Genetic variation in the southern pines: evolution, migration, and adaptation following the Pleistocene (2007)Schmidtling, R. (2007). Genetic variation in the southern pines: evolution, migration, and adaptation following the Pleistocene. General technical report NRS-P-15. Forest Service, Springfield, 28-32. Retrieved from https://www.nrs.fs.fed.us/pubs/gtr/gtr_p-15%20papers/4schmidtling-p-15.pdf Climate has certainly changed over time, requiring genetic change or migration of forest tree species. Little is known about the location of the southern pines during the Pleistocene glaciation, which ended around 14,000 years ago. Macrofossils of spruce (Picea spp.) dating from the late Pleistocene, which are typical of climates much cooler than presently occupied by the southern pines, have been found within the current range of the southern pines, indicating that the climate was considerably colder at that time. From this discovery it is reasonable to assume that the southern pines were situated south of their present range during the Pleistocene and migrated to their current location after the glaciers receded. Variation in adaptive and non-adaptive traits of the southern pines suggests that loblolly pine (Pinus taeda) existed in two refugia, one in south Texas/north Mexico, and one in south Florida. Longleaf pine (P. palustris) probably existed only in the western refugium. Slash pine (P. elliottii), on the other hand, presumably resided only in the Florida refugium, whereas shortleaf pine (P. echinata) is cold-hardy enough to have existed in a continuous distribution across the Gulf Coast. Implications of climate warming on the future of southern pines are discussed
https://www.nrs.fs.fed.us/pubs/gtr/gtr_p-15%20papers/4schmidtling-p-15.pdf |
