@article {Blackwell Publishing, title = {Conserving the evolutionary potential of California valley oak (Quercus lobata Nee): a multivariate genetic approach to conservation planning}, journal = {Molecular Ecology}, volume = {17}, number = {1}, year = {2008}, pages = {139-156}, abstract = {California valley oak (Quercus lobata Nee) is a seriously threatened endemic oak species in California and a keystone species for foothill oak ecosystems. Urban and agricultural development affects a significant fraction of the species{\textquoteright} range and predicted climate change is likely to dislocate many current populations. Here, we explore spatial patterns of multivariate genotypes and genetic diversity throughout the range of valley oak to determine whether ongoing and future patterns of habitat loss could threaten the evolutionary potential of the species by eradicating populations of distinctive genetic composition. This manuscript will address three specific questions: (i) What is the spatial genetic structure of the chloroplast and nuclear genetic markers? (ii) What are the geographical trends in the distribution of chloroplast and nuclear genotypes? (iii) Is there any part of the species{\textquoteright} range where allelic diversity in either the chloroplast or nuclear genomes is particularly high? We analysed six chloroplast and seven nuclear microsatellite genetic markers of individuals widespread across the valley oak range. We then used a multivariate approach correlating genetic markers and geographical variables through a canonical trend surface analysis, followed by GIS mapping of the significant axes. We visualized population allelic richness spatially with GIS tools to identify regions of high diversity. Our findings, based on the distribution of multivariate genotypes and allelic richness, identify areas with distinctive histories and genetic composition that should be given priority in reserve network design, especially because these areas also overlap with landscape change and little degree of protection. Thus, without a careful preservation plan, valuable evolutionary information will be lost for valley oak.}, keywords = {allelic richness canonical trend surface analysis colonization gene flow geographic information system comparative phylogeography spatial autocorrelation geographical structure plant-populations climate-change patterns diversity pollen multilocus petraea}, author = {Grivet, D. and Sork, V. L. and Westfall, R. D. and Davis, F. W.} } @article {328, title = {Estimating anisotropic pollen dispersal: A case study in Quercus lobata}, journal = {Heredity}, volume = {99}, number = {2}, year = {2007}, pages = {193-204}, abstract = {The pollen dispersal distribution is an important element of the neighbourhood size of plant populations. Most methods aimed at estimating the dispersal curve assume that pollen dispersal is isotropic, but evidence indicates that this assumption does not hold for many plant species, particularly wind-pollinated species subject to prevailing winds during the pollination season. We propose here a method of detecting anisotropy of pollen dispersal and of gauging its intensity, based on the estimation of the differentiation of maternal pollen clouds (TWOGENER extraction), assuming that pollen dispersal is bivariate and normally distributed. We applied the new method to a case study in Quercus lobata, detecting only a modest level of anisotropy in pollen dispersal in a direction roughly similar to the prevailing wind direction. Finally, we conducted a simulation to explore the conditions under which anisotropy can be detected with this method, and we show that while anisotropy is detectable, in principle, it requires a large volume of data.}, keywords = {Quercus lobata anisotropy gene flow neighbourhood genetic structure TwoGener}, author = {Austerlitz, F. and Dutech, C. and Smouse, P. E. and Davis, F. W. and Sork, V. L.} } @article {411, title = {Gene flow and fine-scale genetic structure in a wind-pollinated tree species, Quercus lobata (Fagaceaee)}, journal = {American Journal of Botany}, volume = {92}, number = {2}, year = {2005}, pages = {252-261}, abstract = {California Valley oak (Quercus lobata), one of the state{\textquoteright}s most distinctive oak species, has experienced serious demographic attrition since the 19th century, due to human activities. Recent estimates of pollen dispersal suggest a small reproductive neighborhood. Whether small neighborhood size is a recent phenomenon, a consequence of reduced gene flow caused by demographic changes, or whether it has been historically restricted, remains unclear. To examine this question, we have characterized the spatial genetic structure of N = 191 Q. lobata individuals, spread over an area of 230 ha, using eight microsatellite loci. The observed autocorrelogram suggests an historical standard deviation of gene flow distance of about 350 m per generation, higher than contemporary pollen dispersal estimates. To determine whether our estimates were affected by strong prevailing winds from the west{\textendash}northwest, we developed and utilized a novel anisotropic autocorrelation analysis. We detected no more than a hint of anisotropy, and we concluded that adult spatial structure is indicative of strong historical signature of "isolation by distance." This historical estimate provides a useful reference value against which to gauge the future gene flow consequences of ongoing anthropogenic disturbance.