[PCA] strict natives vs cultivars

[Steve Shelly]

Actually, some grass species are obligate selfers (no cross pollination, by
wind or otherwise) - such as blue wildrye (Elymus glaucus).  In those
cases, the genetic variation is likely to be higher within than among
populations - which was found to be true for this species (from studies
using enzyme electrophoresis, anyway; the question in such situations is
always whether such variation is actually adaptive or not).  So the "risk"
of planting seeds from non-local sources in such a case won't be from
genetic interactions as much as from simply using material that is not
adapted ecologically to the planting site (or, hypothetically, might be
"over-adapted").  In any case - as with most questions in restoration
ecology (and science, for that matter), the answers do not lend themselves
easily to generalizations.  It depends on many, many factors - including
the breeding system, life history, ecological relationships, etc. of each
individual species.

There are many studies that have been published on genetic variation in
native plant species - both from an evolutionary and a restoration ecology
perspective.  In particular, try a Google or Google Scholar search on
"restoration genetics" to get a start in the literature.  And search
"Elymus glaucus" to find the study mentioned above.  There was also an
excellent common garden study (a method used to examine morphological and
reproductive variation in the field) done on this species that serves as a
good example.  The lead author was Vicky Erickson (USFS, Oregon).

********************************************************************
Steve Shelly
Regional Botanist/Research Natural Areas Coordinator
U.S. Forest Service, Region 1
P.O. Box 7669, Missoula, Montana  59807
(406) 329-3041
sshelly at fs.fed.us
********************************************************************


                                                                           
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                                                                   Subject 
                                       Re: [PCA] strict natives vs         
                                       cultivars                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




Careful....grasses are wind-pollinated --broadcast far and wide--so I think
you wouldn't expect to get as much genetic variability compared to insect
pollinated plants.

ma

In a message dated 4/9/2008 10:37:15 A.M. Eastern Daylight Time,
bmajka at jfnew.com writes:


 The USDA/ARS actually collected 75 different switch grass samples from
 remnant prairies and cultivars, then compared the genetics, and found very
 few differences. In fact, they found that samples from the same population
 had as much genetic variability as those from broadly geographic areas. To
 my knowledge, this is the first time anyone’s done any actual genetic
 testing of native plants.





 Here’s a link to the article:





 http://www.ars.usda.gov/is/AR/archive/sep07/prairie0907.htm





I have a question regarding the use of cultivars versus straight native
species.  My understanding is that cultivars are native plants that have
been selected for certain characteristics and then reproduced (cloned?).  I
assume this would have a negative impact on diversity of ecotypes.

I am a landscaper and I am attempting to do the right thing for the
environment and want to know which plants to select.  As a design element,
it would be nice to be able to choose cultivars for their specific traits.
In terms of the plants themselves, sometimes the non-cultivated species are
rife with problems.  For example, Michael Dirr advises against using ilex
opaca because of its vulnerability to disease and insect infestation,
whereas he encourages use of cultivars.  Wouldn't it be better to have a
healthy cultivated native?

I know  that this subject is debatable, but I'd love to hear some
conversation about it, or be referred to recent studies or articles where I
could find some solid science to base my decisions on.  My fear is that in
the future, our yards are going to be one of the few places wildlife is
going to have a chance to thrive, and if so, we need to make them as close
to the true natural world as we can.