The spatial structure of variation in salamander survival, body condition and morphology in a headwater stream network
The spatial structure of variation in salamander survival, body condition and morphology in a headwater stream network
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DOI：
10.1111/fwb.13133
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发表时间：
2018-10
影响因子：
2.7
通讯作者：
W. Lowe;Brett R. Addis;Margaret R. Smith;J. Davenport
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文献类型：
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作者：
W. Lowe;Brett R. Addis;Margaret R. Smith;J. Davenport
资助信息国家科学基金会(环境生物学司)，拨款/奖励编号：1114804、1050459、1655653摘要1.了解个体变异的空间结构对于评估物种一级生态和进化反应的机制和规模至关重要。但是，河流的连续性和复杂性使其很难辨别空间结构，而且关于跨越空间尺度的个体变化的数据很少。2.我们的目标是通过测试源流网络中个体变化的空间结构，客观地解决影响斑点蝾螈的生态和进化过程的规模。我们使用3年的空间显式捕获-标记-再捕获数据，来自美国新罕布夏州哈伯德·布鲁克实验森林的四条源头溪流，以检验三个尺度上的个体生存差异：(A)在2公里长的流域之间，(B)在流域内500米的下游和上游河段，以及(C)沿河段的冲沟和池塘生境。我们还测试了个体身体状况和形态的相应空间差异，以深入了解生存差异的原因和意义。3.不同流域的紫斑潜蝇幼虫存活率基本一致，但不同河段和不同栖息地的幼虫存活率不同。上游的幼体存活率高于下游，与仅限于下游的捕食性溪流鲑鱼的分布相吻合。池塘中的幼虫存活率也高于水沟中的幼虫。紫球藻成虫的存活率在各个尺度上都是恒定的。4.下游幼体状况高于上游。在栖息地尺度上，幼虫和成虫的形态都不同：池塘中的个体比流浪中的个体四肢更长。5.在河段尺度上，幼虫存活率和身体状况的负协变表明，在溪流中，适合性和接近的表现之间存在权衡。栖息地在生存和形态上的惊人差异表明，河流中可能存在细微规模的生态-进化相互作用，这可能是由河流和水池中水流和坡度条件的差异驱动的。6.我们的结果表明，幼虫阶段是了解个体、种群和群落水平上影响斑潜蝇的过程的关键。更广泛地说，这项研究在传统的河流精细尺度生态复杂性研究和最近的研究之间提供了一种新的经验联系，这些研究显示了网络尺度上一致的空间动态。通过记录存活率的差异，Body接收日期：2018年2月2日|修订日期：2018年5月3日|接受日期：2018年5月14日DOI：10.1111/fwb.13133
Funding information National Science Foundation (Division of Environmental Biology), Grant/Award Number: 1114804, 1050459, 1655653 Abstract 1. Understanding the spatial structure of individual variation is critical to assessing the mechanisms and scale of species-level ecological and evolutionary responses. But the continuity and complexity of streams can make it difficult to discern spatial structure, and data on individual variation spanning spatial scales are rare. 2. Our goal was to objectively resolve the scale of ecological and evolutionary processes affecting the salamander Gyrinophilus porphyriticus by testing for spatial structure in individual variation across a headwater stream network. We used 3 years of spatially explicit capture–mark–recapture data from four headwater streams in the Hubbard Brook Experimental Forest, New Hampshire, USA, to test for individual variation in survival at three scales: (a) among c. 2-km watersheds, (b) in 500-m downstream and upstream reaches within watersheds and (c) in riffle and pool habitats along reaches. We also tested for corresponding spatial variation in individual body condition and morphology to gain insight on the causes and implications of variation in survival. 3. Survival of G. porphyriticus larvae was constant among watersheds, but differed by reach and habitat. Larval survival was higher in upstream reaches than downstream reaches, matching the distribution of predatory brook trout (Salvelinus fontinalis), which were restricted to downstream reaches. Larval survival was also higher in pools than riffles. Survival of G. porphyriticus adults was constant at all scales. 4. Larval body condition was higher in downstream reaches than upstream reaches. Both larvae and adults differed in morphology at the habitat scale: individuals in pools had longer limbs than individuals in riffles. 5. Negative covariation in larval survival and body condition at the reach scale suggests that there is a trade-off between fitness and proximate performance along streams. The surprising differences between habitats in survival and morphology show the potential for fine-scale ecology–evolution interactions in streams, potentially driven by differences in flow and gradient conditions in riffles and pools. 6. Our results suggest that the larval stage is key to understanding individual, population and community-level processes affecting G. porphyriticus. More broadly, this research provides a novel empirical link between traditional studies of finescale ecological complexity in streams and recent studies showing consistent spatial dynamics at the network scale. By documenting differences in survival, body Received: 2 February 2018 | Revised: 3 May 2018 | Accepted: 14 May 2018 DOI: 10.1111/fwb.13133