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

132 Karel Prach et al.
successional reversal is needed (see Section 6.3). Here, cutting and subsequent
herbicide application might be useful (Marrs 1988).
Unassisted succession on abandoned fields in temperate Europe has often
been very successful, leading to seminatural vegetation with high nature conservation
value (Table 6.1; see Chapter 5). This approach is most successful
in landscapes that have retained traditional agricultural practices, where soils
have not been altered markedly by over-fertilization or drainage, and where
natural habitats still frequently occur in the vicinity (Falinski 1980, Ruprecht
2005). Conversely, in altered landscapes, competitive ruderals (generalists) or
aliens may expand (Prach et al. in press; see Chapter 3). This was demonstrated
on ungrazed, abandoned fields on sandy soils in Hungary, where invasion
by the alien Robinia pseudoacacia was problematic (Csecserits and Rédei
2001).
It is difficult to produce accurate predictions of likely outcomes of unassisted
oldfield succession due to its high stochasticity (Rejmánek 1990). Site
history, moisture status, soil fertility, character of the surrounding landscape,
management implemented, interactions between trophic levels, and random effects
interact and influence the eventual outcome (Pickett et al. 1987, Tilman
1988). Despite these limitations, robust predictions of successional trajectories
at a country-wide scale and their use in restoration programs were possible after
simple categorization of fields on the basis of moisture (wet, mesic, dry) and
nutrient supply (rich, intermediate, nutrient-poor) (Prach et al. 1999).
6.4.2 Succession in Less Disturbed Ecosystems
In the past, grasslands, heathlands, and various wetlands have been created as
a result of human activity (Gimingham 1992). In Europe, these are important
seminatural ecosystems from a conservation viewpoint. They have substantially
degraded and decreased in their extent, but still contain many rare and retreating
species. Their restoration is of high priority.
6.4.2.1 Temperate Grasslands
Species-rich grasslands have declined substantially in Europe because of agricultural
developments during the latter half of the 20th century. They were used
earlier for hay-making and low-intensity grazing (Bakker 1989). Grasslands on
very infertile soils were abandoned whereas on the more fertile soils exploitation
was intensified, including conversion to arable land. Abandonment led to
a decrease in species-richness and a loss of species characteristic of grassland
communities (Diemer et al. 2001, Matějková et al. 2003). The development
of cheap fertilizers enabled intensification and increased soil fertility and crop
productivity, and changed the species composition from slow-growing, small
species to fast-growing, competitive, tall species. As these productive fields
could be used earlier in the season, and more intensively, the competitive advantage
shifted toward early-flowering species, and especially clonal perennials
(van Diggelen et al. 2005).
The normal practice for ecological restoration of grasslands in Europe is to
reintroduce a mowing or grazing regime without adding fertilizer. In the case
where grasslands have been abandoned this may work (Hansson and Fogelfors
2000), but not always (Matějková et al. 2003). In intensively exploited grasslands
this approach often takes a long time (Oomes and Mooi 1981, Bakker