How deregulation, drought and increasing fire impact Amazonian biodiversity

Abstract

Biodiversity contributes to the ecological and climatic stability of the Amazon Basin1,2, but is increasingly threatened by deforestation and fire3,4. Here we quantify these impacts over the past two decades using remote-sensing estimates of fire and deforestation and comprehensive range estimates of 11,514 plant species and 3,079 vertebrate species in the Amazon. Deforestation has led to large amounts of habitat loss, and fires further exacerbate this already substantial impact on Amazonian biodiversity. Since 2001, 103,079–189,755 km² of Amazon rainforest has been impacted by fires, potentially impacting the ranges of 77.3–85.2% of species that are listed as threatened in this region⁵. The impacts of fire on the ranges of species in Amazonia could be as high as 64%, and greater impacts are typically associated with species that have restricted ranges. We find close associations between forest policy, fire-impacted forest area and their potential impacts on biodiversity. In Brazil, forest policies that were initiated in the mid-2000s corresponded to reduced rates of burning. However, relaxed enforcement of these policies in 2019 has seemingly begun to reverse this trend: approximately 4,253–10,343 km² of forest has been impacted by fire, leading to some of the most severe potential impacts on biodiversity since 2009. These results highlight the critical role of policy enforcement in the preservation of biodiversity in the Amazon.

Full text

516 | Nature | Vol 597 | 23 September 2021
Article
How deregulation, drought and increasing
fire impact Amazonian biodiversity
Xiao Feng1,23 ✉, Cory Merow2,23, Zhihua Liu3,23, Daniel S. Park4,5,23, Patrick R. Roehrdanz6,23,
Brian Maitner2,23, Erica A. Newman7,8,23, Brad L. Boyle7,9 , Aaron Lien8,1 0, Joseph R. Burger7,8,11,
Mathias M. Pires12, Paulo M. Brando13,14,15, Mark B. Bush16, Crystal N. H. McMichael17,
Danilo M. Neves18, Efthymios I. Nikolopoulos19, Scott R. Saleska7, Lee Hannah6,
David D. Breshears10, Tom P. Evans20, José R. Soto10, Kacey C. Ernst21 & Brian J. Enquist7,2 2,23
Biodiversity contributes to the ecological and climatic stability of the Amazon Basin1,2,
but is increasingly threatened by deforestation and re3,4. Here we quantify these
impacts over the past two decades using remote-sensing estimates of re and
deforestation and comprehensive range estimates of 11,514 plant species and 3,079
vertebrate species in the Amazon. Deforestation has led to large amounts of habitat
loss, andres further exacerbate this already substantial impact on Amazonian
biodiversity. Since 2001, 103,079–189,755 km2 of Amazon rainforest has been
impacted by res, potentially impacting the ranges of 77.3–85.2% of species that are
listed as threatened in this region5. The impacts of re on the ranges of species in
Amazonia could be as high as 64%, and greater impacts are typically associated with
species that have restricted ranges. We nd close associations between forest policy,
re-impacted forest area and their potential impacts on biodiversity. In Brazil, forest
policies that were initiated in the mid-2000s corresponded to reduced rates of
burning. However, relaxed enforcement of these policies in 2019 has seemingly begun
to reverse this trend: approximately 4,253–10,343 km2 of forest has been impacted by
re, leading to some of the most severe potential impacts on biodiversity since 2009.
These results highlight the critical role of policy enforcement in the preservation of
biodiversity in the Amazon.
The Amazon Basin
6
supports around 40% of the world’s remaining
tropical forests7 and has a vital role in regulating the Earth’s climate8.
Amazonia contains 10% of all known species
6
and it has been estimated
that 1,000 tree species can be found in a single square kilometre of the
forest
9
. Such high biodiversity also enhances ecosystem resilience
through functional diversity
10
and influencing rates of secondary forest
recovery
11
, and has probably enabled Amazonia to remain relatively sta
-
ble and to buffer ecosystem functioning in the face of climate change
1,2
.
However, continued degradation and loss of forest cover and biodiver-
sity therein could undermine ecosystem resilience and hasten an irre-
versible tipping point
12
. Indeed, a loss of 20–25% of Amazonian forests
could precipitate a rapid transition to savannah-like formations13,14.
Since the 1960s, approximately 20% of Amazonian forest cover has
been lost as a result of deforestation and fires15. Forest loss is predicted
to reach 21–40% by 2050, and such habitat loss will have large impacts
on Amazonian biodiversity16,17. In conjunction with ongoing habitat loss
due to deforestation, increasing fires in the Amazon potentially pose
another great threat to biodiversity
4
: because Amazonian species have
largely evolved in the absence of fire, they generally lack adaptations to
fire-related damage (ref. 18 and references therein). Fires associated with
deforestation generally lead to a total loss of forest habitat3, and the burn-
ing of felled vegetation impairs regeneration and facilitates the invasion
of exotic grasses19. Forest fires also have largely negative impacts on the
habitats and long-term fitness of species due to habitat degradation
20–22
.
Repeated burning can result in considerable species loss and turnover
23,24
.
Burning can also initiate a series of positive feedbacks, including increases
in dry fuel loads and midday temperatures, desiccation of biomass and
flammability of native forests at the edges of clearings25.
Fires in the Amazon are collectively influenced by climate, deforesta-
tion, forest fragmentation, selective logging and forest policies
26–28
.
https://doi.org/10.1038/s41586-021-03876-7
Received: 22 November 2019
Accepted: 4 August 2021
Published online: 1 September 2021
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1Department of Geography, Florida State University, Tallahassee, FL, USA. 2Eversource Energy Center and Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA.
3CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China. 4Department of Biological Sciences, Purdue University, West
Lafayette, IN, USA. 5Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA. 6The Moore Center for Science, Conservation International, Arlington, VA, USA. 7Department of
Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA. 8Arizona Institutes for Resilience, University of Arizona, Tucson, AZ, USA. 9Hardner & Gullison Associates, Amherst, NH, USA.
10School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA. 11Department of Biology, University of Kentucky, Lexington, KY, USA. 12Departamento de Biologia Animal,
Universidade Estadual de Campinas, Campinas, Brazil. 13Department of Earth System Science, University of California, Irvine, Irvine, CA, USA. 14Woodwell Climate Research Center, Falmouth, MA,
USA. 15Instituto de Pesquisa Ambiental da Amazônia (IPAM), Brasilia, Brazil. 16Insitute for Global Ecology, Florida Institute of Technology, Melbourne, FL, USA. 17Department of Ecosystem and
Landscape Dynamics, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands. 18Institute of Biological Sciences, Federal University of Minas Gerais,
Belo Horizonte, Brazil. 19Department of Mechanical and Civil Engineering, Florida Institute of Technology, Melbourne, FL, USA. 20School of Geography, Development and Environment, University of
Arizona, Tucson, AZ, USA. 21Department of Epidemiology and Biostatistics, College of Public Health, University of Arizona, Tucson, AZ, USA. 22The Santa Fe Institute, Santa Fe, NM, USA. 23These
authors contributed equally: Xiao Feng, Cory Merow, Zhihua Liu, Daniel S. Park, Patrick R. Roehrdanz, Brian Maitner, Erica A. Newman, Brian J. Enquist. ✉e-mail: fengxiao.sci@gmail.com
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