IMPACTS OF CLIMATE CHANGE ON THE DISTRIBUTION OF LARIX SPP. AND PINUS SYLVESTRIS AND THEIR CLIMATYPES IN SIBERIA.

Inter- and intraspecific effects of climate change were assessed for the dominant conifers of Siberia (60-140°E and 48-75°N): Larix spp. (L. sibirica, L. dahurica, and L. sukaczewii) and Pinus sylvestris. The approach employed a tri-variate (degree-days above 5 °C, degree-days below 0 °C, and a moisture index) estimate of the climatic envelope within which exists the actual ecological distribution of a species and their constituent climatypes (genotypes physiologically attuned to similar environments). Limits of the actual ecological distribution were approximated by reducing the climatic envelope according to effects of permafrost and interspecific competition. Climatypes were mapped within the climatic envelope according to the climatic interval that must separate populations for reasonable assurance of genetic differentiation. This interval was calculated from response functions that related 13-year growth and survival of a species to the difference in climate between the provenance of a climatype and the climate of numerous test sites distributed across Russia. Mapping species' distributions and their climatypes was done for the contemporary climate and for future climates predicted by the HadCM3GGa1 scenario of Hadley Centre. The results showed that if the forests of the future are to reflect the adaptedness of today, the distribution of species will shift and genotypes within species will be redistributed. Some contemporary climatypes are projected to disappear from Siberia while others common elsewhere would evolve. To mitigate these effects, climatypes should be transferred today to the expected future location of their climatic optima, a distance that is likely to approach 700-1200 km for these species. [ABSTRACT FROM AUTHOR]