At this point we can summarize the pinheiro-do-Paraná population diversity features: rare alleles in few populations, alleles with low frequencies at most loci, a variable percentage of polymorphic loci, and low genetic divergence among populations. How can this be explained? The first idea is that these features are intrinsic to the species. Alternatively, the effects of fragmentation followed by exploitation or tree removal, which can be called 'degradation', caused major genetic erosion in this species. The fact that a rare allele was found in The Parque Municipal de Lages (PML), a degraded population, and a higher number of alleles was found on the Fazenda Guamirim Gateados (FGG) suggests that genetic diversity was higher prior to European contact. But how much higher it was than it is today has not been determined yet.
Besides gene flow and generation overlap, which favor genetic exchange, the isolation process could contribute to the low level of inter-populational diversity. The forest fragmentation has occurred within the last 100 years, a recent event in this long-living species' history. Thus, the time after fragmentation has so far been insufficient to allow a more substantial differentiation among populations.
By combining this low amount of genetic variation found among populations with a small-forested area, not bigger than 3% of the original area (Guerra et al., 2000), we could claim the existence of a fragile state of polymorphism in the pinheiro-do-Paraná. From a biological point of view, the larger populations are far apart in most cases. Beneath them, the regeneration is very sparse. The species does not spread as it did in the past. The situation is fragile not only in terms of the amount of genetic variation, but also in terms of areas of conservation. The danger is that any further exploitation of these already threatened populations could reduce the currently fragile level of polymorphism by chance alone.
Although it is often possible to establish the exact status of genetically degraded species, there are populations such as those at Fazenda Guamirim Gateados and EPAGRI Caçador that show greater polymorphism than other populations. Moreover, populations located in transition areas such as ARIE of Victor Meirelles and The Antonio Carlos Reserve should be included in conservation and breeding programs.
The different indexes obtained in this study suggest that any kind of indiscriminate exploitation should be halted immediately to avoid further genetic erosion or increase in the genetic vulnerability of the species. Furthermore, it is necessary to complement and associate this data with that related to the species' auto-ecology to better design adequate conservation and breeding strategies for the sustainable management of the Araucaria angustifolia.
ACKNOWLEDGEMENTS
This project was supported by PADCT/CNPq grant. N.M.F.A. was the recipient of a CAPES fellowship and R.O.N., M.S.R, and M.P.G. were recipients of a CNPq fellowship.
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