Greening of the Arctic Tundra
Villarreal, S., Hollister, R.D., Johnson, D.R., Lara, M.J., Webber, P.J. and Tweedie, C.E. 2012. Tundra vegetation change near Barrow, Alaska (1972-2010). Environmental Research Letters 7: 10.1088/1748-9326/7/1/015508.
Focusing on an area near Barrow at the northernmost point of the Alaskan Coastal Plain (71°18'N, 156°40'W), Villarreal et al. resampled (for species cover and presence, in 1999, 2008 and 2010) 330 marked plots at 33 sites that had been established there in 1972 as part of that year's International Biological Program.
The six scientists report that over the 38-year study period, ecosystem diversity "increased for most plant communities, and wetter communities changed more than dry and moist plant communities." These findings are said by them to support other observational studies, such as that of Wilson and Nilsson (2009). And of the 19 species that comprised more than 80% of the overall relative cover, they say that five had higher relative cover in 2010 than 1972. In addition, they indicate that their results for changes in shrub cover "are somewhat consistent with other long-term observations and experimental studies that report increased shrub abundance (Myers-Smith et al., 2012; Tape et al., 2006; Walker et al., 2006; Sturm et al., 2001)," as well as warming-induced "treeline advancement (Lloyd, 2005; Danby and Hik, 2007)."
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Tape, K., Sturm, M. and Racine, C. 2006. The evidence for shrub expansion in northern Alaska and the Pan-Arctic. Global Change Biology 12: 686-702.
Walker, M.D., Wahren, C.H., Hollister, R.D., Henry, G.H.R., Ahlquist, L.E., Alatalo, J.M., Bret-Harte, M.S., Calef, M.P., Callaghan, T.V., Carroll, A.B., Epstein, H.E., Jónsdóttir, I.S., Klein, J.A. , Magnússon, B.ó., Molau, U., Oberbauer, S.F., Rewa, S.P., Robinson, C.H., Shaver, G.R., Suding, K.N., Thompson, C.C., Tolvanen, A., Totland, Ø., Turner, P.L., Tweedie, C.E., Webber, P.J. and Wookey, P.A. 2006. Plant community responses to experimental warming across the tundra biome. Proceedings of the National Academy of Sciences USA 103: 1342-1346.
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