Response Of Genetic Diversity And Differentiation Of Pinus Massoniana Population To Habitat Fragmentation In Lake Thousand Islands

Habitat fragmentation is reduction of continuous habitat into several smaller spatially isolated remants. It’s a significant threaten to genetic diversity. Theoretically, fragmentation lead to an erosion of genetic variation and increased interpopulation genetic divergence through:elevated inbreeding, reduced interpopulation gene flow, increased interpopulation differentiation, and missing genetic diversity. However, there’s other opinions:they thought that habitat fragmentation may have positive effect other than negative one especially on island-populations. Simultaneously, not only habitat type related to the fragmentation-effect but also species life history. It seems that wind-pollinated spceies which can spread their pollens and seeds long-distance affected by habitat fragmentation slighter than short-distance species. We consider that how fragmentation affect population genetic diversity and differentiation of wind-pollinated species like Pinus massoniana in island habitat.Genetic diversity and differentiation of P. massoniana populations from 26 different-size islands, in Lake Thousand Islands (including the biggest island, Jieshou island), were analyzed in this study using seven pairs of SSR primers. And the results revealed that 1)the island size significantly correlated with the means of individual DBH (diameter at breast height)(P=0.0012) indicating that P. massoniana in smaller islands will be younger; 2)there are weak positive correlations between island area and the number of allele (P=0.3468) and expected heterozygosity (P=0.2775), significant correlations between island area and observed heterozygosity (P=0.0012) and negative correlations between island size and inbreeding coefficient (P=0.007) in the fragmented.3) the degree of isolation did not correlate with genetic diversity which indicated that the genetic diversity in P. massoniana won’t be affected by degree of isolation.4) There has high-genetic-differentiation (F.sr=0.088) among populations but no isolaton by distance(IBD) in this area.In conclusion, genetic diversity in P. massoniana won’t be affected by habitats fragment yet, but it will increase the inbreeding coefficient of P. massoniana in Lake Thousand Isalnds. And it has no significance effect on genetic differentiation among populations.