Animal populations are spatially structured in heterogeneous landscapes, in which local patches with differing vital rates are connected by dispersal of individuals to varying degrees. Although there is evidence that vital rates differ among local populations, much less is understood about how vital rates covary among local patches in spatially heterogeneous landscapes. In this study, we conducted a nine‐year annual mark–recapture survey to characterize spatial covariation of survival and growth for two Japanese native salmonids, white‐spotted charr Salvelinus leucomaenis japonicus and red‐spotted masu salmon Oncorhynchus masou ishikawae, in a headwater stream network composed of distinctly different tributary and mainstem habitats. Spatial structure of survival and growth differed by species and age class, but results provided support for negative covariation between vital rates, where survival was higher in the tributary habitat but growth was higher in the mainstem habitat. Thus, neither habitat was apparently more important than the other, and local habitats with complementary vital rates may make this spatially structured population less vulnerable to environmental change (i.e. portfolio effect). Despite the spatial structure of vital rates and possibilities that fish can exploit spatially distributed resources, movement of fish was limited due partly to a series of low‐head dams that prevented upstream movement of fish in the study area. This study shows that spatial structure of vital rates can be complex and depend on species and age class, and this knowledge is likely paramount to elucidating dynamics of spatially structured populations.

中文翻译：

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流网中鱼类种群生命率的空间协变

动物种群的空间结构在异质景观中，通过不同程度地分散个体，将具有不同生命率的局部斑块连接起来。尽管有证据表明当地居民之间的生命率存在差异，但对于空间异质性景观中局部区域之间的生命率如何变化的了解还很少。在这项研究中，我们进行了为期9年的年度标记回收调查，以表征两种日本本土鲑鱼，白斑鲑鱼Salvelinus leucomaenis japonicus和红斑马苏鱼Oncorhynchus masou ishikawae的生存和生长的空间协变。，在由明显不同的支流和主要生境组成的上游水流网络中。生存和生长的空间结构因物种和年龄类别而异，但结果为生命率之间的负协变提供了支持，在这些变化中，支流生境的生存率较高，而主茎生境的生存率较高。因此，两个生境显然都不比另一个生境重要，并且具有互补生命率的本地生境可能会使这种空间结构化的种群不易受到环境变化的影响（即投资组合效应）。尽管生命率的空间结构和鱼类可以利用空间分布资源的可能性，但鱼类的活动受到一定程度的限制，这是由于一系列低头水坝阻止了鱼类在研究区域内的上游活动。