3. The question: do early-season fires negatively impact
solitary native bees that nest aboveground?
■ Upland longleaf pine forests are fire-dependent ecosystems; prescribed burning is a
necessary tool for biodiversity management and wildfire prevention
■ Prescribed burning is implemented based on conservation priorities. Sandy Hollow
WMA conservation priority is quail, gopher tortoise.
■ How do these burn regimes impact non-target organisms?
■ Trap nesting bees have sensitive ecologies, require a balance between floral resources
and nesting materials
■ Fire may increase floral diversity depending on frequency, but may reduce or eliminate
suitable nesting materials
■ At what scale and burn frequencies are negative impacts on seen?
4. Native bees as a
conservation
priority
Increased interest in pollinators, USDA
initiatives
Louisiana Department ofWildlife and Fisheries
has no invertebrate conservation plan
Pollinators, particularly native bees, would be
a great candidate because of popular interest
Important in natural and agricultural
ecosystems
5. Introduction to longleaf pine ecosystems
Longleaf pine dominates canopy, wiregrass and forbs in the understory, very high plant diversity with over
300 rare and endangered plant species, over 1000 total species
1-3 year burn frequency
Declining ecosystems in the southeast, approximately 3% of historic range mostly in managed tracts
6. Burn mosaics
Mosaic complexity: frequency, intensity, burn
extent, season, multiple scales
Prescribed for: habitat type, conservation goals
Can also apply to natural fire regimes, wildfire,
but typically burn mosaics (pyrodiversity) are a
management goal; programs well-developed
especially in Australia, South Africa (Parr and
Andersen 2006)
Need empirical support to reduce detrimental
impacts (fragmentation)
MODIS imagery, landscape level burn scars
7. Fire as a management tool
Shrubby understory, less frequent burn, rapid
recovery from fire
Grassy understory from frequent burning
Local scale heterogeneity, woody vegetation density, intensity variation, local burn history
8. Variability in size and material attract
different species
Megachilids nest in woody stems Completed nest plugs
9. Trap nesting
bees
Trap nests are simple to construct
Attract solitary native bees that nest
aboveground in hollow stems, 15-20 species
can be collected with just 20 traps (Tscharntke
1998)
Provide community data; habitat complexity
and community stability (Ebeling et. al 2012)
• Brood cell density (abundance)
• Brood parasitism (trophic interactions)
10. Nest
construction
Taxonomy can be determined by nest plug
composition, brood cell construction
Different species have different flight
windows and nesting seasons – early, mid,
late; univoltine, bivoltine, multivoltine
Brood parasites (cleptoparasites) invade
brood cells and lay eggs; steal provisions,
some obligate parasites; host-specific
11. Brood Cells
Example brood cells, linear arrangement,
lengthwise in hollow stem, Osmia lignaria
(Blue Orchard Bees)
Abundance can be determined by counting
brood cells, survival (emerged adults)
Parasitism identified by dissecting nests;
parasitism rates (around 13% - Ebeling et. al
2012)
13. Sampling
Objectives,
Methods
■ Transects measured 50m, 200m, and 350m
from comparison sites (burn v. unburned)
or
■ % completely burned within 300m radius
■ 6 replicates at each distance (or %), 18 traps
per burned site, 18 traps unburned
■ Include pitfall sampling for different invert
community data (ground dwelling
arthropods) and blue vane trapping for
earlier data; adult, non-Apis bees
Solitary bee foraging distance
from nest approx. 300m
Community abundance,
similarity comparisons between
burned, unburned sites along a
gradient
16. ProjectTimeline
■ December – February
2016- Materials set up,
identify sampling sites
■ February 2016- Set up
trap nests, blue vane
traps and pitfall traps to
begin collecting
specimens.
■ November, 2016- Remove all
traps from the field.
■ Feb, 2017 – Anticipated
emergence of trap nesting bees
into emergence chambers.
■ March-June 2017- Data analysis
and reporting.
February 2016 to
November 2016-
Trapping (see table). Sort
collected specimens
according to species.
Week 1 Week 2 Week 3 Week 4 Week 5 Week 6…
Trap nests Monitor - - Monitor - -
Pitfall Set Collect - Set Collect -
Blue vane Set Collect - set Collect -
Table 1 - Example collection timeframe for three trap types over a 6 week period. Pitfall and blue vane traps are set at the beginning of Weeks 1 and 4. The
traps will be collected at the beginning of Weeks 2 and 5. Over this 6 week time period, there will be two 7-day collection periods, which will continue on
this schedule from week 7 through the end of the project. Trap nests will be monitored every 3 weeks for nesting activity or disturbance.
17. References
Ebeling A, KleinA-M, WeisserWW,TscharntkeT (2012) Multitrophic effects of experimental changes
in plant diversity on cavity-nesting bees, wasps, and their parasitoids. Oecologia 169:453–465. doi:
10.1007/s00442-011-2205-8
Parr CL, Andersen AN (2006) Patch Mosaic Burning for BiodiversityConservation: a Critique of the
Pyrodiversity Paradigm. Conserv Biol 20:1610–1619. doi: 10.1111/j.1523-1739.2006.00492.x
TscharntkeT, Gathmann A, Steffan-Dewenter I (1998) Bioindication using trap-nesting bees and
wasps and their natural enemies: community structure and interactions. J Appl Ecol 35:708–719. doi:
10.1046/j.1365-2664.1998.355343.x
