Effect of 7 yr of experimental drought on vegetation dynamics and biomass storage of an eastern Amazonian rainforest.
*At least one climate model predicts severe reductions of rainfall over Amazonia during this century. Long-term throughfall exclusion (TFE) experiments represent the best available means to investigate the resilience of the Amazon rainforest to such droughts. *Results are presented from a 7 yr TFE study at Caxiuanã National Forest, eastern Amazonia. We focus on the impacts of the drought on tree mortality, wood production and above-ground biomass. *Tree mortality in the TFE plot over the experimental period was 2.5% yr(-1), compared with 1.25% yr(-1) in a nearby control plot experiencing normal rainfall. Differences in stem mortality between plots were greatest in the largest (> 40 cm diameter at breast height (dbh)) size class (4.1% yr(-1) in the TFE and 1.4% yr(-1) in the control). Wood production in the TFE plot was c. 30% lower than in the control plot. Together, these changes resulted in a loss of 37.8 +/- 2.0 Mg carbon (C) ha(-1) in the TFE plot (2002-2008), compared with no change in the control. *These results are remarkably consistent with those from another TFE (at Tapajós National Forest), suggesting that eastern Amazonian forests may respond to prolonged drought in a predictable manner.
da Costa
Antonio Carlos Lola
AC
Universidade Federal do Pará, Centro de Geociências, Belém, Pará, Brazil.
Galbraith
David
D
Almeida
Samuel
S
Portela
Bruno Takeshi Tanaka
BT
da Costa
Mauricio
M
Silva Junior
João de Athaydes
Jde A
Braga
Alan P
AP
de Gonçalves
Paulo H L
PH
de Oliveira
Alex A R
AA
Fisher
Rosie
R
Phillips
Oliver L
OL
Metcalfe
Daniel B
DB
Levy
Peter
P
Meir
Patrick
P
D018533:Biomass; D001938:Brazil; D055864:Droughts; D018547:Plant Stems / Q000254:growth & development; D011891:Rain; D012987:Soil; D013997:Time Factors; D014197:Trees / Q000145:classification / Q000254:growth & development*; D014934:Wood / Q000254:growth & development
D012987:Soil