Data from: Specialization and phenological synchrony of plant–pollinator interactions along an altitudinal gradient

1. One of the most noticeable effects of anthropogenic climate change is
the shift in timing of seasonal events towards earlier occurrence. The
high degree of variation in species' phenological shifts has raised
concerns about the temporal decoupling of interspecific interactions, but
the extent and implications of this effect are largely unknown. In the
case of plant–pollinator systems, more specialized species are predicted
to be particularly threatened by phenological decoupling, since they are
assumed to be less flexible in the choice of interaction partners, but
until now this hypothesis has not been tested. 2. In this paper, we
studied phenology and interactions of plant and pollinator communities
along an altitudinal gradient in the Alps as a model for the possible
effects of climate change in time. 3. Our results show that even
relatively specialized pollinators were much more flexible in their use of
plant species as floral resources than their local flower visitation
suggested. We found no relationship between local specialization of
pollinators and the consistency of their visitation patterns across sites,
and also no relationship between specialization and phenological synchrony
of pollinators with particular plants. 4. Thus, in contrast to the
conclusions of a recent simulation study, our results suggest that most
pollinator species included in this study are not threatened by
phenological decoupling from specific flowering plants. However, the
flexibility of many rarely observed pollinator species remains unknown.
Moreover, our results suggest that specialized flower visitors select
plant species based on certain floral traits such as the length of the
nectar holder tube. If that is the case, the observed flexibility of
plant–pollinator interactions likely depends on a high degree of
functional redundancy in the plant community, which may not exist in less
diverse systems.