Response of Bees to Wildfire:
Rockin’ the Shock Phase
Byron Love
Utah State University
USDA ARS Pollinating Insect Research Unit
Photo: Mark Rabdau, 2009
Fire as an Ecosystem Process
Influences plant & animal communities
Resets succession trajectories
Effects of Fire on Natural Systems
Direct mortality due to combustion
Indirect loss of shelter and resources
Temporal Influences of Fire
Acute Phase few hours or days
Shock Phase few months to < 1 year
Recovery Phase 1 to 10 years
Acute Phase: Ignition, Combustion, Pyrolysis
Direct effect through exposure to lethal temperatures
Risk factors:
Fire dynamics
Life stage (adult or immature)
Nesting strategy
Above-ground = high risk
Below-ground = lower risk
(Cane & Neff, 2011)
Photo: Mark Rabdau, 2009
Temporal Influences of Fire
Acute Phase few hours or days
Shock Phase few months to < 1 year
Recovery Phase 1 to 10 years
Indirect effects on bees
Loss of nesting materials
Changes in plant community
Bee community recovers rapidly
Temporal Influences of Fire
Acute Phase few hours or days
Shock Phase few months to < 1 year
Recovery Phase 1 to 10 years
Indirect effect
through removal of
nesting, pollen and
nectar resources
Effects are dependent
on seasonality
Long Butte Fire
21 August, 2010
123,881 hectares (478 sq. miles)
Ready-made transects of Helianthus annuus
Hypothesis:
Bee density, abundance, and species richness will be lower
in the burned habitat compared with adjacent unburned
habitat
Methods
Bee Density Surveys on Helianthus annuus
Measure of pollination service
10 surveys in the burn, 4 outside the perimeter (control)
Pan Trapping
Provides bee abundance and richness
10 colored bowls per 100 meter transect
4 transects in the burn, 4 outside
Traps were open for 4-6 hours
Sampling Over 4 day period, September 3-14, 2010
Min distance to edge = 5 miles
Pan traps
Surveys
Bee Density/100
flowerheads (average + se)
Bee Abundance
(average + se)
Species Richness
(average + se)
Burn
Unburned
(n = 10)
(n = 4)
25 + 11
27 + 4
108
151
(27.0 + 10.5) (37.8 + 6.9)
22
(6.0 + 0.6)
25
(8.6 + 1.1)
P = 0.68
P = 0.42
P = 0.02
Species
Intact
Agapostemon (Agapostemon) angelicus/texanus
32
Agapostemon (Agapostemon) femoratus
0
Agapostemon (Agapostemon) virescens
10
Andrena sp.
0
Anthophora (Heliophila) flexipes
1
Anthophora (Heliophila) petrophila
1
Anthophora (Mystacanthophora) urbana
1
Bombus (Pyrobombus) huntii
1
Bombus (Separatobombus) griseocollis
3
Diadasia enavata
12
Dianthidium (Dianthidium) curvatum
26
Dianthidium (Dianthidium) pudicum
0
Dufourea marginata
0
Halictus (Halictus) ligatus
1
Halictus (Seladonia) tripartitus
9
Lasioglossum (Dialictus) incompletum
13
Lasioglossum (Dialictus) sp.
62
Megachile sp.
1
Megachile (Argyropile) parallela
8
Megachile (Litomegachile) sp.
2
Melissodes sp.
12
Melissodes (Callimelissodes) lupina
2
Melissodes (Eumelissodes) agilis
13
Melissodes (Eumelissodes) bimatris
0
Melissodes (Eumelissodes) grindeliae
4
Melissodes (Eumelissodes) microsticta
12
Perdita sp.
13
Sphecodes sp.
1
Svastra (Epimelissodes) obliqua
2
Triepeolus sp.
1
Xeromelecta (Melectomorpha) californica
0
Burn
77
1
16
3
0
2
3
0
0
12
3
1
10
0
4
20
53
0
1
0
8
0
82
2
48
1
9
0
0
10
1
Long Butte fire bee species list
Species
Intact
Agapostemon (Agapostemon) angelicus/texanus
32
Agapostemon (Agapostemon) femoratus
0
Agapostemon (Agapostemon) virescens
10
Andrena sp.
