Data from: Demographic consequences of greater clonal than sexual reproduction in Dicentra canadensis

Clonality is a widespread life history trait in flowering plants that may
be essential for population persistence, especially in environments where
sexual reproduction is unpredictable. Frequent clonal reproduction,
however, could hinder sexual reproduction by spatially aggregating ramets
that compete with seedlings and reduce inter-genet pollination.
Nevertheless, the role of clonality in relation to variable sexual
reproduction in population dynamics is often overlooked. We combined
population matrix models and pollination experiments to compare the
demographic contributions of clonal and sexual reproduction in three
Dicentra canadensis populations, one in a well-forested landscape and two
in isolated forest remnants. We constructed stage-based transition
matrices from 3 years of census data to evaluate annual population growth
rates, λ. We used loop analysis to evaluate the relative contribution of
different reproductive pathways to λ. Despite strong temporal and spatial
variation in seed set, populations generally showed stable growth rates.
Although we detected some pollen limitation of seed set, manipulative
pollination treatments did not affect population growth rates. Clonal
reproduction contributed significantly more than sexual reproduction to
population growth in the forest remnants. Only at the well-forested site
did sexual reproduction contribute as much as clonal reproduction to
population growth. Flowering plants were more likely to transition to a
smaller size class with reduced reproductive potential in the following
year than similarly sized nonflowering plants, suggesting energy
trade-offs between sexual and clonal reproduction at the individual level.
Seed production had negligible effects on growth and tuber production of
individual plants. Our results demonstrate that clonal reproduction is
vital for population persistence in a system where sexual reproduction is
unpredictable. The bias toward clonality may be driven by low fitness
returns for resource investment in sexual reproduction at the individual
level. However, chronic failure in sexual reproduction may exacerbate the
imbalance between sexual and clonal reproduction and eventually lead to
irreversible loss of sex in the population.