An illustration of the “grow fast or conserve resource” trade-off in Central African forests

Les travaux de Dakis-Yaoba Ouédraogo et de ses collègues sur le dispositif de M’Baïki en République Centrafricaine sont publiés dans la revue Journal of Ecology.

We studied how the growth of tropical semi-deciduous forest tree species responds to drought. We identified different species responses using an original statistical method (the mixture of regressions) that classified species into groups according to their responses to environment. We further tested whether species groups were related to traits linked with strategies of resource acquisition and tolerance to stress (leaf habit, wood density), light requirement (maximum growth rate, regeneration guild) and life-history strategies (adult stature). We found that tree growth generally decreased with drought intensity, and we evidenced nine species groups organized along a continuum of tolerance to drought. The level of drought-tolerance was linked to species potential growth rate: the slower growing the species the more tolerant to drought. We also found that this continuum of tolerance to drought matched a continuum of tolerance to shortage in all resources. This result refutes the hypothesis that, because of a trade-off between below- and above-ground biomass allocation, shade tolerance and drought tolerance would be incompatible. Instead, this result supports the hypothesis of a general continuum of plant strategies, from a resource-conservative strategy (here associated with slow growth, drought tolerance, low sensibility to competition, and shade tolerance) to a strategy of rapid acquisition of resources.

Accès à l'article : link

Actualité rédigée par Dakis Ouédraogo

Publiée : 17/12/2013