Burkhart Jacob J, Peterman William E, Brocato Emily R, Romine Kimberly M, Willis M Madeline S, Ousterhout Brittany H, Anderson Thomas L, Drake Dana L, Rowland Freya E, Semlitsch Raymond D, Eggert Lori S
Division of Biological Sciences University of Missouri Columbia MO USA.
School of Environment and Natural Resources The Ohio State University Columbus OH USA.
Ecol Evol. 2017 May 22;7(13):4670-4681. doi: 10.1002/ece3.3060. eCollection 2017 Jul.
Understanding metapopulation dynamics requires knowledge about local population dynamics and movement in both space and time. Most genetic metapopulation studies use one or two study species across the same landscape to infer population dynamics; however, using multiple co-occurring species allows for testing of hypotheses related to different life history strategies. We used genetic data to study dispersal, as measured by gene flow, in three ambystomatid salamanders (, , and ) and the Central Newt () on the same landscape in Missouri, USA. While all four salamander species are forest dependent organisms that require fishless ponds to reproduce, they differ in breeding phenology and spatial distribution on the landscape. We use these differences in life history and distribution to address the following questions: (1) Are there species-level differences in the observed patterns of genetic diversity and genetic structure? and (2) Is dispersal influenced by landscape resistance? We detected two genetic clusters in and on our landscape; both species breed in the fall and larvae overwinter in ponds. In contrast, no structure was evident in and , species that breed during the spring. Tests for isolation by distance were significant for the three ambystomatids but not for . Landscape resistance also contributed to genetic differentiation for all four species. Our results suggest species-level differences in dispersal ability and breeding phenology are driving observed patterns of genetic differentiation. From an evolutionary standpoint, the observed differences in dispersal distances and genetic structure between fall breeding and spring breeding species may be a result of the trade-off between larval period length and size at metamorphosis which in turn may influence the long-term viability of the metapopulation. Thus, it is important to consider life history differences among closely related and ecologically similar species when making management decisions.
理解集合种群动态需要有关局部种群动态以及时空移动的知识。大多数遗传集合种群研究在同一景观中使用一两种研究物种来推断种群动态；然而，使用多种共存物种能够对与不同生活史策略相关的假设进行检验。我们利用遗传数据研究了美国密苏里州同一景观中三种钝口螈属蝾螈（、和）以及中央蝾螈（）的扩散情况，扩散通过基因流来衡量。虽然所有这四种蝾螈物种都是依赖森林的生物，需要无鱼池塘来繁殖，但它们在繁殖物候和景观中的空间分布上存在差异。我们利用这些生活史和分布上的差异来解决以下问题：（1）在观察到的遗传多样性和遗传结构模式上是否存在物种水平的差异？以及（2）扩散是否受到景观阻力的影响？我们在我们的景观中检测到和存在两个遗传簇；这两个物种都在秋季繁殖，幼体在池塘中越冬。相比之下，在春季繁殖的物种和中没有明显的结构。对三种钝口螈进行的距离隔离检验具有显著性，但对不显著。景观阻力也对所有这四个物种的遗传分化有贡献。我们的结果表明，扩散能力和繁殖物候的物种水平差异正在推动观察到的遗传分化模式。从进化的角度来看，秋季繁殖物种和春季繁殖物种在扩散距离和遗传结构上观察到的差异可能是幼体期长度和变态时大小之间权衡的结果，这反过来可能影响集合种群的长期生存能力。因此，在做出管理决策时，考虑密切相关且生态相似物种之间的生活史差异很重要。
