@article {111,
	title = {Population density as a predictor of genetic variation for woody plant species},
	journal = {Conservation Biology},
	volume = {13},
	year = {1999},
	note = {199900314083ArticleEnglish},
	month = {1999},
	pages = {1079-1087},
	abstract = {As the focus of conservation biology shifts toward multispecies and ecosystem conservation and management, a principal question becomes how we manage species to conserve their long-term evolutionary potential. Few criteria exist for prioritizing which populations within a species should be protected to conserve maximal genetic variation. We designed this study to explore the genetic consequences of using population density as a criterion for selecting populations of woody plant species for conservation. Population density may be an effective gauge of genetic variation for two reasons. First, density often reflects ecological population size, particularly for continuously distributed species, and density is much easier to measure in the field than population size. Second, from an individual species{\textquoteright} perspective, population density may be an indicator of habitat quality. We evaluated the relationship between standard genetic diversity indices and densities of seedlings, small trees, andlarge trees, and we investigated the association between genotypic composition and density measures with canonical correlation analysis for three common tree species (Carya tomentosa, Sassafras albidum, and Quercus alba) from the Missouri Ozarks. We found that population density was not correlated with genetic diversity in large populations of plant species, but density was associated with genotypic composition of populations. That is, populations with small densities had different genotypes than those with large densities. To sample a maximal amount of regional genotypic variation, we recommend choosing plant populations representing a range of densities. Findings from our study should be generally applicable to plant populations that have occupied habitats long enough for natural selection to affect local genotypic composition. Used in conjunction with other established criteria, population density may be a useful rule of thumb for conservation practitioners concerned with themaintenance of adaptive genetic variation in plant species.},
	keywords = {-, -albidum (Lauraceae-), -Plants, [26070-] Fagaceae-, [26215-] Juglandaceae-, [26245-] Lauraceae-, Angiospermae-, Carya-tomentosa (Juglandaceae-), Conservation-, Dicots-, Dicotyledones-, Fagaceae-: Angiosperms-, genetic-variation, habitat-quality, Juglandaceae-: Angiosperms-, Lauraceae-: Angiosperms-, Missouri-Ozarks: Missouri-, Nearctic-region, North-America, Plantae, Plantae-, Plants-, population-density, population-size, Population-Studies, Quercus-alba (Fagaceae-), Sassafras, Spermatophyta-, Spermatophytes-, USA-, Vascular, Vascular-Plants},
	author = {Gram, W.-K. and Sork, V.-L.}
}
@article {59,
	title = {Evidence for local adaptation in closely adjacent subpopulations of northern Red Oak (Quercus rubra L.) expressed as resistance to leaf herbivores},
	journal = {American Naturalist},
	volume = {142},
	year = {1993},
	note = {199497120675ArticleEnglish},
	month = {1993},
	pages = {928-936},
	abstract = {Many studies of herbaceous plant populations have illustrated the potential of adjacent subpopulations to adapt to local ecological conditions. However, the extent to which local adaptation on a small geographical scale can occur in outcrossing tree populations is not well understood. In this study, we reciprocally transplanted acorns from adjacent subpopulations of northern red oak (Quercus rubra L.) occupying north-, southwest-, and west-facing slopes within a 4-ha plot in a Missouri oak-hickory forest. The quantitative character we measured was leaf damage by herbivores on first-year seedlings, because it reflects resistance to insect herbivores-a quantitative trait that could be under different selective pressures in dissimilar microhabitats. We found that seedlings showed the least damage when planted at the site of the maternal plant. This finding provides initial but strong evidence of local adaptation and illustrates that selection associated with leaf herbivory may have a strong impact on the genetic structure of local tree populations. Such a result is unexpected for a widely outcrossing species on such a small geographical scale but indicates that genetic structuring is possible within other plant populations occupying heterogeneous environments.},
	keywords = {[26070-] Fagaceae-, [33000-] Animalia-, Angiospermae-, Animalia-, Animalia- (Animalia-), Animalia-: Animals-, Dicots-, Dicotyledones-, ECOLOGY-, Ecology-: Environmental-Sciences, Evolution-and-Adaptation, Fagaceae-: Angiosperms-, GENETIC-STRUCTURING, Genetics-, Missouri-: USA-, NATURAL-SELECTION, Nearctic-region, North-America, Nutrition-, Plantae-, Plants-, Population-Genetics: Population-Studies, Quercus-rubra (Fagaceae-), Reproduction-, Spermatophyta-, Spermatophytes-, USA-: North-America, Vascular-Plants},
	author = {Sork, V.-L. and Stowe, K.-A. and Hochwender, C.}
}
@article {112,
	title = {Ecology of mast-fruiting in three species of North American deciduous oaks},
	journal = {Ecology},
	volume = {74},
	year = {1993},
	note = {199395129424ArticleEnglish},
	month = {1993},
	pages = {528-541},
