[NatureNS] How is the wild food supply?

From: Christopher Majka <c.majka@ns.sympatico.ca>
To: naturens@chebucto.ns.ca
Date: Wed, 11 Nov 2009 10:14:41 -0400
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There are certainly very few berries around, and the berry pro

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Hi Eleanor,

On 11-Nov-09, at 9:07 AM, Eleanor Lindsay wrote:

> I think there are some very distinct regional differences in this =20
> year's wild food supply. The spruce bark beetle, which I understand =20=

> is native to Nova Scotia and normally kept in check by cold =20
> winters...) has created quite severe and rapid devastation in some =20
> parts of the province, in particular the east side of St Margarets =20
> Bay, (especially Seabright and Glen Margaret), where whole chunks of =20=

> spruce forest have died off in the space of the last 2-3 years and =20
> also, I believe in parts of Antigonish County and Cape Breton. So =20
> cones for squirrels, for example, must be severely reduced or non =20
> existent in these areas.

In North America the name "spruce bark beetle" is normally applied to =20=

Dendroctonus rufipennis, although in Europe, the name indicates =20
another species, Ips typographicus. Dendroctonus rufipennis is a =20
native species in Nova Scotia, indeed it occurs throughout North =20
America from Alaska to Newfoundland and south into the USA wherever =20
spruce grow. Although most of the recent attention on the relationship =20=

of climate change to bark beetle infestations has been devoted to the =20=

mountain pine beetle (Dendroctonus ponderosae), there are considerable =20=

similarities between the two species. There are two climate related =20
effects:

1) Prolonged cold temperatures during the winter can kill some of the =20=

overwintering beetles. As we experience climate change, and prolonged =20=

cold snaps in winter become less frequent, this bioregulation =20
mechanism becomes less effective. For example, studies in the southern =20=

United States on the similar southern pine beetle (Dendroctonus =20
frontalis) have linked outbreaks there to a warming trend from 1960 to =20=

2004 of 3.3=B0C in minimum winter air temperatures.

2) Spruce bark beetles normally complete their life cycles in either =20
one or two years (rarely three, in cold northern regions). As climate =20=

changes and temperatures warm, a greater proportion of beetles can =20
complete their life cycles in a shorter period of time, leading to =20
faster turnover and greater utilization of resources (i.e., they chew =20=

through spruce more quickly ;->).

In other bark beetles, for instance in the genus Ips, that are =20
sometimes univoltine (i.e., one generation per year), or bivoltine =20
(two generations per year), warming temperatures mean that a greater =20
proportion of the population becomes bivoltine, again with the same =20
consequences: population levels increase and they consume more food =20
(most bark beetles are cambium feeders, feeding on the inner bark of =20
trees).

The USDA Forest Service has a good web page on Dendroctonus rufipennis:

http://www.na.fs.fed.us/spfo/pubs/fidls/sprucebeetle/sprucebeetle.htm

Cheers!

Chris


Christopher Majka  <c.majka@ns.sympatico.ca> | Halifax, Nova Scotia, =20
Canada

* Research Associate: Nova Scotia Museum | =
http://museum.gov.ns.ca/mnh/research-asfr.htm
* Review Editor: The Coleopterists Bulletin | http://www.coleopsoc.org/
* Subject Editor: ZooKeys | =
http://pensoftonline.net/zookeys/index.php/journal/index
* Associate Editor: Journal of the Acadian Entomological Society | =
http://www.acadianes.org/journal.html
* Editor: Atlantic Canada Coleoptera | =
http://www.chebucto.ns.ca/Environment/NHR/atlantic_coleoptera.html

"Whenever I hear of the capture of rare beetles, I feel like an old =20
war-horse at the sound of a trumpet." - Charles Darwin


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<html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; ">Hi =
Eleanor,<div><br><div><div>On 11-Nov-09, at 9:07 AM, Eleanor Lindsay =
wrote:</div><br class=3D"Apple-interchange-newline"><blockquote =
type=3D"cite"><div>I think there are some very distinct regional =
differences in this year's wild food supply. The spruce bark beetle, =
which I understand is native to Nova Scotia and normally kept in check =
by cold winters...) has created quite severe and rapid devastation in =
some parts of the province, in particular the east side of St Margarets =
Bay, (especially Seabright and Glen Margaret), where whole chunks of =
spruce forest have died off in the space of the last 2-3 years and also, =
I believe in parts of Antigonish County and Cape Breton. So cones for =
squirrels, for example, must be severely reduced or non existent in =
these areas.<br></div></blockquote></div><br></div><div>In North America =
the name "spruce bark beetle" is normally applied to <i>Dendroctonus =
rufipennis</i>, although in Europe, the name indicates another species, =
<i>Ips typographicus</i>.&nbsp;<span class=3D"Apple-style-span" =
style=3D"font-style: italic; ">Dendroctonus rufipennis</span>&nbsp;is a =
native species in Nova Scotia, indeed it occurs throughout North America =
from Alaska to Newfoundland and south into the USA wherever spruce grow. =
Although most of the recent attention on the relationship of climate =
change to bark beetle infestations has been devoted to the mountain pine =
beetle (<i>Dendroctonus ponderosae</i>), there are considerable =
similarities between the two species. There are two climate related =
effects:</div><div><br></div><div>1) Prolonged cold temperatures during =
the winter can kill some of the overwintering beetles. As we experience =
climate change, and prolonged cold snaps in winter become less frequent, =
this bioregulation mechanism becomes less effective. For example, =
studies in the southern United States on the similar southern&nbsp;pine =
beetle (<i>Dendroctonus frontalis</i>) have linked outbreaks there =
to&nbsp;a warming trend from 1960 to 2004 of 3.3=B0C in minimum winter =
air temperatures.</div><div><br></div><div>2) Spruce bark beetles =
normally complete their life cycles in either one or two years (rarely =
three, in cold northern regions). As climate changes and temperatures =
warm, a greater proportion of beetles can complete their life cycles in =
a shorter period of time, leading to faster turnover and greater =
utilization of resources (i.e., they chew through spruce more quickly =
;-&gt;).&nbsp;</div><div><br></div><div>In other bark beetles, for =
instance in the genus <i>Ips</i>, that are s