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10 Nitrogen Enrichment and Plant Invasions:
the Importance of Nitrogen-Fixing Plants
and Anthropogenic Eutrophication
Michael Scherer-Lorenzen, Harry Olde Venterink,
and Holger Buschmann
10.1 Introduction
The invasion of natural ecosystems by exotic species is an important component
of global environmental change, and poses a major threat to biodiversity.
Other drivers of global change – such as alteration of the atmospheric composition
and associated climate change, changing patterns of land use that fragment
habitats and alter disturbance regimes, and increasing levels of airborne
nitrogen deposition – also influence resource dynamics and species composition
of ecosystems (Sala et al. 2000). Consequently, they all have the potential
to interact with biological invasions and to accelerate this process, for which
evidence is accumulating (Dukes and Mooney 1999; Mooney and Hobbs
2000). In addition, biological invasions themselves can alter the biogeochemistry
of ecosystems through particular traits of the invading species (Ehrenfeld
and Scott 2001). If we wish to understand and eventually predict the ecological
impacts of invasive species, it is thus of particular importance to reveal
the many complex interactions between all elements of global change, and
their effects on ecosystem processes. In this chapter, we focus on alterations of
the nitrogen cycle of terrestrial ecosystems by exotic invasions, and how
nitrogen deposition may influence the success of invaders.
It is not yet possible to predict which exotic species will become invasive,
though successful invaders are often associated with a particular suite of
traits: high seed output, high relative growth rate, high specific leaf area, low
leaf construction costs, high phenotypic plasticity, and high nutrient concentrations
(Rejmanek and Richardson 1996; Daehler 2003; see also Chap. 7).
Species sharing these traits may be specifically capable to capitalize on the
various elements of environmental change (Dukes and Mooney 1999). What
Ecological Studies,Vol. 193
W. Nentwig (Ed.)
Biological Invasions
© Springer-Verlag Berlin Heidelberg 2007