10.25338/B8C04D
Christie, Kyle
0000-0001-8257-2106
University of California, Davis
Harrison, Susan
University of California, Davis
L. Friesen, Maren
Washington State University
Y. Strauss, Sharon
University of California, Davis
Data and analysis scripts for: Co-occurrence patterns at four spatial
scales implicate reproductive processes in shaping community assembly in
clovers
Dryad
dataset
2021
coexistence
heterospecific pollen transfer
reproductive exclusion
Reproductive interference
Trifolium
Mating Systems
National Science Foundation
https://ror.org/021nxhr62
DEB-1342841
2021-09-03T00:00:00Z
2021-09-03T00:00:00Z
en
https://doi.org/10.5281/zenodo.5398561
2618140 bytes
4
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
1. Competition, niche differences, and chance all contribute to community
assembly, yet the role of reproductive interactions between species is
often less appreciated. Closely related plant species that share floral
form, phenology, and habitat often interact through pollination. They
potentially facilitate pollinator attraction, compete for pollination
services, and/or exchange pollen. If reproductive processes are important
to co-occurrence, we predicted that fitness costs of heterospecific pollen
transfer or pollen limitation should result in lower rates of
co-occurrence among outcrossing congeners. In contrast, selfers, which may
be less exposed to heterospecific pollen, and/or less negatively affected
by it, should co-occur more frequently. 2. Flower size is an excellent
proxy for mating system in clovers. Using herbarium records and three
independent field datasets, we documented co-occurrence patterns of
Trifolium at 1m2 - 1km2 scales in California. Using a randomization
procedure to reshuffle matrices of community membership, we generated null
hypotheses for the expected composition of large- and small-flowered
species in Trifolium communities of different sizes. 3. Across all spatial
scales, large-flowered outcrossers were over-represented at sites lacking
congeners, but under-represented in communities with multiple congeners.
Conversely, small-flowered selfers often occupied sites with multiple
other Trifolium species. Patterns for plant height and leaf size, which
are weakly or strongly correlated with flower size, did not explain
co-occurrence patterns as robustly. Regression and model selection
corroborated the null model analyses, indicating that the likelihood of
co-occurrence decreased as flower size, and thus reliance on outcrossing,
increased. 4. Synthesis. This study suggests that reproductive traits and
processes may be significant contributors to community assembly and
co-occurrence in flowering plants.
We gathered Trifolium co-occurrence data from four independent sources: 1)
at 11,447 randomly-sampled points from across California, documenting
occurrences of all Trifolium species as inferred from georeferenced
herbarium records, and 1-kilometer buffers around verified records; 2) in
107 500m2 plots sampled from across California, as described in Harrison
et al. 2006; 3) in 423 4m2 quadrats sampled in 2015 and 2016 at the Bodega
Bay Natural Reserve, as described in Siefert et al. 2018; and 4) from 372
1m2 quadrats sampled annually from 2000-2017 at the McLaughlin Natural
Reserve, as described in Harrison et al. 2015.
All scripts are fully functional with the accompanying .Rdata objects
(which were generated as described in the manuscript through 10,000
randomizations/re-shufflings of the observed co-occurrence data).