The role of genetic diversity and inbreeding of Scots pine stands surviving the effect of unfavourable environmental factors under the presses of climate changes: 3 steps Lithuanian case studies

Abstract

Competition indices had a significant effect on tree health deterioration over the period of high pollution level as well as on recovery over the period of reduced pollution level. The objective of the III case study was to assess differences in the genetic diversity and inbreeding in 2 neighbouring Scots pine stands one of which suffered a damage by needle eating forest pests. These findings indicated that the harm of insect damage was greater for the trees with higher degree of inbreeding than for the trees with lower degree of inbreeding. In general, the environmental stresses may reduce the genetic diversity when groups of genetically similar trees are eliminated leaving less genotypic variants in the stands after the injuries. Pine stands with low inbreeding level were found to be more tolerant to the impact of the unfavourable environmental factors than the stands with high level of inbreeding. Competition index plays there a predisposing or even triggering role for the trees surviving the impacts of unfavourable environmental factors. Genetic diversity of tree populations most likely play a key role in tolerating the forest pest attacks, air pollution including surface ozone, and acid deposition induced damage when more diverse genotypes better tolerate these stresses than the less diverse genotypes. Therefore in the presented study we attempted to detected variation in the genetic diversity and inbreeding of Scots pine population in Lithuania surviving attacks of needle eating forest pests and high level of local environmental pollution under the presses of climate change. To genotype 150-200 sample trees with highly polymorphic nuclear SSR markers multiplexed with EST SSRs in each stand were chosen. 12 nuclear microsatellite loci were studied. DNA was extracted from wood using the ATMAB-method. Tree resistance to the unfavourable environmental factors was detected by applying long-term data set on tree crown defoliation and stem increment dendrochronology. The objective of the I case study was to detect genetic diversity and inbreeding of 3 Scots pine populations growing in different regions of Lithuania surviving the effect of unfavourable climatic condition, regional pollution load of acidifying compounds and surface ozone. The obtained data revealed that tree competition indices have more significant effect on tree condition and productivity than their genotype and inbreeding. The objective of the II case study was to detect the role of the genetic diversity and inbreeding of 3 Sots pine stands located at different distances from nitrogen fertilizer plant “Achema” surviving the changes in emission load from high to low level under the presses of climate changes. The obtained data showed no consistent trend in inbreeding shift when moving from the nitrogen fertiliser plant. However the stands with high inbreeding level were more damaged by the emissions than those with lower level of inbreeding.