RE: [beemonitoring] Quantifying Soil/Bee associations
In a non-scientific study, I borrowed help from the University of Washington’s geology department to analyze gathered Osmia lignaria mud from a variety of successful sources in a 2 hour radius around Seattle. Not surprising was that we found no gravel or beauty bark. We also found no large grains of sand.
When you look at the accompanying spreadsheet, there is a relatively narrow band of chosen “mud” by the bees. Although the mineral content was varied, the size of grain obtained by the bees was fairly common. The Raw Field samples were human excavated mud samples in a variety of sources. The two outlier Bee-Mud samples were from low nesting sites.
In looking at the ends of the tubes, we also noticed variation with how the mud was placed. It was either loosely placed on, or worked over diligently to hold the mud in place. Loosely place on = fairly moist, while smooth was probably from lower moisture soil. Sites that had too wet or too dry mud would presumably not allow the nesting bees to partition their chambers. We felt moisture content is important. Observations of O. lignaria tunneling to find their soil seems to back up our thoughts.
We believe that successful O. lignaria & O. cornifrons nesting must have adequate mud characteristics nearby as well as the right moisture content.
This spring we’ll be conducting a non-science experiment with 500 urban sources. 25% will be the control, 25% will have bee attractant that has recently been developed, 25% will have “correct mud” nearby with a source of variable moisture content, and the final 25% will have both bee attractant and the correct mud. The choice of sites will be random in this large radius. The results will be presented to the Orchard Bee Association for their use in the commercial pollination sector.
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A number of us have been involved in a project to inventory the bees of Badlands National Park in SW South Dakota. Over the past 2 years we have collected over 50,000 bee specimens from the Park and surrounds using standardized (and non-standardized) techniques. We will be evaluating a number of factors that could determine the distribution of species/communities in the park. Vegetation and soil GIS layers are available and very detailed for the Park. Park soils are extreme - varying from constantly eroding gumbo clay formed from past ash deposits ("Badlands") to deep sand associated with wind blown ancient dunes sitting atop buttes.
Clearly habitat and soil type are inter-twined and to some extent both partially determine the other. So, of interest would be to see under what circumstances soil or habitat associations account for more variation.
All that is well and good, but not having a background in soils we are a bit put off by all the possible available soil variables; including things like texture, parent material, organic matter, salinity, drainage class, depth to root restrictive layer, etc.
We would be interested in any one's thoughts on useful soil variable to use in these analyses. We could do a cluster analysis to find useful variables, but it seems like it would be more useful to have some a priori hypotheses about soil characteristics and test them directly.
Sam Droege sdroege@...
w 301-497-5840 h 301-390-7759 fax 301-497-5624
USGS Patuxent Wildlife Research Center
BARC-EAST, BLDG 308, RM 124 10300 Balt. Ave., Beltsville, MD 20705
I rose from marsh mud
I rose from marsh mud,
algae, equisetum, willows,
sweet green, noisy
birds and frogs
to see her wed in the rich
rich silence of the church,
the little white slave-girl
in her diamond fronds.
In aisle and arch
the satin secret collects.
United for life to serve
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Sam- certainly moisture at cell depth during the nesting season can be important…probably it is most directly gotten by sealed samples of dirt that you weigh, dry thoroughly, and reweigh (less trouble than a tensiometer, which is what I use for Nomia melanderi). If you chose to standardize these samples with a hollow corer, then you can get bulk density too. Texture it seems like you will have, which is good. Aspect and slope should matter, esp to a spring bee wanting early morning warm-up. What few studies sample for are attributes of sites that lack nesting bees (or else random samples) to give insights into the range of variables from which bees are choosing. Bill Stephen’s work (attached) laid the groundwork for understanding what the bee Nomia melanderi wants…it is admittedly quite the fussy bee. I also think that, if you get good at finding nests, then the surface right where they go under would be of interest, as I get the impression that ducking under the edge of a grass clump or pebble is preferred when available.
James H. Cane
USDA-ARS Bee Biology and Systematics Lab
Utah State University, Logan, UT 84322 USA
tel: 435-797-3879 FAX: 435-797-0461
web page: www.ars.usda.gov/npa/beelab
I just finished up my masters and my thesis work was on O. cornifrons.
I am working on getting that all published at this time. One article
is being reviewed for Psyche right now, and the other will be sent out
in a couple weeks.
Sam, sorry to get your post slightly off topic! I am very interested
in how soil parameters affect bee community structure. I think its an
understudied factor affecting bee diversity. The topic is, along with
questions about some other habitat parameters, one of the components
of my dissertation (which I am currently writing a proposal for). If I
manage to dig up any good papers on previous studies I will share them