The effects of forestry on Hg bioaccumulation in nemoral/boreal waters and recommendations for good silvicultural practice.
Mercury (Hg) levels are alarmingly high in fish from lakes across Fennoscandia and northern North America. The few published studies on the ways in which silviculture practices influence this problem indicate that forest operations increase Hg in downstream aquatic ecosystems. From these studies, we estimate that between one-tenth and one-quarter of the Hg in the fish of high-latitude, managed forest landscapes can be attributed to harvesting. Forestry, however, did not create the elevated Hg levels in the soils, and waterborne Hg/MeHg concentrations downstream from harvested areas are similar to those from wetlands. Given the current understanding of the way in which silviculture impacts Hg cycling, most of the recommendations for good forest practice in Sweden appear to be appropriate for high-latitude regions, e.g., leaving riparian buffer zones, as well as reducing disturbance at stream crossings and in moist areas. The recommendation to restore wetlands and reduce drainage, however, will likely increase Hg/MeHg loadings to aquatic ecosystems.
Bishop
Kevin
K
Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden. kevin.bishop@vatten.slu.se
Allan
Craig
C
Bringmark
Lage
L
Garcia
Edenise
E
Hellsten
Sofie
S
Högbom
Lars
L
Johansson
Kjell
K
Lomander
Anja
A
Meili
Markus
M
Munthe
John
J
Nilsson
Mats
M
Porvari
Petri
P
Skyllberg
Ulf
U
Sorensen
Rasmus
R
Zetterberg
Therese
T
Akerblom
Staffan
S
D000818:Animals; D003081:Cold Climate; D003247:Conservation of Natural Resources; D004784:Environmental Monitoring; D005399:Fishes / Q000378:metabolism*; D016468:Forestry / Q000592:standards*; D008628:Mercury / Q000378:metabolism*; D013548:Sweden
D008628:Mercury