Environmental Engineering Reference
In-Depth Information
Figure 15.4
Preferential seasonally periods for application of selected restoration techniques within Arctic and
alpine environments.
extremely slowly and life spans exceeding 30 years are
no rarity. Even biodegradation of organically based tex-
tiles like coconut fi bre can take decades and may thus
act as a hinder for revegetation (Uhlig 2008). If artifi -
cial material (e.g. geotextiles) is used for erosion
control, it generally should be degradable over a couple
of years. Furthermore, organic geotextiles such as
coconut or hemp fi bre fabrics are naturally poor in
plant nutrients and thus do not improve soil chemical
properties. Therefore, it has been suggested to develop
erosion control mats constructed from ' site - specifi c
organic matter' (Uhlig 2006). The use of textiles with
improved biodegradability could increase plant nutri-
ent release and soil organic matter enrichment, and
thus promote soil development. Based on our experi-
ence we emphasize that many types of erosion control
material possess a relative high volume. Costs for trans-
port to remote sites can be reduced by using locally
available material such as peat, shrubs or stranded
algae in coastal Arctic areas. Contrary to widespread
belief, the use of seed mixtures consisting of rapid-
growing species has no positive infl uence on the short-
term prevention of erosion (Krautzer
et al
. 2010 ; see
also section 15.4.2 ).
or seeds (e.g. Johnson & van Cleve 1976). Leaving
damaged sites with a soil that resembles the natural
landscape in topography, hydrology and other physical
and chemical properties is the most important practice
for tundra restoration (Forbes & Jefferies 1999). The
extent of the changes in the chemical and physical
characteristics of substrata caused by human activities
often imposes severe limitations on the establishment
of plants (Pyvell & Putwain 1996). A problem-resisting
solution in restoration of a disturbed tundra site is how
to combine revegetation with the re-establishment of
a stable thermal regime (e.g. Johnson & Cleve 1976;
McKendrick 1997). As mentioned, due to temperature-
inhibited nutrient cycling, tundra soils are nutrient
poor, specifi cally in nitrogen and phosphorus (e.g.
McKendrick 1991). Nutrients stocked in plant biomass
or in the superfi cial layers of the soil are often exported
from the ecosystem during or shortly after the distur-
bances (Deshaies
et al
. 2009). Beside, as the site for
microbial activity and nutrient cycling, the organic
layer plays a vital role that depends on site-specifi c
thermal and hydrological properties. Thus, any distur-
bance of the organic layer can cause a dramatic decline
in soil fertility. Therefore, it is important to save all
the topsoil displaced and disturbed in the process of
building and construction activities for later use in res-
toration projects. However, removal, storage and reap-
plication of topsoil should be carefully planned. For
example, the drying out of topsoil during storage
should be avoided or minimized to preserve substrate
Improving s oil c onditions
Effort invested in improving soil conditions prior to
planting or sowing is inversely correlated to the quality
of the growing conditions for newly introduced plants
