There is a wildlife regime change intensifying in the Arctic, and it is scary and unfortunate. Familiar species such as walrus, polar bear, snow crab, cod, beluga, and narwhal are increasingly becoming replaced by southern species. Predation and mass die-offs of marine species are ticking up as climate change warms the Bering, Chukchi, and Beaufort Seas.
Terrestrial species are also undergoing species replacement as the permafrost thaws from global heating. Sea ice is critical for the tundra's permafrost to stay frozen. The loss of the arctic's reflective sea ice minimizes the ability to reflect solar heat to space which protects the planet's air conditioner.
Feedback has caused a regime change with the vegetation that sustains iconic caribou and reindeer hers. These species eat lichen. Woody plants are replacing lichen and other tundra species. The strength of these plants' root systems cracks the frozen soil allowing additional warmth from the lack of sea ice to warm the ground with even more colonization of greenery to flourish as a result. The warming Arctic has increased rainfall, which freezes and makes it impossible for hooved species to locate their lichen, causing caribou and reindeer mass die-offs.
The plants replacing the ecosystem of the tundra along with declining sea ice reflectivity threaten to release carbon stores that have been safely locked away underground for thousands of years. Recently beavers drawn to the explosion of plant life have been building their lodges and flooding the tundra in winter. Ponds will only accelerate methane release furthering our dismal chances of survival.
Recently, the Arctic Beaver Observation Network (A-BON), mainly Dr. Helen Wheeler of Anglia Ruskin University, utilized satellites to document the progress of beaver poleward migration.
Over 12,000 beaver ponds have so far been mapped in western Alaska, with most areas seeing a doubling in the last 20 years. In comparison, analysis of aerial photography of coastal areas of western Alaska from between 1949-55 found no beaver ponds.
Beavers are a keystone species, capable of changing landscapes by creating new ponds and diverting the flow of rivers. Ponds created by beaver dams increase surface water, which in the Arctic is causing permafrost to melt, in turn releasing the greenhouse gasses methane and carbon dioxide.
In western Alaska, research has shown that beavers are the dominant factor in almost two thirds (66%) of cases where surface water has increased. These new ponds can also lead to the introduction of other new species, including fish and invertebrates.
The University of Helsinki, writing in 2018, on how beavers change the Climate.
Growing beaver populations have created a large number of new habitats along rivers and ponds. Beaver dams raise the water level, enabling the dissolution of the organic carbon from the soil. From beaver ponds, carbon is released to the atmosphere. Part of the carbon settles down on the bottom, ending up used by plants or transported downstream in the water.
"An increase in the number of beavers has an impact on the climate since a rising water level affects the interaction between beaver ponds, water and air, as well as the carbon balance of the zone of ground closest to water," says Petri Nummi, University Lecturer at the University of Helsinki.
Current estimates indicate that beaver ponds range from carbon sinks to sources of carbon. Beaver ponds and meadows can fix as much as 470,000 tons of carbon per year or, alternatively, release 820,000 tons of carbon annually. Their overlapping functions as carbon sinks and sources make landscapes moulded by beavers complex.
Impacts on the Tundra: Arctic Beaver Observation Network
Beavers are a keystone species whose engineering is known to heavily influence streams, rivers, riparian corridors, and lakes in North America, Eurasia, and South America (Whitfield et al. 2015). Beavers are known to dramatically change the landscapes they inhabit by harvesting shrubs, saplings, and trees, which they use to construct dams, inundate the surrounding landscape, and create their watery world. Beavers build lodges of mud and vegetation in water that is deep enough for an underwater entrance that remains unfrozen and permits access for them, but not predators. By constructing dams, beavers severely alter the stream flow regime, which facilitates the arrival of new species, including riverine plants, invertebrates, and fish (Bunn and Arthington 2002). Beaver ponds in temperate ecosystems enhance aquatic habitat complexity and biodiversity.
It remains unclear how these impacts will be manifest in the Arctic, where low water temperatures inhibit stream productivity and biodiversity, and where permafrost holds much of the soil together. People living in remote communities are concerned for resources such as fish, water quality, and boat access (Moerlein and Carothers 2012). In an area of northwest Alaska with exceptional satellite imagery coverage, we discovered that beavers are the dominant factor (66%) controlling increases in surface water extent (Jones et al. 2020), which thaws underlying permafrost as it inundates tundra vegetation. Beaver dams divert flow, sometimes catastrophically when they fail, and can thaw and destabilize the landscape (Lewkowicz and Coultish 2004) through fluvio-erosional and thermokarst processes (Fig. 3). Thawing of permafrost associated with new beaver ponds would initially release carbon and methane stored in permafrost, though the magnitude and fate of these fluxes are complex and unknown. Permafrost thaw, thermokarst, and the inception of a more dynamic lowland Arctic ecosystem suggest an exacerbation of effects due to warming air temperatures. As beavers create thermal and biological oases by the thousands, they could provide a foothold for boreal aquatic species, including fish and aquatic invertebrates. For now, however, these remain hypotheses that will spawn downstream studies involving field measurements and local knowledge to answer.
Meanwhile, the Nares Strait is open off of Greenland, funneling sea ice into the Atlantic, temporarily, in mid-December. It shouldn't be.
The writers inClimatee Brief work to keep the Daily Kos community informed and engaged with breaking news about the climate crisis worldwide while providing inspiring stories of environmental heroes, opportunities for direct engagement, and perspectives on the intersection of climate activism with spirituality politics arts.