Data from: Topographic heterogeneity lengthens the duration of pollinator resources

The availability of sufficient and diverse resources across time is
important for maintenance of biodiversity and ecosystem functioning. In
this study we examine the potential for variation in environmental
conditions across topographic gradients to extend floral resource timing.
Flowering time on a landscape may vary across topography due to
differences in abiotic factors, species turnover, or genotypic
differences. However, the extent to which this variation in phenology
affects overall flowering duration on a landscape, and the components of
diversity that influence flowering duration, are unexplored. We
investigate whether differences in flowering time due to topography yield
an overall extension in duration of flowering resources in a northern
California grassland. We recorded flowering time of pollinator resource
species across four successive spring growing seasons (2015-2018) on
paired north and south aspects. Flowering time differences were evaluated
both at the community level and within species present on both paired
aspects. The role of plasticity was examined in an experimental case
study. We found that aspect is a strong determinant of phenology, with
earlier flowering on warmer south-facing slopes. Aspect differences
resulted in complementarity in timing of flowering resources across sites,
as aspects that started flowering earlier also ended earlier.
Complementarity between north and south aspects served to extend the
flowering time of pollinator resources by an average of 4-8 days (8-15%),
depending on the year. This extension can be attributed to both within
species responses to aspect differences as well as species turnover.
Flowering of L. gracilis genotypes was distinct across aspects,
demonstrating that plasticity can drive the extension of flowering
duration. Our findings indicate that heterogeneous topography can extend
overall flowering time of pollinator resources, which may support
pollinator biodiversity. Extension was most pronounced at the community
level, which incorporates species turnover as well as plastic and
genotypic differences within species.