Dispersal is the primary ecological process underpinning spatial dynamics in motile species by generating flux in reproductive locations over time. In migratory species, dispersal can also occur around non-breeding ranges, but this form currently lacks a unifying theoretical framework. We present a novel conceptual model for dispersal in migrants that builds upon existing literature, differentiating ‘reproductive' dispersal (i.e. changes in breeding locations) from ‘non-reproductive' dispersal, which we define as movements resulting in inter-annual or inter-generational changes in non-breeding locations. Crucially, unlike reproductive dispersal where movement outcomes are naturally propagated between generations, the outcomes of non-reproductive dispersal can be non-heritable. We use simulations of a solo-migrant population with a genetically encoded migratory programme to illustrate how variation in this heritability exerts a strong influence on both migratory connectivity and range shift propensity. When exposed to spatially uncoupled shifts in habitable ranges (i.e. seasonal climate niches shifting at different rates), long-term persistence of simulated populations required changes in migratory programmes to arise through heritable forms of non-reproductive dispersal (e.g. mutations in migratory gene complexes). By contrast, non-heritable dispersal mechanisms (e.g. navigation errors) cannot drive long-term shifts in non-breeding ranges, despite being a major component of realised dispersal and migratory connectivity patterns. Migratory connectivity metrics conflate these heritable and non-heritable drivers of non-reproductive dispersal, and therefore have limited power in predicting population responses to environmental change. Our models provide a framework for improving our understanding of spatial dynamics in migratory populations, and highlight the importance of teasing apart the mechanisms that drive migratory variability in order to evaluate and predict range plasticity in migrants.

中文翻译：

---

非繁殖扩散：迁徙范围动态和连通性的重要驱动力

扩散是通过在繁殖地点随时间产生通量来支撑运动物种空间动力学的主要生态过程。在迁徙物种中，扩散也可能发生在非繁殖范围内，但这种形式目前缺乏统一的理论框架。我们提出了一个新的移民扩散概念模型，该模型建立在现有文献的基础上，将“繁殖”扩散（即繁殖地点的变化）与“非繁殖”扩散区分开来，我们将其定义为导致年度间或代际间的运动非繁殖地点的变化。至关重要的是，与运动结果在几代人之间自然传播的生殖传播不同，非生殖传播的结果可能是不可遗传的。我们使用具有基因编码的迁徙计划的单独迁徙种群的模拟来说明这种遗传力的变化如何对迁徙连通性和范围转移倾向产生强烈影响。当暴露于可居住范围的空间不耦合变化（即季节性气候生态位以不同速率变化）时，模拟种群的长期存在需要通过可遗传的非繁殖传播形式（例如迁移基因复合物中的突变）来改变迁徙计划. 相比之下，不可遗传的传播机制（例如导航错误）不能推动非繁殖范围的长期变化，尽管它是已实现的传播和迁徙连接模式的主要组成部分。迁徙连通性指标将这些非繁殖扩散的可遗传和不可遗传驱动因素混为一谈，因此在预测种群对环境变化的反应方面的能力有限。我们的模型为提高我们对迁徙种群空间动态的理解提供了一个框架，并强调了梳理驱动迁徙变异性的机制以评估和预测迁徙者范围可塑性的重要性。