Eco-evolution in size-structured ecosystems: simulation case study of rapid morphological changes in alewife

BMC Evolutionary Biology

Research Article

Xavier Thibert-Plante¹  Jung koo Kang² 

[1] Icelab and Department of Ecology and Environmental Science, Umeå University, Linnaeus va̋g 6, Umeå, Sweden;The Center for Quantitative Sciences in Biomedicine, North Carolina State University, Campus Box 8213, 308 Cox Hall, 27695-8212, Raleigh, NC, USA;Icelab and Department of Ecology and Environmental Science, Umeå University, Linnaeus va̋g 6, Umeå, Sweden;

关键词: Eco-evolution;    Size-structured ecosystem;    Individual-based model;    Ecological power law;    Contemporary evolution;    Functional trait;    Body size;    Fish;    Alewife;   

DOI  :  10.1186/s12862-017-0912-4

 received in 2016-10-21, accepted in 2017-02-14,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundOver the last 300 years, interactions between alewives and zooplankton communities in several lakes in the U.S. have caused the alewives’ morphology to transition rapidly from anadromous to landlocked. Lakes with landlocked alewives contain smaller-bodied zooplankton than those without alewives. Landlocked adult alewives display smaller body sizes, narrower gapes, smaller inter-gill-raker spacings, reach maturity at an earlier age, and are less fecund than anadromous alewives. Additionally, landlocked alewives consume pelagic prey exclusively throughout their lives whereas anadromous alewives make an ontogenetic transition from pelagic to littoral prey. These rapid, well-documented changes in the alewives’ morphology provide important insights into the morphological evolution of fish.Predicting the morphological evolution of fish is crucial for fisheries and ecosystem management, but the involvement of multiple trophic interactions make predictions difficult. To obtain an improved understanding of rapid morphological change in fish, we developed an individual-based model that simulated rapid changes in the body size and gill-raker count of a fish species in a hypothetical, size-structured prey community. Model parameter values were based mainly on data from empirical studies on alewives. We adopted a functional trait approach; consequently, the model explicitly describes the relationships between prey body size, alewife body size, and alewife gill-raker count. We sought to answer two questions: (1) How does the impact of alewife populations on prey feed back to impact alewife size and gill raker number under several alternative scenarios? (2) Will the trajectory of the landlocked alewives’ morphological evolution change after 150–300 years in freshwater?ResultsOver the first 250 years, the alewives’ numbers of gill-rakers only increased when reductions in their body size substantially improved their ability to forage for small prey. Additionally, alewives’ gill-raker counts increased more rapidly as the adverse effects of narrow gill-raker spacings on foraging for large prey were made less severe. For the first 150–250 years, alewives’ growth decreased monotonically, and their gill-raker number increased monotonically. After the first 150–250 years, however, the alewives exhibited multiple evolutionary morphological trajectories in different trophic settings. In several of these settings, their evolutionary trajectories even reversed after the first 150–250 years.ConclusionsAlewives affected the abundance and morphology of their prey, which in turn changed the abundance and morphology of the alewives. Complex low-trophic-level interactions can alter the abundance and characteristics of alewives. This study suggests that the current morphology of recently (∼300 years)-landlocked alewives may not represent an evolutionarily stable state.

【 授权许可】

CC BY   
© The Author(s) 2017

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