Table 3.
Change in community indices over time in control plots and in response to warming at the four sites (AD – Atqasuk dry, AW – Atqasuk wet, BD – Barrow dry, and BW – Barrow wet). The community indices used were cover of live, standing dead, and dead unattached (litter) plant material; the percent of the canopy that was not occupied by vascular plants (Open Canopy); and the diversity metrics species richness and Shannon index. See Table2 for an explanation of the table layout
| Site | C1 | C2 | C3 | C4 | E1 | E2 | E3 | E4 | W1 | W2 | W3 | W4 | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total Live Plants | ||||||||||||||
| AD | 112.6 (2.3) | 100.7 (2.3) | 102.6 (3.1) | 65.3 (2.7) | N | 121.0 (3.2) | 100.8 (4.6) | 96.1 (2.3) | 63.8 (2.6) | . | 8.4 | 0.1 | −6.5 | −1.5 |
| AW | 125.0 (1.3) | 121.2 (1.3) | 128.0 (2.2) | 90.5 (3.5) | N | 121.0 (1.7) | 122.9 (1.7) | 141.4 (1.4) | 88.4 (2.5) | I | −4.0 | 1.8 | 13.4 | −2.1 |
| BD | 72.0 (1.0) | 121.4 (1.0) | 99.3 (1.8) | 114.1 (2.4) | N | 73.0 (1.5) | 106.4 (3.9) | 92.6 (1.8) | 93.1 (2.7) | I | 1.0 | −15.0 | −6.7 | −21.0 |
| BW | 106.1 (3.2) | 137.3 (3.2) | 85.3 (2.2) | 97.8 (5.0) | N | 104.5 (4.7) | 121.7 (6.8) | 78.5 (2.9) | 81.0 (3.7) | I | −1.6 | −15.7 | −6.8 | −16.8 |
| Standing Dead | ||||||||||||||
| AD | 14.6 (1.2) | 7.1 (1.2) | 17.1 (1.9) | 26.3 (2.5) | N | 18.0 (1.4) | 11.0 (1.4) | 18.2 (1.6) | 28.3 (2.4) | C+ | 3.4 | 3.8 | 1.1 | 2.0 |
| AW | 36.2 (1.4) | 43.8 (1.4) | 18.0 (2.1) | 60.8 (2.8) | N | 41.5 (1.6) | 48.5 (2.2) | 24.0 (2.0) | 62.0 (2.7) | C+ | 5.3 | 4.8 | 6.0 | 1.3 |
| BD | 15.1 (0.8) | 11.9 (0.8) | 20.9 (1.9) | 41.2 (3.3) | N | 19.2 (1.3) | 17.7 (1.4) | 35.8 (1.9) | 53.2 (3.6) | D+ | 4.1 | 5.8 | 14.9 | 12.0 |
| BW | 37.1 (2.6) | 36.5 (2.6) | 45.7 (2.7) | 40.0 (2.1) | . | 40.8 (2.3) | 45.0 (4.4) | 61.3 (4.3) | 43.1 (3.4) | C+ | 3.8 | 8.5 | 15.6 | 3.2 |
| Litter | ||||||||||||||
| AD | 22.0 (1.0) | 13.0 (1.0) | 9.9 (1.2) | 49.1 (2.2) | N | 20.8 (1.2) | 16.3 (2.2) | 13.7 (1.5) | 51.0 (2.7) | . | −1.3 | 3.2 | 3.8 | 1.9 |
| AW | 8.4 (0.9) | 4.2 (0.9) | 9.7 (1.9) | 27.8 (2.4) | N | 9.4 (1.1) | 4.3 (0.8) | 3.7 (0.7) | 31.9 (2.5) | I | 1.0 | 0.0 | −6.0 | 4.1 |
