Alpha diversity (rarefied to 10 stations, with error bars indicating standard error) of river benthic macroinvertebrates plotted as a function of the average latitude of stations in each hydrobasin. Hydrobasins are coloured based on country/region State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 68 - Figure 4-32

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 6-1 Current state of monitoring for lake FECs in each Arctic country. State of the Arctic Freshwater Biodiversity Report - Chapter 6 - Page 93 - Figure 6-1

Estimation of diatom assemblage changes over a period of about 200 years (top versus bottom sediment cores). Figure 4-14 Map showing the magnitude of change in diatom assemblages between bottom (pre-industrial) and top (modern) section of the cores, estimated by Bray-Curtis (B-C) dissimilarity. Boundaries for the B-C dissimilarity categories are based on distribution quartiles (0-30%, 30-40%, 40- 50% and >50%), where the lowest values (blue dots) represent the lowest degree of change in diatom assemblage composition between top and bottom sediment core samples in each lake. State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 41 - Figure 4-14

Results of circumpolar assessment of lake littoral benthic macroinvertebrates, indicating (a) the location of littoral benthic macroinvertebrate stations, underlain by circumpolar ecoregions; (b) ecoregions with many littoral benthic macroinvertebrate stations, colored on the basis of alpha diversity rarefied to 80 stations; (c) all ecoregions with littoral benthic macroinvertebrate 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 65 - Figure 4-29

Figure 4-7 Circumpolar assessment of lake diatoms, indicating (a) the location of lake diatom stations, underlain by circumpolar ecoregions; (b) ecoregions with many lake diatom stations, colored on the basis of alpha diversity rarefied to 40 stations; (c) all ecoregions with lake diatom 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 (i.e. species turnover, nestedness, approximately equal contribution, or no diversity) when averaged across hydrobasins in each ecoregio. State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 35 - Figure 4-7

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 3-5 Changes in alpha diversity (red line), predator body size (blue dashed line), and ecosystem metabolism (blue solid line) with a shift in glacial cover from high (left) to low (right). Redrawn from Milner et al. (2017). State of the Arctic Freshwater Biodiversity Report - Chapter 3 - Page 22 - Figure 3-5

Rarefied alpha diversity of river (a) diatoms from benthic samples, (b) benthic macroinvertebrates, and (c) fish in ecoregions across North America. State of the Arctic Freshwater Biodiversity Report - Chapter 5- Page 84 - Figure 5-1

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 3-4 Effects of permafrost thaw slumping on Arctic rivers, including (upper) a photo of thaw slump outflow entering a stream on the Peel Plateau, Northwest Territories, Canada, and (lower) log10-transformed total suspended solids (TSS) in (1) undisturbed, (2) 1-2 disturbance, and (3) > 2 disturbance stream sites, with letters indicating significant differences in mean TSS among disturbance classifications Plot reproduced from Chin et al. (2016). State of the Arctic Freshwater Biodiversity Report - Chapter3 - Page 21 - Figure 3-4