}, keywords = {bearing correlogram California oak genetic autocorrelation analysis microsatellite pollen and seed dispersal tree species wind direction valley oak Quercus lobata}, author = {Dutech, C. and Sork, V. L. and Irwin, A. J. and Smouse, P. E. and Davis, F. W.} } @conference {755, title = {Mating patterns in a savanna population of valley oak, Quercus lobata Ne{\'e}}, booktitle = {Fifth Symposium on Oak Woodlands}, volume = {General Technical Report PSW-GTR-184}, year = {2002}, month = {2002}, pages = {427-439}, publisher = {USDA Forest Service}, organization = {USDA Forest Service}, abstract = {California Valley oak is threatened by landscape alteration and failing recruitment in remnant stands. Its reproductive ecology is a key element of the seedling recruitment process. We first examine the mating system, to determine the extent of inbreeding in a population at Sedgwick Reserve, in Santa Barbara County. We then quantify variation in germination success and acorn size, evaluating their spatial patterns across the site. We collected acorns from 21 mapped focal trees in fall 1999, measured their average seed weight and germination success, and identified their multilocus genotypes. Using a mixed mating model, we observed significant, but modest selfing (outcrossing rate: tm = 0.96) and no mating among relatives (tm {\textendash} ts) = 0.0. The effective pollen donor number was estimated to be between 5 and 7 individuals, depending on the inbreeding coefficient of the adults. These mating results indicate relatively little inbreeding but low numbers of pollen donors. Mothers differed significantly in seed weight (range: ~ 4 - 10 g) and germination percentage (range: 0 {\textendash} 90 percent), and a bivariate analysis showed a gradient across the study site. Such a pattern suggests that environment conditions influence acorn size and germination success. Future work will address whether isolated individuals are at risk of selfing, for the expression of inbreeding depression on seed traits, or a reduction in the effective pollen donor number.}, url = {http://danr.ucop.edu/ihrmp/proceed/symproc40.html}, author = {Sork, V. L. and Davis, F. W. and Dyer, R. J. and Smouse, P. E.} } @article {756, title = {Pollen movement in declining populations of California Valley oak, Quercus lobata: where have all the fathers gone?}, journal = {Molecular Ecology}, volume = {11}, year = {2002}, month = {2002}, pages = {1657-1668}, abstract = {The fragmented populations and reduced population densities that result from human disturbance are issues of growing importance in evolutionary and conservation biology. A key issue is whether remnant individuals become reproductively isolated. California Valley oak (Quercus lobata ) is a widely distributed, endemic species in California, increasingly jeopardized by anthropogenic changes in biota and land use. We studied pollen movement in a savannah population of Valley oak at Sedgwick Reserve, Santa Barbara County, to estimate effective number of pollen donors (N (ep) ) and average distance of effective pollen movement (delta). Using twogener, our recently developed hybrid model of paternity and genetic structure treatments that analyses maternal and progeny multilocus genotypes, we found that current N (ep) = 3.68 individuals. Based on an average adult density of d = 1.19 stems/ha, we assumed a bivariate normal distribution to model current average pollen dispersal distance (delta) and estimated delta= 64.8 m. We then deployed our parameter estimates in spatially explicit models of the Sedgwick population to evaluate the extent to which N (ep) may have changed, as a consequence of progressive stand thinning between 1944 and 1999. Assuming that pollen dispersal distance has not changed, we estimate N (ep) was 4.57 individuals in 1944, when stand density was 1.48. Both estimates indicate fewer effective fathers than one might expect for wind-pollinated species and fewer than observed elsewhere. The results presented here provide a basis for further refinements on modelling pollen movement. If the trends continue, then ongoing demographic attrition could further reduce neighbourhood size in Valley oak resulting in increased risk of reproductive failure and genetic isolation.}, keywords = {Heterogeneity. Landscape. Dispersal. Paternity. Buffers. Flow., Starch-gel electrophoresis. 2-generation analysis. Conservation.}, url = {http://www.blackwell-synergy.com/servlet/useragent?func=synergy\&synergyAction=showAbstract\&doi=10.1046/j.1365-294X.2002.01574.x}, author = {Sork, V. L. and Davis, F. W. and Smouse, P. E. and Apsit, V. J. and Dyer, R. J. and Fernandez, J. F. and Kuhn, B.} }