Plasticity in bog plant nitrogen concentration is related to recent weather conditions

Abstract Background and aims NO x emissions from development of the oil sands resource in the Athabasca Oil Sands Region (AOSR) in Alberta, Canada have caused elevated N deposition, which has led to increased N concentrations in bog Sphagnum mosses and in leaves of some vascular plant species. Here, we address whether climate-related environmental variables affect N concentrations in bog species. Methods Plant samples were collected from 5 bogs in the AOSR, cleaned, dried, ground, and analyzed for N concentrations. Tissue N concentrations in 8 bog plant species were regressed against mean daily air temperature, precipitation, photosynthetically active radiation, atmospheric water potential, and atmospheric vapor pressure deficit over the 5, 10, 15, 20, 25, and 30 days prior to plant sampling using best subset regression. Results Climate-related environmental variables explained 12–61 % of overall variability in plant tissue N concentration. Tissue N concentrations in more deeply rooted vascular species ( Maianthemum trifolium, Rubus chamaemorus, Rhododendron groenlandicum , Picea mariana ) respond to environmental variables over longer periods of time (the previous 25–20 days prior to sampling) than more shallow rooted vascular species ( Vaccinium oxycoccos , Vaccinium vitis-idaea ) or mosses ( Sphagnum capillifolium, Sphagnum fuscum ) (5–10 days prior to sampling). Conclusion In the AOSR, N deposition and climate will continue to change. Understanding how bog plant N concentrations are affected by elevated N deposition from oil sands development and by climate will be key to the ability of monitoring programs to identify oil sands related effects on bog ecosystems across the AOSR.