Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden; Department of Earth Sciences, Uppsala University, Uppsala, Sweden.
Sci Total Environ. 2018 May 1;622-623:1353-1362. doi: 10.1016/j.scitotenv.2017.12.075. Epub 2017 Dec 13.
A number of studies have evaluated the effects of forest harvest on mercury (Hg) concentrations and exports in surface waters, but few studies have tested the effect from forest harvest on the change in fish Hg concentrations over the course of several years after harvest. To address this question, mercury (Hg) concentrations in perch (Perca fluviatilis) muscle tissue from five lakes were analyzed for two years before (2010-2011) and three years after (2013-2015) forest harvest conducted in 2012. Fish Hg concentrations in the clear-cut catchments (n=1373 fish specimens) were related to temporal changes of fish Hg in reference lakes (n=1099 fish specimen) from 19 lakes in the Swedish National Environmental Monitoring Programme. Small (length<100mm) and large perch (length≥100mm) were analyzed separately, due to changing feeding habitats of fish over growing size. There was considerable year-to-year and lake-to-lake variation in fish Hg concentrations (-14%-121%) after forest harvest in the clearcut lakes, according to our first statistical model that count for fish Hg changes. While the effect ascribed to forest harvest varied between years, after three years (in 2015), a significant increase of 26% (p<0.0001) in Hg concentrations of large fish was identified in our second statistical model that pooled all 5 clearcut lakes. The large fish Hg concentrations in the 19 reference lakes also varied, and in 2015 had decreased by 7% (p=0.03) relative to the concentrations in 2010-2011. The majority of the annual changes in fish Hg concentrations in the clearcut lakes after harvest were in the lower range of earlier predictions for high-latitude lakes extrapolated primarily from the effects of forest harvest operations on Hg concentrations in water. Since the risk of forest harvest impacts on Hg extends to fish and not just surface water concentrations, there is even more reason to consider Hg effects in forestry planning, alongside other ecosystem effects.
许多研究评估了森林采伐对地表水中汞（Hg）浓度和排放量的影响，但很少有研究测试森林采伐对鱼类 Hg 浓度在采伐后数年的变化的影响。为了解决这个问题，分析了 2012 年森林采伐前两年（2010-2011 年）和三年后（2013-2015 年）五个湖泊中鲈鱼（Perca fluviatilis）肌肉组织中的汞（Hg）浓度。在瑞典国家环境监测计划的 19 个湖泊中，从参考湖泊（n=1099 个鱼标本）中分析了采伐区（n=1373 个鱼标本）中鱼 Hg 浓度与鱼类 Hg 时间变化的关系。由于鱼类在生长过程中觅食栖息地的变化，小（长度<100mm）和大鲈鱼（长度≥100mm）分别进行了分析。根据我们的第一个统计模型，考虑到鱼 Hg 变化，在采伐后的湖泊中，鱼 Hg 浓度存在相当大的年际和湖泊间变化（-14%-121%）。虽然森林采伐的影响因年份而异，但在第二个统计模型中，在所有 5 个采伐区湖泊中汇总后，在 2015 年，大鲈鱼的 Hg 浓度显著增加了 26%（p<0.0001）。19 个参考湖泊中的大鲈鱼 Hg 浓度也有所不同，与 2010-2011 年相比，2015 年降低了 7%（p=0.03）。在采伐后，在 5 个采伐区湖泊中，鱼 Hg 浓度的年际变化大部分处于高纬度湖泊早期预测值的较低范围，这些预测值主要是基于森林采伐作业对水中 Hg 浓度的影响。由于森林采伐对 Hg 的影响不仅限于地表水浓度，而且还会影响鱼类，因此在森林规划中，除了考虑其他生态系统影响外，还更有理由考虑 Hg 影响。
