科研之友
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摘要
Ontario's hardwood forests are currently subjected to high levels of air pollution, but critical levels at which point adverse effects may occur are poorly known. In this study, we sampled 35 hardwood plots dominated by sugar maple (Acer saccharum Marsh.) located along a contrasting climate, soil acidity, and air pollution gradient in southern Ontario to explore relationships between these potential ecosystem stressors and ecosystem responses. Foliar sulfur (S) and nitrogen (N) contents were positively correlated with modeled deposition, and foliose lichen species richness was negatively correlated with modeled air pollution levels (S deposition, N deposition, and atmospheric ozone AOT40), whereas foliar calcium, magnesium, and manganese contents were correlated with A-horizon soil acidity. Forest floor S and N contents and C/N ratios were related to soil pH, with high S and N contents and low C/N ratios occurring on the more acidic soil in the northern part of the region, which receives the lowest modeled loadings of S and N deposition and experience colder and wetter climate. Forest health as determined by canopy condition was not related to indices of air pollution, climate, or soil acidity, and no relationship was found among air pollution, soil acidity, and ground vegetation species richness or diversity.
- 出版日期2009-11