| BD | 10.1 (0.7) | 8.1 (0.7) | 12.3 (0.9) | 15.3 (1.6) | N | 12.5 (1.2) | 9.5 (1.5) | 12.4 (1.0) | 32.0 (2.6) | I | 2.4 | 1.3 | 0.0 | 16.7 |
| BW | 27.6 (1.5) | 9.4 (1.5) | 26.9 (1.5) | 43.2 (4.3) | N | 32.8 (1.4) | 13.5 (1.7) | 24.7 (2) | 60.2 (3.8) | I | 5.2 | 4.1 | −2.2 | 17.0 |
| Open Canopy | ||||||||||||||
| AD | 53.0 (2.4) | 61.2 (2.4) | 42.8 (2.2) | 45.4 (3.5) | N | 54.5 (2.4) | 56.3 (3.1) | 46.2 (1.8) | 40.5 (3.5) | . | 1.5 | −4.9 | 3.4 | −5.0 |
| AW | 24.6 (1.9) | 23.6 (1.9) | 38.5 (1.9) | 13.1 (1.7) | N | 22.3 (1.9) | 15.5 (1.6) | 26.5 (2.3) | 9.8 (1.2) | I | −2.3 | −8.2 | −12.0 | −3.3 |
| BD | 48.4 (1.6) | 35.9 (1.6) | 40.0 (2.4) | 30.4 (1.7) | N | 41.8 (1.9) | 27.9 (2.3) | 24.6 (1.9) | 13.6 (1.8) | D− | −6.6 | −8.0 | −15.5 | −16.8 |
| BW | 15.2 (2.2) | 9.6 (2.2) | 28.3 (2.4) | 9.8 (1.6) | N | 11.3 (1.2) | 8.0 (0.9) | 21.3 (2.3) | 6.7 (1.0) | C− | −3.9 | −1.7 | −7.0 | −3.2 |
| Species Richness | ||||||||||||||
| AD | 6.4 (0.2) | 5.7 (0.2) | 6.8 (0.2) | 6.0 (0.2) | N | 6.3 (0.2) | 5.8 (0.2) | 6.6 (0.2) | 6.2 (0.2) | . | −0.1 | 0.1 | −0.2 | 0.2 |
| AW | 5.0 (0.2) | 4.9 (0.2) | 5.3 (0.3) | 5.2 (0.1) | . | 4.9 (0.2) | 4.8 (0.1) | 5.0 (0.2) | 5.1 (0.2) | . | −0.1 | −0.1 | −0.3 | 0.0 |
| BD | 5.3 (0.2) | 6.5 (0.2) | 6.5 (0.2) | 6.0 (0.2) | N | 5.5 (0.2) | 6.7 (0.2) | 7.5 (0.2) | 6.6 (0.2) | C+ | 0.2 | 0.2 | 1.0 | 0.6 |
| BW | 7.3 (0.2) | 7.6 (0.2) | 7.3 (0.3) | 6.9 (0.2) | . | 7.3 (0.3) | 7.4 (0.3) | 7.1 (0.2) | 6.3 (0.2) | . | 0.0 | −0.2 | −0.2 | −0.5 |
| Shannon Index | ||||||||||||||
| AD | 0.97 (0.01) | 1.02 (0.02) | 0.99 (0.02) | 0.92 (0.02) | D− | 0.95 (0.01) | 1.00 (0.02) | 1.00 (0.01) | 0.93 (0.02) | . | −0.02 | −0.02 | 0.00 | 0.01 |
| AW | 0.32 (0.01) | 0.37 (0.02) | 0.34 (0.02) | 0.35 (0.02) | N | 0.33 (0.01) | 0.35 (0.01) | 0.31 (0.01) | 0.32 (0.01) | . | 0.01 | −0.02 | −0.02 | −0.03 |
| BD | 0.76 (0.01) | 0.77 (0.02) | 0.80 (0.01) | 0.69 (0.01) | N | 0.75 (0.02) | 0.71 (0.02) | 0.70 (0.02) | 0.63 (0.02) | D− | −0.01 | −0.05 | −0.10 | −0.07 |
| BW | 0.44 (0.02) | 0.44 (0.02) | 0.41 (0.01) | 0.37 (0.01) | N | 0.41 (0.02) | 0.40 (0.01) | 0.40 (0.01) | 0.33 (0.01) | C− | −0.03 | −0.04 | 0.00 | −0.04 |