Changes in snow cover threaten biodiversity of Arctic nature

Many plants that inhabit the northern mountains depend on the snow cover that persists until late spring or summer. Snow protects plants against winter extremes, while reducing the length of the growing season, preventing the establishment of more southern plants. This is why reduced snow cover can pose an even greater threat to Arctic plants than rising temperatures.

In a study published in the famous scientific journal Nature Climate changeResearchers from the University of Helsinki and the Finnish Environment Institute have analyzed the potential effects of temperature changes and snow cover duration on the extinction risk of northern flora. The results show that many plant species can benefit from a warmer climate, but that rapidly retiring snow cover can radiate much of the typical northern mountain flora. Many of these species are already endangered, making their conservation an urgent challenge.

– Although the importance of snow is widely recognized, winter conditions are often ignored when studying the northern and mountainous regions, says Pekka Niittynen, PhD student at the University of Helsinki.

Winter data collection was very difficult, but remote sensing and satellite imagery have allowed detailed monitoring of snow cover since the 1980s.

With the help of remote sensing and species distribution models, we have shown that winter is of paramount importance to the northern nature and the future of its organisms, explains Niittynen.

Many arctic and mountain plants are specialized in growth and flowering for a very short summer. If the duration of snow cover decreases and summers lengthen, more southerly species benefit and may compete with arctic species until extinction.

According to the researchers, the climate in northern regions is changing faster than in the rest of the world, and these changes are particularly violent in winter. This makes the current results all the more significant.

– We are afraid of not knowing exactly how the snow will change as the climate warms up. We can predict temperatures with enough accuracy, but it is more difficult to predict precipitation. With the snow, it's even more uncertain. For example, in some areas of Siberia, the amount of snow may increase due to more precipitation in winter, but the duration of the snow cover in northern countries should be much shorter, says Pekka Niittynen.

– Our results show that future changes in northern species populations could be brutal, which would give rise to unprejudiable ecological surprises, such as the rapid eradication of populations in certain areas and regions. Invasion of flexible species in new places, says lead researcher Risto Heikkinen of the Finnish Institute of the Environment.

– Many iconic species of arctic regions, such as the glacier buttercup, will decline considerably due to the evolution of the snow, said Miska Luoto, professor of natural geography at the University of Helsinki .

Many of the northern mountain species thrive only in the drift zones.

– Decreasing galleries will increase the risk of extinction for plants such as snowcurd, mountain sorrel and mossy plants.

Recently published research focuses on plants, moss and lichen, but the results will likely apply to many other populations of Arctic organisms. Many Arctic species are at risk of extinction if snow-dependent species do not have suitable areas in the vicinity where the snow cover will remain on the ground long enough. There are few ways to adapt to changes in snow cover in arctic areas in practice. This is why mitigation measures of climate change effects are essential to the preservation of the Nordic nature.

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Reference: Pekka Niittynen, Risto K. Heikkinen, Miska Luoto: Snow cover is a neglected factor of biodiversity loss in the Arctic, Nature Climate change letters. https: //do I.org /ten.1038 /s41558-018-0311-x

PhD student Pekka Niittynen, University of Helsinki, Department of Geosciences and Geography, BioGeoClimate Research Group https: // http: // www. Helsinki. fi / en / researchgroups / biogeoclimate-modeling-lab,

Phone: +358 40 6576888

Email: [email protected]

Principal Investigator Risto Heikkinen, Finnish Institute of the Environment

Phone: +358 295 251 151

Email: [email protected]

Professor Miska Luoto, Department of Geosciences and Geography, University of Helsinki, BioGeoClimate Research Group

Phone: +358 44 2727327

Email: [email protected]