Environmental enhancement?

[Kenelm Philip]

	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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