Fig 1.
The 2018 snow cover compared with long-term precipitation patterns in the Arctic.
The three maps show the deviation (in units of standard deviations) of the 2018 season from the 1980 to 2018 normalized precipitation curve on the Pan-Arctic scale (left), the Greenland scale (top middle), and the Zackenberg region (top right), with the black circle marking Zackenberg. For each year, snow precipitation was calculated as total precipitation in November through April, obtained from a high-resolution data-assimilation system and a regional climate model (see Supporting information). The lower right panel shows the annual deviation (in units of standard deviations) from the normalized precipitation curve in the Zackenberg drainage basin from 1980 to 2018. Additional information about data and analyses can be found in S1 Data collection and analyses. Data presented here are available at http://prudence.dmi.dk/data/temp/MOL/PLOS.
Fig 2.
Ecological time series on phenology from Zackenberg in Northeast Greenland.
Individual panels show records on abiotic conditions and phenological events and their associated cumulative distribution plots: (A) Snow cover in second week of June (red) and in third week of July (blue), (B) Julian date for 50% flowering of Dryas sp. in four permanent plots, (C) Julian date for 50% flowering of Salix arctica in four permanent plots, (D) Julian date for 50% flowering of Muscidae emergence in four permanent plots, (E) Julian date for 50% flowering of Chironomidae emergence in four permanent plots, (F) median date for nest initiation of three shorebird species most common in Zackenberg (blue: Dunlin Calidris alpina; red: Sanderling C. alba; orange: ruddy turnstone Arenaria interpres), (G) median date for nest initiation of long-tailed skua (Stercorarius longicaudus). Note that in 1999 and 2018, one late-emerging Dryas plot failed to reach even 50% flowering. No ruddy turnstones were observed to nest in 2018, and no long-tailed skuas to nest in 2014, 2015, and 2018. (The arthropod samples from 2010 were lost in transport, creating a gap in the time series of panels D and E.) In the cumulative distribution graphs, the jagged lines show the number of years (out of 23, except in cases with missing values) in which the respective x-value is exceeded. The dotted lines indicate the 2018 values, with the years to the right of it being the number of years showing a phenology later than 2018. Note that some monitoring plots are consistently late and others early, causing them to reach their maximum value at different points. Panel 2G is missing a dotted line, because in 2018, no long-tailed skuas bred in the area (see Fig 3F). Additional information about data and analyses can be found in S1 Data collection and analyses. Data presented here are available at https://doi.org/10.5281/zenodo.3344483.
Fig 3.
Ecological time series on abundance from Zackenberg in Northeast Greenland.
Individual panels show records on abundances and their associated cumulative distribution plots: (A) Flower densities of Dryas sp. in four permanent plots, (B) flower densities of Salix arctica in four permanent plots, (C) abundances of flies in family Muscidae at four permanent trapping stations, (D) abundances of nonbiting midges in family Chironomidae at four permanent trapping stations, (E) breeding densities of the three most common shorebird species of Zackenberg (blue: Dunlin Calidris alpina; red: Sanderling C. alba; orange: ruddy turnstone Arenaria interpres), (F) breeding density of long-tailed skuas, (G) density of muskoxen (Ovibos moschatus) in the valley, (H) muskox calves recruitment in the valley, (I) number of Arctic fox (Vulpes lagopus) cubs weaned in the valley. (The arthropod samples from 2010 were lost in transport, creating a gap in the time series of panels C and D.) In the cumulative distribution graphs, the jagged lines show the number of years (out of 23, except in cases with missing values) in which the respective x-value is exceeded. The dotted lines indicate the 2018 values, with the years to the left of it being the number of years showing densities lower than 2018. Note that some monitoring plots are characterized by consistently higher densities than others, causing them to reach their maximum value at different points. Additional information about data and analyses can be found in S1 Data collection and analyses. Data presented here are available at https://doi.org/10.5281/zenodo.3344483.