Department of Microbiology, Immunology, and Pathology, Colorado State University, 1619 Campus Delivery, Fort Collins, CO 80523-1619, USA.
Mol Ecol. 2012 Apr;21(7):1617-31. doi: 10.1111/j.1365-294X.2012.05493.x. Epub 2012 Feb 15.
Urbanization can result in the fragmentation of once contiguous natural landscapes into a patchy habitat interspersed within a growing urban matrix. Animals living in fragmented landscapes often have reduced movement among habitat patches because of avoidance of intervening human development, which potentially leads to both reduced gene flow and pathogen transmission between patches. Mammalian carnivores with large home ranges, such as bobcats (Lynx rufus), may be particularly sensitive to habitat fragmentation. We performed genetic analyses on bobcats and their directly transmitted viral pathogen, feline immunodeficiency virus (FIV), to investigate the effects of urbanization on bobcat movement. We predicted that urban development, including major freeways, would limit bobcat movement and result in genetically structured host and pathogen populations. We analysed molecular markers from 106 bobcats and 19 FIV isolates from seropositive animals in urban southern California. Our findings indicate that reduced gene flow between two primary habitat patches has resulted in genetically distinct bobcat subpopulations separated by urban development including a major highway. However, the distribution of genetic diversity among FIV isolates determined through phylogenetic analyses indicates that pathogen genotypes are less spatially structured-exhibiting a more even distribution between habitat fragments. We conclude that the types of movement and contact sufficient for disease transmission occur with enough frequency to preclude structuring among the viral population, but that the bobcat population is structured owing to low levels of effective bobcat migration resulting in gene flow. We illustrate the utility in using multiple molecular markers that differentially detect movement and gene flow between subpopulations when assessing connectivity.
城市化可能导致曾经连续的自然景观破碎化为散布在不断发展的城市基质中的斑块状栖息地。生活在破碎景观中的动物由于避免人为开发的干扰，往往减少了栖息地斑块之间的迁移，这可能导致斑块之间的基因流和病原体传播减少。像山猫（Lynx rufus）这样具有较大栖息地范围的哺乳动物食肉动物，可能对栖息地破碎化特别敏感。我们对山猫及其直接传播的病毒病原体，猫免疫缺陷病毒（FIV）进行了遗传分析，以研究城市化对山猫迁移的影响。我们预测，城市发展，包括主要的高速公路，将限制山猫的迁移，并导致宿主和病原体种群在遗传上形成结构。我们分析了来自加利福尼亚州南部城市的 106 只山猫和 19 只 FIV 分离株的分子标记。我们的研究结果表明，两个主要栖息地斑块之间的基因流减少导致了遗传上不同的山猫亚群，这些亚群被城市发展分隔开来，包括一条主要的高速公路。然而，通过系统发育分析确定的 FIV 分离株的遗传多样性分布表明，病原体基因型的空间结构较少——在栖息地碎片之间表现出更均匀的分布。我们得出结论，传播疾病所需的运动和接触类型发生的频率足以防止病毒种群形成结构，但由于有效山猫迁移导致基因流水平较低，山猫种群存在结构。我们说明了在评估连通性时使用多个分子标记来差异检测亚群之间的运动和基因流的效用。
