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

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

Circumpolar trends in primary productivity as indicated by the maximum Normalised Difference Vegetation Index, 1982–2017. (a) Brown shading indicates negative MaxNDVI trends, green shading indicates positive MaxNDVI trends. (b) Chart of trends for the circumpolar Arctic, Eurasia, and North America. Modified from Frost et al. 2020. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 30 - Figure 3.1

Trends in Arctic terrestrial bird population abundance for four taxonomic groupings in four global flyways. Data are presented as total number of taxa (species, subspecies). Modified from Smith et al. 2020. These broad patterns were generally consistent across flyways, with some exceptions. Fewer waterfowl populations increased in the Central Asian and East Asian–Australasian Flyways. The largest proportion of declining species was among the waders in all but the Central Asian Flyway where the trends of a large majority of waders are unknown. Although declines were more prevalent among waders than other taxonomic groups in both the African–Eurasian and Americas Flyways, the former had a substantially larger number of stable and increasing species than the latter (Figure 3-23). STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 55 - Figure 3.23

Change in plant phenology over time based on published studies, ranging from 9 to 21 years of duration. The bars show the proportion of observations where timing of phenological events advanced (earlier) was stable or were delayed (later) over time. The darker portions of each bar represent visible decrease, stable state, or increase results, and lighter portions represent marginally significant change. The numbers above each bar indicate the number of observations in that group. Figure from Bjorkman et al. 2020. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 31- Figure 3.3

Number of non-native plant taxa that have become naturalised across the Arctic. No naturalised non-native taxa are recorded from Wrangel Island, Ellesmere Land – northern Greenland, Anabar-Olenyok and Frans Josef Land. Modified from Wasowicz et al. 2020 STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 32 - Figure 3.4

There is a great variation and heterogeneity among terrestrial Arctic ecosystems. This is further described as biogeographical areas in the Annotated Checklist of the Pan-Arctic Flora (Elven et al. 2020), as vegetation zones (Walker et al. 2005, Raynolds et al 2019) or as ecoregions recognised by Terrestrial Ecoregions of the World (Olson et al. 2001). The START focuses on high and low Arctic regions consistent with the CAVM’s subzones A to E, as shown in Figure 1-2 and Figure 2-1 STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 2 - Page 19 - Figure 2.1

Conceptual model of Arctic terrestrial mammals, showing FECs, interactions with other biotic groups and examples of drivers and attributes relevant at various spatial scales. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 67 - Figure 3.28

Change in forb, graminoid and shrub abundance by species or functional group over time based on local field studies across the Arctic, ranging from 5 to 43 years of duration. The bars show the proportion of observed decreasing, stable and increasing change in abundance, based on published studies. The darker portions of each bar represent a significant decrease, stable state, or increase, and lighter shading represents marginally significant change. The numbers above each bar indicate the number of observations in that group. Modified from Bjorkman et al. 2020. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 31- Figure 3.2

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