Environmental Engineering Reference
In-Depth Information
work-intensive management of alpine meadows in high
zones, with regular measures taken, such as the removal
of stones and bushes and the rapid restoration of points
where erosion has begun in the course of a possibly
long process of reforesting, can also lead to the mass-
ive formation of shell-shaped erosion scarp. Mostly
affected are pastures below the potential forest line
with deeply crevassed soil and a slope gradient of over
30°. Those areas showing shell-shaped erosion scarp
are mainly those that have not been utilized (i.e. mowed
or grazed) for many years (Bernhaupt 1980). Plant
communities, in which the formation of shell-shaped
erosion scarp appears, are marked by a high share
of biomass-rich grasses and high-growing herbs.
The root horizon is relatively low and uniform. The
formation of a sliding horizon is fostered in this way.
Stable plant communities, in comparison, comprise
somewhat loose swards and low growth. They form
relatively small amounts of biomass above the sur-
face, but relatively high amounts of root biomass.
of whether terrain corrections have been made in the
course of constructing ski runs, or forest and alpine-
meadow trails, measures for the improvement of
tourism infrastructure or torrent and avalanche bar-
riers, only a combination of high-quality plant mater-
ial or seed adapted to the site with the optimum
restoration technique will bring permanent success. The
use of seed mixtures is only sensible in high zones
within which the species can reproduce. This border
is generally achieved at altitudes of 2300-2400 m. The
planning of restoration at extremely high altitudes (over
2000 m) is to be carried out by appropriately trained
experts with sufficient experience. The methods used
are suitable for the climatic and geobotanical con-
ditions and are principally for the restoration of alpine
ecological systems. For the production of vegetation
cover that is similar or identical to nature in areas
with no primary agricultural use, the methods given
here can be recommended for all altitudes in the
subalpine-alpine zones.
Natural re-vegetation
15.3.4 Plant growth and vegetation
Currently to be seen as site-specific and restorable
according to the latest advances in the field are areas
subject to human influence, somewhat nutrition-rich
plant communities as the basis for various grazing
lands, former cattle resting places and fields of high
perennials and shrub communities. The recultivation
of areas not subject to human influence, exposed alpine
grasslands (curved sedge, cushion sedge, high-altitude
formations of horst sedge grasslands, etc.) is currently
hardly possible, as is that of windy ridge communit-
ies (the community of the three-leaved rush, etc.). There
is no commercial seed available of the characteristic
species of these types of vegetation (some are also
beyond production). Moreover, the majority of these
natural grasslands cannot be planted; many of them
die shortly after transplantation.
In principle, it is possible in high zones to permit
natural successive procedures. Due to specialized
considerations for nature protection, this strategy is
sometimes (with appropriately favourable conditions
and awareness of the danger of erosion) favoured over
other restoration methods, or at least combined with
them. The substratum and site conditions will define
the development of the vegetation. The spreading of
mulch materials or geological textiles, facilitating
In most cases, above all in the alpine zone, natural
development back to the original vegetation units
within human planning periods is not to be expected.
With respect to sufficient protection against erosion,
the first target function of restoration in high zones
is usually the achievement of stable grassland. Pre-
vious damage mostly leads to the destruction of the
vegetated earth or affects the eroded areas with a lack
of humus groundcover. The results are mostly more
or less a lack of fine soil, stony restoration bases with
slight water-storage capacity and a high tendency to
erode (Chambers 1997). To achieve sufficient protec-
tion against erosion restoration measures must take
place as quickly as possible.
15.4 Approaches for sustainable
restoration in alpine environments
15.4.1 General
Restoration at high altitudes is subject to limits.
With increasing altitude, restoration following building
measures always becomes more difficult. Irrespective
