Timber Harvest Alters Mercury Bioaccumulation and Food Webs in Headwater Streams

Release Date:

Land use change is an important driver of global mercury cycling. Timber harvest is a common land use that can alter associated aquatic ecosystems, yet little is known about how it affects mercury concentrations and associated food web changes. 

Researchers evaluated mercury bioaccumulation in ten paired catchments in the Coast Range, Oregon that were either entirely clear-cut, clear-cut with riparian buffer, or left unharvested. Mercury concentrations in stream insects and salamanders differed among all three catchment types, yet these concentrations were not related to the mercury in stream water. Instead, stream organisms in clear-cut catchments had the highest mercury concentrations because they relied more heavily on food from instream primary producers rather than terrestrial litter inputs, such as leaves. Streams in clear cuts had a less diverse food web base than unharvested streams or streams with riparian buffers. Mercury in songbirds was also elevated following timber harvest. Findings highlight the importance of understanding food web responses to landscape disturbances when assessing mercury bioaccumulation. 
 

Willacker Jr., J.J., Eagles-Smith, C.A., Kowalski, B.M., Danehy, R.J., Jackson, A.K., Adams, E.M., Evers, D.C., Eckley, C.S., Tate, M.T., Krabbenhoft, D.P., 2019, Timber harvest alters mercury bioaccumulation and food web structure in headwater streams: Environmental Pollution, https://doi.org/10.1016/j.envpol.2019.07.025

Related Content

Filter Total Items: 3
Date published: November 16, 2017
Status: Active

Contaminant Ecology Research Team (FRESC)

The FRESC Contaminant Ecology research program evaluates the distribution, movement, and ecological effects of environmental contaminants across the landscape and strives to provide relevant science in support of natural resource conservation, management, and decision making.

Date published: November 13, 2017
Status: Active

Habitat and Land-Use Influences on Contaminant Bioaccumulation

The distribution and occurrence of contaminants and the associated biological exposure in ecological systems are driven by complex interactions between contaminant sources and mobilization pathways that are overlaid upon the habitat requirements of at-risk organisms. Moreover, landscape structure and land uses can strongly influence the driving processes of contaminant cycling, as well as the...

Date published: November 6, 2017
Status: Active

Contaminant Bioaccumulation through Food Webs

This is a broad theme representing the largest component of the Contaminant Ecology Research Program, acting as a bridge between the “Habitat and Land Use Influences” and “Ecological Effects” themes. “Contaminant Bioaccumulation” focuses on quantifying the transfer or movement of contaminants through food webs, and identifying the primary landscape factors and ecological mechanisms that are...