Abstract Detail

Conservation Biology

Macdonald, S. Ellen [1], Fenn, Mark [2], Davies, Mervyn [3].

Forest vegetation responses to atmospheric deposition associated with oil sands mining operations.

Commercial scale mining and processing of bituminous sands (oil sands) in northeastern Alberta Canada, which began in 1967, is associated with increasing emissions and deposition of sulfur (S) and nitrogen (N) compounds as well as base cations (BC). The Wood Buffalo Environmental Association’s Terrestrial Ecosystem Effects Monitoring Program was initiated to address concerns about the impacts of these industrial emissions on the surrounding boreal forest landscape. They established a monitoring program using a network of sites in jack pine (Pinus banksiana) forests located at varying distances and directions from the center of oil sands mining activity. We will present an analysis of relationships between forest vegetation and estimated atmospheric deposition or exposure derived using two approaches: 1) Mapped spatial patterns of throughfall and bulk deposition of sulfur (S), nitrogen (N) and base cations (BC) based on data from a distributed network of ion exchange resin (IER) collectors; and 2) ambient annual SO₂ and NO₂ concentrations, total S and N deposition, and potential acid input (PAI) deposition (defined by total S and N deposition minus measured BC deposition) based on CALMET/CALPUFF dispersion model predictions. Understory vegetation cover and richness were positively related to several of the deposition variables and negatively related to distance from the emissions source region. A model selection procedure showed that two deposition variables were most strongly related to the vegetation responses: 1) PAI deposition based on the CALPUFF model using the bulk base cation measurements; or 2) Throughfall base cation deposition based on the IER data. The models had moderate to low explanatory power with R² values ranging from 0.22 to 0.35. The vegetation responses were largely due to increased richness and cover of forbs and trailing shrubs and effects were notable largely within 20 km of the emissions source. The results are consistent with a fertilization effect of deposition on vegetation and this likely reflects the fact that any potential acidification effects of N and S deposition are buffered by BC deposition. BC inputs could, themselves, be having a fertilization effect. Dendrochronological analyses provide further insight.

1 - University of Alberta, Dept. of Renewable Resources, Gsb 751, Edmonton, AB, T6G 2H1, Canada
2 - United States Dept. of Agriculture - Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA, 92507, USA
3 - Stantec Consulting, 200-325 25th Street SE , Calgary, AB, T2A 7H8, Canada

Keywords:
pollution
boreal forest
Community ecology
oil sands mining.

Presentation Type: Oral Paper:Papers for Topics
Session: 63
Location: Salon 19/20/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 8:15 AM
Number: 63001
Abstract ID:360
Candidate for Awards:None