Silent Spring Revisited

[Robert Thorn]

As an addendum to John Shuey's comments, I recently set up a honeybee
hive on a 350-acre preserve of mixed forest and fields run by Denison
University in central Ohio.  Since it was important for me to assess if
any other wild hives were present (as we wanted to be sure that any
honeybees we caught were from our hive), I intensively surveyed the
preserve for a year before putting in the hive.  Not a honeybee was
found, but there were many native bees.  We've continued our survey for
the past 2 years after the hive was put in, and have noticed a modest
drop-off of several larger pollinators like a few kinds of Bumblebees
and some solitary Anthophorid bees. Smaller bees seem unaffected.  A
concurrent butterfly survey has failed to show any drop-off of
butterflies so far, but that's being run by another faculty member and I
don't know the specifics yet.  It appears that there has been no shift
in forb abundance in those 3 years (although we don't have quantitative
data on this) so honeybees and native pollinators may be
interchangeable.

As a caveat, though, this site has a good mix of native habitats that
can support the various nesting & feeding preferences of a wide array of
native pollinators.  Before coming to Denison, I worked in a much more
typical agricultural setting - the Waterman farms complex of Ohio State
University.  While I don't have hard data, it would still be a solid
conclusion that native pollinators were lacking there.  Only a few of
the most hardy bees - some small halictids, the alfalfa leafcutter bee,
and the 2 most cosmopolitan bumblebees (Bombus fervidus & B. impatiens)
- were ever much in evidence, and never in very large numbers. The
butterfly fauna wa also very depauperate. Honeybees, though, were common
due to the presence of a large beeyard.  This farm is managed using the
'clean farming' techniques common to many midwestern farms.  This is a
euphemism for eliminating hedgerows and edges as well as controlling
'weed' buildup with regular large applications of broad-spectrum
herbicides.  The likely inferred lesson is that if you remove the native
habitat, you remove the native pollinators.

Rob Thorn