Tiddy Isabelle C, Schneider Kevin, Elmer Kathryn R
School of Biodiversity, One Health & Veterinary Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK.
J Fish Biol. 2024 Mar;104(3):517-535. doi: 10.1111/jfb.15621. Epub 2023 Dec 10.
Determining how environmental conditions contribute to divergence among populations and drive speciation is fundamental to resolving mechanisms and understanding outcomes in evolutionary biology. Postglacial freshwater fish species in the Northern Hemisphere are ideal biological systems to explore the effects of environment on diversification in morphology, ecology, and genetics (ecomorph divergences) within lakes. To date, various environmental factors have been implicated in the presence of multiple ecomorphs within particular lakes or regions. However, concerted evidence for generalizable patterns in environmental variables associated with speciation across geographical regions and across species and genera has been lacking. Here, we aimed to identify key biotic and abiotic factors associated with ecological divergence of postglacial freshwater fish species into multiple sympatric ecomorphs, focusing on species in the well-studied, widespread, and co-distributed genera Gasterosteus, Salvelinus, and Coregonus (stickleback, charr, and whitefish, respectively). We found that the presence of multiple sympatric ecomorphs tended to be associated with increasing lake surface area, maximum depth, and nutrient availability. In addition, predation, competition, and prey availability were suggested to play a role in divergence into multiple ecomorphs, but the effects of biotic factors require further study. Although we identified several environmental factors correlated with the presence of multiple ecomorphs, there were substantial data gaps across species and regions. An improved understanding of these systems may provide insight into both generalizable environmental factors involved in speciation in other systems, and potential ecological and evolutionary responses of species complexes when these variables are altered by environmental change.
确定环境条件如何导致种群间的分化并推动物种形成，是解决进化生物学中的机制问题和理解其结果的基础。北半球冰期后的淡水鱼类物种是探索环境对湖泊内形态、生态和遗传学（生态形态分化）多样化影响的理想生物系统。迄今为止，各种环境因素已被认为与特定湖泊或区域内多种生态形态的存在有关。然而，缺乏关于跨地理区域、跨物种和属的与物种形成相关的环境变量的可推广模式的一致证据。在这里，我们旨在确定与冰期后淡水鱼类物种生态分化为多个同域生态形态相关的关键生物和非生物因素，重点关注研究充分、分布广泛且共同分布的属——棘鱼属、红点鲑属和白鲑属（分别为刺鱼、红点鲑和白鱼）中的物种。我们发现，多个同域生态形态的存在往往与湖泊表面积增加、最大深度增加和养分可用性增加有关。此外，捕食、竞争和猎物可用性被认为在分化为多个生态形态中起作用，但生物因素的影响需要进一步研究。尽管我们确定了几个与多个生态形态的存在相关的环境因素，但物种和区域之间存在大量数据缺口。更好地理解这些系统可能有助于深入了解其他系统中物种形成所涉及的可推广环境因素，以及当这些变量因环境变化而改变时物种复合体的潜在生态和进化反应。
