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Hi Steve &All, Dec 11, 2015
Thanks for the links. These bring out another key element; habitat loss
and I would hope they include habitat degradation under this banner. This is
fundamental; halve the habitat and you halve the numbers. And they also
relate to decline in number of individuals which will tend to be weighted in
terms of the more abundant insects.
The decline in numbers of species is a different matter entirely and,
true enough, if species which have never been named go extinct then their
loss can not be detected. But protection of habitat would slow or halt any
decline which is beyond the normal rate so this seems to me a pointless
exercise when the job at hand should be to slow or reverse effective habitat
loss.
And this gives me an opportunity to briefly get up on a soapbox. This
rapid decline has been under way for 70 years at the very least but anyone
who owns a house with more than a tiny lawn can, if they so chose, act to
provide/enhance insect habitat on the land area over which they have
control; mainly by not destroying potential habitat. Examples include; mow
narrow paths with a bush scythe, let the rest flower and go the seed before
scythe mowing, encourage a diversity of broad-leaved weeds, use a rotary
mower mostly to grind leaves so they don't blow away and reduce brush to
chips, compost most or all food waste and all 'yard waste', turning compost
piles can become a chore so don't worry because invertebrates, molds, slime
molds and fleshy fungi will take care of that in their own good time, use no
herbicides and no insecticides other than carefully directed materials such
as soapy water or Rotenone on diatomaceous earth.
End of sermon,
Yt, Dave Webster, Kentville
----- Original Message -----
From: "Stephen Shaw" <srshaw@Dal.Ca>
To: <naturens@chebucto.ns.ca>
Sent: Thursday, December 10, 2015 12:07 AM
Subject: RE: [NatureNS] Insect decline
> Hi Dave, others,
> Haven't read it but was somewhat surprised as there are various guesses at
> the number of insects out there, estimated to account for >90% of all
> metazoan species (that is, not including unicells, bacteria etc). That's
> perhaps ~10 million insect species worldwide but only ~1 million so far
> described, so who is able to say anything concrete given the missing 9
> million, or is even surveying the known 1 million? Seemingly done by
> selective sampling: a serious survey in the journal 'Science' in 2014 did
> conclude there has been about a 45% reduction in invertebrate numbers in
> the last 30 years, inversely mirroring the doubling of the human
> population. You can read a bit for free from the publicity dept of the
> last scientist author, of University College London:
> https://www.ucl.ac.uk/news/news-articles/0714/240714_invertebrate-numbers
> which links to the original journal article in Science
> http://www.sciencemag.org/content/345/6195/401
> where you can at least read the paper's Abstract.
> Steve (Hfx)
> ________________________________________
> From: naturens-owner@chebucto.ns.ca [naturens-owner@chebucto.ns.ca] on
> behalf of David & Alison Webster [dwebster@glinx.com]
> Sent: Wednesday, December 9, 2015 7:09 PM
> To: NatureNS@chebucto.ns.ca
> Subject: [NatureNS] Insect decline
>
> Dear All, Dec 9, 2015
> There is an article about declining populations of insects in the Dec.
> 2015 (Wildlife Issue) of Canadian Geographic. The article has an author
> (Leslie Anthony) but oddly enough no title.
> There are many vectors at play, and most are not mentioned, but the
> effect of highway fatalities receives considerable emphasis. And the
> figures
> quoted are based on bodies recovered; consequently a huge underestimate. I
> suspect many are ruptured by abrupt pressure changes, flattened on impact
> or
> swirled beyond the road margin.
>
> Yours truly, Dave Webster, Kentville
>
>
> -----
> No virus found in this message.
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