gather poisons from the plants they eat and modify them for use as aphrodisiacs. As fast as plants can evolve new defences, the remarkable adaptive abilities of leaf – eaters will eventually allow them to overcome these, too. Successful damage limitation is the best that plants can hope for in the continually escalating arms race.

JUNGLE PARTNERSHIPS

There are times when PLANTS go to great lengths to persuade animals to feed on them. To produce the fittest possible, genetically diverse offspring, they produce sexually – through cross – pollination – and so require a delivery system to ensure their pollen reaches another flower of the same species. In the still, windless environment of the RAINFOREST, most plants rely on animals as couriers, often producing SPECIAL FLOWERS with food or other lures to attract specific helpers. Though many RAINFOREST TREES takes 30 to 40 years to mature and rarely flower annually, when they do, they put enormous effort into the process. Their flowers and fruit are often spectacular and result in incredible quantities of seed – 1 ha (2.5 acres) of LOWLAND RAINFOREST produces as much weight of fruit and seed as 12 ha (30 acres) of temperate oak woodland. Plants can gain an edge over rivals by dispersing these seeds as widely as possible. Luscious fruits are therefore designed to attract highly mobile carriers, including monkeys, bats and birds, resulting in yet another complex web of relationships.

PERFUME MERCHANTS

FLOWERS in the RAINFOREST tend to be large, colourful and highly scented. Those of the balsa tree, for instance, are 12 cm 5 inches) long and 8 cm (3 inches) across at the mouth. Many flowers are brilliant colours to attract their pollinators, especially if these are birds. The Sarawak mistletoe, for instance, attracts flowerpeckers with bright red flowers which have petals that spring open when the birds brush by, revealing a nectar reward. In the still, moist forest air, scent carriers over long distances, and rainforest flowers use it to draw in pollinators. The range and inventiveness of these scents remarkable. Orchids in particular have complex flowers with a repertoire of sophisticated perfumes. The Madagascan comet orchid, for instance, attracts

moths with a powerful scent resembling perfumed soap. Others draw in pollinators such as flies or carrion beetless by mimicking the foul odours of putrescence. Quite a few flowers that trade at this end of market add to the illusion with colours which mimic rotting flesh. The variety of fetid smells they produce its quite overwhelming. Aristoluchia vines produce elaborate flytraps that smell like rotting fish. The flowers of the calabash tree open at night to release a smell of sweaty cheese, irresistible to bats. But the champion stinkers have to be the monster rafflesians, which grow in the forests of Southeast Asia. Not only does Rafflesia arnoldii produce the largest flower in the world at up to 0.9 m (3 feet) across, but its flower emits one of the most revolting smells in the plant kingdom. With just a few days to ensure pollen is collected and deposited, Rafflesia makes every effort to attract flies, growing a huge, red, carcass – like flower on the forest floor that reeks of rotting meat.

 

EVERYONE’S FAVOURITE FRUIT

FIGS are among the most common RAINFOREST PLANTS, and lots of animals have developed a taste for their fruit. Across all three tropical continents, figs are the single most important source of food for rainforest fruit – eaters. In Central America, 26 species of birds have been found feeding from just one species, and in MALAYA, in just three hours, 47 species of birds were seen feeding on one tree alone. The result is that fig seeds seem to get everywhere. As many as 20 species of fig may be thriving in any one area of a forest, from small bushes to the stranglers with their extraordinary trunks and aerial roots. When a strangler fig seed lodges in the branch of another tree, it grows by sending out long roots down to the ground and then producing aerial roots, eventually smothering the host. Each species of strangler has its own specific wasp pollinator, and all species produce masses of fruit -. some upwards of 100,000 on a single tree. Since they produce fruit all year round, figs are crucial source of food during times when other fruits are scarce.

