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    - Photo via Universidade Federal de Lavras - |
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International News
Published on Tuesday, June 28, 2022 By the A.M. Costa Rica wire services
A major study into landscape changes in the Brazilian Amazon sheds new light on the many environmental threats the biome faces, but also offers encouraging opportunities for ecological sustainability in the world's most biodiverse tropical forest, according to a study made by scientists from Brazil and the United Kingdom.
The study's findings are critical because as the Amazon jungle moves closer towards a 'tipping point', they provide a robust evidence base to inform urgently needed conservation and regeneration priorities in the forest. They show that gains can be achieved through a range of actions, including, but not limited to, halting deforestation.
Scientists examined the ecological impacts caused by changes people are making to forest landscapes in two regions of the Brazilian State of Pará, Santarém and Paragominas.
"While the focus to date has been on deforestation, we know tropical forests landscapes are being altered by a much broader range of human activities," said lead researcher Cássio Alencar Nunes from Universidade Federal de Lavras in Brazil and Lancaster University in the United Kingdom.
According to Alencar, these modifications include deforestation and degradation of primary forest, For example, through selective logging and fires, but even deforested landscapes are changing as agricultural abandonment leads to secondary forest regrowth. As a result, many tropical landscapes are now a mosaic of non-forest land uses, regenerating secondary forests, and degraded primary forests.
By investigating the rate of transformation between different land-uses and their impacts on the ecological condition, the researchers identified the transitions that are common and have high ecological impacts, as well as those that have large impacts but occur less frequently.
"Our results have revealed a richer understanding of how people are affecting the Amazon rainforest and its ecosystem," Nunes said.
Collecting data from 310 plots and examining more than 2,000 species of trees, lianas, birds and insects, researchers looked how changes impact biodiversity. They also looked at carbon and soil properties.
Researchers also used data published from 2006-2019 about how quickly the landscape has changed over the past decade.
Their
results show that transitions from
primary and secondary forests to
pasture through deforestation
amounted to 24,000 square kilometers
a year. They found that species
richness of almost all biodiversity
groups declined between 18 and 100
percent across plots where primary
or secondary forest had been
converted to pasture or mechanized
agriculture. Transitions
from forest to mechanized
agriculture had the most ecological
impact but occurred less frequently
than conversion of forests to
pasture. "Deforestation
of primary forests to create pasture
is the most damaging land-use change
in the Brazilian Amazon," Nunes
said. "Our results show that
transitions from primary forests to
pasture were always classed as 'high
impact, high rate' for biodiversity,
carbon storage and soil properties.
This underlines the critical and
urgent importance of combating
deforestation, which has been
increasing in the past few years." However,
the study also revealed
opportunities for positive action,
for example highlighting the
importance of protecting secondary
forests and allowing them to mature.
They found that the diversity of
large trees doubled and small tree
diversity increased by 55 percent
when young secondary forests became
older than 20 years, bringing
biodiversity and carbon storage
gains. Other
results revealed less obvious forms
of degradation that are affecting
the Amazon's ecology. They found
that changing between types of
farming, from cattle pasture to more
intensive mechanized agriculture,
also diminishes biodiversity, with
the diversity of ants and birds
decreasing by 30 percent and 59
percent. "By
reducing the amount of land that is
converted to mechanical farming, and
by allowing secondary forests to
regrow, we can deliver significant
ecological restoration gains in the
Amazon jungle," Nunes said Co-author
Jos Barlow, Professor of
Conservation Science at the
Lancaster Environment Centre of the
Lancaster University, highlighted
that the study has further
implications for conservation and
policy. "Our
results emphasize yet again the
importance of tackling
deforestation, as well as the
additional benefits of avoiding
degradation and enhancing the
permanence of secondary forests.
However, achieving this will require
transforming the way Amazon
rainforest is currently being
managed, including much better
integration of science, policy and
local practices,” Barlow said. "We
also highlight the need to focus on
biodiversity as well as carbon in
tropical forests, of the three
ecosystem components that we
analyzed, biodiversity was the most
affected by all the land-use
changes. We hope that biodiversity
can be included in climate change
mitigation actions, and that this
will be emphasized in the upcoming
COP15 on Biodiversity.”
------------ How should this analysis help to define actions to protect Amazonia? We would like to know your thoughts on this story. Send your comments to news@amcostarica.com
  
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