Life history traits and exploitation affect the spatial mean-variance relationship in fish abundance
Life history traits and exploitation affect the spatial mean-variance relationship in fish abundance
复制标题
DOI：
10.1890/15-1270.1
复制
发表时间：
2016-05-01
期刊：
影响因子：
4.8
通讯作者：
Hsieh, Chih-hao
中科院分区：
文献类型：
--
作者：
Kuo, Ting-Chun;Mandal, Sandip;Hsieh, Chih-hao
捕鱼预计会改变鱼类的空间异质性。泰勒幂律中的指数B（V = aM（B））是衡量空间变异（V）随种群平均多度（M）变化的有效指标，B越大，表明种群的空间聚集潜力越大（即，更多的异质性）。理论预测B与生活史特征有关，但缺乏经验证据。使用50年的时空数据从加州当前生态系统，我们研究了捕捞和生活史的影响泰勒指数，通过比较空间分布的开发和未开发的鱼类生活在相同的环境。我们发现，未开发的物种具有较小的尺寸和世代时间表现出较大的B，支持理论预测。与此相反，这种关系在开发的物种是弱得多，大开发的物种的指数高于未开发的物种具有相似的性状。我们的研究结果表明，捕鱼可能会增加一个物种的空间聚集潜力，可能通过降低其大小/年龄结构。移动窗口的互相关分析的结果B与年龄结构指标（平均年龄和年龄均匀度）的一些开发的物种证实了我们的研究结果。此外，通过将我们的研究结果与其他基本生态模式（占有-丰度和大小-丰度关系）联系起来，我们为监测指数B用于管理目的的有用性提供了理论依据。我们认为，年龄/大小截断的物种可能有较低的恢复率的空间占用，和一个物种的空间方差质量关系可能是非线性的。我们的研究结果提供了理论依据，解释为什么渔业管理策略应该关注的年龄和空间结构的变化，开发鱼类。
Fishing is expected to alter the spatial heterogeneity of fishes. As an effective index to quantify spatial heterogeneity, the exponent b in Taylor's power law (V = aM(b)) measures how spatial variance (V) varies with changes in mean abundance (M) of a population, with larger b indicating higher spatial aggregation potential (i.e., more heterogeneity). Theory predicts b is related with life history traits, but empirical evidence is lacking. Using 50-yr spatiotemporal data from the California Current Ecosystem, we examined fishing and life history effects on Taylor's exponent by comparing spatial distributions of exploited and unexploited fishes living in the same environment. We found that unexploited species with smaller size and generation time exhibit larger b, supporting theoretical prediction. In contrast, this relationship in exploited species is much weaker, as the exponents of large exploited species were higher than unexploited species with similar traits. Our results suggest that fishing may increase spatial aggregation potential of a species, likely through degrading their size/age structure. Results of moving-window cross-correlation analyses on b vs. age structure indices (mean age and age evenness) for some exploited species corroborate our findings. Furthermore, through linking our findings to other fundamental ecological patterns (occupancy-abundance and size-abundance relationships), we provide theoretical arguments for the usefulness of monitoring the exponent b for management purposes. We propose that age/size-truncated species might have lower recovery rate in spatial occupancy, and the spatial variance-mass relationship of a species might be non-linear. Our findings provide theoretical basis explaining why fishery management strategy should be concerned with changes to the age and spatial structure of exploited fishes.