Invasive hybridization has variable effects on survival among salmonid populations

Human-mediated hybridization threatens global biodiversity, but the fitness consequences of hybridization are poorly understood, especially in vertebrates. We used capture-recapture data from 5,249 individuals in three hybridizing populations of invasive rainbow trout (Oncorhynchus mykiss) and native cutthroat trout (O. clarkii) to quantify the effects of rainbow trout genetic admixture and environmental conditions on survival. Seasonal variation in environmental conditions interacted with individual admixture to influence seasonal survival. Overall, annual survival declined with admixture at the warmest site (juvenile hybrids with 25% non-native ancestry had 20.7% lower annual survival than non-hybridized cutthroat trout) but increased with admixture at the coldest site (juvenile hybrids with 25% non-native ancestry had 19.7% higher survival than non-hybridized cutthroat trout), providing evidence that fitness effects of hybridization vary in a context-dependent manner. Furthermore, hi...

人类介导的杂交威胁全球生物多样性，但学界对杂交的适合度效应仍缺乏深入认知，在脊椎动物类群中这一问题尤为突出。本研究依托来自入侵性虹鳟（*Oncorhynchus mykiss*）与本土切喉鳟（*O. clarkii*）三个杂交种群的5249个个体的标记重捕数据，量化了虹鳟遗传血统混合比例与环境条件对个体存活的影响。研究发现，环境条件的季节变化与个体遗传血统混合比例相互作用，共同影响季节存活率。总体而言，在最热的研究样点，年存活率随遗传血统混合比例升高而下降——携带25%非本土血统的幼年杂交个体，其年存活率较非杂交切喉鳟低20.7%；而在最冷的研究样点，年存活率则随遗传血统混合比例升高而上升——携带25%非本土血统的幼年杂交个体，其年存活率较非杂交切喉鳟高19.7%，这一结果证实杂交的适合度效应具有环境依赖性。此外，本研究……