FOREST PERTURBATIONS AND BIODIVERSITY DURING THE LAST 10 THOUSAND YEARS IN FRENCH-GUIANA

Tropical forests can be described as a mosaic of juxtaposed eco-units corresponding to different stages of regeneration after treefals. Howe ver, these small-scale regeneration mechanisms alone cannot account fo r the different patterns of species distribution, plant communities an d population structures found in this habitat. The presence of charcoa l layers in the soil and the study of sediments along streams suggest that large-scale forest fires deeply affected the tropical forest vege tation, even in high rainfall areas such as French Guiana. Many atypic al plant distribution and population structure patterns, in relation t o what would be expected from present-time regeneration processes, can be explained by these large-scale events which happened during the la st few thousand years. (C) Elsevier, Paris.