Targeted Grazing by Highland Cattle: Less Green Alder, More Plant Biodiversity

A recent Agroscope study highlights the potential of Highland cattle to control the spread of green alder and restore plant diversity on mountain pastures.

Green alder(Alnus viridis) is a shrub species which encroaches mountain pastures in Central Europe, with negative economic and ecological consequences.

Targeted grazing by robust breeds of cattle may limit its spread and help to restore pastures, but the long-term effectiveness of this practice and its impact on plant diversity and forage quality over time remains unclear.

Agroscope conducted a study on two alpine pastures encroached by A. viridis: Bovonne in Switzerland, where Highland cattle were introduced in 2019, and Val Vogna in Italy, where they were introduced in 2009. The researchers characterised changes in vegetation cover over the past decades by analysing satellite images, conducted vegetation surveys by assessing the impact of Highland cattle on plant diversity and pastoral value between 2019 and 2024, and evaluated animal movement patterns using GPS tracking.

Shrubland cover

Long-term image analysis shows that shrubland cover declined at the two sites following the introduction of Highland cattle: from 17 to 16.3 hectares over five years at Bovonne (-4%), and from 34.6 to 31.8 hectares over 14 years at Val Vogna (-8%).

Plant diversity and forage quality

The vegetation surveys carried out in 2019 and 2024 show that average species richness increased from 25.5 (number of species recorded on 25 m²) to 32.2 at Bovonne and from 30.6 to 32.9 at Val Vogna.  The pastoral value – index that combines forage yield and quality – of open pastures at Bovonne improved from 12.9 to 17.7 (on a scale of 0 to 100). 

Cattle movement

Cattle movement patterns indicate a preference for pastures rather than shrublands, although at Bovonne they increasingly grazed within the green alder stands over time.