[Pollinator] Wisconsin Department of Natural Resources to track declining bumble bees

Thu Feb 5 12:51:46 PST 2009

Dear all:

I am glad to see this helpful and timely support for bumble bee
conservation by the Wisconsin DNR.

I have one concern, not about this press release in particular, which is
excellent, but about discussion of bumble bee declines in general.
Specifically, I do not think it is helpful to invoke habitat loss and
pesticide use as an important cause of Bombus (Bombus) declines.
Mentioning these factors may seem appropriate as a matter of fairness or
completeness, because they might plausibly contribute to any bee declines,
but in my opinion the available evidence argues against their relevance in
this case.

Most significantly, the timing of abrupt continental-scale declines in
Bombus (Bombus) and of their Bombus (Psithyrus) social parasites (likely
at least as threatened as their hosts) does not correspond to any
documented changes in habitat or pesticide use, and the lack of any known
correspondence with these factors is one of the most salient features of
these declines. Many and perhaps most bumble bee species belonging to
other subgenera such as Pyrobombus remain generally abundant, and Bombus
(Bombus) and their B. (Psithyrus) parasites also remained numerous until
the  mid-late 1990s, despite massive changes in habitat and pesticide use
across the continent during the 1940s-1990s and before. If a pesticide
were involved, why should this have differentially harmed Bombus (Bombus)
and not other related bumble bee subgenera such as Bombus (Pyrobombus)?

Invoking general causes potentially relevant to declines in any bee taxa
does not help to correctly identify the precise biological and
sociological reasons why Bombus (Bombus) declined abruptly and drastically
whereas most other bee taxa remained numerous in the same habitats with
presumably the same or similar pesticide exposures. Whatever the relevant
causes, they are definitely particular to Bombus (Bombus) and do not apply
to other bumble bee subgenera such as Pyrobombus. In addition to being
taxon-specific, the relevant causes must date precisely to the mid 1990s.

Inclusion of imprecise and irrelevant causes when discussing the Bombus
(Bombus) and B. (Psithyrus) declines of greatest concern only helps to
diffuse what should be a sharply focused effort to identify the true
causes and responsible parties and to prevent future declines of this
sort.

Loss of nesting habitat and floral resources is plausible as a primary
cause of large-scale declines in certain bumble bee species such as B.
pensylvanicus and their parasite B. variabilis, but declines in these
species seem to have begun long before the mid-1990s and do not correspond
in timing or extent with those of Bombus (Bombus) and B. (Psithyrus).

In my opinion it is best to discuss events believed to be causally
unrelated separately, even if this may require us to contend with
burdensome concepts such as bumble bee subgenera.

John

>    Email not displaying correctly? View it in your
> browser.<http://www.xerces.org/press-releases/wisconsin_bumble_bees.html>
>   <http://www.xerces.org/press-releases/wisconsin_bumble_bees.html>
> <http://www.xerces.org/press-releases/wisconsin_bumble_bees.html>
>
> For Immediate Release
> February 4, 2009
>
> Contacts:
> *Eric Mader*, National Pollinator Outreach Coordinator, The Xerces Society;
> (608) 628-4951
> *Bill Smith*, Natural Heritage Inventory Program Zoologist, WI DNR;
(608)
> 266-0924
>
> WISCONSIN DEPARTMENT OF NATURAL RESOURCES
>
> TO TRACK DECLINING BUMBLE BEES
>
> Madison, WI: Two of Wisconsin's bumble bees have been added to the
Wisconsin
> Department of Natural Resources' Special Concern List.
>
> This action, a response to dramatically declining populations of the
yellowbanded bumble bee (*Bombus terricola*) and the rusty-patched
bumble
> bee (*Bombus affinis*), will result in official monitoring of both
species
> through the DNR's Natural Heritage Inventory database. Field biologists
will
> now start keeping records of when and where these species are found.
Over
> time, this database will provide a picture of the bees' abundance and
distribution in the state.
>
> "This is a very significant step", said Eric Mader, National Pollinator
Outreach Coordinator for the Xerces Society. "The Department of Natural
Resources has taken the first step in protecting these species."
>
> Both species were once among the most common of state's bumble bees
prior
> to
> the late 1990's. In a 1995 survey, over 90% of all bumble bees collected in
> the northern part of the state were the yellowbanded bumble bee.  Recent
surveys have found that the yellowbanded and rusty-patched bumble bees
represent less than 1% of all bumble bees observed in the region.
>
> "This is really a very dramatic decline", said Sarina Jepsen, Endangered
Species Coordinator for the Xerces Society and co-author of a recent
status
> review of the species. "The two bumble bees have declined across the
eastern
> U.S. and a closely related species, the western bumble bee is
experiencing
> similar declines on the west coast."
>
> This decline is especially alarming because bumble bees are important
pollinators of many native plants, as well as some of the state's
high-value
> agricultural crops, including cranberries. Several studies have shown
that
> on a bee-for-bee basis bumble bees are several times more efficient than
honey bees for some crops.
>
> The exact reason for the decline of these species is unclear. The
leading
> theory is that one or more European bumble bee diseases were introduced
to
> North America during efforts by a European company to rear American
bumble
> bees for managed crop pollination in their European facility. However,
habitat loss as well as pesticide use are likely contributing factors.
The
> decline of these bumble bees does not appear directly related to similar
highly publicized declines of the non-native European honey bee
> (*Apis**mellifera
> *).
>
> In 2007 and 2008, isolated populations of the yellowbanded bumble bee
were
> found around the towns of Mountain, Manitowish Waters, and Two Rivers in
northeastern Wisconsin. There is also a 2007 report from the
UW-Milwaukee
> Cedarburg Bog Field Station, in Ozaukee Co. These populations represent the
> only remaining known yellow-banded bumble bees in the Midwest. While the
rusty-patched bumble bee has not been documented in the state in recent
years, some individuals have been found in isolated areas of Illinois.
>
> The Status Review of Three Formerly Common Species of Bumble Bee in the
Subgenus
> Bombus<http://www.xerces.org/wp-content/uploads/2008/12/xerces_2008_bombus_status_review.pdf>documents
the decline of these two species throughout their native ranges in the
eastern U.S. It also includes information on the decline of the western
> bumble bee in the western U.S.
>
> Download the report or read more about declining bumble
> bees<http://www.xerces.org/bumblebees/>
>  <http://www.xerces.org/bumblebees/>Read about the rusty-patched
> bumble bee<http://www.xerces.org/rusty-patched-bumble-bee/>
>  <http://www.xerces.org/bumblebees/>Read about the yellowbanded bumble
> bee<http://www.xerces.org/yellow-banded-bumble-bee/>
>
> PHOTO CREDIT
> The rusty-patched bumble bee (*Bombus affinis*) by Johanna James-Heinz
>
> ###
>
> The Xerces Society • 4828 SE Hawthorne Blvd. Portland, Oregon 97215 USA
•
> tel 503.232.6639
>
> join <http://www.xerces.org/join/> • give <http://www.xerces.org/give/>
•
> contact <http://www.xerces.org/contact-us/> <info at xerces.org> •
> unsubscribe<http://www.xerces.org/newsletter-optout/>
>
> Copyright (C) 2008 The Xerces Society. All rights reserved.
> _______________________________________________
> Pollinator mailing list
> Pollinator at lists.sonic.net
> http://lists.sonic.net/mailman/listinfo/pollinator
>

-- 
John S. Ascher, Ph.D.
Bee Database Project Manager
Division of Invertebrate Zoology
American Museum of Natural History
Central Park West @ 79th St.
New York, NY 10024-5192
work phone: 212-496-3447
mobile phone: 917-407-0378