دانلود رایگان مقاله پیامدهای استراتژی برای حفاظت از تنوع ژنتیکی گیاهی

ABSTRACT

Conservation biologists have drawn up a range of guidelines for the conservation of genetic diversity—to maximise the chances that populations of threatened species persist, and to conserve this variation for its potential utility. However, our understanding of the effectiveness of conservation guidelines for maintaining genetic diversity in situ is limited. Furthermore, we lack information on how species-level variation in mating system affects these genetic conservation strategies. We used the British geographical ranges of eight widespread but declining plant species, varying in breeding system, as a model to assess the effectiveness of guidelines for the in-situ conservation of neutral genetic diversity. By applying simulated in-situ conservation scenarios to amplified fragment length polymorphism data, we show that the conservation of one population (the “minimum-set” approach) would retain ~70% of common allelic variation, but few or no rare alleles (alleles with frequency ≤ 0.05). Our results indicate that the conservation of N35% of populations would be needed to reach the Convention on Biological Diversity's recommendation to conserve 70% of genetic diversity in situ, as applied to rare alleles (~10 populations within each species' British range). The capture of genetic variation in simulated conservation networks was insensitive to breeding system. However, a spatially stratified approach to population selection led to significantly greater capture rates for common alleles in two of our study species, relative to a spatially random strategy. Our study highlights the challenges of conserving genetic variation, and emphasises the vulnerability of genetic biodiversity to reductions in the extent of species' ranges.

4.6. Conclusions

Our results show that in-situ conservation networks should easily capture a large proportion of the common allelic variation present within species of conservation concern, regardless of their mating system. In contrast, rare allelic variation is likely to be captured much less efficiently, and our results suggest that the genetic consequences of in-situ conservation strategies will differ most in their effects on these rare variants. For species that are currently relatively widespread, an in-situ conservation guideline of a minimum of 10 populations, selected using a spatially stratified design, could prove a useful complement to CPC's five-population guideline for ex-situ conservation. Such an approach would likely enhance the conservation of rare allelic variation in situ, and assist in reaching the most recent CBD guidelines on the conservation of genetic biodiversity