Final published version
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Leaf-litter production in human-modified Amazonian forests following the El Niño-mediated drought and fires of 2015–2016
AU - Oliveira de Morais, T.M.
AU - Berenguer, E.
AU - Barlow, J.
AU - França, F.
AU - Lennox, G.D.
AU - Malhi, Y.
AU - Chesini Rossi, L.
AU - Maria Moraes de Seixas, M.
AU - Ferreira, J.
PY - 2021/9/15
Y1 - 2021/9/15
N2 - Leaf-litter production is an essential part of the carbon cycle of tropical forests. In the Amazon, it is influenced by climate, presenting high levels during the driest months of the year. However, it is less established how extreme climatic events may impact leaf-litter production in the long term. Even more unclear is how litter production is affected by human-driven disturbances. Here we examine the effects of the 2015–16 El Niño drought and subsequent fires in the leaf-litter production of human-modified Amazonian forests, thus investigating the interactions of a climatic extreme with anthropogenic disturbances on this key process of the Amazonian carbon cycle. We sampled leaf litter from April 2015 until March 2019 across 20 plots located in the eastern Brazilian Amazon, in a total of 11,548 samples. Plots were distributed along a pre-El Niño gradient of human disturbance, including undisturbed, logged, logged-and-burned, and secondary forests. All plots were impacted by the extreme drought caused by the 2015–16 El Niño, and eight were also impacted by understory fires. We found a significant and non-linear relationship between precipitation and monthly leaf-litter production – above 300 mm of monthly precipitation, the production of leaf-litter becomes independent of rainfall. Surprisingly, this relationship was not influenced by pre-El Niño forest disturbance class. During the El Niño, leaf-litter production was higher, decreasing sharply in the following year, especially in El Niño-fire-affected forests. Between 2017 and 2019, all forests experienced a gradual increase in the production of leaf litter. However, the mechanisms behind this increase remain unclear and are likely different between forests affected only by the El Niño drought and those affected by both the drought and fires. Our results suggest that while leaf-litter production may be insensitive to past human disturbances, it is affected, in the short term, by extreme climatic events, especially in forests impacted by El Niño fires.
AB - Leaf-litter production is an essential part of the carbon cycle of tropical forests. In the Amazon, it is influenced by climate, presenting high levels during the driest months of the year. However, it is less established how extreme climatic events may impact leaf-litter production in the long term. Even more unclear is how litter production is affected by human-driven disturbances. Here we examine the effects of the 2015–16 El Niño drought and subsequent fires in the leaf-litter production of human-modified Amazonian forests, thus investigating the interactions of a climatic extreme with anthropogenic disturbances on this key process of the Amazonian carbon cycle. We sampled leaf litter from April 2015 until March 2019 across 20 plots located in the eastern Brazilian Amazon, in a total of 11,548 samples. Plots were distributed along a pre-El Niño gradient of human disturbance, including undisturbed, logged, logged-and-burned, and secondary forests. All plots were impacted by the extreme drought caused by the 2015–16 El Niño, and eight were also impacted by understory fires. We found a significant and non-linear relationship between precipitation and monthly leaf-litter production – above 300 mm of monthly precipitation, the production of leaf-litter becomes independent of rainfall. Surprisingly, this relationship was not influenced by pre-El Niño forest disturbance class. During the El Niño, leaf-litter production was higher, decreasing sharply in the following year, especially in El Niño-fire-affected forests. Between 2017 and 2019, all forests experienced a gradual increase in the production of leaf litter. However, the mechanisms behind this increase remain unclear and are likely different between forests affected only by the El Niño drought and those affected by both the drought and fires. Our results suggest that while leaf-litter production may be insensitive to past human disturbances, it is affected, in the short term, by extreme climatic events, especially in forests impacted by El Niño fires.
KW - Amazon
KW - Carbon cycling
KW - Drought
KW - El Niño
KW - Litter
KW - Wildfire
KW - Fires
KW - Forestry
KW - Amazonian forests
KW - Carbon cycles
KW - Climatic events
KW - EL Nino
KW - Human disturbances
KW - Leaf litter
KW - Leaf litter productions
KW - Tropical forest
KW - Carbon
U2 - 10.1016/j.foreco.2021.119441
DO - 10.1016/j.foreco.2021.119441
M3 - Journal article
VL - 496
JO - Forest Ecology and Management
JF - Forest Ecology and Management
SN - 0378-1127
M1 - 119441
ER -