These impact factors affect the abundance of flora and fauna in each element of the ecosystem. Anything that has an impact on one level of the food chain affects the one above it, until ultimately the entire ecosystem is affected. The food chain in the Arctic Ocean is simpler than that in other oceans, which indicates that the Arctic ecosystem is more vulnerable to external shocks than other ocean ecosystems. This complex web of bio-relationships is poorly understood at present. If pollution occurs at one level of the food chain, it quickly permeates the upper levels as well, until finally indigenous peoples in the Arctic are affected by the bioconcentration of pollutants.
The vastness of the NSR encompasses a richly diverse population of species at each level of the ecosystem. Because it cannot practically assess all of the flora and fauna in the Arctic, INSROP limited its study of environmental impact to issues of high priority. INSROP selected a number of indicator species by screening according to an environmental assessment index called Valued Ecosystem Components (VECs), in which issues are weighted their value in monitoring environmental impact and the ease with which data can be gathered, taking into consideration such factors as the conditions of navigation and distribution of habitats (Table 4.5-1). Although not all of the VECs are fully available, the VECs have been entered into the Geographical Information System (GIS) to compile a database called the Dynamic Environmental Atlas (DEA). One example of the information contained in the DEA is the distribution of polar bear, one of the species at the apex of the Arctic food chain. This distribution is mapped as in Figure 4.5-4. Undeniably these data suffer from a lack of quantitative rigor, but to INSROP they are priceless, as they represent the first such data ever provided by Russia on this topic-data that are indispensable to the environmental assessment in Section 4.5.4.