The Amazon region, Earth's most
important ecosystem, is home to more than 400 Indigenous groups that use
thousands of rainforest plant species. They pass on their knowledge of the
flora primarily through oral tradition, usually from parents or other family
members to their children. This creates a "living library of
knowledge" about how to use native plants. Until now, little was known
about how this treasure trove of knowledge is affected by the combined effects
of climate change and language loss. A new study by the University of Zurich
(UZH) provides the first reliable scientific data on the impact of global
change on the biocultural heritage of the Amazon region.
To investigate the value of the
Amazon region's biocultural heritage, the research group led by UZH professor
of tropical plant diversity and ethnobotany Rodrigo Cámara Leret began by
compiling a database documenting all reports on plant use in Amazonian
countries and territories (Brazil, Peru, Colombia, Bolivia, Ecuador, Venezuela,
Guyana, Suriname and French Guiana). The researchers collaborated with Patrick
Roehrdanz, director of climate change and biodiversity at Conservation
International's Moore Center for Science in the United States.
Commenting on the significance of
the database, study leader Cámara Leret says, "For the first time, we
synthesized information dispersed across 700 references spanning more than 500
years, revealing that Amazonian peoples use at least one-third of the region's
known plant species." In absolute terms, this amounts to 5,796 plant
species. The study is published in the journal Nature.
Indigenous peoples use 5,796 plant species
Although the database represents a
major step forward, Cámara Leret believes that further ethnobotanical fieldwork
will lead to important new discoveries. "For example, our participatory
work with the Indigenous Cacua people led to the description of a new canopy
palm species previously unknown to science, despite being locally abundant and
long recognized by the Cacua as a key source of food security," he says.
Plants play a key role in
Indigenous societies in many ways: as food, including legumes, peach palms and
patauá oil; in cultural practices such as communal customs or hunting; in
construction; and as medicine.
"Tobacco, for example, is a
plant that is used in many ways in everyday life," Cámara Leret explains.
Indigenous people not only chew the leaves of the tobacco plant as a stimulant,
but also burn them before entering the rainforest to signal the arrival of
humans. The distinctive smell is said to appease the forest spirits and give
dangerous animals, such as snakes, time to retreat.
"Such everyday rituals reflect
a respect for nature and an awareness of humanity's dependence on the
rainforest," says co-author Jordi Bascompte, professor of ecology at UZH.
Moreover, such rituals define the cultural identity of Indigenous groups, just
as French or Italian cuisine helps define the identity of those countries.
One-third fewer plants used in future
In a second step, the researchers
fed the collected plant-use data into 8,429 species distribution models and
simulated the future of these plants based on three climate scenarios from the
Intergovernmental Panel on Climate Change (IPCC). However, many of the plant
species currently in use are already rare and found only in a few areas, where
they are increasingly being displaced by hyperdominant species.
The researchers have now shown that
between 2060 and 2080, the ranges of plant species used by humans will shrink
more significantly due to climate change than those of plant species not used
by humans. Specifically, Indigenous cultures may lose an average of 28% to 34%
of the plant species they use and 18% to 23% of the associated ecosystem
services as a result of climate change.
Biocultural heritage to decline by 26%
By focusing on plants used by
humans, the researchers were able to combine the effects of species loss with
language extinction in the Amazon. When a plant species goes extinct, its
Indigenous name, uses and benefits are lost as well, along with knowledge of
its role in the rainforest ecosystem. As a result, the valuable body of
knowledge about the world's richest flora, which also helps shape cultural
identity, is gradually disappearing.
The study quantifies for the first
time the extent to which the biocultural heritage of the Amazon region is
expected to diminish as a result of species and language extinction from 2060
to 2080: by 26%.
"It turns out that the plants
that Indigenous communities rely on could be decimated more severely than
previously thought," says Cámara Leret. "But our results also suggest
that the climate tipping point for Amazonia will not only impact biological
diversity but also interact with language threat and cascade across the unique
cultural heritage of the biome."
Guide to biocultural restoration
The study's findings, together with
the publicly available dataset, may help guide biocultural restoration in the
Amazon region, according to Cámara Leret. "We want our results to help
stop, or even reverse, growing global change impacts on ecosystems and cultural
traditions." It is important to continue documenting knowledge about
Amazonian flora in writing, in partnership with local Indigenous communities,
while also preserving the tradition of oral transmission.
Roehrdanz confirms, "Effective
conservation will depend on recognizing Indigenous knowledge systems as
fundamental to effective environmental stewardship. The study will help
identify the locations where preserving culture and nature in tandem can have
real impact for species that are currently under threat."
Bascompte adds, "Recognizing this intimate dependence between the ecological and cultural heritages is key to assessing nature's contributions to people."
Provided by University of Zurich
Source: Indigenous peoples in the Amazon face massive cultural and ecological loss due to climate change
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