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Re: Subject: extinct species

Roxanne Bittman <rbittman at dfg_ca.gov> wrote:
> Subject: extinct species
> And I repeat, your aquarium bred plants are
> not the same
> genetically as those that were in the wild and may
> or may not
> successfully reestablish due to either changes in
> the adaptive ability
> of the plant or in the environment; sometimes these
> things are hard to
> figure out in nature as you'd expect.  I suspect
> that the poor
> translocation record for plants (I am not discussing
> fish or cheetahs
> here now) has to do with subtle changes in the
> environment that make it
> difficult for the plant to persist.  Note I say
> "persist".  It may
> indeed grow for a year, or 3 years.  We seldom
> monitor for over 5 years,
> and in one case I know well, an aquatic endangered
> plant was
> translocated (Lilaeopsis masonii) and it persisted
> for 5 years only to
> blink out after 7.  Noone in industry wants to pay
> for what it really
> costs to do these experiments correctly.  Few think
> in the long term. 
> So, translocation experiments tend to fail; over 90%
> fail in our area as
> reported the Endangered Species Program of Dept of
> Fish and Game in two
> separate reports.

Ouch.  90% fail.  I would think the "unknowns"
go up dramatically in long-term experiments too...
how do you know it wasn't that hard winter in
the fourth year that influenced viability in
the seventh, or blow-down five miles away that
helped spike the parasite to overwhelmed the
translocated population?  ;-)

We've seen the same thing in ecotype boundaries
where the environment really does change.  For
example, "tree line" means just that... it's the
line where on one side a species is viable, and
the other it is not.  While survivial is marginal
at tree line, it's also true that the tree line
moves over time.  There are many areas over the
high plains of the US where trees existed when 
the pioneers cut across (1800's), then the trees
were cleared for farmland, and now there's
interest in replanting.  However, in the last
150 years the treeline has moved:  We're a little
warmer and drier now, and it's just enough to 
prohibit germination.  If you skip that stage
and plant, the trees have a hard time until
they reach some size and perform microclimate
modification (cooler and wetter on the forest
floor), but it's still true that the area is
warmer and drier now than it was 150 years ago.

I would think this is harder for aquatic plants,
since temperature changes and sediment and 
water table changes and chemicals in the water
table seem like they would impact aquatic plant
species viability quite a lot.  The example above
was for Pinus ponderosa, which grows several 
hundred years and has a very thick bark to protect
it from fire.  I don't see many aquatic plants
with such a robust lipid or epidermal layer.


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