Levels and Dynamics of Genetic Diversity in the French Guiana
Rainforest
H.CARON, E.BANDOU, A.KREMER, S.DUMAS, G.MARQUE
INRA BP45 - 33611 Gazinet FRANCE
© Photo courtesy of INRA.
Tropical rain forests are characterized by their high species richness. On
average the number of tree species per ha amounts to a few hundreds. These species exhibit
as well a great diversity in their life history traits, their dispersion mechanisms and
their distribution patterns.
We launched a long term research project aiming at identifying key factors
responsible of the maintenance of genetic diversity in complex tropical ecosystems.
Fifteen species that show contrasting life history traits have been
selected and will be monitored for several biological and genetical descriptors : mating
system, pollen and seed dispersal, level of diversity, spatial genetic structures. The
monitoring is conducted on nuclear and chloroplast DNA.
Two different spatial distribution patterns of adult trees in the Paracou stand
Results of the first investigations based on 5 species, indicate that the
level of genetic diversity is related to the outcrossing rate rather than to the census
number
The genetic monitoring provided also insights in the population dynamics
of tropical tree species. Contrary to temperate species, tropical tree stands function as
metapopulations : populations of a given species do not stay at a same site, they move
from place to place at each generation; this is indicated by the maintenance of high
levels of chloroplast DNA polymorphism within populations as shown by Dicorynia
guianensis.
To download poster of results from the French Guyane plots in PowerPoint format
(6788KB) click here
To view poster of results from the French Guyane plots in JPEG format (119KB) click here
