Boosting Native Pollinator and Beneficial Insect Abundance from Spring to Fall Across Multiple Crops Using Water, Nesting, and Wildflower Enrichments.

Commodities

Practices

The U.S. food supply is endangered by declines in honeybees and a
lack of possible pollinators in the future.  Compounding the
problem is a loss of native pollinator habitat, global climate
change, pollution, and the need to boost production. 

The best alternative to honeybees is the native bees already
present in the environment [9-15,20].  With nearly 3500
species in North America alone, the diversity of different forms,
pollen-strategies, and behaviors of native bees provides a wide
range of use for agricultural operations. Relying on several
native bee species with varying behaviors and adaptations is a
solution to varying climate conditions resulting from global
climate change [19].

Past research suggests two main methods of boosting native bees
in agricultural areas: (a) providing nesting habitats and (b)
providing additional floral resources (particularly during
periods of low food availability).

Based on current studies of Eastern Central Georgia (e.g. coastal
plain areas with sandy well-drained soils), 3 main habitat
enrichments are: (1) season-long food supply, (2) water, and (3)
additional nesting areas need boosting.

The farm in this experiment grows blueberries and cucurbits
(cucumbers, watermelon, and pumpkins), allowing native bee
activity to be measured over the whole growing season. 
These crops provide a range of flowering times: blueberries
(March-April), cucumbers (June-July), watermelon (July), and
pumpkin (July-August). May will be a period of no crop flowers.

Habitat Enrichment Corridor

The first resource to be added to the habitat enrichment corridor
is a season-long food supply. Stocking the corridor with
different wildflower species will provide a season-long food
supply.  The most beneficial wildflower plants have been
identified as (1) Indian Blanket (Gaillardia pulchella)
(2) Black-eye Susan (Rudbeckia hirto), and (3) Swamp
Sunflower (Helianthus angustifolius). Several additional
wildflower plants will also be tested (e.g. tickseed, asters,
mints).

The second resource to be added is water.  Current climate
patterns in Central Georgia impacted by global climate change
indicate very hot summers with few days of rainfall.  The
lack of water may keep native bees from certain agricultural
areas. It should be noted that managed bees, like honeybees, are
provided with additional food and water resources at their hives
by their beekeepers.

The third resource to be added is nesting habitat. In the
Southeastern U.S. region, the most useful native bees are ground
nesting bees that could also nest in the wildflower corridors.
These ground nesting native bees include Southeastern Blueberry
Bees (Habropoda laboriosa), sweat bees (Genera:
Augochlorella, Halictus, Lasioglossum), and bumble bees
(Genus Bombus). Cavity nesting bees such as Mason Bees
(Genus Osmia) may play a role in early season
pollination, while leaf cutter bees (Genus Megachile)
may also play an important role in summer flowering crops. 
Bee houses with nesting tubes will be added to the corridors for
cavity nesting bees.

Studies have shown floral enhancements on the edges of orchards
and farms have had a significant effect in recruiting or bringing
in more native bees. Now, scientists need to explore what is
really going on in the wildflower patches during each major
period of the growing season.  Specifically, we need to know
what is going on during the (1) pre-bloom period, (2) bloom
period of the target crop, and the (3) post-bloom period/summer
dearth period (period of few floral resources).

The main purpose of the proposed study is to assess the habitat
enrichment corridors to boost native bee and beneficial wasps
over the whole agricultural season.  The results of the
proposed project will answer:

(1) Which wildflower species are the best at recruiting native
bees pre-bloom and during bloom of the blueberries?  (Spring
Period, March -April)

(2) Which wildflower species are the best at maintaining native
bees during post-bloom period (a time of no flowers)? (a time of
no flowers)?  (Early Summer, May)

(3) Which wildflower species best support bee populations during
bloom of cucurbits (cucumbers, squash, watermelon, and pumpkins)?
(Summer/Fall Period, June-September)

(4) Which wildflower species are the best at maintaining native
bees during post- bloom (a time of no flowers) of cucurbits?
(October)

These answers will assist in the development of an ideal
wildflower mix that will boost target native bee abundances by
providing the correct wildflower resources.  These resources
will both increase native bee pollination activities within the
farm during the current season and will promote greater offspring
production, leading to higher abundances of native bees in
subsequent seasons.

