Collaborative Research: Landscape Patterns of Pollen Movements in Declining Populations of California Valley Oak, Quercus Lobata

碎片化和种群减少危及许多物种的生存。过度的生殖隔离会导致有价值的等位基因的丧失，减少遗传变异，导致近亲交配衰退，降低人口适合度，并导致生殖失败。当树木种群减少到分散和聚集的个体时，花粉运动对连通性至关重要。该项目开发了一种新的方法，可以覆盖景观规模的区域，并可以集成到景观变化的空间显式模拟建模中。这些新工具被用来调查一种受威胁的树种--加州山谷橡树(Quercus Lobata)。利用等位酶和微卫星基因型别，研究人员检查了三个目标：(1)他们将在不同同种密度的景观中表征单株树木的生殖隔离。(2)他们将研究成虫遗传结构和花粉池的时间异质性对估计花粉移动的影响。(3)他们将把估计参数纳入地理模型，以模拟历史和未来人口下降的影响。这个项目是研究基因流动的进化动态及其景观规模保护/恢复后果的一个很好的案例。它将适用于加州的一种关键树种，这种树种因住宅和农业开发而经历栖息地丧失和退化，这种情况需要为未来的管理和政策决策提供信息。这项研究将从进化生物学、保护生物学、地理学和受威胁物种的公共政策等方面进行衔接。

Davis0089495Fragmentation and population declines jeopardize the survival of many species. Excessive reproductive isolation can cause a loss of valuable alleles, decrease genetic variation, induce inbreeding depression, reduce demographic fitness, and lead to reproductive failure. When tree populations are reduced to scattered and clustered individuals, pollen movement is critical to connectivity. This project develops a novel approach that can cover landscape-scale areas and can be integrated into spatially explicit simulation modeling of landscape changes. These new tools are deployed to investigate a threatened tree species, California Valley oak (Quercus lobata). Using allozyme and microsatellite genotypes, the investigators examine three objectives: (1) They will characterize reproductive isolation of individual trees in landscapes with variable conspecific density. (2) They will examine the impact of adult genetic structure and temporal heterogeneity of pollen pools on estimates of pollen movement. (3) They will incorporate estimated parameters into geographic models to simulate the impact of historical and future population decline.This project represents an excellent case study of the evolutionary dynamics of gene flow and its landscape scale conservation/restoration consequences. It will be applied to a critical California tree species experiencing habitat loss and degradation from residential and agricultural development, a situation in need of information for future management and policy decisions. This research will dovetail issues from evolutionary biology, conservation biology, geography, and public policy of the threatened species.