LONG – DISTANCE TRANSPORT

The best pollinators for long – distance dispersal are strong flyers such as birds, bats, hawk moths and insects that forage over long distances. The most common of these are bees, and in most RAINFORESTS, they perform the daytime pollination duties. Orchid bees, for instance, will use the same daily routes of more than 20 km (12 miles) in search of food, collecting and refueling at the same plants along the way. They may also have complex relationships with their providers. Female orchid bees are large enough to lift the hood and collect the nectar inside, in advertently pollinating the flower as they do so. But the colourful males of these bees visit orchids, specific ones that usually grow on branches of the Brazil – nut tree. They collect perfume from the orchids, pollinating them as they move from flower to flower. When they have enough, they mass together in a swarm, buzzing and diving in a performed mass to attract the attention of the females feeding from the Brazil – not tree flowers. It is an elegant system of mutual interdependence between the tree, specific orchids and specific bees. Though insects are the most important daytime pollinators, birds are also busy in many rainforests. In South and Central America, hummingbirds have the monopoly, while in African and Asian forests, sunbirds do the same job. At night, the work falls to bats. Flowers specifically adapted to the needs of bats are easy to spot, being usually while or light – coloured (bats locate their flowers at a distance by SONAR, not SIGHT) and easily accessible, with large quantities by nectar. Those in the Parkia genus hang down from the CANOPY in pom – pom – like clusters on long stalks. Each cluster has a mass of pollen – bearing stamens, which shower a bat in pollen as it lands momentarily to sip the nectar.

 

HEAVY DUTY DISPERSAL

With so little wind in the FOREST, most plants must also use animals to disperse their seeds and fruit, though this transaction is a little more complicated. While plants want animals to eat their fruit and consequently disperse their seeds, they want to protect the seeds themselves from being damaged or eaten or at least to ensure that some survive to germinate.

 

The strategy of FIG TREES is to produce hundreds of tiny, gritty seeds in small, tasty, easily digested fruit, which many different animals enjoy. A fruiting fig tree is always a big event in the forest, drawing animals from all around. In Central Africa, for instance, it would be quite possible to see lowland gorillas, chimpanzees, three or four monkeys, squirrels and many different species of birds all feasting together in one tree. By flooding the market with millions of seeds inside tons of fruit, the fig tree has increased its chances of at least some progeny being dispersed. But this comes at a price – tiny seeds have very limited reserves and must germinate fast if they are to survive. Most other plants in the FOREST choose to produce larger, more nutritious seeds, which are dispersed by specific couriers – specialist birds and bats that eat almost nothing but fruit. TOUCANS in SOUTH and CENTRAL AMERICA, large fruit -eating bats in Southeast Asia and the Palm – nut vulture in WEST AFRICA are all specialist fruit – eaters that thrive on the rainforest’s need to spread seeds. Fruits aimed at birds are often brightly coloured and conspicuous, while dull – coloured, pungent fruits such as wild bananas are meant for the more scent – conscious bats. The RAINFOREST provides such an abundance of easy pickings that many fruit – eating animals are able to spend time and energy on other things. In the rich FORESTS of New Papua Guinea, for instance, birds of paradise are able to invest energy in spectacular and extravagant plumage and devote time to collaborate courtship displays. In some cases, the relationship between a plant and its seed – disperser is so close that it becomes one – to one. Though more than 20 species of birds feed on the fruits of the COSTARICAN tree.- Casearia corymbosa, only one behaves in a way that  makes it the perfect seed disperser. Tityras are small, silver birds with black face masks, easily spotted by hawks. To avoid being caught, tityras snatch fruit from the tree and dash off to eat it under cover, thus moving the seeds to places where they may have a better chance of finding room to grow. In their efforts to evade predators, tityras have become the only birds successfully to disperse cassava seeds, and now the tree and birds are totally dependent on each other. The Brazil – nut tree depends on the absent mindedness of one particular animal, the AGOUTI, to disperse its nuts. The Agouti is the only animal that can break the hard outer shell of a Brazil – nut cluster. It will eat and destroy a good deal of the seeds inside, but it buries others and forgets where many of them are – absent – mindedness that gives the nuts a chance to germinate. Some of the largest trees produce huge seeds or nuts – far too big for any but the largest mammals to disperse. Their fruits drop to the ground, creating a feast just below the tree. In African RAINFORESTS, elephants will move in on such a bonanza, gorging themselves and later depositing the seeds in a rich manure of faeces some distance away.

 

PREDATORY INTENT

Of all the RAINFOREST ANIMALS, the most frustratingly elusive are the large meat – eating predators. You can spend years working in the jungles of SOUTH AMERICA without ever seeing a Jaguar, and the leopards that prowl the forest of WEST AFRICA are far more difficult to spot than their shy relatives in the drier parts of Africa. Compared to the enormous diversity of rainforest plants and plant – eaters, there are relatively few predators, especially larger ones. Yet their members are still greater than in other forests, largely because there are so many insects available to feed on. In fact, most rainforest predators are insectivores, and many of the predators are invertebrates themselves.

