Beaver reservoirs have variable effects on downstream mercury in boreal stream food webs across harvested watersheds

abstract: “Beaver reservoirs and forestry are landscape disturbances that can increase the transfer of mercury (Hg) to stream food webs through increased mobilization from forest soils and methylation within the landscape, and through changes to food web structure. Both disturbances are widespread and co-occur throughout Canada’s boreal region, yet their combined effects on Hg bioaccumulation have not been studied. We sampled upstream and downstream of beaver reservoirs in harvested (n= 3) and non-harvested (n= 3) watersheds in Northwestern Ontario, Canada, for water, food sources (biofilm, leaves, and detritus), macroinvertebrate consumers (herbivorous and predatory), and top predators (fishes). When only harvesting effects were considered (upstream of reservoirs), Hg concentrations ([Hg]) of water, aquatic food sources and consumers, and trophic magnification slopes were highest in harvested compared …” authors:

• Celine ME Lajoie
• Karen A Kidd
• Colleen Dawson
• Wai Ying Lam
• Carl PJ Mitchell
• E_Emilson
• Robert W Mackereth featured: false projects: [] publication: ‘Environmental Research: Ecology’ publication_short: '' publication_types:
• “2” date: ‘2025-12-12T00:00:00Z’ publishDate: ‘2026-01-02’ title: ‘Beaver reservoirs have variable effects on downstream mercury in boreal stream food webs across harvested watersheds’ url_pdf: “https://iopscience.iop.org/article/10.1088/2752-664X/ae227b/pdf" url_source: “https://iopscience.iop.org/article/10.1088/2752-664X/ae227b/meta"