A Habitat-Classification Framework and Typology for Understanding, Valuing, and Managing Invasive Species Impacts - Management of Invasive Weeds - page 88

Suding et al. 2004; Hobbs et al. 2006; Cramer et al. 2008). In Seychelles, for
instance, initial colonization of deforested land by the alien tree Cinnamomum
verum has probably strongly shaped most secondary successions on these tropical
oceanic islands for the past 200 years (Kueffer et al. 2007b) (Fig. 5.4).

5.5.2 Functional Type of Invasive Alien Species

Most commonly, abandoned habitat will initially have conditions similar to anthro-
pogenic habitat, and alien species invading anthropogenic habitat may also most
commonly invade abandoned habitat in an early phase of secondary succession.
Initially, the established vegetation is often partly or mostly composed of alien spe-
cies that have been planted for particular traits (e.g., nitrogen fixation, fast-growth,
adaptation to grazing). Such selected traits may have a strong influence on commu-
nity functioning and ecosystem processes. The (contingent) initial species composi-
tion may therefore have an important influence on community development and lead
to alternative succession scenarios (compare e.g. Suding et al. 2004). Similar to
native ecosystems, in abandoned habitat traits of dominant species are expected to
change over time due to succession (Prach et al. 1999), but patterns may be less pre-
dictable than in native ecosystems (Hobbs et al. 2006). This is because a reduced but

Fig. 5.4 Secondary successions in abandoned habitat. Large areas on the oceanic island of the
Seychelles are covered by a secondary forest dominated by the invasive tree Cinnamomum verum .
This novel ecosystem formed after major deforestation in the early nineteenth century, and pro-
vides important ecosystem services such as erosion control and protection of water catchments.
The fruits of C. verum are a major food source for several endemic frugivorous animals, and the
strong belowground root competition of the species apparently facilitates the regeneration of
native species compared to invasive species (Kueffer et al. 2007b) (Photo Eva Schumacher)