Boreal plants colonize the Arctic and could accelerate permafrost thawing.

Barcelona, ​​Sep 22 (EFE).- A scientific study led by the Center for Ecological Research and Forestry Applications (CREAF) at the University of Barcelona and the University of Edinburgh (Scotland, Great Britain) warns that boreal plants are colonizing the Arctic and could accelerate the thawing of permafrost.

This study, published in the journal Ecology Letters, warns that plant species capable of living in both low-latitude tundra and boreal forests are gaining ground in the Arctic.

According to the study's authors, "although we live thinking that plants don't move, they do and can transform an entire landscape."

The research's conclusions establish that boreal species are expanding in the Arctic, especially those previously present in the tundra, in a process known as borealization.

Eurasia and the alpine areas are where there is the greatest expansion.

This process occurs primarily in Eurasia and in alpine regions, where the distance to the boreal forest is shorter, facilitating the dispersal of these species.

Researchers believe that if this trend continues, the transformation of the tundra landscape could have cascading consequences, accelerating permafrost thawing or disrupting caribou migration, for example.

It would also affect indigenous communities in the Arctic, who hunt or graze these animals and use certain plants as food.

Specifically, the boreal species that tend to be the best colonizers are grasses and shrubs, and the scientific team warns that the expansion of these species could have effects on the climate, wildlife, and human communities.

Typical tundra lichens, for example, are the main food of caribou and reindeer.

The problem is that, under the shade of the bushes, the lichens could recede, and if they decrease, so does the food supply for these animals.

This, in turn, threatens the livelihoods of indigenous communities who depend on hunting and grazing, and who also feed on some typical tundra plants.

The climate can also be affected by borealization.

The climate could also be affected by borealization, since when shrubs and other woody species expand, they trap more snow in winter and cover the ground in summer.

This changes ground temperatures and can accelerate the thawing of permafrost, which can result in the release of large amounts of carbon trapped in this "frozen icebox" for millennia and contribute to global warming.

Mariana García Criado, a researcher at CREAF and the University of Edinburgh and first author of the study, explains that the scientific team has confirmed that plants native to the boreal forest and the boreal-tundra transition "are expanding in Arctic regions, albeit at different rates depending on the region."

The expansion of boreal vegetation is also greatest in the warmer and wetter areas of the Arctic, conditions that favor plant establishment.

So far, they have not found a direct relationship with the increase in temperature in the areas studied, probably because the greatest temperature increases occur at high latitudes, where boreal species have greater difficulty reaching.

The study also analyzed which characteristics make some plants more successful in their spread than others, and found that shorter boreal species are more likely to advance in the tundra than taller ones.

Furthermore, grasses and shrubs have colonized more plots than herbaceous species, thanks to adaptive advantages such as capturing nutrients from the soil more efficiently.

Some examples of boreal species that have reached a large number of plots are the grass Carex bigelowii (Bigelow's beech) and the shrub Vaccinium vitis-idaea (cranberry).

Four decades of expeditions

To conduct the research, the team analyzed data from the international ITEX (International Tundra Experiment) consortium, which has been collecting information from permanent plots distributed throughout the Arctic for four decades.

In total, more than 1,100 plots and 287 plant species were studied, sampled between 1981 and 2023.

The next step in this research, García Criado says, will be to study the impacts of the borealization process on ecosystems and indigenous communities in the Arctic.

They also want to find out how lichen and moss populations are changing in polar regions, "something that is still largely unknown," the same researcher points out.

The study was led by the University of Edinburgh and CREAF, but also includes the participation of more than 30 research institutions around the world. EFE

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