Subalpine deciduous scrub

This habitat type comprises (sub)alpine and (sub)arctic alder (Alnus viridis), willow (Salix spp.), dwarf birch (Betula nana) and other deciduous scrub. Also Potentilla fruticosa dominated scrub that appears in the Bulgarian mountains (F2.336) is included. The stand height of the habitat in most cases is between 1 and 5 meters. Low dwarf willow communities are excluded from this habitat and instead included in type F2.1. Also excluded in the (sub)alpine and (sub)arctic belts are willow scrub on alluvial soils (habitat F9.1) and willow scrub in waterlogged fens and mires (habitat F9.2). Alnus viridis scrub is found throughout the subalpine belts of all mountain ranges of central Europe. This shrub is a pioneer species in humid sites on deeper soils that are regularly disturbed, like on steep, north-exposed slopes where avalanches occur occasionally. On sites cleared by avalanches, Alnus viridis may be found in lower (montane) altitudes as well. It is found in the Alps and Carpathians. On Corsica a different subspecies Alnus viridis subsp. suaveolens grows in a similar habitat. Salix species (S. appendiculata, S. glabra, S. hastata, S. waldsteiniana) may dominate a lower shrub layer or – in lower altitudes – form its own scrub type in similar sites. The type contains several Salix species that are (regional) rare in the temperate mountain regions. Accompanying species are often from tall herb communities, for example, Adenostyles alliariae or Cicerbita alpina, or from subalpine heathlands. In the southern outcrops of the Alps and along the Dinarides, Rhamnus fallax dominates communities of this habitat. In the subarctic and boreal regions on similar slopes Salix lapponum, Salix glauca, Salix hastata, Salix phylicifolia may grow in a mixture of tall-herb species and Vaccinium myrtillus, Phyllodoce caerulea, and/or Juniperus communis. The same willows are found along creeks and rivers, as part of the habitat alluvial scrub (F9.1). The geological substrate of the habitat is diverse, covering for example both marl and limestone. The habitat appears in open sites with high soil moisture and moderate-rich in nutrients. The species of the type are well adapted to low temperature and snow accumulation. These deciduous scrubs are the pioneer communities on screes and in areas cleared by avalanches because the shrub species are able to regrow from roots and stumps. Therefore, they also have a significant role in the prevention of erosion and snow slides. Propitious sites for these communities can be found also along streams because of humidity, small soil partitions and disturbance caused by the water stream. The habitat can also appear as a succession stage in subalpine pastures or meadows, where grazing or haymaking is no longer maintained. These communities are mainly of secondary origin. But as they survive snow slips better than tree species, they can build permanent (paraclimatic) communities under the influence of avalanches or streams, in sites where tree species cannot survive.

Indicators of quality:

These habitats are mainly of secondary origin. They are threatened by logging or burning, erosion or snow slips, and channeling of streams, as well as by succession towards forest. The following characteristics can be considered as indicators of good quality:

• species richness of shrub species,

• presence of breeding birds and other fauna,

• long-term maintenance because of natural disturbance regime.

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats