Increasing dominance of large lianas in Amazonian forests.
Ecological orthodoxy suggests that old-growth forests should be close to dynamic equilibrium, but this view has been challenged by recent findings that neotropical forests are accumulating carbon and biomass, possibly in response to the increasing atmospheric concentrations of carbon dioxide. However, it is unclear whether the recent increase in tree biomass has been accompanied by a shift in community composition. Such changes could reduce or enhance the carbon storage potential of old-growth forests in the long term. Here we show that non-fragmented Amazon forests are experiencing a concerted increase in the density, basal area and mean size of woody climbing plants (lianas). Over the last two decades of the twentieth century the dominance of large lianas relative to trees has increased by 1.7-4.6% a year. Lianas enhance tree mortality and suppress tree growth, so their rapid increase implies that the tropical terrestrial carbon sink may shut down sooner than current models suggest. Predictions of future tropical carbon fluxes will need to account for the changing composition and dynamics of supposedly undisturbed forests.
Centre for Biodiversity and Conservation, School of Geography, University of Leeds LS2 9JT, UK. o.phillips@geog.leeds.ac.uk
Oliver L
OL
Phillips
Rodolfo
R
Vásquez Martínez
Luzmila
L
Arroyo
Timothy R
TR
Baker
Timothy
T
Killeen
Simon L
SL
Lewis
Yadvinder
Y
Malhi
Abel
A
Monteagudo Mendoza
David
D
Neill
Percy
P
Núñez Vargas
Miguel
M
Alexiades
Carlos
C
Cerón
Anthony
A
Di Fiore
Terry
T
Erwin
Anthony
A
Jardim
Walter
W
Palacios
Mario
M
Saldias
Barbara
B
Vinceti
D000704:Analysis of Variance; D018533:Biomass; D001938:Brazil; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D002489:Central America; D002980:Climate; D017753:Ecosystem; D006172:Guyana; D010944:Plants / Q000378:metabolism*; D011891:Rain; D012987:Soil; D013020:South America; D013997:Time Factors; D014197:Trees / Q000254:growth & development* / Q000378:metabolism*; D014934:Wood
D012987:Soil; D002245:Carbon Dioxide; D002244:Carbon