	abstract = {We conducted an 8-yr study of flower and acorn production in three species of oak in east-central Missouri (USA): white oak (Quercus alba), red oak (Q. rubra), and black oak (Q. velutina). The goal was to evaluate whether mast -fruiting, the synchronous production of large seed crops followed by small seed crops, is simply a response to weather conditions or is actually an evolved reproductivity strategy. In this paper, we address four specific questions: (1) Are annual fluctuations in acron crop size the result of synchronous production of acorns by individuals? (2) Are large acorn crops the result of large flower crops and/or high survival of those flowers to mature fruit? (3) To what extent do weather variables account for variation in acorn production among years? (4) Does acorn crop size correlate negatively with prior acorn production? Red oak and white oak showed a greater degree of mast -fruiting than did black oak. Within a species, individuals tended to produce large acorn crops in the same years, but each species differed in which years they produced large crops. The size of a given acorn crop was determined by both flower abundance and survival of flowers to fruit. Principal components and multiple-regression analyses were used to describe the relationship between weather variables and acorn production. The first principal component explained the largest amount of the variation in black oak (R-2 = 0.55) and red oak (R-2 = 0.89). In white oak, two principal components combined to explain 77\% of the variation in acorn production. The weather variables that were associated with these principal components included spring temperature (positive effect) and summer drought (negative effect). Past acorn production had a major impact on the size of the current acorn crop, with each species showing a different pattern. In black oak, the current acorn crop was negatively correlated with the crop 3 yr prior but positively correlated with the crop 2 yr prior. In red oak, acorn crop size 1, 2, and 3 yr prior had negative correlations with current acorn crop, while acorn crop size 4 yr prior was positively correlated. In white oak, there were negative correlations between acorn crop size and crop size 1, 2, and 4 yr prior but a positive correlation with the acorn crop size 3 yr prior. These data are consistent with the hypothesis that mast-fruiting species must store resources during some years in order to produce a mast crop. We discuss the possibility that these three species may have inherent cycles of reproduction that are modified by the impact of weather conditions, black oak with 2-yr cycles, white oak with 3-yr cycles, and red oak with 4-yr cycles. We conclude that the patterns of acorn production for black oak, red oak, and white oak are not simply responses to weather events but are also a function of prior reproductive events. This suggests that masting is an evolved reproductive strategy.},
	keywords = {(Fagaceae-), [26070-] Fagaceae-, ACORN-CROP-SIZE, Angiospermae-, Climatology-: Environmental-Sciences, Dicots-, Dicotyledones-, DROUGHT-, Ecology-: Environmental-Sciences, Fagaceae-: Angiosperms-, FLOWER-ABUNDANCE, Missouri-: USA-, Nearctic-region, North-America, Physiology-, Plantae-, Plants-, Quercus-alba (Fagaceae-), Quercus-rubra (Fagaceae-), Quercus-velutina, Reproduction-, REPRODUCTIVE-STRATEGY, Spermatophyta-, Spermatophytes-, TEMPERATURE-, USA-: North-America, Vascular-Plants, WEATHER-},
	author = {Sork, V.-L. and Bramble, J. and Sexton, O.}
}
@article {65,
	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},
	note = {200200321338ArticleEnglish},
	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 (Nep) 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 Nep = 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 Nep may have changed, as a consequence of progressive stand thinning between 1944 and 1999. Assuming that pollen dispersal distance has not changed, we estimate Nep 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 = {[26070-] Fagaceae-, adult-density, Angiospermae-, declining-populations, Dicots-, Dicotyledones-, Fagaceae-: Angiosperms-, genetic-isolation, human-disturbance, Nearctic-region, North-America, Plantae-, Plants-, pollen-movement, Population-Genetics: Population-Studies, Quercus-lobata (Fagaceae-): California-Valley-oak, reproductive-failure, Santa-Barbara-County: California-, Sedgwick-Reserve, Spermatophyta-, Spermatophytes-, TWOGENER-model, USA-, Vascular-Plants},
	author = {Sork, V.-L. and Davis, F.-W. and Smouse, P.-E. and Apsit, V.-J. and Dyer, R.-J. and Fernandez-M, J.-F. and Kuhn, B.}
}
@article {45,
	title = {Gene flow and fine-scale genetic structure in a wind-pollinated tree species Quercus lobata (Fagaceaee)},
	journal = {American Journal of Botany},
	volume = {92},
	year = {2005},
	note = {200500182047ArticleEnglish},
	month = {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-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 = {-Molecular-Biophysics, [26070-] Fagaceae-, Angiospermae-, anisotropy-, Biogeography-: Population-Studies, California-: USA-, demographic-attrition, Dicots-, Dicotyledones-, Fagaceae-: Angiosperms-, gene-flow, microsatellite-loci, Molecular-Genetics: Biochemistry-and, Nearctic-region, North-America, Plantae-, Plants-, pollen-: reproductive-system, Quercus-lobata (Fagaceae-): species-, Reproductive-System: Reproduction-, Spermatophyta-, Spermatophytes-, Vascular-Plants, wind-pollination},
	author = {Dutech, C. and Sork, V.L. and Irwin, A.J. and Smouse, P.E. and Davis, F.W.}
}
