Nguyen Minh Tam

Cycads occur in lowland forests and are threatened by their degradation, fragmentation
and over-exploitation. Our results indicate that cycad population sizes were very small (less
100 individuals) with high propagules. These increased mating between closely related individuals
growing in clumps. The allozyme data show although all studied cycads maintained high
levels of genetic diversity, an average of 0.556 (0.491 in C. hoabinhensis to 0.598 in C. chevalieri),
the degree of inbreeding was high. Factors that contribute to the high levels of genetic variability
include dioecy, perennial and complex habitat structure. The priorities for cycad conservation is
discussed as well.