Department of Biology, California State University, Northridge, Northridge, CA.
W.K. Kellogg Biological Station, Department of Integrative Biology, Michigan State University, Hickory Corners, MI.
J Hered. 2018 Mar 16;109(3):243-252. doi: 10.1093/jhered/esx088.
Fire regimes influence natural populations of organisms in diverse ways, via direct effects on population dynamics as well as indirect effects on habitat and ecosystem processes. Although many amphibian species have evolved to persist in fire-dependent ecosystems, the effects of fire on the genetic diversity of amphibian populations remain relatively unexplored. We examined how different aspects of fire history relate to population genetic diversity and structure of an abundant anuran, Hyla femoralis, in a large, intact area of Florida scrub containing hundreds of seasonally inundated ponds. Specifically, we assessed the overall population genetic structure and examined whether variation in time since fire, fire intensity, or historical fire frequency at breeding sites explained spatial variation in genetic diversity. Based on our sampling of 17 breeding aggregations within the 2,100-ha study area, neither recent nor frequent fire reduce genetic diversity or restrict connectivity among ponds for H. femoralis. Overall, mean effective population sizes were large (average range = 68-572). We detected a positive trend between effective population size (Ne) and average intensity of the most-recent fire, with this factor explaining 42% of the variation in Ne. Our results contrast with previous studies that consistently demonstrate strong relationships between fire history and population genetic structure of scrub-associated lizard species, suggesting that H. femoralis is resilient to a wide range of fire regimes. More generally, our study contributes to understanding the roles of life-history characteristics and environmental unpredictability in shaping organisms' responses to fire.
火灾以多种方式影响生物的自然种群，包括直接影响种群动态，以及间接影响栖息地和生态系统过程。尽管许多两栖动物物种已经进化到能够在依赖火灾的生态系统中生存，但火灾对两栖动物种群遗传多样性的影响仍相对未知。我们研究了不同的火灾历史方面如何与一种丰富的蛙类（Hyla femoralis）的种群遗传多样性和结构相关，该蛙类存在于佛罗里达州灌木丛的一个大型完整区域，其中包含数百个季节性淹没的池塘。具体来说，我们评估了总体种群遗传结构，并研究了火灾发生时间、火灾强度或繁殖地历史火灾频率的变化是否解释了遗传多样性的空间变化。基于我们在 2100 公顷研究区域内 17 个繁殖群的抽样，近期火灾或频繁火灾都不会降低 H. femoralis 的遗传多样性或限制池塘之间的连通性。总体而言，有效种群规模较大（平均范围为 68-572）。我们发现有效种群大小（Ne）与最近一次火灾的平均强度之间存在正相关趋势，这一因素解释了 Ne 变化的 42%。我们的结果与之前的研究形成对比，之前的研究一致表明火灾历史与灌木丛相关蜥蜴物种的种群遗传结构之间存在强烈关系，这表明 H. femoralis 对广泛的火灾发生频率具有很强的适应能力。更一般地说，我们的研究有助于理解生活史特征和环境不确定性在塑造生物体对火灾的反应中的作用。