Each region of the U.S. varies in farming conditions, bloom
times, and variety of native bee species available for
pollination activities [20,21].  Regional studies such as
the proposed study are essential in gathering accurate
information on which wildflower species have the best native bee
recruitment characteristics.

Past research of Georgia’s native bees has focused on the
northern apple producing areas of Georgia.  This will be one
of the first studies of native bees in Eastern Central Georgia
(e.g. coastal plain area with sandy well-drained soils). 
Thus, the study’s results will also allow a comparison of native
bees’ seasonal diversities and abundances between native bees in
Northern Georgia (clay soils) versus Eastern Central Georgia
(sandy soils).

Other pollinators including pollinating flies, pollinating wasps,
and butterflies could benefit from the addition of pollinator
friendly habitats.  Current pollinator studies have
identified native beneficial wasp species present in central and
southern Georgia farms (personal observation). Specifically,
hairy flower wasps (Family Scoliidae) have been observed to occur
in large numbers at several different farms. 

This group of wasps has been identified as beneficial predators
of pest beetles and provide significant pollination of numerous
flowers [21]. Thus, this study will also study and survey wasps
in addition to the native bees.  It should be noted:
Scoliidae wasps are not often seen in the North Georgia (clay
soils) orchards and farms.

The proposed study plans to examine the following key questions:

• Do habitat enrichment corridors stocked with food, water, and
  nesting areas increase native bee abundance and diversity?
• Which wildflower species are best at recruiting different
  target native bee groups?
• Do habitat enrichment corridors stocked with food, water, and
  nesting areas increase other beneficial insects (e.g. hairy
  flower wasps)?

To measure the effectiveness of habitat enrichment corridors, we
will monitor native bees and beneficial insect abundance and
diversity from March to October. This study will be conducted at
Pinefield Eco Farm, located in Hephzibah, Georgia.  We have
gathered 2 years of baseline data on native bee abundance and
diversity at this farm.

On the farm, we will create six plots of blueberry bushes (3
control and 3 experimental) and six plots of cucurbits (3 control
and 3 experimental). Each experimental plot will have an adjacent
habitat enrichment corridor. 

Blueberry Plot (Blueberries flower March –
April)

The three blueberry “experimental” plots will consist of 5 rows
of blueberry bushes roughly 1500 ft² (50 x 30 feet)
with an adjacent habitat enrichment corridor roughly 400
ft² (50 ft x 8 ft). The three blueberry “control”
plots will have the same layout, but will lack the habitat
enrichment corridor.  The blueberry experiment and control
plots are separated by a small forest (more than 1000 feet
across).

Cucurbit Plots (cucumbers, squash, watermelon,
pumpkins) ( Cucurbits flower June-August)

The three cucurbit “experimental” plots will consist of 12 rows:
3 cucumber, 3 squash, 3 watermelon, and 3 pumpkin (roughly 1200
ft² (50 x 24 feet) with an adjacent habitat enrichment
corridor roughly 200 ft² (50 ft x 8 ft). The three
cucurbit “control” plots will have the same layout but will lack
the habitat enrichment corridor.  The blueberry experiment
plots and an additional open area will separate the cucurbit
control and experiments plots.

The Habitat Enrichment Corridor (Water, nesting, and
food enrichments)

The habitat enrichment corridor will be seeded with 20+
wildflower species.  The main wildflower species of interest
are: (1) Indian Blanket (Gaillardia pulchella) (2)
Black-eye Susan (Rudbeckia hirto), (3) Swamp Sunflower
(Helianthus angustifolius).  The goal is to have 3
or more wildflower species blooming in each of the seasons
(spring, summer, and fall).