0
Anthophora (Heliophila) flexipes
1
Anthophora (Heliophila) petrophila
1
Anthophora (Mystacanthophora) urbana
1
Bombus (Pyrobombus) huntii
1
Bombus (Separatobombus) griseocollis
3
Diadasia enavata
12
Dianthidium (Dianthidium) curvatum
26
Dianthidium (Dianthidium) pudicum
0
Dufourea marginata
0
Halictus (Halictus) ligatus
1
Halictus (Seladonia) tripartitus
9
Lasioglossum (Dialictus) incompletum
13
Lasioglossum (Dialictus) sp.
62
Megachile sp.
1
Megachile (Argyropile) parallela
8
Megachile (Litomegachile) sp.
2
Melissodes sp.
12
Melissodes (Callimelissodes) lupina
2
Melissodes (Eumelissodes) agilis
13
Melissodes (Eumelissodes) bimatris
0
Melissodes (Eumelissodes) grindeliae
4
Melissodes (Eumelissodes) microsticta
12
Perdita sp.
13
Sphecodes sp.
1
Svastra (Epimelissodes) obliqua
2
Triepeolus sp.
1
Xeromelecta (Melectomorpha) californica
0
Burn
77
1
16
3
0
2
3
0
0
12
3
1
10
0
4
20
53
0
1
0
8
0
82
2
48
1
9
0
0
10
1
Long Butte fire bee species list
Agapostemon & Melissodes
Deep ground nesters (>>5cm)
Species
Intact
Agapostemon (Agapostemon) angelicus/texanus
32
Agapostemon (Agapostemon) femoratus
0
Agapostemon (Agapostemon) virescens
10
Andrena sp.
0
Anthophora (Heliophila) flexipes
1
Anthophora (Heliophila) petrophila
1
Anthophora (Mystacanthophora) urbana
1
Bombus (Pyrobombus) huntii
1
Bombus (Separatobombus) griseocollis
3
Diadasia enavata
12
Dianthidium (Dianthidium) curvatum
26
Dianthidium (Dianthidium) pudicum
0
Dufourea marginata
0
Halictus (Halictus) ligatus
1
Halictus (Seladonia) tripartitus
9
Lasioglossum (Dialictus) incompletum
13
Lasioglossum (Dialictus) sp.
62
Megachile sp.
1
Megachile (Argyropile) parallela
8
Megachile (Litomegachile) sp.
2
Melissodes sp.
12
Melissodes (Callimelissodes) lupina
2
Melissodes (Eumelissodes) agilis
13
Melissodes (Eumelissodes) bimatris
0
Melissodes (Eumelissodes) grindeliae
4
Melissodes (Eumelissodes) microsticta
12
Perdita sp.
13
Sphecodes sp.
1
Svastra (Epimelissodes) obliqua
2
Triepeolus sp.
1
Xeromelecta (Melectomorpha) californica
0
Burn
77
1
16
3
0
2
3
0
0
12
3
1
10
0
4
20
53
0
1
0
8
0
82
2
48
1
9
0
0
10
1
Dianthidium
Surface nesters
•Megachile parallela
Shallow ground nester (2cm)
Conclusions
Adult bees survived the Acute
Phase of wildfire
Bee abundance during Shock
Phase may be related to
presence of unburned floral
resources
Bee richness decreased during
the Shock Phase
Ground nesting species were
favored over surface and
shallow nesting species
Response of Perennial Forbs to Fire
Surviving bees require suitable bloom in the 1st post fire year
Literature focuses on the response of populations and
communities
Response of individuals is not well known
Let’s burn stuff and see what happens!
Treatment Variables
Plant characteristics
Heating regimes
Seasonality
Response Variables
Productivity
Reproduction
Comments and Suggestions PLEASE!
byron.love@ars.usda.gov
Acknowledgements:
Jim Cane, USDA ARS, Logan, Utah
Nancy Shaw, USDA USFS, Boise, Idaho
Seth Naftziger, USDA ARS, Logan, Utah