Colonization of microclimates

Rich Thomson rthomson at
Fri Jun 5 14:03:53 EST 1992

(Disclaimer: I'm not a botanist and I don't play one on TV)

About two hours south of Salt Lake City there are some lava fields
with interesting microclimates.  The lava fields themselves formed
underneath Lake Bonneville and erupted up through the lake to form
islands.  Now that the lake is gone, they remain as local high points
in the surrounding terrain.  They are located close to the Wasatch
front, a mountain range running North-South through the state.  The
Wasatch front is high enough that storm systems from the west end up
depositing much of their precipitation on them before the storm makes
it to the Rocky Mountains farther to the east.

The microclimates are located at the bottom of rifts in the lava
fields and in the bowls formed from collapsed lava pools and tubes.
These local minima act as cold traps.  The insulating properties of
the lava also provide cool areas where tube entrances or crevices have
been left behind.  If a rift system happens to run east-west, there
is an even larger chance that the bottom of the rift supports a
variety of plant life distinct from the plant life on the surface.
The geometry results in the bottom of the rift being exposed to a
smaller amount of direct sunlight than the surface of the lava field

Sometimes cool, moist air exits from underneath the lava field at
these rifts and "fumaroles" (most often a fumarole vents hot air,
though).  The local water table is fairly high with artesian wells and
a variety of hot and cold springs.  The Pahvant valley is farmed using
these water sources to raise alfalfa and hay for cattle.

In these fissures, rifts and vents I have observed a number of
different mosses.  The growing season is also extended in these
sheltered areas (often there will be green grass at the bottom of a
rift while all the surface grass has long since gone brown).  Although
I have obtained an excellently illustrated book called _Mosses of Utah
and the West_ by Seville Flowers, I have yet to bring any specimens
back for identification.

The nearby Pahvant range of mountains supports a wider variety of
plant life due to the larger amount of moisture received and higher
elevation.  However, the microclimates would seem to be able to
support a wider variety of plants than those able to survive on the
surface of the lava fields (sage, juniper, etc.).  Could plants from
the nearby Pahvant range and/or other nearby localities survive in
these microclimates?  Would it be possible for a person to act as a
"steward" and enhance colonization of these microclimates, thus
increasing the diversity in this locale?  It seems unlikely to me that
plants would be able to colonize these microclimates unaided (unless
they were remnants from the Lake Bonneville period; but that is
unlikely since most of the area containing microclimates now was
under water then).  The wind could carry spores and seeds, but the
predominant winds blow towards the mountains from the microclimated

As an aside, this brings up the idea of "stewardship" in general,
where man acts as an active agent for the increase of biodiversity
instead of the usual behavior as an agent decreasing biodiversity and
fostering gigantic monocrops.

						-- Rich
	Repeal the personal income tax; vote Libertarian in 1992.
Disclaimer: I speak for myself, except as noted; Copyright 1992 Rich Thomson
UUCP: ...!uunet!!rthomson			Rich Thomson
Internet: rthomson at	IRC: _Rich_		PEXt Programmer

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