Population trends for springtails in Empetrum nigrum plant community in Kobbefjord, Greenland, 2007–2017. (a) mean population abundance of total Collembola in individuals per square metre, (b) mean number of species per sample, and (c) Shannon-Wiener diversity index per sample. Vertical error bars are standard errors of the mean. Solid lines indicate significant regression lines. Modified from Gillespie et al. 2020a. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 40 - Figure 3.13

Several smaller populations of caribou inhabit sub-Arctic portions of Alaska, including five populations along the Aleutian Archipelago and west coast. These populations are considered part of the migratory tundra ecotype based on genetics, although in some instances their ecology and habitat are similar to the mountain caribou ecotype found in western Canada. Population dynamics and trends for these populations are variable (Figure 3-29). They are managed by the Alaska Department of Fish and Game through hunting quotas. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 72 - Figure 3.29

Abundance of the copepod Calanus glacialis in the Chukchi Sea, 1945-2012 (after Ershova et al. 2015b). STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/plankton" target="_blank">Chapter 3</a> - Page 75 - Figure 3.2.6

Macrofauna distribution of biomass (g wet fixed weight m-2) in the Barents Sea over three time periods: 1924-32 (Figure A), 1968-70 (Figure B) and 2003 (Figure C, constructed from original archive data, except for area south of 72° N where digitized megafaunal-data taken from Anisimova et al. (2010) was used. Adapted from Denisenko (2013). Blue boxes delineate the areas within which the zoobenthos biomass values were compared. STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/benthos" target="_blank">Chapter 3</a> - Page 96- Figure 3.3.3

Fish diversity characteristics in three geographical regions: Alaska, Iceland, and Fennoscandia. Gamma diversity is based the total number of species sampled in hydrobasins of each ecoregion. Alpha diversity shows the mean basin species richness (95% confidence interval) and beta diversity shows the component of beta diversity, nestedness or turnover, that dominated within each of the ecoregions; gamma, alpha, and beta diversity estimates were based on a subset of basins where a minimum of 10 stations were sampled. All maps are drawn to the same scale. State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 77 - Figure 4-39

The U.S. National Ice Center (NIC) is an inter-agency sea ice analysis and forecasting center comprised of the Department of Commerce/NOAA, the Department of Defense/U.S. Navy, and the Department of Homeland Security/U.S. Coast Guard components. Since 1972, NIC has produced Arctic and Antarctic sea ice charts. This data set is comprised of Arctic sea ice concentration climatology derived from the NIC weekly or biweekly operational ice-chart time series. The charts used in the climatology are from 1972 through 2007; and the monthly climatology products are median, maximum, minimum, first quartile, and third quartile concentrations, as well as frequency of occurrence of ice at any concentration for the entire period of record as well as for 10-year and 5-year periods. NIC charts are produced through the analyses of available in situ, remote sensing, and model data sources. They are generated primarily for mission planning and safety of navigation. NIC charts generally show more ice than do passive microwave derived sea ice concentrations, particularly in the summer when passive microwave algorithms tend to underestimate ice concentration. The record of sea ice concentration from the NIC series is believed to be more accurate than that from passive microwave sensors, especially from the mid-1990s on (see references at the end of this documentation), but it lacks the consistency of some passive microwave time series. Source: <a href="http://nsidc.org/data/G02172" target="_blank">NSIDC</a> Reference: National Ice Center. 2006, updated 2009. National Ice Center Arctic sea ice charts and climatologies in gridded format. Edited and compiled by F. Fetterer and C. Fowler. Boulder, Colorado USA: National Snow and Ice Data Center. Source: <a href="http://nsidc.org/data/G02172" target="_blank">NSIDC</a>

Defines the area covered by the the Arctic Assessment and Monitoring Programme (AMAP www.amap.no) working group of the Arctic Council.

Abiotic drivers in North America, including (a) long-term average maximum August air temperature, (b) spatial distribution of ice sheets in the last glaciation of the North American Arctic region, and (c) geological setting of bedrock geology underlying North America. Panel (a) source Fick and Hijmans (2017). Panel (b) adapted from: Physical Geology by Steve Earle, freely available at http://open.bccampus.ca. Panel (c) source: Geogratis. State of the Arctic Freshwater Biodiversity Report - Chapter 5 - Page 86 - Figure 5-3

Circumpolar permafrost extent overlain on ecoregions used in SAFBR analysis, indicating continuous (90-100%), discontinuous (50-90%), sporadic (10-50%), and isolated (0-10%) permafrost extent. Source for permafrost layer: Brown et al. (2002). State of the Arctic Freshwater Biodiversity Report - Chapter 5 - Page 89 - Figure 5-6

The Conservation of Arctic Flora and Fauna (CAFF) and Protection of the Arctic Marine Environments (PAME) working groups of the Arctic Council developed this indicator report. It provides an overview of the status and trends of protected areas in the Arctic. The data used represents the results of the 2016 update to the Protected Areas Database submitted by each of the Arctic Council member states (Annex 1). This report uses the International Union for the Conservation of Nature (IUCN) definition for protected areas (see Box 1) which includes a wide range of Management Categories – from strict nature reserve to protection with sustainable use. Consequently, the level of protection and governance of these areas varies throughout the circumpolar region and its countries.