Linking Restoration and Ecological Succession (Springer ... - Inecol

128 Karel Prach et al.
There are, however, situations where unassisted or slightly manipulated succession
is not effective; e.g., on very acidic or toxic substrata, or under extremely
dry conditions. Acidic sites in an East German coal mining district were without
any vegetation 70 years after abandonment (Wiegleb and Felinks 2001).
In such cases, physical manipulation of the environment is essential within the
Primary Management Phase. Liming, topsoiling, and covering of the surface
by other organic or inert material are frequently used. Hydroseeding may help
to overcome adverse site moisture conditions (Munshower 1994, Ninot et al.
2001). Some technical reclamation is also needed on easily eroded sites: in
northeastern Spain, unassisted succession created seminatural communities on
dumps from coal mining. However, the vegetation cover produced was inadequate
for site stability (Ninot et al. 2001). Technical measures are also needed
in the case of outputs of toxic substances from some mine tailings (Whisenant
1999).
We are convinced that unassisted succession should be suitable for restoring
many mine wastes. Unfortunately, this is often prevented by legislation or
practice that obligates mining companies to restore disturbed sites quickly. In
some countries, there has recently been progress in this area; in some German
coal mining districts, at least 15% of the area disturbed by mining must be left
for unassisted succession (Wiegleb and Felinks 2001).
Sand and gravel pits and stone quarries are best left for unassisted succession,
especially if the disturbed site is small (Prach 2003; Figs. 6.3 and 6.4).
These sites provide important nutrient-poor refugia for species under threat in
the surrounding fertile landscape. If mining sites are not too extensive, do not
produce any pollution, do not damage any valuable locality, and are aesthetically
acceptable, they can even increase landscape diversity. These conclusions
Figure 6.3 An abandoned sand pit in southern Czech Republic, 12 years after cessation
of sand extraction. A spontaneous stand, dominated by Scots pine (Pinus sylvestris)
appears at the rear of the photo, planted Scots pine in the foreground. The technical
reclamation was not needed as unassisted succession proceeded faster toward the target
of a seminatural pine forest.