environmental enhancement again

[Andrew Warren]

Norbert's observation brought up one point that I can't help but mention.
Euphydryas editha taylori, a taxon that occurs(d) from Oregon's Willamette
Valley north through inland valleys to Vancouver Island, BC, was
considered extinct in Oregon in the early 1990's.  Shortly after arriving
in Oregon, I had the good fortune and luck to stumble across a very large,
apparently healthy population of this bug just outside of Corvallis, under
a powerline right-or-way.  Besides about two, small, natural meadows where
the
butterfly also breeds and occurs in good numbers (less than 1/4 mi. from
the powerline cut), this powerline is the only known habitat for the taxon
in Oregon.  Adults often swarm under this cut, and are not found even 20
feet up or down the hill (even though much of this was recently clear-cut
and appeared suitable for checkerspots to my unknowing eyes).  The
"powers that be" who
manage these power lines clear all the vegetation that cannot be driven
over from this and nearby powerline cuts every 5-8 years (from what I can
tell)- they rapidly become overgrown with poison ivy, oaks, madrones, and
of course douglas firs.  Or they get choked out first by the invasive,
introduced Scotch Broom.  Interestingly, these early-successional
power-line cuts are the best sites for Callophrys species (sensu lato) 
that I know of in the ORE coast range (if you don't know,
a VERY rainy place).  They are full of strawberry plants (the preferred
nectar source for taylori and perhaps a vital component of the habitat for
taylori). 

So this is a taxon that DEPENDS on early successional habitats to
reproduce (and who knows what else it needs...).  Land management
practices in the Coast Ranges and valleys certainly have not favored this
butterfly.  Interestingly, the "typical" larval food plant for Euphydryas
editha through most of its range is Castilleja (in almost all of Oregon,
anyway); however the possible original host Castilleja species in the
Willamette Valley is also nearly extinct, and occurs only at a few sites
(but not at the taylori site).
The taylori's W of Corvallis feed on Plantago lanceolata, a widespread
introduced "weed" (that occurs as a dense ground cover in areas under this
powerline cut).  [note, however that the BC butterfly book indicates a
native Plantago species as the a host for taylori, so perhaps the
host-switch to lanceolata, which has presumably occurred separately in OR
and WA - BC is not so dramatic].

An uneducated attempt at protecting this butterfly and site could
discourage the cyclical disruption of the vegetation taking over these
artificially
created prairies, and slowly (or rapidly?) choke out the butterfly.
Talk about a double whammy!  A "prairie" obligate stuck living in a
rainforest, that has only managed to survive on a human-introduced larval
food plant...

This April-May flying taxon is listed (as of 1999) as a candidate for
placement on the threatened or Endangered species lists in Washington
State (or maybe it
has been listed now?) where it is has been intensively studied at the two
or three remaining sites (one of which is a military bombing range) where
it is holding on (see Potter, A., J. Fleckenstein, S. Richardson & D.
Hays.  1999.  Washington State ststus report for the mardon skipper.
Washington Department of Fish and Wildlife, Olympia.  39pp).  Taylori is
endangered in British Columbia where it is still known from only 1 single
site.  

A quote from p. 311 of the
BC butterfly book by Guppy and Shepard further illustrates my point: "The
last [pop. of taylori] to become extinct, in the early 1990's, did so
because its habitat was overrun by Scotch broom (CSG).  This habitat was a
powerline right-of-way that had been kept clear as a Christmas tree farm.
After the tree farm was abandoned, BC Hydro adopted a policy of
encouraging Scotch broom growth to reduce tree regeneration under
powerlines.  The one healthy population is on Hornby Island, where there
is no significant Scotch broom.  The local community is monitoring Scotch
broom so that it does not invade the habitat of Taylor's Checkerspot."  
Note that Shepard (2000) reported the larvae from Hornby Island to feed on
a native Plantago, utriculatum.  

Andy Warren


On Tue, 15 Jan 2002, Kondla, Norbert FOR:EX wrote:

> Just a couple of observations:
> Ian Sheldon observed: "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."
> Yes succession is natural. Where this is a concern is when it is not
> accompanied by the natural or historically prevalent disturbance regime.
> This is a reality in many parts of the planet. Close to home it is a serious
> issue because we have been suppressing forest fires for almost 100 years.
> This has resulted in both unnatural tree encroachment into formerly
> unforested habitats and also unnatural tree ingrowth and canopy closure -
> even tho the process itself is quite natural. This of course has profound
> effects on the organisms that cannot live under forest canopies. In parts of
> western North America eg. Arizona there are ecological restoration efforts
> underway to deal with this situation. A clear case of horrendous damage has
> been well documented in Europe. The issue is the butterflies that depend on
> early seral habitats and which then have become endangered because the
> previous 'disturbing'/habitat maintaining practices ceased or the habitat
> became protected. This has created a number of endangered species that need
> not have gone that way. In my view, creating endangered species through
> changes in land use practices and allowing natural succession to continue
> unchecked is indeed horrendous damage. 
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Norbert Kondla  P.Biol., RPBio.
> Ministry of Sustainable Resource Management
> 845 Columbia Avenue, Castlegar, British Columbia V1N 1H3
> Phone 250-365-8610
> Mailto:Norbert.Kondla at gems3.gov.bc.ca       
> http://www.env.gov.bc.ca
> 
> 
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