SMALL FRY

With so much insect food on offer, it is hardly surprising that there are insectivores in all the rainforest – animal groups. Many of the small mammal predators specialize in insects. Up in the CANOPY of the AMAZON RAINFOREST, tree anteaters attack the nests of ants and termites. These social insects have a daunting combined biting power, but thick furs protects the anteater, and the ant – eating pangolins of Africa and Asia add a defence of bony scales. Though many of the primates depend on leaves and fruit, some have become insect specialists as well. The shy lorises of Asia and pottos of Africa, for instance, use their dexterous fingers to deal with the tricky defense mechanisms many insects have developed. The chimpanzee perhaps the ultimate jungle omnivore – has used its intelligence to exploit practically every source of food, including insects. Famously, chimps have learnt to shape special tools to dip into the termite mounds and extract the juicy inmates. If you are a bird watcher, the insect – eaters are probably among the easiest birds to spot. One of the most conspicuous sights in the forest of CENTRAL AMERICA is the brightly coloured JACAMAR, which sits upright on a perch before dashing out to catch a passing butterfly. In the African rainforest, bee – eaters behave in much the same way and have developed a clever whipping technique to remove the stings from the bees they catch. Woodpeckers as a group are highly successful insectivores and occur in many RAINFORESTS. Some not only raid termite nests for food but also make their nests within these earthy structures. Even hummingbirds and sunbirds, which normally feed on NECTAR, recognize the high nutritional value of insects and catch them for their growing chicks. But the most impressive spectacle provided by the insect – eating birds must be the multi – species flocks that pass noisily through the forest, routing out their prey.  You often hear them coming, because they call all the time to stay in contact. By creating a wave of movement, all the birds benefit from the resulting disturbance. Other birds specialize in following behind army and driver ants as they march through the forest. Any insects that fly from the jaws of the ants are snapped up by the ant birds.

ALL AS ONE, SMAL AS BIG

With so much invertebrate prey on offer, it is hardly surprising that there is an enormous variety of invertebrate predators in the RAINFOREST. But without any doubt, the most impressive have to be the army ants of SOUTH AMERICA and driver ants of AFRICA. Both use the same rather terrifying blitzkrieg technique, in which the whole colony, many thousands   strong,  is constantly on the move across the forest floor in a black stream of hungry mandibles. Through strength in numbers, the ants can easily overcome large insects, lizards, small birds – almost anything that crosses their path. Stories of driver ants entering villages and  eating babies in their cribs are probably exaggerated, but there is no doubt that, after army ants have passed through the forest, the floor can be denuded of all life for weeks. The warmth of the tropics has produced other invertebrate horror stories. Many invertebrates are able to grow to such a size that the can be formidable predators even on vertebrates. The best example must be the TARANTULA  SPIDERS of SOUTH AMERICA, which can have a legspan width greater than 25 cm (10 inches ) and can easily take tree frogs or small birds. MANTIDS also grow to record sizes. In the RAINFORESTS of MALAYSIA you find large and beautiful flower mantids that are perfect flower mimics of the orchids in which they wait. Insects attracted to these ‘flowers’ discover themselves to be on the menu when the mantid strikes.

THE FLESH – EATERS

True flesh – eaters, like us, face a problem in the RAINFOREST; they find it a tangled and impenetrable jungle. This is no place for running cheetahs or stooping falcons. Most have opted to be small and agile like the ocelots or margays of South America or slender like the civets and genets of Africa and Asia. There is only one exception in each of the continents – the jaguar in South America, the forest tiger in Asia and the leopard in Africa. All these large cats are limited in numbers by the comparative low density of large forest herbivorous. Likewise, moist of the birds of prey are limited in number and are usually small with rounded wings and the ability to jink quickly between the branches. Each major rainforest block, though, does have at least one large, spectacular eagle at the top of the predatory tree. The harpy eagle in South America, the monkey – eating eagle of the Philippines and crowned eagle of Africa have all specialized in taking forest monkeys.