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Half of the Amazonian tree species are endangered
December 2015
no. 489
The Tumuk Humak Mountains in the middle of the Amazon forest, on the southern border with Guyana (© IRD / D. Sabatier)
One in two tree species in the Amazon could be endangered. The Amazon Tree
Diversity Network international consortium, which includes the IRD, has just
revealed in the Science Advances journal that, according to the predicted
deforestation scenarios, 36% to 57% of Amazonian species are at risk of
disappearing, i.e. up to 8,700 species out of the 15,000 estimated during the
first inventory of the Amazonian Basin, published two years ago.
According to these results, when considered at the scale of the planet, it is
feared that 40,000 tropical tree species may be exposed to a risk of extinction
and that the proportion of endangered plants on the planet has increased to
one fifth.
Useful facts
2
With nearly 6 million km spread across 9 countries (mainly Brazil but also Bolivia, Peru, Ecuador,
Colombia, Venezuela, Guyana, Suriname and French Guiana), the Amazon is the world’s largest
tropical rainforest. It is also the richest in terms of biodiversity. However, it is threatened by
deforestation and climate change. One fifth of the Amazon forest has disappeared since 1970.
Contact / Subscription – [email protected]
Communication and information sharing department – Research Institute for Development (IRD)
One in two tree species could disappear due to deforestation in the Amazon. This has just been
revealed by a vast international study published in the Science Advances journal, involving nearly
160 scientists, including IRD researchers, assembled under the banner of the Amazon Tree
Diversity Network.
Red alert for 8,700 tree species
According to the criteria of the International Union for Conservation of Nature (UICN) – the most
commonly used to determine the conservation status of any species – the research team believes
that 36% to 57% of Amazonian tree species are threatened with extinction, i.e. up to 8,700
species, including the famous Brazilian walnut, which has significant economic implications for
the countries of the region. To date, only a minute part of these species features on the NGO’s
red list. Some may even disappear before they can be observed and described…
Should these results be confirmed, the amount of endangered plants on the planet would
increase to 22%.
Simulating the variation in the population size of each species
In 2013, the research team had already published the first inventory of Amazonian Basin trees in
the Science journal. Through statistical calculation, the total number of species had then been
estimated at 15,000 – compared to the 12,000 identified to date on the planet. This initial
inventory also helped assess the distribution area and number of individuals per species. In the
new study, the researchers modelled the variation in the population sizes of each species, based
on the different deforestation scenarios identified.
Destruction of up to one third of the forest by 2050
With the construction of dams and mines, forest fires and
droughts increased by climate change, etc., the Amazon
forest is facing a wave of threats. Specialists believe that
nearly 20% of the forest has disappeared since the 1970s.
By 2050, based on the predicted deforestation scenarios,
it should shrink by up to another 30%. In the best case
scenario, in which protected areas (national parks,
indigenous reservations implemented to reinforce the
territorial rights of aboriginal people) would contribute to
the preservation of the vegetation, the surface area of the
forest will still be reduced by 10%.
Mining site in Guyana (© IRD/ D. Sabatier)
This trend can be observed throughout the intertropical zone. The new study claims that some
40,000 tropical tree species across the world could be facing the same risk of extinction.
Partners
Amazon Tree Diversity Network organisations from approximately twenty different countries.
References
Hans ter Steege et al. Estimating the global conservation status of more than 15,000 Amazonian tree
species. Science Advances, 2015, Vol. 1, no. 10, e1500936. DOI: 10.1126/sciadv.1500936
Scientific contacts
Jean-François Molino, IRD researcher
T.+33 (0)4 67 61 75 47; [email protected]
Daniel Sabatier, IRD researcher
T. + 33 (0)4 67 61 65 83; [email protected]
’Botany and modelling of plant and vegetation architecture’ joint research unit - AMAP (IRD / Cirad /
CNRS / Inra / Montpellier University)
Contact / Subscription – [email protected]
Communication and information sharing department – Research Institute for Development (IRD)