A nature reserve encloses a space with a remarkable natural heritage (an original natural environment, the habitat of a rare plant or animal species, or the presence of geological or archaeological sites). Reserves make it possible to protect this heritage thanks to their particularly stringent legal framework. The running of the reserve is entrusted to a public or private body selected by the authorities depending upon objectives defined in advance. Most of the time it is a matter of preserving or reconstituting habitats or endangered species populations, of enabling scientific and technical studies, and of informing the public about the natural heritage. All of these objectives are laid out in a management plan drawn up and implemented by a conservation administrator working for a management organisation.

In France there are 323 nature reserves (counting both the mainland and overseas areas) covering 2,848,000ha, of which the French Southern Lands just off the Antarctic make up 2,270,000ha. French Guiana has its fair share with seven nature reserves of major interest, the most isolated of which is the La Trinité reserve.

La Trinité : an unspoiled world

La Trinité reserve covers an area of 760km2 andis the fourth largest French reserve. Since 13th May 1997 it has been run by the French National Forestry Office (Office National des Forêts).

Lying over fifty kilometres away from the nearest road network, and so only accessible by a pirogue along the Mana or Sinnamary, or else by helicopter, La Trinité’s primary aim is not to welcome the public. The reserve was created in 1996 to protect and study an extremely isolated area which had therefore never been subject to human pressure. This isolated geographical location had protected the forest from legal and illegal human activities such as poaching, deforestation, and so on. The absence of any gold deposits – a stroke of luck here in French Guiana – meant that it was not affected by miners looking for gold. That is why the La Trinité reserve is a privileged place to study the wildlife and flora of the primal forests.

The first scientific missions date back to 1970. Within ten or so years they confirmed just how original the flora of this zone was. In addition to this, archaeological studies revealed three major prehistoric sites: a rock shelter with a 300m² chamber and two groove sites. Lastly the reserve is of specific geological interest thanks to the enormous inselbergs, or “savannah rocks” (Mont 501, Roche Bénitier). These natural characteristics make up a particularly striking and unique landscape (vast stretches of forest with enormous cliffs rising up here and there.

Studies of the Roche Bénitier

Even though the inselbergs only cover 5% of La Trinité, they are exceptional sites standing several hundred metres high above the forests and so have always stimulated the curiosity of researchers.

Mont 501 and the Roche Bénitier with its cliffs over 300 metres tall have original wildlife and flora which are wholly specific to these extremely hot, dry places. During the day the sun beats down directly on the rock and its temperature can reach 75°C. In this hostile habitat heat-resistant flora have nevertheless developed, thanks to the action of living microorganisms called cyanobacteria which are able to resist extreme conditions. These organisms are the first to move in, and shelter in the slightest fissure where they are able to fix the atmospheric nitrogen and carbon and, powered purely by the sun, are able to eat away at the granite and so create a thin layer of soil. A lot later the first plant species take hold on this substrate. A herbaceous cluster of suffrutescent plants, normally composed of no more than a dozen species, starts to develop. In particular it includes a sort of wild pineapple called Pitcairnia geyskesii, as well as other species endemic to the inselbergs in French Guiana and Surinam. The clumps grow to 40 or 50cm tall and can survive on skeletal soil (no more than 2 to 4cm deep). This ground cover of grasses is soon replaced by shrubs and trees of an average height of 4 to 5 metres, and that can colonise slopes of up to 62%. The dominant species are the Clusiaceae Quapoya scandens and the Bombax Rhodognaphalopsis flaviflora.

In the rainy season water streaming down the slopes can sometimes uproot the shrubs and tufts of grass which are then carried down to the bottom of the inselberg. The rock becomes bare once again and the plant cycle starts all over again.

Forests can develop on the top of the inselberg if the slope is not too steep. This is the case for Roche Bénitier, where the forest at the top seems to differ to an unusual degree from the forest underneath, a singularity due to be confirmed by scientific studies over the coming years.

Far from complete inventory

La Trinité is first and foremost a well conserved primal forest. Tropical forests around the world are retreating at an alarming rate, and researchers are in a race against time to try to inventory as many animal and plant species as possible. Three or four missions are carried out each year by teams of scientists drawn from different specialities so as to try to acquire a better understanding of the enormous diversity of the forest.

Ornithologists (bird specialists) and mammalogists (specialists in mammals) lay out long trails through the forest that they then follow very slowly so as to gather as many visual and auditory observations as possible of the birds and mammals. As for the botanists they come armed – with rifles. The leaves of the trees are often out of reach and so the easiest way to take a sample is with a rifle. At night entomologists set up mercury vapour light bulbs connected to a generator and never fail to attract all the insects.

In the early evening bat biologists set up enormous nets (6 to 18 metres long by 2.50 metres high) to catch bats which are then removed from the net and their weights, length of forearm, sex, state of maturity, and (for female adults) their breeding status are all carefully recorded for each individual.

Night is also the best moment for herpetologists. Capturing snakes is more hit and miss as they have a relatively low density. Amphibians, however, can be looked for by day or night. The best spots are places with water, tree stumps, trunks, and piles of litter. Mont Tabulaire, the highest peak in the reserve, is topped by a sub-mountain forest and an altitudinal transect of it has been studied so as to learn about the distribution of frogs as a function of altitude. This research has revealed the existence of a new species of frog of the Pristimantis genus which only lives above 400 metres and which is found on the various hills in La Trinité – Mont Tabulaire, Mont 501, Roche Bénitier, and so on. The fact that they are found in various sites at some distance from each other might indicate that conditions were more humid in the past. The small populations of this new species which are currently found in isolated pockets were once in contact with each other when the climate in French Guiana was probably cooler and fresher.

Thus over the past ten years, 71 species of amphibians, 5 species of turtles, 1 cayman species (the grey cayman), 25 species of lizards, 38 species of snakes, 336 species of birds, 46 species of bats, 39 species of non-flying mammals, 39 species of fish (for which no research was conducted prior to 2001), and 1412 species of insects have been inventoried. In addition to this by 1 January 2006, 1269 species of plants had been found.

Despite these surprisingly high figures several groups, such as reptiles, have not been studied in sufficient detail and many species are still to waiting to be discovered.

The new management plan (2007- 2011) continues with the policy of privileging prospection and looking for animal species. Another project relates to studying the flora of the forest by recording all the trees in various sectors with a diameter of 10 centimetres or more, which will make it possible to gradually draw up a map of the forest types in the nature reserve.

Many species as well as many mechanisms controlling the ecosystems are still to be discovered and studied. There is no shortage of research subjects and the importance of understanding, protecting, and maintaining biodiversity is now accepted by all.

In 2006 the World Conservation Union announced that a quarter of mammals, one third of amphibians, one bird out of every eight, and nearly one half of all plant species around the world were endangered. A fair proportion of these species are only found in tropical rainforests, and so are highly endangered due to deforestation (at the current pace it is estimated that the equatorial forests will have disappeared within 150 years).

Protecting biodiversity would seem to have recently become a major concern for our society, and many people are speaking out to inform the public about the ecological crisis we are going through. However, despite a series of international summits they do not always result in action by decision-makers, who often pay greater attention to what agricultural and industrial lobbies have to say than they do to the concerns of environmentalists.

Whilst the forests in neighbouring countries (and especially Brazil) are disappearing at an alarming rate and the land used instead for agrofuels, the forests on the Guiana Shield are in an enviably good state of conservation. The Nouragues and La Trinité reserves, together with the vast Guiana Amazonian Park, provide a refuge for the wildlife and flora, guaranteeing the survival of one of the finest natural systems on the planet.