impact of ecological burns

[Shueyi at aol.com]

 In a message dated 97-09-14 19:36:45 EDT, diane falk writes:
 
 I'd like to provide some detailed commentary on what I consider to be a very
mis-informed commentary.
 
 << greetings david,
 < as one of three new sites to reintroduce and support the karner blue
  <Butterfly in northeastern illinois, usa the pros and cons of burning
  <have grown quite intense.
 
 First, as a member of the recovery team for this species, there are no
approved re-introduction sites for the Karner Blue Butterfly (KBB) in the US
at this time.  There is some talk, but that is all.
 
 <  while burning erradicates aggressive species
  <of plants, the resulting air pollution increases public and health
  <issues.  you pondered impact upon butterflies and inverts.  well,...
  <the negative impact of fire upon second generation eggs lain in lupine
  <host plant debris comes to mind immediately.
 
 There are some negative imapacts to eggs - they are literrally consumed by
fire.  But all managers of KBB sites are required to develop burn rotations
that allow recolonization following a prescribed burn.  
 
 < second, inverts wintering over in plant matter <and at the soil surface
 < level are destroyed by the consuming flames.<
 < third,...in our more densely populated region, open burning will soon
 < become a "novelty" of the past.  clean air activists await prairie
 < project installation quite well aware that controlled burns often will
 < follow.  taking the _heat_ is none too pleasent.
 
 As for the air impacts, even in highly urbanized areas, even EPA realizes
that fire is an essential part of oak barrens ecology.  Given tha EPA
actually released on oak ecosystems recovery plan (KBB's are restrcted to Oak
Barrens), I doubt that they will be going against their own recomendations
about the importance of fire any time soon.  
 
 < our solution at serendipity gardens for the karner blue and lupine
 < support will attempt to mow overgrowth no less than eight inches above
 < soil level.  my own personal bias with the lupine host is to increase
 < that in areas most heavily supporting dense lupine growth to err on the
 < side of the karner's survival.  time will approve/disapprove of our
 < future efforts.
 
 Mowing controls woody incroachment into KBB habitats very well.  But mowing
also increases densities of exotic species in these habitats, species that
can litteraly convert a species rich oak barrens habitat into a near
monoculture of exotic species.  Mowing also alters nutrient cycling, and
allows N to build in the soil.  A recent paper in Science by Tom Givnish
demonstrated that in the absence of fire, N-fixing legumes  drop out of
 barrens habitats - presumably because they loose there competive edge as N
builds in the soil (fire literally releases the nitrogen into the air -
reducing the N in the soil).  KBB hostplants are legumes, and decrease under
fire-suppressed condition.
 
 < let's review additional impact of fires and spread a wee bit o' wisdom.
 < very respectfully,
 
 The wee bit of wisdom presented by Diane is indeed a wee bit.  By focusing
in of a single species and noting that fire fire does indeed cause sort-tern
negative impacts to that species, it is very easy to ignore the key role fire
plays as an ecosystem process.  KBB habitats are fire dependant -  the main
reason that this butterfly is US-Endangered is becuase its habitat has become
shrubbed over becuase of fire-suppression.  Many of the rare plants of oak
barrens are also state endagered because of fire suppression, and mowing will
not help them at all.  If we continue to take simplistic approaches to
complex problems, the natural world is screwed.  
 
 
 John Shuey >>