Effects of climate change and pollen supplementation on the reproductive
success of two grassland plant species
Abstract
Climate change has the potential to alter plant reproductive success
directly and indirectly through disruptions in animal pollination.
Climate models project altered seasonal precipitation patterns and thus
the effects of climate change on available resources and pollination
services will depend on the season. Plants have evolved reproductive
strategies to minimize pollen and resource limitations, and therefore we
expect that the disruption of climate change might cause plants to be
more pollen limited in seasons that become wetter than they were
historically. In this study, we conducted a pollen supplementation
experiment within the Global Change Experiment Facility (GCEF) in
Central Germany. The GCEF experimentally manipulates future climate
based on a realistic scenario of climate change for the region (drier
summers and wetter springs and falls) in a native grassland ecosystem.
We quantified seed production of two perennial species Dianthus
carthusianorum and Scabiosa ochroleuca in response to pollination
treatments (control, supplement), climate treatments (ambient and
future) and season (summer and fall). Dianthus carthusianorum produced
more seeds in future climate conditions independent of the season, but
only when given supplemental pollen. Both species showed an increased
reproduction in summer compared to the fall. We did not find any
evidence for our expectation of higher pollen limitation in the future
climate and fall season (i.e. no three-way interaction pollination x
season x climate), which might be explained by the high drought
tolerance and generalized pollination of our focal plant species. We
conclude that plant reproductive success might be limited by the
services of animal pollinators in future climates, and have many
suggestions for future studies that are necessary to understand the
context-dependence and underlying mechanisms of plant reproductive
responses to climate.