Data from: Spatial storage effect promotes biodiversity during adaptive radiation

Many ecological communities are enormously diverse. Variation in environmental conditions over time and space provides opportunities for temporal and spatial storage effects to operate, potentially promoting species coexistence and biodiversity. While several studies have provided empirical evidence supporting the significance of temporal storage effect for coexistence, empirical tests of the role of spatial storage effect are rare. In particular, we know little about how spatial storage effect contributes to biodiversity over evolutionary timescales. Here we report the first experimental study on the role of spatial storage effect in the maintenance of biodiversity in evolving metacommunities, using the bacterium Pseudomonas fluorescens SBW25 as a laboratory model of adaptive radiation. We found that intercommunity spatial heterogeneity promoted phenotypic diversity of P. fluorescens in the presence of dispersal among local communities, by allowing the spatial storage effect to operate. Mechanistically, greater niche differences among P. fluorescens phenotypes arose in metacommunities with intercommunity spatial heterogeneity, facilitating negative frequency-dependent selection, and thus, the coexistence among P. fluorescens phenotypes. These results highlight the importance of spatial storage effect for biodiversity over evolutionary timescales.

众多生态群落具有极高的物种多样性。时空环境条件的变异为时间存储效应（temporal storage effect）与空间存储效应（spatial storage effect）的发挥提供了契机，有望推动物种共存与生物多样性维持。尽管已有多项研究为时间存储效应在物种共存中的重要性提供了实证支撑，但针对空间存储效应作用的实证检验仍较为匮乏。尤为关键的是，我们对空间存储效应如何在进化时间尺度上影响生物多样性仍知之甚少。本研究以荧光假单胞菌（Pseudomonas fluorescens）SBW25作为适应性辐射（adaptive radiation）的实验室模型，首次开展了进化集合群落（metacommunities）中空间存储效应在维持生物多样性方面作用的实验研究。研究发现，当本地群落间存在扩散时，借助空间存储效应的运作，群落间空间异质性可提升荧光假单胞菌的表型多样性。从机制层面来看，在具有群落间空间异质性的集合群落中，荧光假单胞菌不同表型间的生态位分化程度更高，这会促进负频率依赖选择（negative frequency-dependent selection），进而推动荧光假单胞菌不同表型的共存。上述研究结果凸显了空间存储效应在进化时间尺度上对生物多样性维持的重要意义。