1. Wild Bee Abundance and Diversity in Relation to Landscapes
Surrounding Iowa Vegetable Farms
Jarrett Jensen, Andrew Ridgway, Ai Wen, and Kenneth Elgersma
Department of Biology, University of Northern Iowa
Acknowledgements
I would like to thank Ben Nettleton for helping collect all of the data and identifying many,
many bees.
This material is based upon work supported in part by the National Science Foundation
Grant Number EPSC-1101284. Any opinions, findings, and conclusions or recommendations
expressed in this material are those of the author(s) and do not necessarily reflect the views
of the National Science Foundation."
References
1. Andersson et al 2013 Landscape Heterogeneity and farming practice alter the species
composition and taxonomic breadth of pollinator communities
Methods
Catching the Bees
 Set up pan traps on
the farm
 Put colored cups into the pan traps and filled with soapy water
 Sweep netted for 20 minutes on the farm
 Came back to the farm in 24 hours to collect the cups from the pan
traps
*Repeated this process every 2 weeks
Processing the Bees
 Removed the bees from the cups and washed with water and ethanol
 Dried the bees
 Pinned the bees
 Identified the bees
GIS/GPS
 Mapped out each farm using GIS program
 Used GPS to define landscape features on the farm
 Used GIS program to calculate landscape percentages both within
the farm boundary, and within a 1-km radius of the farm (the
approximate foraging distance of large bees)
Conclusions
 Higher amounts of on-farm natural landscape favors
higher abundance
 Bee abundance is not as tightly correlated with the
surrounding landscape as it is with on-farm landscape
 High bee abundance and diversity is still possible with
low natural landscape surrounding the farms.
 More natural landscape on or surrounding the farm
favors higher diversity of bees
 The types of bees found varied significantly from farm to
farm, with some farms (3,4,5,7, & 8) being dominated by
very distinct types of bees.
Introduction
Iowa vegetable farmers rely heavily on insect pollinators such as bees and butterflies to produce crop on their farms. Wild bees provide free pollination, but as the
abundance and diversity of wild bees is declining, farmers are looking for ways to promote wild bees. Bees are affected by the different types of landscapes on and
around vegetable farms, which can include corn and soybean fields, ponds, woodlands, wetlands, buildings, vegetable plots, and natural habitat. Because both the
surrounding and on-farm landscapes could play major roles in the wild bee abundance and diversity, we investigated the impact of landscape factors on bee
abundance and diversity at vegetable farms in central and eastern Iowa.
Farm 1
Farm 2
Farm 3
Farm 4
Farm 5
Farm 6
Farm 7 Farm 8
Farm 9
Farm 10
0
50
100
150
200
250
0 10 20 30 40 50 60 70 80 90 100
TotalNumberofBees
Percent of Natural Landscape on Farm
Total Number of Bees vs. Percent of Natural
Landscape on the Farm
Farm 1
Farm 2
Farm 3
Farm 4
Farm 5
Farm 6
Farm 7 Farm 8
Farm 9
Farm 10
0
50
100
150
200
250
0 5 10 15 20 25 30 35 40 45
TotalNumberofBees
Percent of Natural Landscape Surrounding Farm
Total Number of Bees vs. Percent of Natural
Landscape Surrounding Farm
Results
50 10 15 20 25 30 35 40 45
0
50
100
150
200
250
0
50
100
150
200
250
10 20 30 40 50 60 70 80 90 100