Box plot represents the homogeneity of assemblages in high Arctic (n=190), low Arctic (n=370) and sub-Arctic lakes (n=1151), i.e., the distance of individual lake phytoplankton assemblages to the group centroid in multivariate space. The mean distance to the centroid for each of the regions can be seen as an estimated of beta diversity, with increasing distance equating to greater differences among assemblages. State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 48 - Figure 4-18

Figure 4 17 Results of circumpolar assessment of lake phytoplankton,(a) the location of phytoplankton stations, underlain by circumpolar ecoregions; (b) ecoregions with many phytoplankton stations, colored on the basis of alpha diversity rarefied to 35 stations; (c) all ecoregions with phytoplankton 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 56 - Figure 4-17

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

Local diatom species richness of Arctic diatom assemblages from stream scrapes, 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 species richness at the sampling sites. State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 37 - Figure 4-10

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

Redundancy analysis of percentage species taxa share (taxa richness relative to richness of all taxa) among 5 FECs (phytoplankton, macrophytes, zooplankton, benthic macroinvertebrates and fish) in 13 Fennoscandian lakes (panels A and B) and among 3 FECs in 39 Fennoscandian lakes (panels C and D).The upper panels show lake ordinations, while the bottom panels show explanatory environmental variables (red arrows), as indicated by permutation tests (p < 0.05). Avg%Richness: average species taxa richness as a percentage of richness of all FECs (i.e., including benthic algae if present); %Richness BMI: relative taxa share in benthic macroinvertebrates; %EvergreenNLF: percentage cover of evergreen needle-leaf forests. State of the Arctic Freshwater Biodiversity Report - Chapter 5 - Page 87 - Figure 5-4

Figure 4-5 Terrestrial ecoregions that are included within the circumpolar region within the CAFF boundary and/or the ABA boundaries. Source: Terrestrial Ecoregions of the World (TEOW; Olson et al. 2001). State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 28 - Figure 4-5

Temporal patterns in % abundance of Atlantic salmon, brown trout, and anadromous Arctic charr from catch statistics in northern Norway rivers monitored from 1993 to 2016, including basins dominated by (a) rivers and (b) lakes. State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 81- Figure 4-42

Maximum LTA (long-term average) August air temperatures for the circumpolar region, with ecoregions used in the analysis of the SAFBR outlined in black. Source for temperature layer: Fick and Hijmans (2017). State of the Arctic Freshwater Biodiversity Report - Chapter 5 - Page 89 - Figure 5-5

Figure 3-6. The hypothesized effects of rising mean water temperature on biodiversity (as total species number) of Arctic freshwater ecosystems. A pulsed increase in gamma biodiversity (a) results from the combination of high eurythermal invasion and establishment and low stenothermic loss with increasing water temperature. A pulsed decrease in gamma biodiversity (b) results from the combination of low eurythermal invasion and establishment and high stenothermic loss. Rapid increases (c) and slow increases (d) in species diversity occur, respectively, with high eurythermal invasion and establishment coupled with high stenothermic loss or low eurythermal invasion and establishment and low stenothermic loss as temperatures increase. For simplification, barriers to dispersal have been assumed to be limited in these models. State of the Arctic Freshwater Biodiversity Report - Chapter 3 - Page 23 - Figure 3-6