10.5061/DRYAD.RFJ6Q579H
Resasco, Julian
0000-0003-1605-3038
University of Colorado Boulder
Chacoff, Natacha
National University of Tucumán
Vázquez, Diego
0000-0002-3449-5748
Centro Científico Tecnológico - Mendoza
Plant-pollinator interactions between generalists persist over time and space
Dryad
dataset
2021
FOS: Biological sciences
National Science Foundation
https://ror.org/021nxhr62
NSF Postdoctoral Research Fellowship in Biology (award 1309192)
University of Colorado System
https://ror.org/00jc20583
2022-03-31T00:00:00Z
2021-04-01T00:00:00Z
en
1495949 bytes
5
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Generalist species are the linchpins of networks, as they are important
for maintaining network structure and function. Previous studies have
shown that interactions between generalists tend to occur consistently
across years and sites. However, the link between temporal and spatial
interaction persistence across scales remains unclear. To address this
gap, we collected data on plant-pollinator interactions throughout the
flowering period for five years across six plots in a subalpine meadow in
the Rocky Mountains. We found that interactions between generalists tended
to persist more in time and space such that interactions near the network
core were more frequently recorded across years, within seasons, and among
plots. We posit that species’ tolerance of environmental variation across
time and space plays a key role in generalization by regulating
spatiotemporal overlap with interaction partners. Our results imply a role
of spatiotemporal environmental variation in organizing species
interactions, marrying niche concepts that emphasize species environmental
constraints and their community role.
We conducted this study in a subalpine meadow at the University of
Colorado’s Mountain Research Station (40°01'48" N,
105°32'26" W), located at 2900 m of elevation 22 km west of
Boulder, CO, USA. The meadow faces east and is surrounded by aspen and
spruce-fir forest. We collected interaction data weekly during the entire
flowering period from 2015 to 2019. The flowering season at the study site
typically starts after snowmelt in late May to early June and extends to
late September. Interactions were recorded on 16–18 weeks per year. We
sampled on average 6.95 (±1.17 SD) days apart. On each sampling date, we
sampled plant-pollinator interactions in six 20-30 m × 2 m plots (five 30
m × 2 m and one 20 m × 2 m) by observing flowers (plant-centered
sampling). Plots were at a similar elevation, 2962 - 2978m. Sampling was
conducted in fair weather during mornings between 8:00 am and 12:00 pm, a
time range when pollinator activity is high and before the onset of
thunderstorms that often occur at mid-day during the summer in the Rocky
Mountains. We sampled plant-pollinator interactions within each plot (in
random order) by doing 15-min surveys in which we carefully observed all
flowers for visitors while walking the periphery of plots to minimize
trampling. When we observed an interaction, defined as a pollinator
contacting the reproductive structures of a flower, we recorded the
identity of the plant and pollinator species. Insect pollinators were
collected with aspirators or aerial nets for later identification in the
laboratory. Expert entomologists (see Acknowledgements) assisted with
insects that are difficult to identify. We compiled all the observations
from the study into a species x species plant-pollinator interaction
matrix, sorting rows and columns to maximize binary nestedness. This
sorting organizes plant species (top-to-bottom in rows) and pollinator
species (left-to-right in columns) from most to least generalist according
to their degree (number of partner species) such that generalist species
are packed into the top left corner of the matrix. Using this matrix
organization we created three matrices with cell values representing each
variable of temporal or spatial persistence: the number of years, the span
of days (phenophase, the maximum date minus the minimum date in which an
interaction was recorded), and the number of plots in which interactions
were recorded.