Shrub influence on soil moisture, nutrients, temperature and species composition, 2019 - 2020.

Shrubification, the expansion and densification of shrubs, is
occurring in arctic and alpine zones across the globe (Myers-Smith
et al., 2011)⁠. This alteration is primarily driven by warming
temperatures (Elmendorf et al., 2012b, 2012a)⁠, and can have major
consequences for the existing vegetation (Anthelme et al., 2007;
Pajunen et al., 2011; Venn et al., 2014)⁠ and for nutrient pools
(Sturm et al., 2005; DeMarco et al., 2014)⁠ due to the abiotic and
biotic effects of shrubs. Shrubs accumulate snow which insulates the
ground during the winter and provides more moisture later in the
season (Liston et al., 2002)⁠. During the summer, shrubs provide
shade and wind protection. Additionally, shrubs can increase the
soil nitrogen (N) pool through their high input of plant material
into the soil (DeMarco et al., 2014). These small-scale climatic and
soil alterations have important consequences for plant community
dynamics in the arctic and alpine. References: Anthelme, F., Villaret, J.-C., and Brun, J.-J., 2007: Shrub
encroachment in the Alps gives rise to the convergence of sub-alpine
communities on a regional scale. Journal of Vegetation Science,
18(3):355–362. DeMarco, J., Mack, M. C., and Bret-Harte, M. S., 2014: Effects of
arctic shrub expansion on biophysical vs . biogeochemical drivers of
litter decomposition. Ecological Society of America,
95(7):1861–1875. Elmendorf, S. C., Henry, G. H. R., Hollister, R. D., Björk, R. G.,
Bjorkman, A. D., Callaghan, T. V., Collier, L. S., Cooper, E. J.,
Cornelissen, J. H. C., Day, T. A., Fosaa, A. M., Gould, W. A.,
Grétarsdóttir, J., Harte, J., Hermanutz, L., Hik, D. S., Hofgaard,
A., Jarrad, F., Jónsdóttir, I. S., Keuper, F., Klanderud, K., Klein,
J. A., Koh, S., Kudo, G., Lang, S. I., Loewen, V., May, J. L.,
Mercado, J., Michelsen, A., Molau, U., Myers-Smith, I. H.,
Oberbauer, S. F., Pieper, S., Post, E., Rixen, C., Robinson, C. H.,
Schmidt, N. M., Shaver, G. R., Stenström, A., Tolvanen, A., Totland,
Ø., Troxler, T., Wahren, C. H., Webber, P. J., Welker, J. M., and
Wookey, P. A., 2012a:. Global assessment of experimental climate
warming on tundra vegetation: Heterogeneity over space and time.
Ecology Letters, 15(2):164–175. Elmendorf, S. C., Henry, G. H. R., Hollister, R. D., Björk, R. G.,
Boulanger-Lapointe, N., Cooper, E. J., Cornelissen, J. H. C., Day,
T. A., Dorrepaal, E., Elumeeva, T. G., Gill, M., Gould, W. A.,
Harte, J., Hik, D. S., Hofgaard, A., Johnson, D. R., Johnstone, J.
F., Jónsdóttir, I. S., Jorgenson, J. C., Klanderud, K., Klein, J.
A., Koh, S., Kudo, G., Lara, M., Lévesque, E., Magnússon, B., May,
J. L., Mercado-Díaz, J. A., Michelsen, A., Molau, U., Myers-Smith,
I. H., Oberbauer, S. F., Onipchenko, V. G., Rixen, C., Martin
Schmidt, N., Shaver, G. R., Spasojevic, M. J., Pórhallsdóttir, P.
E., Tolvanen, A., Troxler, T., Tweedie, C. E., Villareal, S.,
Wahren, C. H., Walker, X., Webber, P. J., Welker, J. M., and Wipf,
S., 2012b:. Plot-scale evidence of tundra vegetation change and
links to recent summer warming. Nature Climate Change, 2(6):453–457. Liston, G. E., Mcfadden, J. P., Sturm, M., and Pielke, R. A., 2002:
Modelled changes in arctic tundra snow, energy and moisture fluxes
due to increased shrubs. Global Change Biology, 8(1):17–32.