Linking Specialisation and Stability of Plant ... - OPUS Würzburg

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C A N P L A N T- P O L L I N AT O R I N T E R A C T I O N S
P R O M O T E P L A N T D I V E R S I T Y ? 1
3.1 abstract
In the light of rapid losses of biodiversity worldwide, it has
become more important than ever to study the factors that ensure
the continued existence of diverse ecological communities.
Whereas the diversity-enhancing effects of antagonistic interactions
are relatively well understood, much less is known about
the contribution of mutualistic interactions to the maintenance
of biodiversity. The current study assesses the influence of the
presence of pollinators on the diversity of plant communities
with alternative means of reproduction beside animal pollination.
In contrast to the conclusions of a recent more general
model of plant-animal mutualisms, the results of our numerical
simulations suggest that interactions with pollinators do
not generally promote plant diversity. Despite a potential for
increased plant species richness through the positive effect of
pollinators on plant birth rates, species richness of plants was
mostly negatively affected by the presence of pollinators, regardless
of the structure of the interaction network. Our results
imply that for plant communities with alternative means of reproduction,
the loss of pollinators will usually not lead to decreased
diversity. However, whereas the immediate effects of
pollinator loss on plant community composition may be negligible,
the long-term population genetic consequences are likely
to be severe.
3.2 introduction
Confronted with the fact that biodiversity is not evenly distributed
across space and time, ecologists have long sought
to understand the mechanisms underlying the observed diversity
patterns. Whilst rates of speciation and global extinction
determine the size and composition of the pool of regionally
occurring species, the subset of species that form a local community
is a product of colonization and extinction processes
on a shorter time scale. Interspecific interactions play an impor-
1 Article by G. Benadi, N. Blüthgen, T. Hovestadt and H.-J. Poethke
Submitted to The American Naturalist
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