Environmental enhancement?

[Ian Sheldon]

Hi all,

Further to Norbert's last email on disturbance:

In 1992 I did some research on butterflies in the rainforests of Borneo and
looked into species diversity in different forest types, notably primary and
secondary forest. The area selected included riverine habitats, recent clear
cuts, young secondary forest, mature secondary forest and primary forest.
The diversity of habitats made it a haven for any lepidopterist. The thrill
of the chase was greatest in secondary forest and clearings. While
disturbance led to different species, the overall species mosaic would be
severely compromised if lepidopterists advocated clearcutting to increase
butterfly abundance! (An unlikely situation i admit.) Doesnt it, though,
become a question of ethics as to the right of existence of opportunists
relying on disturbance? I am not sure one can inflict "horrendous damage" on
species that rely on disturbance and that are being ousted by natural
selection. It is natural selection after all. While I like the idea of
sustaining populations of Apodemia mormo, I would not really welcome the
idea of inudstrialist's jumping on a diversity bandwagon, vouching that if
they make a mess here and there they might help the population of A. mormo
or some other species.

I have to say I really enjoyed butterfly watching in southern Saskatchewan
this year. In a roadside culvert close to the US border, alfalfa had taken
hold and was about the only healthy growth for miles and miles during the
drought. It became an oasis of such proportions that I have never seen such
butterfly density in North America before.

Here's to anticipating a summer of butterfly watching in culverts, clearcuts
and construction sites.

Ian Sheldon

----- Original Message -----
From: "Kondla, Norbert FOR:EX" <Norbert.Kondla at gems3.gov.bc.ca>
To: <fnkwp at aurora.alaska.edu>; <leps-l at lists.yale.edu>
Cc: "'altabugs'" <albertabugs at majordomo.srv.ualberta.ca>
Sent: Monday, January 14, 2002 3:03 PM
Subject: BUGS: RE: Environmental enhancement?


> Thanks to Ken for sharing these interesting examples of unplanned
> enhancement for butterflies. There are plenty more examples from around
the
> globe and I would be interested in more exmaples that others wish to share
> with the rest of us lepsters. Just one Yukon example that I observed in
> 1999. A roadside strip that had been bladed in the past and had developed
a
> completely unnatural very dense growth of Penstemon sp. This allowed the
> resident Euphydryas anicia helvia population to explode to amazing level.
A
> BC example has to do with an endangered species (ssp actually): Apodemia
> mormo is red listed in BC and the largest population owes its existence to
> the fact that a natural slope was reshaped by railroad construction many
> years ago. The resulting soil conditions allowed the Eriogonum niveum
plants
> to expand and multiply into a denser than normal stand. In turn this has
> allowed the Apodemia population to expand several orders of magnitude
above
> those under natural conditions.  Old airstrips and even areas near new
> airstrips, borrow pits from road construction etc  are great spots for
> butterflies and have been seen to result in unnatural densities of things
> like Pieris marginalis, Euchloe, Parnassius, Oeneis chryxus etc. The
reason
> is creation and/or maintenance of early seral habitats and proliferation
of
> the host plants of these butterflies. If we tried to "protect" everything
we
> would instead be doing horrendous damage to those species who are crowded
> out by natural succession and which need disturbance to survive. The
Euchloe
> do not care at all if a stand of Arabis is growing on a natural
disturbance
> or if it is there because a human on a bulldozer bared some soil.  All
> apparent environmental damage is not damage to all organisms; it simply
> provides a different environment which is then often used by different
> species.  There is no waste in nature; everything gets used by something.
>
> -----Original Message-----
> From: Kenelm Philip [mailto:fnkwp at aurora.alaska.edu]
> Sent: Monday, January 14, 2002 1:55 PM
> To: leps-l at lists.yale.edu
> Subject: Environmental enhancement?
>
>
>
> In the light of the current thread about environmental degradation
> and its severe impact on butterflies, I thought it might be of interest
> to bring up a couple of (minor) counter-examples in Alaska.
>
> 1) The roadside along the Haines Highway north of Haines, Alaska, is now
> lined with dandelions. According to the natives, these were unknown along
> the river valley in the old days. Judging by what I saw in May 1994, the
> roadside dandelions are acting as an excellent concentrating mechanism for
> the local butterflies, especially _Anthocharis sara_.
>
> 2) The gravel pad under the Aleska oil pipeline has, in some areas, become
> a good collecting site for certain species of butterflies. I first noticed
> this in 1979, near Galbraith Lake--the pipeline pad had a concentration of
> _Oeneis bore_ (which was widely distributed over the adjacent tussock
> tundra). In 1991, at a Dalton Highway site with the odd name of 'Oil Spill
> Hill', the pipeline gravel pad had been taken over with both grasses and
> legumes. The legumes had concentrated several species of _Colias_ that
> were more sparsely distributed over the Sagavanirktok River floodplain,
> and the grasses supported a dense population of _Oeneis bore_ and _O.
> excubitor_ (= _O. alpina_).
>
> This last summer I had the opportunity to check Oil Spill Hill
> for a second time. The legumes were no longer there, so there were no
> _Colias_--but the grasses were doing fine, and there were very high con-
> centrations of _Oeneis bore_ and _O. excubitor_. _O. excubitor_ was having
> a good summer (unlike many other butterfly species in 2001) on the North
> Slope, but at no other site did we find such a dense population as under
> the pipeline at Oil Spill Hill.
>
> 3) A number of small airstrips in eastern Alaska have produced good crops
> of legumes. These have not subsequently vanished, like the ones at Oil
> Spill Hill--possibly because the strips are regularly mowed. These strips
> have dense populations of _Colias krauthii kluanensis_ (or _C. christina
> kluanensis_ according to some), and also support other _Colias_ species.
>
> Note: I am not trying to defend environmental degradation! I have
> seen its effects, even up here. However, every once in a while something
> good occurs, at least from the viewpoint of lepidopterists.
>
> Ken Philip
> fnkwp at uaf.edu
>
>
>
>
>
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