REGULAR ARTICLE Plant production and nitrogen accumulation above- and belowground in low and tall birch tundra communities: the influence of snow and litter Mathew R. Vankoughnett & Paul Grogan Received: 31 December 2015 /Accepted: 10 May 2016 # Springer International Publishing Switzerland 2016 Abstract Background and Aim A vegetation transition to taller and denser deciduous shrub tundra is currently occur- ring in many locations across the low Arctic, and is associated with climate change. Here, we investigated if deeper snow is a mechanism for enhanced shrub growth. Methods To determine if a moderate and climatically realistic increase in snow depth can enhance shrub pro- ductivity, we compared growth responses between am- bient and experimentally deepened snow plots in low birch hummock tundra. To determine the potential in- fluence of factors other than deepened snow that are associated with taller, denser shrubs, we also compared shrub growth between low birch hummock and tall birch-dominated tundra. Results Neither deciduous shrub above- nor below- ground production nor nitrogen accumulation was en- hanced by deepened snow. However, deciduous birch shrub new shoot production was 23× larger and total vascular shoot to belowground biomass ratios were higher in the tall birch tundra than the birch hummock (~0.7 and ~0.4, respectively), indicating that the combi- nation of deeper snow together with other internal feed- backs greatly enhanced birch growth. Conclusions Together, our results strongly suggest that the much larger litter production in tall birch ecosystems is an important internal feedback that may or may not interact with deeper snow to promote birch growth in tall shrub tundra. Keywords Arctic . Betula . Increased snow . Plant production . Shrub expansion . Snow-shrub feedback hypothesis Introduction The Arctic has experienced substantial climate warming in recent decades (Overpeck 1997; ACIA 2004), which has coincided with increased plant productivity and leaf phytomass in the vegetation across the Arctic (Goetz et al. 2005; Forbes et al. 2010; Beck and Goetz 2011; Xu et al. 2013). Observational and experimental data indi- cate that this increased plant productivity and leaf phytomass is at least partially caused by increased growth of deciduous shrubs, such as willow (Salix spp.), alder (Alnus spp.), and birch (Betula spp.) (Sturm et al. 2001; Tape et al. 2006; Myers-Smith et al. 2011; Elmendorf et al. 2012a, 2012b). A transition from low stature tundra vegetation to tall deciduous shrubs is expected to reduce albedo (Sturm et al. 2005a; Chapin Plant Soil DOI 10.1007/s11104-016-2921-2 Responsible Editor: Jeffrey Walck. Electronic supplementary material The online version of this article (doi:10.1007/s11104-016-2921-2) contains supplementary material, which is available to authorized users. M. R. Vankoughnett (*) Department of Biological Science, University of Wisconsin-Richland, Richland Center, WI 53581, USA e-mail: mathew.vankoughnett@uwc.edu P. Grogan Department of Biology, Queen’ s University, Kingston, ON K7L 3N6, Canada