Researchers point to the vulnerability of Central African forests
In Gabon, the forest covers 90% of the territory.
Ageos / AFP
Text by: Jérôme Duval
5 mins
Published on April 21, 2021 in the journal
Nature,
an international study coordinated by researchers from IRD and CIRAD, identifies for the first time the forest areas most vulnerable to the increase in climatic and human pressures expected in the coming decades .
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Cameroon, Gabon, Republic of Congo, Democratic Republic of Congo and Central African Republic. Five Central African countries in which one of the largest reservoirs of biodiversity extends, the second largest tropical forest in the world. A region with many distinct forests, each of which reacts differently to climatic pressures and to those exerted by man, explains Maxime Réjou-Méchain, ecologist at the Institute for Research for Development (IRD) and first author of the study.
This study updates the first transnational mapping of forest types in the region. Impressive quantitative work,
accessible online
on the website of the Center for International Cooperation in Agricultural Research for Development (CIRAD). It is based on a huge dataset of almost 6 million trees. To realize the extent of the resources used,
"it is estimated that if a single person were to reproduce this data set, it would take 1000 years of field work"
, specifies Maxime Réjou-Méchain. The objective of this research is to combine this data with future climatic and anthropogenic scenarios in order to understand which forests would be most likely to be affected.
Vulnerability, taking into account the climate scenarios of the Intergovernmental Panel on Climate Change (IPCC) and the United Nations population projections expected at the end of the century, is however far from homogeneous. The DRC, the Atlantic forest in Gabon and in the south of the Republic of Congo, the forest margins, in particular in Cameroon, are regions more sensitive than others to climatic and demographic changes.
For Maxime Réjou-Méchain, the stake is clearly on the Democratic Republic of Congo (DRC):
“The country is home to half of the tropical forests of Central Africa and combines both anthropogenic and climatic pressures.
There is an exploding demographics.
It is estimated that between 2000 and 2085, the population of the DRC will be multiplied by seven. Potentially by 2085, there may not be much left in the DRC if nothing is done today ”
, asserts he does.
Slash-and-burn, the leading cause of deforestation
If industrial agriculture, mainly intended for export, is developing, in particular on oil palm, cocoa, cassava, rubber or corn,
"slash-and-burn agriculture, linked to the
population
explosion ,
remains the leading cause of deforestation in Central Africa ”
, continues Maxime Réjou-Méchain. Slash-and-burn is an agrarian mode of operation practiced for at least 2000 years which consists in clearing by fire plots (often in forests where the land is richer), used for subsistence cultivation before being left in wasteland.
"With demographic pressure, fallow times are becoming shorter and shorter, and more and more areas are being exploited"
, completes the researcher.
He also argues that alternative energy sources remain to be found to replace charcoal, still from tropical forests to supply large cities like Kinshasa.
Prevent the isolation of forest islands to preserve biodiversity
Do not fragment the forest, maintain connectivity between protected areas for the movement of animal and plant species and preservation of biodiversity;
the researchers insist on this key aspect.
"We want to encourage the establishment of permanent contacts, thanks to preserved or reconstituted corridors, between the large forest areas considered to be the least vulnerable"
, explains Sylvie Gourlet-Fleury, forest ecologist at CIRAD, in the Forests and Societies research unit. .
“This would make it possible to maintain the flow of genes between these different zones (thanks in particular to the maintenance of the circulation of fauna, which disperses the seeds of a large part of the species present) and thus to preserve diversity. It is imperative to maintain these corridors, to recreate them by replanting natural forest species, or to allow them to regenerate. "
For Maxime Réjou-Méchain,
“a good impact of this study would be to see our maps of vulnerability and floristic composition brought to the attention of decision-makers, scientists and foresters, to decide on strategies that ensure a future for the tropical forests of Central Africa. "
The researcher plans to forward to some politicians of the work area it sees as
" decision support tool "
.
Once the file is on the decision makers' desk, the ball will be in their court.
The stakes are high.
Between 2010 and 2020, 1.5 to 2 million hectares of forests disappeared each year in the Central and West Africa zone.
"One of the concerns is that the forests of certain regions of Central Africa, in Cameroon and in the DRC in particular, suffer the same fate as in West Africa where the dense humid tropical forests have almost disappeared"
, warns Sylvie Gourlet. -Fleury.
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