In the center of each habitat enrichment corridor, a bee house
with 6 – 9 mm diameter natural reed clusters (300 reeds per
corridor) will be placed.  Spring bees (e.g. Mason Bees) and
Summer Bees (e.g. Leaf Cutter bees) will use this nesting
resource.  Nest boxes will be 4 feet above the ground on
poles. In October, we will assess which diameter size reed worked
best. 

In the center of the habitat, a bee watering station will be
placed next to the nest boxes. We will evaluate 3 types of
watering stations (Foxhound 1/2 gallon reservoir, Sunvara 8 oz
bee water feeder, and Zavhoz feeding bowl feeder). The 3 types of
watering stations will be zip tied to 2 stacked cinderblocks for
stability. 

Objective 1: Measure native bee and beneficial insect
abundance in blueberry and cucurbit plots during each of the 5
major periods of the growing season.

To gather the data needed to test this objective, we will use a
range of sampling methods proven to accurately sample native bee
abundance and diversity in North Georgia Apple Orchards, based on
a modified Bee Inventory Plot Design [11]. 

This project begins in April 2024.  However, we will perform
12 samples each year (March (x2), April (x2), May (x2), June
(x2), July (x1), August (x1), September (x1), and October (x1) in
each plot. Pre-Bloom Sampling (March),
Blueberry Bloom (April), and
Post-Bloom/Summer Floral Dearth (May) and
Summer Cucurbit Bloom (June, July, August) and
Post-Bloom (September, October).  

Each of the six plots will be passively sampled using a total of
6 sets of bowl traps (each set consists of 1 UV blue bowl, 1 UV
yellow bowl, and 1 white bowl), 2 vane traps, and 1 malaise trap.
In addition, active sampling will be performed by timed sweep
netting of 30 minutes in each plot.   

In each plot, the bowls will be laid out in an “X” formation from
the plot’s site corners. One vane trap will be placed on one side
of the plot and the other vane trap will be placed on the
opposite side of the plot. The malaise trap will be place on the
edge of the plot in the middle row. 

All bee samples collected will be stored in 95% ethanol and taken
back to Georgia Gwinnett College.  Professor Schlueter will
lead 10-12 GGC undergraduates in sorting the samples and
identifying the bees. (Most students are from underrepresented
groups - See Diversity, Equity and Inclusion grant section below)

Objective 2: Assess the success of each type of
enrichment in the habitat enrichment corridor.

Wildflower Assessment

We will assess the success of wildflowers by doing a bee
visitation count.  Each collection day students will perform
a 30-minute timed bee count on the wildflowers.  Students
will observe and record which species of wildflower had a bee
visiting it.  If possible, students will take a photograph
of the bee for later identification.

Nesting Assessment

Bee houses with 6 – 9 mm diameter natural reed clusters (300
reeds per enrichment corridor) will be placed in each plot. 
In October, we will assess which diameter size reed worked best
by measuring the reed diameter size of each reed and determining
if stem nesting bees used the reed for nesting.

Water Assessment

We will evaluate 3 types of watering stations (Foxhound
1/2-gallon reservoir, Sunvara 8 oz bee water feeder, and Zavhoz
feeding bowl feeder).  Students will observe and record
which water station had a bee visiting it.  If possible,
students will take a photograph of the bee for later
identification.

Objective 3: Determine which target bee species is
present on specific wildflowers in each of the major periods of
the growing season.

There are five major periods of concern: Pre-bloom, Bloom, and
Post-Bloom/Summer Dearth (Poor food availability in farms),
Summer Cucurbit Bloom (June, July, August) and
Post-Bloom (September, October).

Researchers use video cameras to monitor flowering wildflower
species. Video cameras will record each bee that lands on a
targeted wildflower species.  After performing the bee
visitation count (objective 2), students and researchers will
walk through the habitat enrichment corridor, attempting to
photograph and/or collect bees.  Collected bees will be
taken to GGC for identification.