Long‐term survival probability, not current habitat quality, predicts dispersal distance in a stream salamander
Long‐term survival probability, not current habitat quality, predicts dispersal distance in a stream salamander
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预测溪蝾螈的扩散距离的是长期生存概率，而不是当前栖息地质量
DOI：
10.1002/ecy.2982
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发表时间：
2020
期刊：
影响因子：
4.8
通讯作者：
Lowe, Winsor H.
中科院分区：
文献类型：
--
作者：
Addis, Brett R.;Lowe, Winsor H.
分散进化为一种适应性机制，以优化整个景观中的个体适应度。具体地说，分散代表了一种逃避环境条件变化导致的健康成本的机制。几十年的经验研究表明，个体利用当地的栖息地线索来做出行动决定，但理论预测，在具有随机时空变化历史的环境中，扩散也可以作为一种固定的特征进化，与当地条件无关。然而，到目前为止，条件和固定的扩散演化模型主要是使用移民数据(停留与离开)来评估的，而不是扩散距离：更全面的扩散衡量标准。我们的目标是测试条件或固定的扩散演化模型是否可以预测斑点火蜥蜴溪流中扩散距离的变化。我们使用美国新罕布夏州中部哈伯德布鲁克实验森林三条源头溪流中4年的空间显式捕获-标记-重新捕获(CMR)数据来量化栖息地条件的变化。我们使用身体状况作为个体可以用来做出扩散决策的局部栖息地质量的指数，并使用多状态CMR模型估计的生存概率作为由于长期环境变化而导致的死亡风险的指数。我们发现，扩散距离随着生存概率的下降而增加，这表明火蜥蜴在危险的环境中分散得更远。扩散距离与身体状况的空间变化无关，这表明火蜥蜴并不是基于当地栖息地的质量来决定扩散距离的。我们的研究首次为固定的扩散演化模型提供了经验支持，该模型预测扩散演化是对时空环境变化历史的响应，而不是对当前栖息地条件的有条件响应。更广泛地说，这项研究强调了评估不同环境变化尺度的价值，以获得对扩散演化的更全面和更平衡的理解。
Dispersal evolves as an adaptive mechanism to optimize individual fitness across the landscape. Specifically, dispersal represents a mechanism to escape fitness costs resulting from changes in environmental conditions. Decades of empirical work suggest that individuals use local habitat cues to make movement decisions, but theory predicts that dispersal can also evolve as a fixed trait, independent of local conditions, in environments characterized by a history of stochastic spatiotemporal variation. Until now, however, both conditional and fixed models of dispersal evolution have primarily been evaluated using emigration data (stay vs. leave), and not dispersal distances: a more comprehensive measure of dispersal. Our goal was to test whether conditional or fixed models of dispersal evolution predict variation in dispersal distance in the stream salamanderGyrinophilus porphyriticus.We quantified variation in habitat conditions using measures of salamander performance from 4 yr of spatially explicit, capture–mark–recapture (CMR) data across three headwater streams in the Hubbard Brook Experimental Forest in central New Hampshire, USA. We used body condition as an index of local habitat quality that individuals may use to make dispersal decisions, and survival probability estimated from multistate CMR models as an index of mortality risk resulting from the long‐term history of environmental variation. We found that dispersal distances increased with declining survival probability, indicating that salamanders disperse further in risky environments. Dispersal distances were unrelated to spatial variation in body condition, suggesting that salamanders do not base dispersal distance decisions on local habitat quality. Our study provides the first empirical support for fixed models of dispersal evolution, which predict that dispersal evolves in response to a history of spatiotemporal environmental variation, rather than as a conditional response to current habitat conditions. More broadly, this study underscores the value of assessing alternative scales of environmental variation to gain a more complete and balanced understanding of dispersal evolution.