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Plant and pollinator interactions from British Columbia from Oak Savannah, Shrub-Steppe, and restored hedgerows

Citation

Guzman, Laura Melissa; Chamberlain, Scott; Elle, Elizabeth (2022), Plant and pollinator interactions from British Columbia from Oak Savannah, Shrub-Steppe, and restored hedgerows, Dryad, Dataset, https://doi.org/10.5061/dryad.c59zw3r7t

Abstract

This dataset contains the data analyzed in "Guzman, L.M., Chamberlain, S. and Elle, E. (2021) Network robustness and structure depends on the phenological characteristics of plants and pollinators. Ecology and Evolution"

The data comprises plant-pollinator interactions collected in three ecosystems (Oak Savannah, Shrub-Steppe and restored hedgerows) from British Columbia. These three vegetation types comprised three different studies. The average distance between sites within studies was 19km, 18km and 29km for the oak savannah, shrub-steppe and hedgerows respectively. For simplicity we use “pollinator” throughout this paper to refer to insects and hummingbirds observed visiting flowers and contacting reproductive organs, although their effectiveness at transfer of pollen has not been assessed.  The networks were comprised largely of bees, with wasps and hoverflies also common.  Less common were butterflies and beetles.  The plants were largely forbs with some shrubs;  insect-pollinated trees were not sampled for largely logistical reasons of tree height but tended to be uncommon in these ecosystems.

Methods

A total of 33 mutualistic plant-pollinator networks were studied in British Columbia, Canada: oak savannah (12 networks), shrub-steppe (8 networks), and restored hedgerows (13 networks). 

Data were collected for two of three vegetation types using the plot method, and for the third using the transect method. Plots are generally more appropriate when the plant species in the community are very patchily distributed (Gibson et al. 2011), as they were in these regions. The plot method focuses on individual plant species, observing each plant species for an equal amount of time. For oak savannah sites (within the Coastal Douglas Fir biogeoclimatic zone), we collected data on species interactions in 1-ha plots at each of six sites in both 2009 and 2010, resulting in 12 networks. Each plot was surveyed about every 7-10 days, 10-12 times per season between late April and early July, the majority of the flowering period. Over the flowering period we attempted to visit sites morning, midday, and afternoon on different survey dates to reduce bias due to flight time differences among visiting insects. During each survey date, each plant species in flower was observed for a 10 min period by each of two surveyors, on haphazard walks throughout the plot.  All flower visitors were collected and identified to the lowest taxonomic level possible. For the eight shrub-steppe sites (in the Bunchgrass biogeoclimatic zone), data were collected as for oak-savannah sites, but surveys were from the beginning of April through the end of July, 2010, for a total of 12 samples per site.  These sites were only sampled in one year (2010) and resulted in 8 networks. 

For the restored hedgerows sites, data were collected using a “transect” method, in which the plants along the transect were observed for a set amount of time, with time observed per plant species varying among species depending on their occurrence in the transect. Transects are more appropriate when plants are not clumped, but are widely scattered throughout a study site (Gibson et al. 2011), and in this case most of the restorations (within the coastal Western Hemlock biogeoclimatic zone) were linear, making transects efficient. Sampling was equal across all 13 sites, occurring approximately every 2 weeks, for a total of 9 samples between late April and the end of August, 2013. Hedgerow sampling resulted in 13 networks from 13 sites where each network was comprised of 9 samples. The transect was walked for 15 minutes by each of two observers during each sample date, and each site was again observed equally during morning, midday, and afternoon on different sample dates. Once again, all flower visitors were collected and identified to the lowest taxonomic level possible.

Usage Notes

The readme file contains information about the different columns found in the data. 

Funding