In 2017, the SAMBR synthesized data about biodiversity in Arctic marine ecosystems around the circumpolar Arctic. SAMBR highlighted observed changes and relevant monitoring gaps using data compiled through 2015. In 2021 an update was provided on the status of seabirds in circumpolar Arctic using data from 2016–2019. Most changes reflect access to improved population estimates, orimproved data for monitoring trends,independent of recognized trends in population size.

Alpha diversity (rarefied to 10 stations, with error bars indicating standard error) of littoral lake benthic macroinvertebrates plotted as a function of the average latitude of stations in each hydrobasin. Hydrobasins are coloured by country/region. State of the Arctic Freshwater Biodiversity Report - Chapter 4- Page 68 - Figure 4-31

Trends in kittiwake colonies 2001-2010, based on linear regression with year as the explanatory variable. Slope of the regression is red = negative trend, blue = positive trend; shaded circle = significant trend (at p<0.05), open circle = non-significant trend. Non-significant deviation from zero could imply a stable population, but in some cases was due to low sample size and low power. Provided with permission from Descamps et al. (in prep). STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/seabirds" target="_blank">Chapter 3</a> - Page 135 - Figure 3.5.3 This figure is compiled from data from researchers working throughout circumpolar regions, primarily members of the Circumpolar Seabird Group, an EN of CAFF/seabirds. Dr. Sebastien Decamps conducted the analysis and produced the original figure; the full results will be available in an article in prep titled: “Descamps et al. in prep. Circumpolar dynamics of black-legged kittiwakes track large-scale environmental shifts and oceans' warming rate.” [expected submission spring 2016]. Colony population trends were analyzed using a linear regression with the year as explanatory variable. Based on slope of the regression (which cannot be exactly 0) colonies are either Declining (Slope of the regression <0) or Increasing (Slope of the regression >0). (Colonies may have had a negative but not significant slope, and could be stable but for some others, the slope is not significant due to small sample size / low power; thus we cannot say that all colonies with a non- significant slope are stable. The threshold was put at 5% to assess the significance of the trend.

Phytoplankton percent composition by dominant classes across the three Arctic regions, using relative presence across stations calculated from from presence – absence data. State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 48 - Figure 4-19

Figure 4 9 Local diatom species richness of Arctic lake surface sediments, showing (left) richness as a function of latitude, and (right) site-specific richness. A LOESS smoother (blue line) with a span of 0.75 and a 95% confidence interval (grey shading) was applied to the data (left) to better highlight the general trend. Coloured circles on the map indicate the species richness at the sampling sites. State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 37 - Figure 4-9

Results of circumpolar assessment of lake zooplankton, focused just on crustaceans, and indicating (a) the location of crustacean zooplankton stations, underlain by circumpolar ecoregions; (b) ecoregions with many crustacean zooplankton stations, colored on the basis of alpha diversity rarefied to 25 stations; (c) all ecoregions with crustacean zooplankton stations, colored on the basis of alpha diversity rarefied to 10 stations; (d) ecoregions with at least two stations in a hydrobasin, colored on the basis of the dominant component of beta diversity (species turnover, nestedness, approximately equal contribution, or no diversity) when averaged across hydrobasins in each ecoregion. State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 58 - Figure 4-25

Many population counts of gregarious migrant species, such as waders and geese, take place along the flyways and at wintering grounds outside the Arctic which stresses the importance of continued development of movement ecology studies. Monitoring of FEC attributes related to breeding success and links to environmental drivers within the Arctic takes place in a wide network of research sites across the Arctic, although with low coverage of the high Arctic zone (Figure 3-25) STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 58 - Figure 3.25

Although the circumpolar countries endeavor to support monitoring programs that provide good coverage of Arctic and subarctic regions, this ideal is constrained by the high costs associated with repeated sampling of a large set of lakes and rivers in areas that often are very remote. Consequently, freshwater monitoring has sparse, spatial coverage in large parts of the Arctic, with only Fennoscandia and Iceland having extensive monitoring coverage of lakes and streams Figure 6-2 Current state of monitoring for river FECs in each Arctic country State of the Arctic Freshwater Biodiversity Report - Chapter 6 - Page 94 - Figure 6-2

Status of monitoring activities for each Focal Ecosystem Component (i.e., selected species groups) across each Arctic Marine Area as included in this report. STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/monitoring-status-and-advice" target="_blank">Key Findings</a> - Page 5 - Figure 1

Trend quality categories are: (1) data are lacking such that trends are unknown, (2) regional and site-specific monitoring allow for assumptions of trend, (3) international monitoring allows estimation of trend direction, and (4) rigorously designed international monitoring programmes yield estimates of precision. Modified from Smith et al. 2020. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapte31 - Page 59 - Figure 3.26