A drastic decline in caribou and shorebird populations reflects the terrible changes taking place in the arctic tundra, according to a new report from the Arctic Council.
The terrestrial Arctic covers an area of approximately 2.7 square meters (7 square meters), marked by extreme cold, drought, high winds and seasonal darkness. Species living in this environment have adapted to thrive in the harsh conditions. But the climate crisis has turned these survival strategies upside down, according to the State of Arctic Terrestrial Biodiversity report published by the Council’s Working Group on the Conservation of Arctic Flora and Fauna (Caff).
“Climate change is the main driver of change in Arctic terrestrial ecosystems, causing diverse, unpredictable and significant impacts that are expected to intensify,” the report says.
The Arctic is warming twice as fast as the rest of the world, resulting in extreme weather events, species from the south moving north and the emergence and spread of pathogens among native species. The report, released Thursday at the Council’s ministerial meeting in Reykjavik, is the first to assess the status and trends of arctic species living on land, following Caff’s 2017 assessment of marine biodiversity.
The report drew on decades of circumpolar biodiversity monitoring to provide insight into the changes taking place in the region. It seems the Arctic is getting greener and shrubs are gaining ground, slowly replacing mosses and lichens on the tundra. At the Zackenberg research station in northeast Greenland, scientists found that important pollinator flies declined by 80% between 1996 and 2014, suggesting a climate-induced lag between the time of plant flowering and pollinator flight activity.
Of the 88 species of shorebirds, or waders, examined, 20% experienced declines in all populations, while well over half had at least one declining population. “In the arctic tundra, shorebirds are the most diverse group of birds; if you’re Inuit, those are the backyard birds in your environment, ”said Paul Allen Smith, biologist at Environment and Climate Change Canada and bird specialist in the report. In the East Asian-Australasian Flyway, a flyway connecting high latitudes to the Pacific Ocean, 88% of shorebirds are in decline. This, Smith said, is likely due to habitat loss in the Yellow Sea region of Asia, where the birds spend their winters. It is estimated that under different climate scenarios, 80% of high Arctic shorebirds could also lose much of their northern breeding grounds over the next 50 years.
For caribou, with herds moving from Russia to Alaska, the climate signal has been more difficult to separate from the noise. “Caribou populations fluctuate naturally and have cycles of abundance,” Christine Cuyler, a consultant at the Greenland Natural Resources Institute and caribou and muskox expert, explained to the report. “But for some, the amplitude has increased. Today we are seeing fluctuations beyond known historical levels. “
The majority of migratory tundra and woodland caribou populations have declined in recent years, with a few exceptions. The Bathurst herd, which runs from the Northwest Territories of Canada to Nunavut, fell 98% between 1986 and 2018. Cuyler said several factors are likely behind these declines, including decreased availability. food, rain-on-snow events and pestering insects, which prevent ungulates. to eat and gain enough weight to survive the winter.
Warmer temperatures have also led to the emergence of pathogens which have had a negative effect on the health of some animals. In 2012, an outbreak of erysipelas, a bacterial infection that affects the skin, killed approximately 150 muskoxen on Banks Island, Northwest Territories.
« [The bacterium] is common around the world, but it was not normal for it to appear in the Arctic, ”Cuyler said. “He’s normally dormant because of the cool temperatures. The warming of the Arctic is making a real difference. In addition, mammals pushed north by higher temperatures can also bring new diseases and parasites that could affect naive native species.
According to the report, these migrants are altering predator-prey interactions in the north. Red foxes are known to compete for the same dens as arctic foxes and even kill them. In Alaska, brown bears kill muskoxen. “This is something totally new” that has only been seen for the past 20 years, Cuyler said. “And it’s devastating.”
Ultimately, as climatic zones and species move north, the terrestrial ecosystem of the Arctic will shrink. “Extreme events – weather conditions, forest fires and insect outbreaks – will leave their mark for several years in a system like the Arctic,” said Niels Martin Schmidt, senior researcher at Aarhus University and contributor to the report, “because everything takes a long time to regenerate.” He added that “sustainable ecosystem-based monitoring” is needed to be able to track these changes over time.
“We need to understand how species interact to fully understand the consequences of climate change on biodiversity loss.”