@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.} }