The Arctic Species Trend Index 4 September 2014 This article is part of a series highlighting issues from the Conservation of Arctic Flora and Fauna (CAFF) working group’s landmark Arctic Biodiversity Assessment. This week focuses on evaluating trends in species abundance. [Click here to view or download the full-size map] Evaluating trends in species abundance reveals much about broad changes in biodiversity. The Arctic Species Trend Index (ASTI) was developed for this purpose and uses population trend data from 890 populations of 323 vertebrate species (37% of known Arctic vertebrate species). The ASTI is the Arctic component of a global index of vertebrate species trends, the Living Planet Index (LPI). The data collected in the ASTI can be used to look at patterns in species trends as well as see how these trends are related to other changes in Arctic ecosystems. This map illustrates the over 366 sites with trend information in the Arctic Species Trend Index. As can be seen from the map, the locations of these sites are not evenly spread across the Arctic region with monitoring efforts concentrated in the Bering Sea, northern Scandinavia and Iceland, and more sparse efforts in northern Canada, northern Russia and northern Greenland. This pattern largely reflects the logistical reality that remote areas with limited human populations are associated with limited monitoring coverage, and generally more resource intensive to reach. Click here to learn about the ASTI key findings in the ABA. Click here to see more information from the Arctic Species Trend Index. For more biodiversity graphics, please click here to visit the Arctic Biodiversity Data Service. Image credit: CAFF. Caption: This map gives a sense of the scope of the Arctic Species Trend Index. For the full-size graphic, see the link in the article.