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.
Phillips
Oliver L
OL
Centre for Biodiversity and Conservation, School of Geography, University of Leeds LS2 9JT, UK. o.phillips@geog.leeds.ac.uk
Vásquez Martínez
Rodolfo
R
Arroyo
Luzmila
L
Baker
Timothy R
TR
Killeen
Timothy
T
Lewis
Simon L
SL
Malhi
Yadvinder
Y
Monteagudo Mendoza
Abel
A
Neill
David
D
Núñez Vargas
Percy
P
Alexiades
Miguel
M
Cerón
Carlos
C
Di Fiore
Anthony
A
Erwin
Terry
T
Jardim
Anthony
A
Palacios
Walter
W
Saldias
Mario
M
Vinceti
Barbara
B
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