Environmental enhancement?

[Kondla, Norbert FOR:EX]

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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