The stable nitrogen isotope composition of dominant species in various/particular types of tundra in the studied area from the lowest to the highest <i>δ</i>¹⁵N mean values (refer to Fig 2 and Table 1).

<p>The Box-Whisker plot shows minimum and maximum (caps at the end of each box), the lower and upper quartiles (orange box), and the median (line inside the box). The numbers in the top table reflect the estimated relative mean contribution from the three major N-sources to total N-pool, separately for each type of tundra. The estimate of N-contributions based on <i>δ</i>¹⁵N, botanical, and algological studies, and is given as an N-percent incorporated by plants from each N-source. “All”—refers to mean for all sampled plants from each tundra location as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136536#pone.0136536.s004" target="_blank">S1 Table</a>. Tundra type symbols/ abbreviations–see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136536#pone.0136536.t001" target="_blank">Table 1</a>.