According to the results of the project “Remote sensing the habitats of Northern Lapland”, the current situation of more than half of the mountain birch forests and treeless mountain heaths has weakened to varying degrees. This worrisome situation has come to light in the final report of the collaborative project between National Parks Finland and the Finnish Environment Institute (Syke), published today. The project surveyed nearly three million hectares of Northern Lapland’s nature conservation and wilderness areas in 2020–2023.

Material generated through the use of remote sensing data, terrain tests and machine intelligence in the project “Remote sensing the habitats of Northern Lapland” is the most accurate data ever collected on the occurrence and status of natural habitats in Northern Lapland’s protected and wilderness areas:

• Final report, part 1 (in Finnish, julkaisut.metsa.fi)
• Final report, part 2 (in Finnish, julkaisut.metsa.fi)

Terrain data was collected from 4,500 field test sites covering the entire project area.

According to the assessment of endangered habitats, completed in 2018, more than one third of fell habitat types are endangered. Of the large-scale habitats, the status of mountain heaths, mountain birch forests and palsa mires, in particular, has deteriorated.

The main reasons for the situation are climate change and reindeer grazing, and their combined effects.

– The consequences of climate change include an increase in the damage caused by geometrid moths in mountain birch forests, decrease of coniferous forests in lower slopes of the fells, overgrowth of shrubs, and the loss of palsa mires. Reindeer grazing prevents the overgrowth of open areas, but strong grazing pressure weakens the regenerative capacity of mountain birch forests and weakens the state of lichenous areas, says Service Owner Elisa Pääkkö from National Parks Finland.

The condition of mountain heaths has declined in large areas, as four fifths of mountain heaths in the nature conservation and wilderness areas have deteriorated to varying degrees. This is primarily due to the wear of lichenous areas and the spread of trees, especially pine, to mountain heaths.

Mountain birch forests are consumed as food when mild winters fail to destroy moth eggs

In Northern Lapland, the status of mountain birch forests varies greatly depending on the area. Negative changes in the mountain birch forests are particularly evident in the Kaldoaivi and Paistunturi Wilderness Areas of Utsjoki, as well as in the Kevo Strict Nature Reserve, in some parts of the Muotkatunturi Wilderness Area in Inari, and at Kilpisjärvi, particularly in the Malla Strict Nature Reserve.

The status of mountain birch forests is significantly affected by the regenerative capacity of birch forests and the occurrence of damage caused by geometrid moths. Mild winters fail to kill the eggs of geometrid moths, which means that there are greater numbers of moths that eat Mountain Birch (Betula pubescens subsp. czerepanovii) leaves in the summer. The eggs only die in temperatures below -36 degrees Celsius.

One half of the mountain birch forests in Northern Lapland are in excellent condition and the other half are deteriorated to varying degrees. The main reason for the deterioration is that, due to the strong summer grazing of reindeer, mountain birch forests have not been able to regenerate.

– Birch forests’ inability to recover, on the other hand, has resulted in extensive birch deaths due to the mass occurrences of geometrid moths in the 1960s and 2000s, says Pääkkö.

Based on the data collected, 45,000 hectares of mountain birch forests have been destroyed in Northern Lapland in the 2000s, and 95,000 hectares of previously destroyed mountain birch forests have still not recovered. This is more than the total area of the cities of Helsinki, Espoo and Vantaa combined. 

Large-scale mountain birch forests in excellent condition are found in areas with a grazing rotation system that works well for mountain birch forests.

– For example, there are areas at Lemmenjoki, in the Urho Kekkonen National Park and the Käsivarsi region, where mountain birch forests are thriving, thanks to excellent grazing cycles, says Pääkkö.

Pine-dominated natural forests in the protected and wilderness areas of Northern Lapland are largely in an excellent condition, and forestry is not practised in the protected and wilderness areas.

The resulting data assists in monitoring biodiversity

With the loss of biodiversity, nature is less likely to recover from disturbances such as those caused by climate change. In the Arctic region, global warming is estimated to be up to four times faster than the Earth’s average.

– We need more regular monitoring of how, and how fast, nature is changing. Most recently, the state of nature in Northern Lapland was surveyed more extensively in the 1990s. At that time, different methods were in use. If habitat monitoring is carried out so rarely, much remains undetected. Our data shows that we need to increase the effort in Finland particularly to improve the condition of mountain heaths and mountain birch forests. The fact that mountain heaths and mountain birch forests are located in protected areas does not alone safeguard their preservation, says Pääkkö.

National Parks Finland is working to redirect biodiversity loss onto a path of recovery by 2030, and the aim of Syke is also to prevent biodiversity loss and to develop the monitoring of its status. The EU’s biodiversity strategy is also aimed at halting biodiversity loss. It also aims to improve the management of protected areas.

– The project results suggest that we should foster the use different monitoring methods that are mutually supportive in order to develop habitat monitoring. By harnessing the ability of different remote sensing methods to produce data on habitats and, on the other hand, by taking their shortcomings, uncertainties and costs into account, we can obtain significantly more comprehensive monitoring data on the state of nature in areas that are vast and difficult to reach, says Saku Anttila, Unit Director at Syke.

Facts: mountain heaths and mountain birch forests

• Mountain heaths and mountain birch forests are habitat types occurring in Lapland.
• Mountain heaths are treeless areas located at the top of fells. There are different types of mountain heaths: in some, Crowberries (Empetrum nigrum) and European Blueberries (Vaccinium myrtillus) grow, while lichen grows in others. There are nine different types of mountain heaths in Finland.
• Mountain Birch (Betula pubescens subsp. czerepanovii) is a subspecies of Downy Birch (Betula pubescens) that grows on the slopes of fells. There are nine different types of mountain birch forests in Finland. The types of mountain birch forests vary depending on what kind of vegetation grows in the area in addition to Mountain Birches. For example, mountain birch forests may be barren and lichenous, or, on the other hand, herb-rich areas, where numerous Globeflowers (Trollius europaeus) grow around birches.