Biodiversity-Based Empirical Critical Loads of Nitrogen Deposition in the Athabasca Oil Sands Region
Anthropogenic nitrogen (N) emissions can have considerable effects on terrestrial ecosystems, with chronic N deposition leading to changes in plant species composition. The Athabasca Oil Sands Region (AOSR) represents a large point source of N emissions, which has prompted concern for surrounding ha...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-04-01
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| Series: | Nitrogen |
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| Online Access: | https://www.mdpi.com/2504-3129/4/2/12 |
| _version_ | 1797593200398958592 |
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| author | Nicole Vandinther Julian Aherne |
| author_facet | Nicole Vandinther Julian Aherne |
| author_sort | Nicole Vandinther |
| collection | DOAJ |
| description | Anthropogenic nitrogen (N) emissions can have considerable effects on terrestrial ecosystems, with chronic N deposition leading to changes in plant species composition. The Athabasca Oil Sands Region (AOSR) represents a large point source of N emissions, which has prompted concern for surrounding habitats. The objective of this study was to determine the relative importance of N deposition as a driver of plant species community composition against bioclimatic and soil chemical variables. Further, we sought to identify community thresholds in plant species composition across a N deposition gradient. This assessment was performed for 46 Jack pine (<i>Pinus banksiana</i> Lamb.)-dominant forest sites surrounding the AOSR spanning Alberta and Saskatchewan. In total, 35 environmental variables were evaluated using redundancy analysis (RDA), followed by gradient forest analysis applied to plant species abundance data. Soil chemical variables accounted for just over 26% of the total explainable variation in the dataset, followed by bioclimatic variables (19%) and deposition variables (5%), but joint effects between variables also explained a significant portion of the total variation (<i>p</i> < 0.001). Total deposited nitrogen (TDN), and sulphur (TDS) along with bioclimatic and soil chemical variables, were identified as important variables in gradient forest analysis. A single, definitive threshold across TDN was identified at approximately 5.6 kg N ha<sup>−1</sup> yr<sup>−1</sup> (while a TDS threshold was found at 14.4 kg S ha<sup>−1</sup> yr<sup>−1</sup>). The TDN threshold range was associated primarily with changepoints for several vascular species (<i>Pyrola asarifolia</i>, <i>Pyrola chlorantha</i>, <i>Cornus canadensis</i>, and <i>Arctostaphylos uva-ursi</i>) and bryophyte and lichen species (<i>Pleurozium schreberi</i>, <i>Vulpicida pinastri</i>, and <i>Dicranum polysetum</i>). These results suggest that across Jack pine-dominant forests surrounding the AOSR, the biodiversity-based empirical critical load of nutrient N is 5.6 kg N ha<sup>−1</sup> yr<sup>−1</sup>. |
| first_indexed | 2024-03-11T02:05:34Z |
| format | Article |
| id | doaj.art-abd01603a1584d6cb87ef9a0773dcb3f |
| institution | Directory Open Access Journal |
| issn | 2504-3129 |
| language | English |
| last_indexed | 2024-03-11T02:05:34Z |
| publishDate | 2023-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nitrogen |
| spelling | doaj.art-abd01603a1584d6cb87ef9a0773dcb3f2023-11-18T11:54:52ZengMDPI AGNitrogen2504-31292023-04-014216919310.3390/nitrogen4020012Biodiversity-Based Empirical Critical Loads of Nitrogen Deposition in the Athabasca Oil Sands RegionNicole Vandinther0Julian Aherne1School of Environment, Trent University, Peterborough, ON K9J 0G2, CanadaSchool of Environment, Trent University, Peterborough, ON K9J 0G2, CanadaAnthropogenic nitrogen (N) emissions can have considerable effects on terrestrial ecosystems, with chronic N deposition leading to changes in plant species composition. The Athabasca Oil Sands Region (AOSR) represents a large point source of N emissions, which has prompted concern for surrounding habitats. The objective of this study was to determine the relative importance of N deposition as a driver of plant species community composition against bioclimatic and soil chemical variables. Further, we sought to identify community thresholds in plant species composition across a N deposition gradient. This assessment was performed for 46 Jack pine (<i>Pinus banksiana</i> Lamb.)-dominant forest sites surrounding the AOSR spanning Alberta and Saskatchewan. In total, 35 environmental variables were evaluated using redundancy analysis (RDA), followed by gradient forest analysis applied to plant species abundance data. Soil chemical variables accounted for just over 26% of the total explainable variation in the dataset, followed by bioclimatic variables (19%) and deposition variables (5%), but joint effects between variables also explained a significant portion of the total variation (<i>p</i> < 0.001). Total deposited nitrogen (TDN), and sulphur (TDS) along with bioclimatic and soil chemical variables, were identified as important variables in gradient forest analysis. A single, definitive threshold across TDN was identified at approximately 5.6 kg N ha<sup>−1</sup> yr<sup>−1</sup> (while a TDS threshold was found at 14.4 kg S ha<sup>−1</sup> yr<sup>−1</sup>). The TDN threshold range was associated primarily with changepoints for several vascular species (<i>Pyrola asarifolia</i>, <i>Pyrola chlorantha</i>, <i>Cornus canadensis</i>, and <i>Arctostaphylos uva-ursi</i>) and bryophyte and lichen species (<i>Pleurozium schreberi</i>, <i>Vulpicida pinastri</i>, and <i>Dicranum polysetum</i>). These results suggest that across Jack pine-dominant forests surrounding the AOSR, the biodiversity-based empirical critical load of nutrient N is 5.6 kg N ha<sup>−1</sup> yr<sup>−1</sup>.https://www.mdpi.com/2504-3129/4/2/12gradient forest analysisJack pine forestredundancy analysiscommunity threshold |
| spellingShingle | Nicole Vandinther Julian Aherne Biodiversity-Based Empirical Critical Loads of Nitrogen Deposition in the Athabasca Oil Sands Region Nitrogen gradient forest analysis Jack pine forest redundancy analysis community threshold |
| title | Biodiversity-Based Empirical Critical Loads of Nitrogen Deposition in the Athabasca Oil Sands Region |
| title_full | Biodiversity-Based Empirical Critical Loads of Nitrogen Deposition in the Athabasca Oil Sands Region |
| title_fullStr | Biodiversity-Based Empirical Critical Loads of Nitrogen Deposition in the Athabasca Oil Sands Region |
| title_full_unstemmed | Biodiversity-Based Empirical Critical Loads of Nitrogen Deposition in the Athabasca Oil Sands Region |
| title_short | Biodiversity-Based Empirical Critical Loads of Nitrogen Deposition in the Athabasca Oil Sands Region |
| title_sort | biodiversity based empirical critical loads of nitrogen deposition in the athabasca oil sands region |
| topic | gradient forest analysis Jack pine forest redundancy analysis community threshold |
| url | https://www.mdpi.com/2504-3129/4/2/12 |
| work_keys_str_mv | AT nicolevandinther biodiversitybasedempiricalcriticalloadsofnitrogendepositionintheathabascaoilsandsregion AT julianaherne biodiversitybasedempiricalcriticalloadsofnitrogendepositionintheathabascaoilsandsregion |