Lemmings are currently being monitored at 38 sites. Their status and trends were determined based on data from these sites as well as recent data (since 2000) from an additional 11 previous monitoring sites (Figure 3-31). Of those sites monitored, Fennoscandia is overrepresented relative to the geographical area it covers, whereas Russia is underrepresented. Based on the skewed geographical coverage, more information is available for some species of lemmings than others, particularly the Norwegian lemming. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 80 - Figure 3.31

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

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

Trends and distribution of muskoxen populations based on Table 3-5. Modified from Cuyler et al. 2020. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 79 - Figure 3.30

Temporal trends of arthropod abundance for three habitat types at Zackenberg Research Station, Greenland, 1996–2016. Data are grouped as the FEC ‘arthropod prey for vertebrates’ and separated by habitat type. Solid lines indicate significant regression lines at the p<0.05. Modified from Gillespie et al. 2020a. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 39 - Figure 3.9

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

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

There are few true Arctic specialist birds that remain in the Arctic throughout their annual cycle. They include the willow and rock ptarmigan (Lagopus lagopus and L. muta), gyrfalcon (Falco rusticolus), snowy owl (Bubo scandiacus), Arctic redpoll (Carduelis hornemanni) and northern raven (Corvus corax)—a cosmopolitan species with resident populations in the Arctic. All other terrestrial Arctic-breeding bird species migrate to warmer regions during the northern winter, connecting the Arctic to all corners of the globe. Hence, their distributions are influenced by the routes they follow. These distinct migration routes are referred to as flyways and are defined by a combination of ecological and political boundaries and differ in spatial scale. The CBMP refers to the traditional four north–south flyways, in addition to a circumpolar flyway representing the few species that remain largely within the Arctic year-round (Figure 3-20). STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 48- Figure 3.20

Current state of monitoring for Arctic terrestrial biodiversity FECs in each Arctic state. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 4 - Page 102 - Figure 4.1