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Journal article
Simulated N and S deposition affected soil chemistry and understory plant communities in a boreal forest in western Canada
Journal of Plant Ecology, Vol.11(4), pp.511-523
11
2018
Web of Science ID: WOS:000433291100001
Abstract
Aims
We conducted a simulated nitrogen (N) and sulfur (S) deposition experiment from 2006 to 2012 to answer the following questions: (i) does chronic N and S deposition decrease cation concentrations in the soil and foliage of understory plant species, and (ii) does chronic N and S deposition decrease plant diversity and alter species composition of the understory plant community in a boreal forest in western Canada where intensifying industrial activities are increasing N and S deposition?
Methods
Our field site was a mixedwood boreal forest stand located ~100 km southeast of Fort McMurray, Alberta, Canada. The experiment involved a 2 × 2 factorial design, with two levels each of N (0 and 30 kg N ha⁻¹ yr⁻¹; applied as NH4NO3) and S addition (0 and 30 kg S ha⁻¹ yr⁻¹; applied as Na₂SO₄). Four blocks were established in July 2006, each with four plots of 20 × 20 m randomly assigned to the treatments. Soil and understory vegetation were sampled and cover (%) of individual species of herb (height ≤ 0.5 m) and shrub (height 0.5–1 m) layers was determined in August 2012.
Important Findings
Seven years after the treatments began, N addition increased dissolved organic carbon and N in the mineral soil (P < 0.05), whereas S addition decreased exchangeable cations (P < 0.05) in the forest floor. In the shrub layer, species evenness, and overall diversity were decreased by N addition (P < 0.05) due to increases in abundance of nitrophilous species and S addition (P < 0.01) due to decreased cation concentrations in soils. Total shrub cover decreased with S addition (P < 0.10). Nitrogen and S addition affected neither species richness nor evenness in the herb layer. However, permutational multivariate analysis of variance and non-metric multidimensional scaling analyses (based on plant cover) indicated that the effect of N and S addition on understory plant species composition in the both shrub and herb layers was species-specific. Addition of N decreased foliar phosphorus and potassium concentrations in some species, suggesting potential risk of N-meditated nutrient imbalance in those species. Our results indicate that long-term elevated levels of N and S deposition can negatively impact plant nutrition and decrease the diversity of the understory plant community in boreal forests in northern Alberta, Canada. However, considering that the current N and S deposition rates in northern Alberta are much lower than the rates used in this study, N and S deposition should not negatively affect plant diversity in the near future.
Details
- Title
- Simulated N and S deposition affected soil chemistry and understory plant communities in a boreal forest in western Canada
- Publication Details
- Journal of Plant Ecology, Vol.11(4), pp.511-523
- Resource Type
- Journal article
- Publisher
- Oxford University Press on behalf of the Institute of Botany, Chinese Academy of Sciences and the Botanical Society of China; United Kingdom
- Series
- 11
- Copyright
- © The Author(s) 2017.
- Identifiers
- WOS:000433291100001; 99380090344106600
- Academic Unit
- Biology; Hal Marcus College of Science and Engineering
- Language
- English