Quantifying spatial subsidies of freshwater fish in large lakes

量化大型湖泊淡水鱼的空间补贴

• 批准号: RGPIN-2020-05500
• 负责人: Fisk, Aaron
• 金额: $ 4.74万
• 依托单位: University of Windsor
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=717159
• 关键词: Quantifying; spatial; subsidies; freshwater; fish

Trophic interactions of species are a key driver that structure food webs and ultimately ecosystem function and health. In combination with resource availability, these interactions contribute to defining the ecological role of a species. When resources are insufficient, mobile species need to move to new regions or habitats to meet energetic requirements. These movements can be short, such as when individuals move to a new habitat for a short period to feed, or long, when they are linked to seasonal changes in ecosystem productivity or environmental conditions. In both cases, movements can have consistent temporal and spatial patterns. When a species or population uses a second or multiple habitats for energetic needs, or to increase its productivity, it can be referred to as a spatial subsidy. Spatial subsidies are often critical for supporting higher trophic level species, such as shark species on coral reefs, and often explain confusing observed ecological phenomena, such as inverted food-web biomass pyramids. Spatial subsidies are recognized as important components of marine ecosystems but are poorly studied or understood in freshwater ecosystems, despite their significant effects on nutrient cycling, productivity, and food webs. Freshwater ecosystems are vital for human and environmental health but are under intense pressure from multiple stressors, and there is a need to better understand their structure and function. My program will quantify the feeding and movement ecology of freshwater fish species to better understand the prevalence and importance of spatial subsidies in large lakes. This research will use chemical tracers, stomach contents, and acoustic telemetry to define diet, habitat use, and movements of different fish species in three regions of the Laurentian Great Lakes. These data will populate Ecopath models to quantify trophic pathways and food-web structure to estimate the importance of spatial subsidies for these systems. The first field project will be in the Detroit River and will assess the importance of metabolic activity variation across two predator fish species over smaller areas. The second project, in Lake Erie, will quantify the importance of different lake basins on the diet and movement of less and highly mobile fish species. The third project, in Lake Ontario, will assess the importance of movement and diet on growth rates in four predator fish. These projects will use eight fish species with different life histories. The three study systems vary in characteristicse.g., productivity (Erie > Ontario); and depth (Ontario > Erie > Detroit)which will allow this research to identify key mechanisms and processes that influence spatial subsidies in freshwater ecosystems. This project will also include laboratory studies to quantify chemical tracer (amino acid and sulfur stable isotopes) turnover and diet tissue discrimination factors in fish to better inform the food web projects.

物种间的营养相互作用是构建食物网并最终影响生态系统功能和健康的关键驱动力。结合资源的可用性，这些相互作用有助于确定物种的生态作用。当资源不足时，流动物种需要迁移到新的区域或栖息地以满足能量需求。这些迁移可以是短期的，比如个体短期迁移到新的栖息地觅食，也可以是长期的，比如与生态系统生产力或环境条件的季节性变化有关。在这两种情况下，运动都具有一致的时间和空间模式。当一个物种或种群使用第二个或多个栖息地来满足能量需求或提高其生产力时，可称为空间补贴。空间补贴通常对支持高营养级物种（如珊瑚礁上的鲨鱼物种）至关重要，并经常解释观察到的令人困惑的生态现象，如颠倒的食物网生物量金字塔。空间补贴被认为是海洋生态系统的重要组成部分，但对淡水生态系统的研究或了解甚少，尽管它们对养分循环、生产力和食物网有重大影响。淡水生态系统对人类和环境健康至关重要，但受到多种应激源的巨大压力，需要更好地了解其结构和功能。