Spatial drivers of instability in marine size-spectrum ecosystems

JOURNAL OF THEORETICAL BIOLOGY

卷:517

Article

Xu, Nuo¹  Delius, Gustav W.²  Zhang, Lai¹  Thygesen, Uffe H.^3,4  Andersen, Ken H.⁴ 

[1] Yangzhou Univ, Sch Math Sci, Yangzhou 225002, Jiangsu, Peoples R China

[2] Univ York, Dept Math, York YO10 5DD, N Yorkshire, England

[3] Tech Univ Denmark, Dept Appl Math & Comp Sci, Lyngby, Denmark

[4] Tech Univ Denmark, Ctr Ocean Life, Natl Inst Aquat Resources, Lyngby, Denmark

关键词: Size-spectrum model;    Marine ecosystems;    Fitness-taxis;    Stability;    Diffusion;    Travelling patterns;   

DOI  :  10.1016/j.jtbi.2021.110631

来源: Elsevier

【 摘 要 】

Size-spectrum models are a recent class of models describing the dynamics of a whole community based on a description of individual organisms. The models are motivated by marine ecosystems where they cover the size range from multicellular plankton to the largest fish. We propose to extend the sizespectrum model with spatial components. The spatial dynamics is governed by a random motion and a directed movement in the direction of increased fitness, which we call `fitness-taxis'. We use the model to explore whether spatial irregularities of marine communities can occur due to the internal dynamics of predator-prey interactions and spatial movements. This corresponds to a pattern-formation analysis generalized to an entire ecosystem but is not limited to one prey and one predator population. The analyses take the form of Fourier analysis and numerical experiments. Results show that diffusion always stabilizes the equilibrium but fitness-taxis destabilizes it, leading to non-stationary spatially inhomogeneous population densities, which are travelling in size. However, there is a strong asymmetry between fitness-induced destabilizing effects and diffusion-induced stabilizing effects with the latter dominating over the former. These findings reveal that fitness taxis acts as a possible mechanism behind pattern formations in ecosystems with high diversity of organism sizes, which can drive the emergence of spatial heterogeneity even in a spatially homogeneous environment. (C) 2021 Elsevier Ltd. All rights reserved.

【 授权许可】

Free