Effects of local changes in active layer and soil climate on seasonal foliar nitrogen concentrations of three boreal forest shrubs

• Published in: Canadian Journal of Forest Research
• Main Authors: Rohrs-Richey, Jennifer K., Mulder, Christa P.H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2007
• Subjects: Ecology; Forestry; Global and Planetary Change; Caribou-Poker Creeks Research Watershed; permafrost; Alaska
• Online Access: http://dx.doi.org/10.1139/x06-230; http://www.nrcresearchpress.com/doi/full-xml/10.1139/x06-230; http://www.nrcresearchpress.com/doi/pdf/10.1139/x06-230

Caribou Poker Creeks Research Watershed is a boreal forest watershed in Interior Alaska that is susceptible to regional warming and permafrost thaw. We measured seasonal foliar N concentrations of the black spruce understory shrubs, Vaccinium uliginosum L., Vaccinium vitis-idaea L., and Ledum palustre L. on north- and south-facing sides of the watershed. We predicted that the shrubs would respond to small-scale changes in active layer and soil climate, and we expected similar responses according to growth strategy (evergreen or deciduous). Overall, foliar N in shrubs was higher on warmer, drier soils with deep active layers: +7.9% N in V. uliginosum, +11.1% N in V. vitis-idaea, and +9.4% N in L. palustre. Each shrub had species-specific foliar N patterns that could not be categorized by growth strategy and were not well explained by soil climate or active layer. Leaf mineral nutrition is influenced by multiple processes, and foliar N was best explained by the combination of environmental variables operating at the study site. For Caribou Poker Creeks Research Watershed, we can expect increased N status of the black spruce understory along with continued climate warming, but changes cannot be predicted based on growth strategy.