01821nas a2200157   4500008004100000245009700041210006900138260000900207300001200216490000800228520131000236100001801546700001301564700002401577856006201601       2009                        eng d00aBiogeographical Distribution of Chloroplast Diversity in Northern Red Oak (Quercus rubra L.)0 aBiogeographical Distribution of Chloroplast Diversity in Norther  c2009  a134-1450 v1613 aWe mapped the biogeographical distribution of chloroplast haplotypes in northern red oak (Quercus rubra L.) to test the hypotheses that the founder effects during postglacial migration will result in a latitudinal gradient of haplotype diversity with exhaustion of haplotype richness at the extreme northern edge of the range. PCR-RFLP markers for 23 populations of Q. rubra in old growth and minimally disturbed forests across 13,000 km2 of the contemporary range revealed only four of the five haplotypes detected previously at 12 sites in Indiana. The four northernmost populations were fixed for either haplotype I or haplotype II, the two most common haplotypes. Haplotype richness declined poleward, but the biogeographical pattern of 829 haplotypes across the 35 sites did not clearly indicate postglacial migration routes along latitudinal gradients from the southern edges of the study area. Although Q. rubra and the European white oak Q. robur L. are both early successional species that recolonized vast areas as the glaciers retreated, the data indicate that Q. rubra has lower chloroplast haplotype richness, suggesting that the population dynamics of Q. rubra prior to or during Pleistocene climate fluctuations may have differed from the population dynamics of the European white oak taxa.1 aBIRCHENKO, I.1 aFENG, Y.1 aROMERO-SEVERSON, J.  uhttp://www.bioone.org/doi/abs/10.1674/0003-0031-161.1.13401063nas a2200217   4500008004100000245015500041210006900196260000900265300001200274490000800286520036400294100002000658700001500678700001400693700001800707700001300725700001400738700001500752700001600767856006200783       2009                        eng d00aAge Structure and Genetic Diversity of Four Quercus macrocarpa (Michx.) Populations in Fragmented Oak Savanna along the Central Minnesota River Valley0 aAge Structure and Genetic Diversity of Four Quercus macrocarpa M  c2009  a301-3120 v1613 aOnly 0.02% of historic oak savanna exists today. To provide management recommendations, we characterized age-class structure, measured cover of competing tree species and estimated genetic variation within and among four Quercus macrocarpa Michx (bur oak) populations in the Minnesota River Valley. At each site, few middle-aged bur oaks existed, most were 901 aKittelson, P.M.1 aPinahs, C.1 aDwyer, J.1 aIngersoll, A.1 aMans, E.1 aRieke, J.1 aRutman, B.1 aVolenec, M.  uhttp://www.bioone.org/doi/abs/10.1674/0003-0031-161.2.301