Relationship of habitat variability to population size in a stream fish.
Relationship of habitat variability to population size in a stream fish.
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溪流鱼类栖息地变异性与种群规模的关系。
DOI：
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发表时间：
2014
影响因子：
5
通讯作者：
Dylan J. Fraser
中科院分区：
文献类型：
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作者：
Jacquelyn L. A. Wood;Sebastian Belmar;Jeffrey A. Hutchings;Dylan J. Fraser
生境变异性和种群规模之间的关系在破碎的栖息地是知之甚少，但可能有重要的进化后果。例如，碎片化可以（1）改变生境特征，并通过扩展，选择制度，在一个一致的方向，人口和他们占据的片段的大小减少（方向假设）;或（2）增加生境的变异性相似大小的人口片段大小减少（变量假设）。我们调查了这些替代品的基础上多年的栖息地，人口和遗传数据，从19个不同的人口普查规模（N）和有效数量的育种者（N（B））的流鱼碎片化的人口。平均栖息地参数显着相关的N和N（B），但形式的关系各不相同，并没有证据表明一致的方向性差异的栖息地参数从小到大的人口规模。小种群表现出更广泛的栖息地参数的方差比大种群，并在较小程度上，小种群也有更大的变异性，平均栖息地参数，可能信号更多样化的选择制度。这些结果表明，许多不同的环境与自然界中的小种群规模有关，这与经常引用的假设相反，即小种群往往只发生在边缘环境中。除了在小群体中运行的有据可查的人口统计和遗传随机性之外，我们的工作还提出了小群体对未来环境变化表现出更多可变性和可能更不可预测的进化反应的可能性。
The relationship between habitat variability and population size in fragmented habitats is poorly understood, yet might have important evolutionary consequences. For instance, fragmentation could (1) shift habitat characteristics, and by extension, selective regimes, in a consistent direction as populations and the fragments they occupy are reduced in size (directional hypothesis): or (2) increase variability in habitats among similarly sized populations as fragment size decreases (variable hypothesis). We investigated these alternatives based on multiyear habitat, demographic, and genetic data from 19 fragmented populations of a stream fish varying in census size (N) and effective number of breeders (N(b)). Mean habitat parameters were significantly related to N and N(b), but the forms of the relationships varied, and there was no evidence of consistent directional differences in habitat parameters from small to large population size. Small populations exhibited a wider range of variances in habitat parameters than large populations, and to a lesser extent, small populations also had greater variability in mean habitat parameters, possibly signaling more diverse selective regimes. These results suggest that many different environments are associated with small population size in nature, counter to the frequently cited assumption that small populations tend to occur only in marginal environments. In addition to well-documented demographic and genetic stochasticity operating within small populations, our work raises the possibility that small populations exhibit more variable and potentially less predictable evolutionary responses to future environmental change.