Predicted biodiversity changes in the Arctic

The Arctic ecosystem

For certain habitats in the Arctic, species diversity is considered low compared to European marine ecosystems at lower latitudes. However, during the brief summers with their long day-lengths, the abundance of species is relatively high due to the large numbers of fast growing food organisms. This seasonal availability of enormous quantities of food attracts animals higher up the food chain, such as whales, and provides sufficient energy for other top predators (e.g., seals, polar bears) to survive the long winter.

Predictions

Polar bear © Sea Mammal Research Unit

Increase of Arctic species

With increasing temperatures, there will be an increase in species from southern latitudes and the larger native predators will have to share the available food with them. Smaller pelagic fish and other species will benefit from a modified food web with a wider distribution of biomass at intermediate trophic levels, so that greater species diversity can be expected. The abundance and distribution of native species will change, which will significantly impact the community structure and ecosystem function[.

Habitat loss

The response of top predators to habitat loss (loss of sea ice) and to changes in food sources will differ depending on whether they are ice obligate (i.e., polar bear, ringed seals), ice-associated (i.e., certain seals, white whale, narwhal, bowhead whale and walrus) or seasonal migrants (i.e., fin and minke whale).

Polar bears are particularly at risk since their habitat (the ice) is reducing and possibilities for a northward shift in distribution are limited. The loss of polar bears and other top predators in particular will not only affect the functioning of the Arctic ecosystem but also indigent human populations and their traditional way of life (e.g., hunting).