Bernthal Fionn R, Armstrong John D, Nislow Keith H, Metcalfe Neil B
Institute of Biodiversity Animal Health and Comparative Medicine University of Glasgow Glasgow UK.
Marine Scotland - Science Freshwater Fisheries Laboratory Faskally Pitlochry UK.
Aquat Conserv. 2022 Jun;32(6):1073-1091. doi: 10.1002/aqc.3811. Epub 2022 Mar 29.
Freshwater catchments can experience nutrient deficits that result in reduced primary and secondary productivity. The most commonly limiting nutrients are nitrogen and phosphorus, either separately or together. This review considers the impact of increasing nutrient limitation in temperate basin stream and river systems, focusing on upland areas that currently or previously supported wild Atlantic salmon () populations.Anthropogenic changes to land use and increases in river barriers have altered upland nutrient dynamics, with particular impacts on salmon and other migratory fish species which may be net importers of nutrients to upland streams. Declining salmon populations may further reduce nutrient sources, reducing ecosystem and fisheries productivity below desired levels.Experimental manipulations of nutrient levels have examined the impacts of this cultural oligotrophication. There is evidence that growth and biomass of juvenile salmon can be increased via appropriate additions of nutrients, offering potential as a conservation tool. However, further research is required to understand the long-term effects of these additions on salmon populations and stream ecosystems, and to assess the vulnerability of downstream habitats to eutrophication as a result.Although purposeful nutrient addition with the aim of enhancing and conserving salmonid populations may be justified in some cases, it should be undertaken in an adaptive management framework. In addition, nutrient addition should be linked to nutrient retention and processing, and integrated into large-scale habitat restoration and recovery efforts.Both the scientific and the management community should recognize that the ecological costs and benefits associated with adding nutrients to salmon streams may change in a non-stationary world.
淡水集水区可能会出现营养物质短缺的情况，这会导致初级和次级生产力下降。最常见的限制性营养物质是氮和磷，单独或共同起作用。本综述考虑了温带流域溪流和河流系统中营养限制加剧的影响，重点关注目前或以前有野生大西洋鲑鱼（）种群的高地地区。土地利用的人为变化和河流障碍物的增加改变了高地的营养动态，对鲑鱼和其他洄游鱼类物种产生了特别影响，这些物种可能是高地溪流营养物质的净输入者。鲑鱼数量的下降可能会进一步减少营养来源，使生态系统和渔业生产力降至低于预期的水平。对营养水平的实验性操纵研究了这种人为造成的贫营养化的影响。有证据表明，通过适当添加营养物质可以增加幼鲑的生长和生物量，这为作为一种保护工具提供了潜力。然而，需要进一步研究来了解这些添加物对鲑鱼种群和溪流生态系统的长期影响，并评估下游栖息地因富营养化而受到的脆弱性。尽管在某些情况下，为了增加和保护鲑鱼种群而有目的地添加营养物质可能是合理的，但应该在适应性管理框架内进行。此外，营养物质的添加应该与营养物质的保留和处理相联系，并纳入大规模的栖息地恢复和修复工作中。科学界和管理界都应该认识到，在一个非静止的世界里，向鲑鱼溪流添加营养物质所带来的生态成本和效益可能会发生变化。
