Assessing anthropogenic impact on boreal lakes with historical fish species distribution data and hydrogeochemical modeling.
Bottom Line: Quantifying the effects of human activity on the natural environment is dependent on credible estimates of reference conditions to define the state of the environment before the onset of adverse human impacts.In 2010, MAGIC predicted chemical recovery in 50% of the lakes, however roach only recolonized in five lakes after 1990, showing a lag between chemical and biological recovery.Based on our results, we show how the conceptual model can be used to understand and prioritize management of physico-chemical and ecological effects of anthropogenic stressors on surface water quality.
Affiliation: Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, Uppsala, SE-750 07, Sweden.Show MeSH
Mentions: The novel results suggest a conceptual model for making priorities of measures when there is an effect on a valuable indicator species. This model was derived from the assessment of lake acidification, but we propose that a conceptual model based on Fig.3a and b can be used for understanding the effects of human stressors on the natural environment more generally (Fig.7). The region where significant anthropogenic effects are suggested as a result of deviations from reference conditions based on physico-chemical criteria can be divided into four parts: (i) there is no effect on the chosen species as the change in physico-chemical environment was too small to have any ecologically meaningful effect on the biological indicator; (ii) substantial chemical change where biological conditions shifted from favorable to unfavorable; (iii) no effect on the chosen species because conditions during the reference state were unfavorable for the species; (iv) an accepted deviation from reference conditions. This conceptual model can be applied more generally using a positive deviation from reference conditions (iv) and a higher threshold based on physico-chemical criteria. This includes parameters (e.g., temperature, nutrients, and metals) where higher values are usually considered negative for the biological target organisms.
Affiliation: Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, Uppsala, SE-750 07, Sweden.