Regional differences are more pronounced in the insectivore guild (Figure 3-24). Although diversity of waders was moderate in the East Asian–Australasian Flyway, 88% (15 of 17) of taxa with known trends were declining—the largest proportion of any group. Both short-term (the last 15 years) and long-term (more than 30 years) trends were available for 157 taxa. Trends were unchanged over the two time periods for 80% of taxa, improved for 11% and worsened for 9%.. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 56 - Figure 3.24

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

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

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

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

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

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

The Arctic terrestrial food web includes the exchange of energy and nutrients. Arrows to and from the driver boxes indicate the relative effect and counter effect of different types of drivers on the ecosystem. STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 2 - Page 26- Figure 2.4

The baseline survey and ongoing monitoring required to adequately describe Arctic arthropod biodiversity and to identify trends is largely lacking. Although some existing publications reporting long-term and extensive sampling exist, they are limited in species level information, taxonomic coverage and/or geographic location/extent (Figure 3-19) STATE OF THE ARCTIC TERRESTRIAL BIODIVERSITY REPORT - Chapter 3 - Page 44 - Figure 3.19

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